P66_A_B_M9_E

AVIATION MAINTENANCE TRAINING CENTRE

MT.147.02

M9 HUMAN FACTORS

EASA PART-66 CAT A/B1/B2 ISSUE: 1MAR2006

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Training Manual

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g n i n i a r T l a c i n h c e T a s n a h t f u L

y l n O s e s o p r u P g n i n i a r T r o F

HUMAN FACTORS

EASA PART-66 M.9

M9 HUMAN FACTORS

Anthroprometric man - Leonardo d’Vinci


HUMAN FACTORS M9.1 GENERAL

CAT A/B1/B2

M.9

M9.1 GENERAL The need to take human factors into account; Incidents attributable to human factors/human error; ’Murphy’s’ law.

INTRODUCTION Air transport is considered as one of the safest means of travelling in the world today, yet every now and again an accident occurs which shakes our complacency. All too often, as we look at the cause of the accident, we will say: ”How could such simple error have combined to cause such a catastrophe?” An in−depth review of the events after the fact will reveal, time and again, that a series of human errors (known also as a chain of events) was allowed to from until the accident occurred. In about one accident out of ten, maintenance errors are part of the chain of events. If we brake the chain of events at the maintenance level, the accident will not happen.

What you will gain from this workshop is very much related to what you are prepared to invest into it. Be open minded − but if you disagree with anything that is being said, feel free to speak up. Take the time to glance through this book from time to time in the future. It may help you to avoid mistakes and safe you from having to pay the price for them. y l n O s e s o p r u P g n i n i a r T r o F

EASA PART 66

What is maintenance Human Factors? In the most straightforward terms, Human Factors are those conditions that affect a human in the aviation maintenance work environment. Often, a Human Factors class begins by asking participants to list human factors that affect work performance. The following list is only a small sample of the possible topics of human factors those participants might list: Fatigue, poor communication, personal life problems, smelly fumes, loud noises, slippery floors, snow, incomplete or incorrect documentation, poor instructions, substance abuse, poor training, poorly designed testing for skill and knowledge, bad lighting, unrealistic deadlines, lack of spare parts and tools, poor tool control, boring repetitive jobs, a rush to complete jobs. The list may be endless. Some problems are minor but can become major. In most cases more than one of these factors contributes to a problem. During this course we will consider most of these human factors that may contribute to an incident or accident event. Costs Not only does human error in maintenance compromise safety, it also costs money. For example, the manufacturers estimate that;  the cost of an in−flight engine shutdown is about $500,000.  A flight cancellation costs a minimum of $50,000.  An average ground damage accident is about $100,000 when ramp equipment contacts an aircraft. The airlines lose at least $billion per year from human error. The industry can hardly afford such losses now, or at any time. We must do better. Attention to human factors can help us to improve safety and to return the airline business to profitability.




EASA PART 66 CAT A/B1/B2

M.9

Chain of Events

Figure 1

Introduction to Human Factors (HF)



CAT A/B1/B2

M.9 DISCIPLINES OF HUMAN FACTORS Introduction Human factors is comprised of many disciplines, which is the reason human factors has no single definition. We can review 10 of the human factors disciplines with the chart .

Computer Science Computer scientists study the graphical user interface to be sure that humans can easily operate software. Therefore, Computer Science remains an excellent example of human factors.

Educational Psychology Educational Psychologists study how people learn. Excellent training programs are often the result of using applied educational psychology.

Cognitive Science Cognitive Science studies how humans think, how they solve problems and the ways in which they process information. This knowledge can be critical to design of equipment, software, and documentation.

Industrial Engineering Industrial Engineering is the study of humans at work, using a systematic approach to understand how people work, and then to design the job and the equipment accordingly.


EASA PART 66

Safety Engineering Safety Engineering applies to worker safety, with respect to topics like safety equipment, labelling, rules, and such things.

Clinic Psychology Clinical psychology deals with your psychological composure. It can address topics like emotions, motivation, fears and such things.

Medical Science Medical Science applies to topics such as vision, hearing, balance, and overall health issues.

Experimental Psychology Experimental Psychology is usually conducted in laboratories to compare differences and similarities between groups.

Organizational Psychology Organizational Psychology looks at how people work within various size groups. Organizational Psychologists have made excellent contributions to the field of Crew Resource Management, which is mandatory training for flight crews, and important to maintenance crews.

Anthropometry Anthropometrics is the study of factors such as size, strength, reach and other dimensions that can be quantified to match the machine to the human. Example: An original coca−cola bottle, for example, was designed to fit the average human hand, thus making it easy to hold the bottle and drink a lot of the product.




M.9

Clinische Psychology Industrial Engineering


Experimental Psychology

Educational Psychologie

Anthroprometry

Organisational Psychology

Computer Science

Medical Science

Cognitive Science Safety Engineering

Figure 2

Disciplins of Human Factors




M.9 HISTORICAL REVIEW It is difficult to identify the exact historical beginnings of the various disciplines of Human Factors. With respect to anthropometrics − the size and strength of the human − you can refer to Leonardo D’Vinci’s (1452 to 1519) Anthropometric man. Another perspective is the research of Frank (1868 to 1924) and Lillian Gilbreth, (1878 to 1972), Industrial Engineers who studied medical operating procedures in the early 1900’s. They created the verbal protocol whereby the receiver repeats any command given. The repetition helps to ensure clear communication. That protocol continues today in air traffic control communications. The psychologists Sigmund Freud (1856−1939) and Kurt Lewin (1890−1947) also conducted human factors work.

1400

1500 Leonardo D’Vinci


Aviation Human Factors started in the early 1900’s when aircraft designers began to consider aircraft compatibility with the human. At the same time, military researchers were already looking at medical factors concerning pilots. In World War II, many governments were mass−producing military aircraft. Engineers had to consider such factors as control design and instrument layout for compatibility with pilots. By the 1950’s, the US Air Force was conducting experiments evaluating human personalities so as to better match people to their military job assignment. In 1988, the U.S. Government passed a law named the Aviation Safety Act, which demanded that the FAA conduct research on human factors in aviation, including factors related to aviation maintenance personnel. In that year in Hawaii, a B737, experienced an in−flight break−up which, through investigation, was found to have had many human factors as the root cause of the incident. This incident generated much public concern about maintenance human factors. Throughout the 90’s, the FAA conducted extensive research on maintenance human factors. Much of that research evolved into regulatory guidelines for human factors training, like the material delivered in this class.

1600

1700

1800

1900

Frank und Lillian Gilbreth




M.9

HUMAN FACTOR

AVIATION

1900

1920

Wright 1903

1940

1960 Optimisation human /maschine

1980 1988: B737 „Cabriolet“ y l n O s e s o p r u P g n i n i a r T r o F

US Congress 1988

2000 JAA EASA

Figure 3

Historical Review




M.9 STATISTICS Introduction Statistics tell a story, often showing the relative safety of a system or airplane. Most airline safety statistics demonstrate that the system is extremely safe. It is difficult to improve the worldwide airline safety rate − less than 3 accidents per 1 million departures. The Boeing Company publishes an annual worldwide safety record, summarized here. Notice that safety improved radically from 1959 to 1969, but since then has improved only slightly. The number of fatalities is quite variable, and almost a matter of chance from one year to the next. This chart illustrates at least three facts:  First, airline travel is very safe.  Second, the safety rate is not improving much.

Link: www.boeing.com/commercial/safety

Third, if the safety rate remains the same while the number of departures increases, there will be an increased number of accidents. For example, there were about 17 Million Departures worldwide in the year 2000, equalling 51 accidents. That means somewhere in the world, one airliner accident takes place each week. That is not acceptable. 


Figure 4

Acident Statistics





M.9

Accident rate approx. 3 Accidents per 1 Million flights

3/million

x

Figure 5

17million

=

51

= ONE PER WEEK!

Accident Statistics - Boeing Study




M.9 ACCIDENTS Boeing data shows that the primary causes of accidents are:  Flight crew,  Airplane,  Weather,  and Maintenance  along with many other factors.

100% human 80%

Another study, conducted during the eighties to early nineties, showed that maintenance related accidents were the 2nd leading cause of fatalities. What causes these accidents? Experts agree that about 80% of these accidents are a result of human error. Therefore we must pay attention to human factors if we are going to improve the overall safety of the world’s airlines.

technical

20% 1910

2000

Figure 6


80 / 20 Rule





M.9

Figure 7

Reasons for Accidents




M.9 INFLUENCE OF MAINTENANCE (3 STUDIES) maintenance Influence on Incidents and Accidents 1. Boeing: In the early 90’s, Boeing completed a study of the 7 most common errors that led to a shutdown of an engine when the aircraft was in flight (called in−flight shutdown). They studied 276 in−flight shutdowns for that research. The causes were:  incomplete installation − 33%;  damage of a part during installation − 14.5%;  improper installation − 11%; 

and equipment missing − 11%.

2. Pratt and Whitney: Pratt and Whitney looked at the causes of 120 in−flight shutdowns on B747 aircraft. Here is what they found:  Missing parts; incorrect parts; incorrect installation and more. This list is not much different from what Boeing found in their study. 3. The Civil Aviation Authority (CAA) of the United Kingdom conducted a 3−year study of maintenance. Not surprisingly, their findings were similar to the other studies.  Incorrect installation, wrong fitting of parts, cross connections of electrical wires and more were to blame...

1 6

7

2

5 4 y l n O s e s o p r u P g n i n i a r T r o F

3 1 3

4 5

2

6 7




M.9

Incorrect Installation

Missing Parts

Wrong Parts Wrong Parts Crosswiring Incorrect Installation Foreign Objects (Tools) left in Aircrafts

Inadequate Lubrication

Worn/damaged Parts Incorrect installation of Seals (O-Rings)

Covers, Cowlings and Access Panels left open or not secured properly

Fuel and Oil Filler caps missing y l n O s e s o p r u P g n i n i a r T r o F

Nuts and Bolts improperly secured/lockwired Nuts and Bolts overtightened

Landing Gear ground lock pins

Nuts and Bolts loose

not removed

3−Year Period (Aircrafts > 5,7 Tons)

Figure 8

B747: 120 Inflight - Shut downs

Maintenance Influence on Incidents and Accidents




M.9 EXAMPLES OF ACCIDENTS

CRASH

American Airlines

1979

American Airlines DC10 - Chickago O’Hare, 1979

For example, in 1979 in Chicago, an engine separated from a DC10 aircraft shortly after takeoff. With no altitude for recovery, the aircraft crashed within a kilometer of O’Hare Field. It was found that unconventional work procedures during an engine change contributed to a structural failure that caused this engine separation. Further, other DC−10 operators knew of this imminently dangerous condition, but the information was not communicated with sufficient urgency to all of the industry. Today, with more industry reporting and faster data sharing, this type of communication problem is less of a human factor.

DC 10

1 Kilometer

CHICAGO O’Hare


Continental Express EMB120 The Continental Express crash is a classic example of human factors error with a fatal ending. The Aircraft was a Regional Turboprop Embraer 120. Incomplete installation of a de−icing system caused the leading edge of the right horizontal stabilizer to separate in flight. The flight crew was unable to control the aircraft. A variety of human factors contributed to this accident; however, the most obvious was associated with poor written and verbal communication during shift turnover. You can read the entire report, and many others, on the FAA website at

http://www.hfskyway.faa.gov

Continental Express EMB 120 1994

47 MISSING SCREW FASTENERS




M.9 Easter Airlines L1011 - Miami 1981 Another example, from the early eighties, is an incident at the former Eastern Airlines. A Lockheed L1011 with 3 engines, departed Miami with 175 people on board, bound for Nassau, Bahamas. It was meant to be a very short hop on this tourist flight. About 15 minutes after take−off on descent to Nassau, the pilot experienced low oil pressure and high oil temperature on all three engines. After two engines failed, the aircraft landed back in Miami.

Take Off

Low Oil Pressure / High Oil Temperature

Eastern Airlines L1011

1982

Dual Engine Failure

The cause of the failure was missing O−Ring gaskets on the Primary Magnetic Chip Detectors, which were changed just prior to takeoff. The NTSB said the probable cause of the accident was the omission of all the O−ring seals on the master chip detector assemblies, leading to the loss of lubrication, and damage to the airplane’s three engines as a result of the failure of mechanics to follow the established and proper procedures for the installation of master chip detectors in the engine lubrication system, the repeated failure of supervisory personnel to require mechanics to comply strictly with the prescribed installation procedure s, and the failure of Eastern Air Lines management to assess adequately the significance of similar previous occurrences and to act effectively to institute corrective action. Contributing to the cause of the accident was the failure of Federal Aviation Administration maintenance inspectors to assess the significance of the incidents involving master chip detectors and to take effective surveillance and enforcement measures to prevent the recurrence of the incidents. This event was not a loss−of−life disaster, just a multi−million dollar loss to Eastern. It should not have happened! y l n O s e s o p r u P g n i n i a r T r o F

Miami

ENGINE FAILURE

Nassau





M.9 Aloha Airlines B737−200 - Hawaii, 1988 In 1988, a Boeing 737−200 operated by Aloha Airlines Inc. experienced an explosive decompression and structural failure at 24,000 feet/ 8000 Meters, while en route from Hilo to Honolulu, Hawaii. Approximately 18 feet of the cabin skin and structure aft of the cabin entrance door and above the passenger floor line separated from the airplane during flight. There were 89 passengers and 6 crew members on board. One flight attendant was swept overboard during the decompression. The flight crew performed an emergency descent and landed at Kahului Airport on the Island of Maui. The safety issues discussed in the final NTSB report included: ...the quality of air carrier maintenance programs and the FAA surveillance of those programs, and the human factors aspects of air carrier maintenance and inspection for the continuing airworthiness of transport category airplanes... The ”Human Factors” included repair procedures, training, and certification and qualification of mechanics and inspectors .

Kuaui

1988

Aloha Airlines B737 Oahu Molokai

Honolulu

BREAK - UP 89 Passengers

Kuhului

6 Crew

HAWAII

1 Flight Attendant Hilo Maui




M.9 United Airlines DC10, Sioux City, 1989 In 1989 a United Airlines DC10 had a critical engine failure that disabled the aircraft’s flight controls. The aircraft was enroute from Denver to Chicago, but crash landed in Sioux City Iowa. The flight crew performed heroically to land the airplane.

The NTSB Accident report indicated ”inadequate consideration given to human factors limitations in the inspection and quality control procedures used by United Airlines’ engine overhaul facility. This resulted in the failure to detect a fatigue crack originating from a previously undetected metallurgical defect in the #1 fan disk. The separation, fragmentation, and forceful discharge of uncontained stage 1 fan rotor assembly parts led to the loss of the three hydraulic systems that powered the airplane’s flight controls. ’This accident led to increased human factors attention to the processes and procedures associated with inspection of turbine engine rotating components.’

1989

United Airlines DC 10

SIOUX CITY Chicago

Denver

Engine Failure

Northwest Airlines B747


Northwest Airlines B747−200 - Narita, 1994 In 1994, Northwest Airlines experienced a serious ”engine drag” upon landing at Narita, Japan. The aircraft was landing on an intermediate stop from Hong Kong to New York JFK Airport. The aircraft stopped on a taxiway at Narita with the front of the No. 1 engine touching the ground. The lower forward engine nose cowl had been ground away as it dragged along the runway. Local fire fighters rapidly extinguished a fire near the No. 1 engine. The reason that the engine fell from the aircraft was that an aft fuse pin was installed, about 30 days prior, without its proper locking devices. The event investigation discovered that the locking device was found, in a small cloth bag, back in the US facility where the heavy maintenance check was performed.

1994

New York

NARITA Tokyo

No. 1 engine touching the ground. lower fwd engine nose cowl grounded away fire near the No. 1 engine

Hong Kong





M.9 Valu-Jet DC9 - Florida, 1995 This accident involved a cargo fire. The fuel for the fire was old aircraft tires and aircraft passenger oxygen generation canisters. The Aircraft was a DC−9 enroute from Miami to Atlanta. The long list of human factors that contributed to this accident included the following: Insufficient training of mechanics and of cargo handlers ;  failure to follow procedures;  failure to secure and label hazardous cargo;  and insufficient regulatory oversight. In this example there were many errors by workers, their company, and the regulators. You can read the entire report, and many others, on the FAA website at http://www.hfskyway.faa.gov http://www.hfskyway.faa.gov

Valu-Jet DC9 - Atlanta, 1995 In 1995, a ValuJet DC−9 had a catastrophic turbine blade failure at the start of takeoff roll in Atlanta. As the aircraft began its takeoff roll, occupants, and even the air traffic controllers heard a ”loud bang.” The right engine fire warning light illuminated, the flight crew of the following airplane reported to the ValuJet crew that the right engine was on fire, and the takeoff was rejected. Shrapnel from the right engine penetrated the fuselage and the right engine main fuel line, and a cabin fire erupted. The airplane was stopped on the runway and evacuated. The fuselage was destroyed. What was the cause? Human factors! The previous operator of the aircraft failed to perform a proper inspection on a 7th stage high compressor disk. Further, they did not maintain an adequate record keeping system or use ”process sheets” to document the step−by−step overhaul/inspection procedures.

Valu-Jet

1995

Aircraft tires

Oxygen generators (PAX OXYGEN)

Atlanta

FIRE Miami




M.9

Valu-Jet

1995

- loud bang! - Firewarning activated - Engine #2 caught fire - Take-Off aborted - Fire in Cabin - Passengers where evacuated y l n O s e s o p r u P g n i n i a r T r o F

Figure 9

Aircraft Accidents/Incidents - Examples





M.9 SHELL - MODEL General The SHEL model was created by Professor Edwards in the early 1970’s. The original purpose was to teach flight crews about Crew Resource Management (CRM). However, the model also helps us to understand maintenance environments. The SHELL model is comprised of the following parts:  S for Software;  H for hardware;  E for Environment;  L(L) and there are two Ls for Lifeware. Explaination  S, the first letter in the Shell Model, applies to Software. Software with regard to SHELL is not necessarily computer software. It refers to such things as the rules and procedures of operation, technical manuals, and information to support system operation.  The H is the Hardware, which are quite clearly the tools, hangars, aircraft, buildings and other such physical things.  E represents the Environment, which is actually two distinctly different environments: − the physical work environment, including factors like temperature, lighting or humidity and − the political and social environment. That includes abstract factors like corporate communications or company profitability.  The L in Shell stands for Lifeware, and uses 2 Ls. − The first L represents the individual Human characteristics like knowledge, skills, experience, attitude and culture. − The second L refers to the human in groups, including such factors as teamwork, communication, group norms and leadership. In summary, if you can remember the word SHELL, like the oil company, you can remember key considerations for Human Factors.

Software Hardware Environment Liveware

Prof. Edwards (1970)




M.9

H ardware

S oftware

E nvironment

Physical Environment

Political & Social Environment


L iveware

People in groups

Individual

Figure 10

SHEL(L) Model





M.9 MURPHY’S LAW Most mechanics and engineers know of the fictitious character named ”Murphy.” The origin of ”Murphy” is unclear, but the name is often used as the example of the mechanic that makes mistakes. Interestingly enough, the regulators believe that you should know ”Murphy’s Law” as part of human factors. Murphy’s Law is: ”If something can go wrong, it will.” Thus, you should always plan for the possible errors that may result from ”Murphy’s Law.”




M.9

MURPHY’s LAW

If something can go wrong - it will!


Figure 11

Murphy’s Law


HUMAN FACTORS M9.2 HUMAN PERFORMANCE & LIMITATIONS

CAT A/B1/B2

M.9

M9.2 HUMAN PERFORMANCE AND LIMITATIONS Vision;

THE FIVE SENSES

Hearing;

The five senses are:  touch,  smell,  taste,  sight  and hearing. Sense of balance is often included in the senses. However, this is incorrect. Balance is produced in the brain from signals received from the eyes, the inner ear and forces acting on the body. These three signals must be in the right proportions. If not, you will lose your sense of balance. Flight simulators make use of this by simulating movement.

Information processing; Attention and perception; Memory; Claustrophobia and physical access.

INTRODUCTION General We can take it for granted that technology does not function 100%. What does this mean for humans? This chapter gives you an insight into the human body and its shortcomings. We want to concentrate here on the following three areas:  the five human senses,  the processing of information in the brain  and phobias, such as claustrophobia. You already know much about these things, but the authorities require us to treat this subject.


EASA PART 66

Taste, Smell and Touch Touch is when the sensors in the skin perceive temperature and pressure and transfer the information to the brain. Sense of touch can, for example, enable us to work with our hands and warn us of injuries. Cells in the nose enable us to smell. Some maintenance tasks require a ”sniff check” in order to determine a system error. To taste something, you need the ”sensors” in the mouth and the nose. That is why food tastes different when you have a cold. However, tasting should play NO part in maintenance! At least we are not aware of any ’taste-checks’




M.9

SIGHT

Informationsprocessing 5 Senses HEARING

Phobias

SMELL

TASTE

TOUCH


>SENSE OF BALANCE<

Figure 12

Introduction / 5 Senses




M.9

SIGHT / THE HUMAN EYE General Description It is important to explain the function of the eyes so that we can better understand sight and possible visual impairments. The eye has four main tasks:  The perception of brightness,  color,  space and  form and movement.

The eye is similar to a simple camera with a shutter, a lens and a light−sensitive background. In the case of the eye these are called: − IRIS, − LENS and − RETINA. Light passes through the cornea, the pupil and the lens onto the retina, stimulating light−sensitive cells. This stimulation produces small electrical impulses that are transmitted to the brain via the optic nerve. The eye adapts constantly to changing visual tasks. These include − ADAPTATION − controlling the incidence of light; − ACCOMMODATION − focusing; − and FIXATION − locating direction. All three activities are physiologically dependent on each other and are controlled by six muscles.

Lense

Shutter

Llight sensitive background Camera

RETINA PUPIL

OPTIC NERVE CORNEA


LENSE

Figure 13

Sight - The Human Eye


HUMAN FACTORS M9.2 HUMAN PERFORMANCE & LIMITATIONS Impairments The subject ”Limitations to Visual Performance”. At present there are no JAA/ EASA regulations governing the visual ability of technical personnel. Airlines and airport authorities often have their own guidelines governing the driving of vehicles or the taxiing and towing of aircraft on the apron. Each individual should be made aware of possible impairments to sight and their risks, including:


M.9 Negative Influence on Sight

1. Substances Medication, Alcohol, Cigaretts, etc....

2. Environment

Substances taken into the body  such as medicine, alcohol, nicotine or drugs, which may reduce the supply of blood and oxygen to the eyes. Environmental influences,  for example amount of light, clarity of the air, fog, mist or dazzling, also affect the power of vision. Older people are often more affected by dazzling than younger ones.  We adapt to brightness very quickly; fully adapting to darkness can take up to 30 minutes.


Medical/physical factors Visual defects such as short or long−sightedness, and signs of old age, such as cataracts and glaucoma are among the ”medical/physical factors” which can lead to risks.  Shortsightedness, long−sightedness, curvature of the cornea and axial defects, long−sightedness caused by the ageing process, cataracts, glaucoma, and color blindness are visual impairments.  Most visual impairments can easily be corrected with eyeglasses.  Long−sightedness caused by the ageing process begins after the age of 40. The great danger lies in the gradual reduction in the power of sight.  Cataracts and glaucoma are mostly a result of ageing. Often only an operation will prevent blindness.  Congenital color blindness can unfortunately not be cured. In the case of red−green color blindness good lighting can improve sight. Many of those affected are unaware of their impairment, as the brain replaces the missing color.

Amount of Light, Clarity of the air, Fog, Dazzling ....

3. Medical factors Visual defects: (short- and long-sighteness) Diseases (cataracts, glaucoma, etc.)

Figure 14

SIGHT - Negative Influences



CAT A/B1/B2

M.9

HEARING / THE HUMAN EAR General Description The ear has two main tasks − to provide hearing and balance. Both are important for our occupation − here we will deal mainly with hearing. The ear is made up of the outer, middle and inner ear. The three sections transform sound waves into nerve impulses, which the brain recognises as sounds. The sound waves are directed to the eardrum through the auditory canal. The vibrations are ”mechanically” transferred to the membrane of the cochlea, which is filled with liquid, by small bones in the ear. The liquid oscillates, stimulating millions of tiny hairs, which in turn stimulate the nerves.

The hearing range of a healthy, young individual is from 20 Hz (Hertz) to 20,000 Hz. It is most sensitive at about 3,000 Hz. When flying or diving you often have an unpleasant sensation in the ears. The cavity of the middle ear is connected to the mouth and throat by the ”Eustachian tube”. In extreme cases, if ventilation is limited or if a great change of pressure suddenly occurs, the eardrums can burst.


EASA PART 66

Pressure of Sound Pressure of sound influences hearing. The auditory threshold is 0 dB(A) (decibels). The pain threshold is at 140 dB − damage to hearing can be expected above 150 dB (A). In the middle ear there is a ”natural” protection mechanism, which protects the ear temporarily from sound levels above 80 dB(A). This reflex can hold back a maximum of 20 dB(A). If noise occurs suddenly (for example in an explosion), the ear is completely unprotected. Over a longer period of time a loss of hearing can result. In Germany and other countries, ear protection, by law, must be worn at sound levels above 90 dB(A). Not only the sound level but also the period of exposure is decisive. The limit is reduced to 85 dB(A) if exposure is more than 4 hours.

Jet during Take-off

Saw

...TRUCK normal conversation

...CAR passing... Ventilators of Computers

whispering

Forrest

Figure 15

Typical Noise Levels



Hearing Range:


M.9

approx. 20 Hz to 20.000Hz (highest sensity at approx. 3.000 Hz)

Auditory Range: 0 dB(A) Painthreshold: 140 dB(A)

OUTER EAR

INNER EAR - COCHLEA - AUDITORY NERVE

MIDDLE ERA y l n O s e s o p r u P g n i n i a r T r o F

”Eustachain Tube” AUDITORY CHANNEL EAR DRUM

EAR BONES

Figure 16

Hearing - The Human Ear



CAT A/B1/B2

M.9

INFORMATION PROCESSING Introduction All impressions of sense are transmitted to the brain via nerves. This simple diagram shows you how the information is processed. The model consists of the following modules:  signal input and store,  attention mechanism,  awareness module,  decision generator,  short−term memory,  long−term memory,  

motor neuron programs and actions with feedback.

Signal Input (and Storage) The first module is the signal input and store. The impressions of sense are received here and stored temporarily for up to 2 seconds. Images are stored for about half a second. In this way it is possible to hear spoken words as sentences and images as films.


EASA PART 66

Attention If information has been received, the brain concentrates on particular elements. This is called attention. There are four different kinds of attention: 1. divided attention, 2. focusing attention, 3. persistent attention and 4. selective attention. The attention mechanism switches back and forth between them. Divided attention is often found in the workplace, as performing different tasks is constantly demanded of us. Focusing attention, on the other hand, is concentrated on one individual aspect. For example, you are waiting for a signal lamp to illuminate.

You need persistent attention for activities that take longer, like inspections.

Selective attention reacts to key information. If you hear your own name in the background, the mechanism immediately switches to this conversation − a perfect form of distraction. Awareness Awareness assembles information in such a way that the environment becomes recognisable. Input data is organised, interpreted and combined into parcels of information. Sight is a good example. The optical nerve delivers inverse, two−dimensional data. Using a ”visual program” which is learnt during the first few weeks of life, the correct image of space is created. Experience prevents correct data from being rejected and false data from being transferred. Among other things, awareness provides us with faces, melodies and illusions. Decision Generator Up to now we have only concentrated on data and information. But what task does the ”decision generator” have? That is what allows us to make the decision! Your brain combines information from the senses with your experience and your knowledge. Perhaps you have developed several solutions, but have decided on only one. That is what the decision generator does.

Crosscheck if corrections are necessary. That is also a part of reaching a decision (Feedback loop). In aviation technology you must make a decision according to the situation:  ”fire alarm” when engine is idle, − quick succession of trained hand movements,  locating errors in a complex system, − going through check items step by step, yes/no decisions or incorporating experience and knowledge.




M.9

Signal Input & Storage

Attention Mechanism

Awareness Module


Short-term Memeory

Decision Generator

Motor Neuron Programmes

Action & Feedback Figure 17

Information Processing (1)

Long-term Memory



HUMAN FACTORS M9.2 HUMAN PERFORMANCE & LIMITATIONS Memory Memory is imperative for repetitive actions and for learning new things. It serves as a store, without which we could not deal with the flood of information. Memory comes in three types:  ultra short−term memory,  short−term memory  and long−term memory. The ”decision generator” uses the short and long−term memories.

The short−term memory serves as an interim store for information. You could call it the ”RAM“ of the brain. Under normal conditions the ability to store information temporarily is sufficient. If the load on the decision generator is great, the short−term memory is pushed to its limits. In the computer world the ”RAM” is extended if you want to increase its capacity. And how is it with people? Training or ”grouping information” can increase efficiency. For example, remember the following telephone number − 0496951696. As a row of numbers is difficult. In groups it is easier. You can increase the capacity of the short−term memory by repeating things in your mind or by linking the information to images or concepts. Long−term memory has almost endless capacity and stores our knowledge, personal experiences, values and social norms, abilities and processes. The information is filed in the semantic and episodic memories. − The semantic memory stores factual knowledge such as language, rules and formulas. The data is not tied to time or place. − The episodic memory stores experiences. The corresponding circumstances are also stored at the same time as the event. The episodic memory is strongly influenced by personal expectations. Thus, different people may store the same event in completely different ways. An example of this is the often−conflicting accounts made by eyewitnesses.


M.9 Motor Neuron Program Do you remember your first driving lesson? Your brain had to give the following commands every time:  first push down the clutch − then change gears − slowly let out the clutch! − Once you perform this action many times it becomes an automatic process. You don’t have to think about it. The action is stored in the motor neuron program where many of your reflexes are also stored.




M.9

Signal Input & Storage

Attention Mechanism

Awareness Module


Short-term Memeory

Decision Generator

Motor Neuron Programmes

Action & Feedback Figure 18

Information Processing (2)

Long-term Memory


HUMAN FACTORS M9.2 HUMAN PERFORMANCE & LIMITATIONS LIMITATIONS OF INFORMATION PROCESSING Technicians know that any system can work defectively. The information processing system of the brain can, too. So what can lead to wrong data being processed?  Usually, the person chose the ”wrong awareness”: Important data does in fact reach the brain but is not recognised and processed.  Missing data is replaced by knowledge and experience.  Wrong decisions result. Usually we look for information that confirms our ’mental model’ and not for that which questions it. If the information does not fit, it is suppressed. Investigation reports then contain the phrase: ”... that didn’t occur to me...“ Tips In the case of deceptive awareness, the signals are received but they are not processed correctly. Conjuring tricks are often based on this weakness in the system.


The following suggestions can help you to counteract illusions, forgetfullness and other memory−related limitations:  use up−to−date manuals, make notes and use aids, such as trouble shooting flow charts, to make decisions when looking for errors. If no flow chart exists, then you can make one. Plan blocks of decisions and pay attention to feedback. Good teamwork here is invaluable.  Do not just look for information that supports your way of thinking. After you consider other opinions and do not find alternatives then you can fully support your ideas.  Question your information and data.


M.9




M.9

use Up-to-date Manuals... take notes... uses Trouble-shooting-flowcharts...

Don’t just look for data confirming ’your mental model’...


question information and data...

Figure 19

Information Processing - Limitations and Tips





M.9

PHOBIAS A phobia is a compulsive feeling of terror of particular situations or things. Contrary to fear, a phobia is usually without basis. There are different types of phobia:  fear of animals such as spiders − arachnophobia,  fear of crowds of people − known as agoraphobia,  fear of enclosed spaces − known as claustrophobia,  and fear of heights − called acrophobia. In aviation, claustrophobia and acrophobia are the most common. Claustrophobia The official definition of claustrophobia is: − ”abnormal fear of enclosed spaces”. It occurs in various ways. In enclosed spaces most of us feel uneasy. This is quite normal and is a natural protective mechanism. The dangerous thing about claustrophobia is when this uneasiness becomes panic−stricken fear. During such an attack the person can no longer calm himself; in other words, self−control fails entirely. What can be done about claustrophobia?  The sufferer can free himself from the enclosed space BEFORE an attack. To do this, the warning signals must be recognised and taken seriously.  Once the panic attack has set in, colleagues must try to get the sufferer out of the area. In conclusion, claustrophobia is difficult to foresee. There must be a collective attitude that it can affect everyone, not only the victim but also the helper.

Acrophobia Most people suffer some degree of vertigo. Nobody can fly, which may explain the normal respect for heights above 1.50 m. The abnormal, panic reaction to heights is what is really dangerous. Sudden acrophobia is less common than claustrophobia. A real sufferer could hardly climb onto a chair without a panic attack. During maintenance you must often work at great heights. Safety lines and suitable platforms lessen the risk of a fall and give you a feeling of security. Particularly at low heights, people often thoughtlessly do without safety aids. If the phobia sets in, two protection mechanisms are missing:  The natural protection mechanism is missing - your body tenses up.  Artificial protection mechanisms, for example, are safety lines.

Team attitude can lessen dangers. So expressions like ”Hey, stop putting it on” should disappear from your vocabulary.




M.9

Claustrophobia

Acrophobia

m c 0 5 1 y l n O s e s o p r u P g n i n i a r T r o F

Figure 20

Phobias


HUMAN FACTORS M9.3 SOCIAL PSYCHOLOGY


M.9

M9.3 SOCIAL PSYCHOLOGY Responsibility: individual and group; Motivation and de−motivation; Peer pressure; Culture issues;

SOCIAL ENVIRONMENT

Team working; Management, supervision and leadership.

INTRODUCTION General

The aircraft engineer works within a system. He introduces his knowledge, ability and characteristics into this system and is influenced by other factors. These factors are the direct work environment, organisation or company culture, regulations inside and outside the company and the economic and political environment of society at large.


- social Environment / Motivation - Responsibilities - Peer Pressure - Culture Issues - Teamwork - Leadership




M.9

Knowledge

Ability/Skill

Character

See Chapter M9.5 Physical Environment

Economic & Political Environment Direct Environment


Rules and Regulations

Figure 21

Oraginsation/Company Culture

Social Psychology - Introduction



CAT A/B1/B2

M.9 Influences Every company has its own culture. This includes:  company philosophy and policy,  procedures,  selection and training criteria,  and the quality assurance system. The influence that the organisation exerts on the engineer can be positive or negative. Impact The organisation can have a positive influence, if it encourages its employees − financially or with career incentives, or if it takes notice of problems and takes measures to solve them. Negative influences arise if, for example, the organisation exerts pressure on the technician to operate on a tight time schedule or to work with an inadequate budget. At some point, the individual realises that particular factors are having an effect on the quality of his work.

What is the consequence? Apart from latent dissatisfaction, fluctuation and absenteeism will increase. The result is an increase in human errors. Where does this come from? From de−motivation.


EASA PART 66




M.9

Positive

solving of problems takes notice of problems Career Company;

financially

Philosophy and Policy Procedures Latent Dissatisfaction

Selection/Training Criteria

tight timeframes Quality Assurance System low budgets


Fluctuation

other

Absenteeism Negative

Figure 22

Organisational Influences on Employees




M.9 MOTIVATION Maslow’s Hierarchy of Needs A well known theory on the subject of motivation stems from MASLOW − Maslow’s Hierarchy of Needs. Maslow postulated that two different motivation forces drive people:  Fulfilment of basic physiological and psychological needs,  and the realisation of individual potential. The hierarchy shows the corresponding steps. Where does the ”typical” aircraft technician belong in this simplified structure? The technician can achieve the lower levels by earning money and thus:  buy food,  finance a home  and provide for a family. The middle level is influenced strongly by the social environment:  social standing,  prestige and recognition. As a result, most technicians do strive for the Maslow level of achieving full individual potential.

Abraham H. Maslow (1908 - 1970)

... SELFREALISATION

.

... RESPECT ... AFFILIATION ... SAFETY PHYSIOLOGICAL NEEDS


Figure 23

Maslow’s Hierachy of Needs




M.9

Social Environment

Need for Respect Need for Affiliation


Need for Safety Physiological Needs

Figu Figure re 24

Moti Motiva vatio tion n (Mas (Maslo low’ w’s s Hie Hiera rach chy y of Need Needs) s)



CAT A/B1/B2

M.9 Motivation / De-Motivation How can we recognise highly motivated people?  They perform at a high level and get results.  They are energetic, enthusiastic, and set goals.  They are cooperative problem solvers.  They readily assume responsibility  and are willing to accept change.

De−motivated people have a different set of characteristics:  They may be indifferent,  have little safety awareness,  manage time poorly and are frequently absent,  exaggerate problems and difficulties,  create disputes and grievances,  rarely cooperate to solve problems,  and are opposed to change. Caution: Not everything may be labelled de−motivation. Many of these items are serious signs of stress!


EASA PART 66




M.9

Performance Opposed for Changes

MOTIVATION

Lack of Co-operation Exaggarates Problems

DE-MOTIVATION

Poor Time Management High Absent Rate Low Safety Margins

Goals

Indifferent

Enthusiasm Energetic Time


Many of these items are serious signs of stress!

Figu Figure re 25

Moti Motiva vati tion on / De-M De-Mot otiv ivat atio ion n



CAT A/B1/B2

M.9 RESPONSIBILITIES ”An aircraft technician carries a lot of responsibility!” And what about the other occupations within aviation? What does ”responsible” really mean? Somebody must be accountable for the tasks he has been given. He takes this responsibility individually and within the group setting.

The individual is given tasks − usually from within a group − for which he takes responsibility. A good example of this is the job card for an inspection. In accordance with your qualifications, you carry out this job and sign it off. This proven method guarantees ”traceability”.  Who did what and when? But what does the responsibility of the individual involve? We must examine whether he is permitted and able to carry out the task.  The ”permission” is determined by the task and the qualifications of the individual to carry out this task.  The ”ability” depends on many factors, such as tools, materials, time and many other things.  And to complete the list: ”willingness” also plays a role.


EASA PART 66




M.9

RESPONSIBILITY - Individual

WHO?


WHAT?

Figure 26

WHEN?

Individual Responsibility



CAT A/B1/B2

M.9 Group Responsibility

Group responsibility is often limited to the following formula: ”Group responsibility is the sum of all individual responsibilities.” Unfortunately this is the wrong approach. Of course, the inspection is divided among several job cards, and thus to individuals, but group responsibility refers to the general goal, for example, to do the inspection within a given time. Group responsibility has the following advantages: 1. Everybody feels responsible for the group result. 2. Safety awareness applies to the job as a whole. 3. Mutual supervision is offered and accepted. 4. Achieving the goal is regarded as a challenge. 5. Several people carry the burden of responsibility.


EASA PART 66

The disadvantages are:  Several people carry the burden of responsibility. No, this is not a mistake! Almost all positive aspects of group responsibility can also be ”killers”. 1) The burden of responsibility is blurred − Who should do what at what time? 2) Safety: with the help of others you can take greater risks. 3) Achieving the goal: it can result in unhealthy competition between teams. 4) Mutual supervision: ”Some one else can fix it − it’s time for me to take a nap!” The team as a whole must take on group responsibility. Team structure and culture determine if group responsibility will succeed or not.




M.9

Group Responsibility Disadvantages Advantages

Notes


1. Everybody feels responsible for the group result. 2. Safety awareness applies to the job as a whole. 3. Mutual supervision is offered and accepted. 4. Achieving the goal is regarded as a challenge. 5. Several people carry the burden of responsibility.

Figure 27

Group Responsibility





M.9 PEER PRESSURE Do you know the expression ”peer pressure” or group compulsion or pressure from colleagues? This can exert a massive influence on work. Think of the statement: ”Everybody must pull his weight − there are NO exceptions”. But what if they do not pull their weight or have reservations about whether or not ”this is the right way”? This is exactly where pressure sets in. On the one hand you want to belong. On the other hand you have reservations. A certain level of conformity to the group is imperative. But sometimes adaptation goes too far, and unfortunately the borderline is not always clear. Further, pressure is not always applied openly. You perceive the pressure or maybe you think you perceive it. The following factors influence the individual’s susceptibility to pressure from others:  the cultural environment: In some countries the individual has little value. The community is everything.  sex: in general, women tend to conform more than men.  knowledge and experience: the newcomer tends to follow the majority, above all if he feels he has too little knowledge or experience.  self−esteem: people with low self−esteem will give in to pressure more easily.  relationships: Conformity is greater if the members of the group know each other well. What if colleagues exert pressure on you to do the job ”properly” or make high demands regarding safety? Should resist this pressure? Or is it better to conform? Usually the individual gives in to pressure if he hears such things as ”Stop making a fuss.” or ”Forget the manual. This is the way we do it.” It depends on how you should react. With regard to safety it is clear. There must be a safety culture within the group and ”everybody must pull his weight − there are NO exceptions.” Only in this way can peer pressure be tolerated.




M.9

Please take the Manual...

Come on, don’t be chicken...


This Job can be done without a Manual...

You will not climb on the dock without safety ropes!

Figure 28

Peer Pressure



CAT A/B1/B2

M.9 CULTURE ISSUES General What springs to mind when you hear the expression ”cultural issues”? Do you think about ”the company?”. The image shows various ”cultures” of a company:  ”safety culture”,  ”technical culture”,  ”business culture”,

”cultures within the teams and groups”  and ”location culture”. How do the circles interact with each other? The head of the organisation does not define every culture - many ”cultures” develop independently. However, the head of the organisation is in the best position to influence all cultures. 

Cultures


EASA PART 66

Safety Culture What does ”safety culture” mean? In the ”ICAO Human Factors Digest No. 10” it says: ”... safety culture is the sum of attitudes, norms, roles and social and technical practices, which aim to minimise dangerous and risky conditions for employees, managers, customers and the general public.”

Professor James Reason, one of the leaders in the field of human factors, offers the following hypothesis on this: ...safety culture is the motor giving the system the goal of ”maximum safety”, independently of persons and current economic demands... Some efforts are needed to guarantee a culture of safety: 1. The construction of a safety information system to collect relevant incidents as well as audit reports, analyze them and distribute the conclusions to everybody. 2. The creation of an atmosphere of trust, within which employees are encouraged to pass on information relevant to safety. In this respect the distinction between acceptable and unacceptable behaviour must be made clear. 3. Respect for the knowledge, ability and experience of staff and direct superiors. 4. The establishment of a learning culture, in which competence is developed to draw the right conclusions from events, and in which there is a willingness to carry through important reforms when necessary. The culture of an organisation can be more accurately measured by deeds rather than words. What is the use of a highly− praised safety system if it is not implemented on the working level? Everybody has to participate. Training and ”tools” such as information systems must be accepted and used. It is the job of management to make these aids available and to encourage their usage.




M.9

Safety Culture 1. Construction of a Safety Information System 2. Atmosphere of Trust 3. Respect for the knowledge, ability and experience 4. Establishment of a learning culture

...safety culture is the motor giving the system the goal of ”maximum safety”, independently of persons and current economic demands...

Collect Incident/Audit Reports


Distribution of clues

analyse

Figure 29

Safety Culture



CAT A/B1/B2

M.9 TEAMWORK General Within a society there are many groups, for example: men between 18 and 25, women with a university degree, red−haired children ... In aircraft maintenance there are also numerous groups:  the group of mechanics,  the group of electricians,  line maintenance personnel, etc. ”Team vs. Group”

Does a ”team of mechanics” exist? What distinguishes the team from the group?  A team consists of persons working together to achieve a common goal.  Alternatively, a team can consist of members working in parallel to achieve the goal.  A team consists of a recognised ”leader” and at least one ”follower”.  The goal defines the composition of a team.  The cohesion and functioning of the team must be maintained.


EASA PART 66




M.9

Mechanics

Electricians Team

„Line Maintenance“


GROUPS

Figure 30

GOAL

Group vs. Team



CAT A/B1/B2

M.9 Maintaining a Team and important lubricants. What is necessary to keep a team together?  communication,   

cooperation, coordination and mutual support.

Communication is very important, and should not be underestimated as a factor in carrying out safe and efficient maintenance work. Communication problems are the main cause of maintenance errors in aviation. For this reason, a separate chapter (M9.7 Communication) will be devoted to communication. Cooperation is an important ”adhesive” for the team. Openness, honesty and fairness increase cohesion and mutual respect. Members of the team must treat disagreements with respect, and team leaders should play an active and important role in solving them. Coordination means: 1. Delegating: tasks must be clearly and fairly allocated according to the abilities of the team members. 2. Checking: delegated tasks must be monitored and 3. priorities must be set: Priorities should be subject to change if difficulties or new circumstances arise. y l n O s e s o p r u P g n i n i a r T r o F

EASA PART 66

Mutual support is the ”heart” of every team. It forms the basis for team identity. Every member introduces his own strengths and weaknesses into the team. The art is to employ everyone according to his abilities, and to compensate for his weak points. It is a part of mutual support to point out somebody’s mistakes realistically and constructively, and to be of assistance regarding solutions.

Why was ”having parties together” not mentioned as imperative for maintaining a team? It is the expression for ”social contact”. It may boost morale, but is not essential for working in a team. It can strengthen ties within the team but it also holds risks. For example: what about the colleague who has (had) alcohol problems, and as a result steers clear of team parties? Would he otherwise be a better member of the team? The ”team gearbox” is often oiled only at parties − other lubricants remain untouched. In this scenario, you would not have a team, just a ”group of happy workers”.




M.9

Very important, and should not be underestimated as a factor

COMMUNICATION

Communication problems are the main cause of maintenance errors in aviation

COORDINATION

Deligate Monitoring Set priorities Difficulties

COOPERATION Openess

Rearrange

Honesty Fairness

MUTUAL SUPPORT y l n O s e s o p r u P g n i n i a r T r o F

Strenght and Weaknesses Employ according abilities Compensate weak points Critise constructively Offer support

Figure 31

Maintaining a Team

’crease’ cohesion and mutual respect




M.9 MANAGEMENT, SUPERVISION AND LEADERSHIP General In large organisations, leadership is found on various levels. Management lays down company policy, makes business decisions and has little direct contact with the employees and their work. Supervisors serve as a link between management and the work groups or teams. They put directives into practice and are responsible for personnel planning in their respective areas.

Team leaders are in direct contact with the workers and their work. Differing leadership approaches are needed in various job areas. Work group leaders are often under pressure as they are the link between the management and the teams. On the one hand the company management provides them with economic data, customer orders and procedures. On the other hand there is feedback coming from the teams, such as reporting off sick, unforeseen difficulties and unscheduled tasks. The art of work group leadership is to mediate between both sides.

THEY!

WE!

Management Work Group Leaders

PRESENT?

Matters of Safety What is the relationship between management and safety? You frequently hear the words US and THEM. We must succeed in making safety OUR affair. Each level plays its part in this. Think of ”safety culture”! y l n O s e s o p r u P g n i n i a r T r o F

THEY?

Work Groups

OUR!!

FUTURE!

Management Work Group Leaders Work Groups




M.9

Have you noticed the new procdures?

Company Politics Business Decisions Little Contact to Work Groups Link

Which?

Yes!

Sure!

Personnel Planning Put Directives into Practice

Management Work Group Leaders Work Groups


Economic Data

Off Sick Reports

Customer Orders

Unforeseen Difficulties

Procedures

Unscheduled Tasks

Management Work Group Leaders

Work Groups

Figure 32

Leadership

Differing leadership approaches are needed in various job areas


HUMAN FACTORS M9.4 FACTORS AFFECTING PERFORMANCE

CAT A/B1/B2

M.9

M9.4 FACTORS AFFECTING PERFORMANCE Fitness/health;

Illegal Drugs

Stress: domestic and work related;

Illegal drugs, as well as the ’legal drug’ alcohol, can lead to loss of license according to EASA Part 66.B.500 (old JAR 66.65).

Time pressure and deadlines;

And, of course, drug use is a criminal offense in many countries. Most company security checks discover any court records involving illegal drugs.

Workload: overload and underload; Sleep and fatigue, shiftwork; Alcohol, medication, drug abuse.

INTRODUCTION General There are many factors that can lead to a reduction in human performance. In this chapter the following subjects are covered: health and fitness, stress, work load, sleep, fatigue and shift work, as well as alcohol, medicines and drug abuse.

Important Note


EASA PART 66

Even so the regulation JAR 66.50 was not transformed into the new EASA Part 66 regularies(!), the chapter ’health and fitness’ is still subject of EASA Part 66 M.9 Basic Training. Therefore we have decided to refer to the regulations (and useful advices) of the ’old’ JAR 66.50 in this book.

Fitness and Health At the medical on entering employment, basic fitness was ascertained. The employer takes responsibility for this. You are responsible for maintaining your fitness. A rule of thumb may help for medicines:  You are not fit for work if the instructions in the packet say you should not drive a car!




M.9

Fitness / Health

Stress

A l c o h o ,l M e d i c a t i o n , D r u g a b u s e

d a o l k r o W

Sleep, Fatigue and Shift work y l n O s e s o p r u P g n i n i a r T r o F

JAR 66.50 imposes a requirement that certifying staff must not exercise the privileges of their certification authorisation if they know or suspect that their physical or mental condition renders them unfit.

Figure 33

Factors Affecting Performance




M.9

STRESS General Stress − a word often used in our society. Today, ”stress” has become almost a measure of performance. The more you are under stress, the more you have managed to do. What is stress, anyway? In itself stress is a normal and healthy phenomenon.  You are affected by a particular incident − the so−called stressor. 

STRESS

Your reaction to the stressor is known as stress response. − If there is an immediate reaction which eliminates the stress, you feel good. ”I’ve done it!” We can call this type of stress ” positive stress.” − If the physical reaction finds no release, the stress ”messengers” are stored in the body, resulting in adverse consequences. This is ”negative stress”.

= Stress


Performance




M.9

POSITVE STRESS

NEGATIVE STRESS

STRESSOR

STRESS RESPONSE

No Reaktion

Immediate Reaktion


STRESSOR

- ’Messengers’ are stored - Decrease in Performance - Negative Symptomes

- ’Messengers’ are decreased - ’Boost’ of Performance - Feeling Well

Figure 34

Stress - General


HUMAN FACTORS M9.4 FACTORS AFFECTING PERFORMANCE Negative Stress When we talk about stress, we usually mean adverse or ”negative stress”. What are some typical stressors? There are two main groups: 1. External factors, such as:  noise, environmental poisons or overstimulation, for example from watching too much television and 2. Internal factors, such as:  anger, sorrow, performance pressure, physical exertion and sickness. What are the Effects of Negative Stress? The physical reaction always begins in the same way: Typical stress hormones, such as adrenaline, are produced in excess, followed by an increase in blood pressure. The reactions that follow vary from individual to individual. People may react to stress hormones and increased blood pressure with headache, sleeplessness, heart trouble, stomach pains, diarrhoea, skin irritation, allergies, tenseness or muscle cramp.

Typical psychological stress reactions are: nervous unrest, irritability and sleep disorders.


Counter Meassures 1. Accept that some stress is useful in achieving a certain level of performance. 2. Do not take on too much. Stress is often self−made − by putting too many demands on yourself at work, at home or in your leisure time. Regarding leisure time stress you should heed the advice ’It’s better not to overdo it’. 3. Fight stress. This can be done in two ways.  Reduce the stressors, which means: − Do not overestimate problems. − Do not try to solve problems when under severe stress. You can think more clearly and your concentration is better when you are relaxed. − Try to reduce tension through such methods as yoga and relaxation through self−hypnosis and secondly...  Transform stress into physical activity, − i.e. do sports, go for a walk, or do physical work that you enjoy.


M.9 STRESSORS INTERNAL FACTORS

EXTERNAL FACTORS Noise

Environmental Poisons

Anger Sorrow Pressure Physical Exertion

others

Overstimulation




M.9

Physical Reactions

Psychological Reactions

Headaches

Nervous Unrest

Sleeplessness

Irritatiability

Heart Troubles

Sleep Disorders

Stomachaches Diarrhoea Skin Irirtation Allergies y l n O s e s o p r u P g n i n i a r T r o F

Tensions or Muscle Cramps

Figure 35

Negative Stress - Reactions and Counter Measures


HUMAN FACTORS M9.4 FACTORS AFFECTING PERFORMANCE WORKLOAD Your workload depends on three things: 1. The task itself − the physical and mental demands which are made. 2. The accompanying conditions, such as precision, time frame, outside control, environmental factors, and 3. Yourself. How good is your ability and knowledge, your experience in the field, your health and fitness and your emotional state, such as stress level, mood and degree of stimulation. Arousal Stimulation, also known as arousal, influences your performance. Performance may suffer considerably if you are over− or under−stimulated. Only if stimulation is in the ’middle ground’ can peak performance be achieved. But what is the right right level of stimulation? That is a very individual thing and also depends on your daily conditions. What causes a slump in performance? If we are not stimulated sufficiently, our attention becomes blunted and we are overcome by indifference or boredom during an activity. If we are inundated by stimulation, our attention tries to focus itself only on the most important things at the expense of the total performance of our brains. In the case of extreme over−stimulation we are no longer aware of new information. This can also be a stressor!



M.9



physical

Task itself...


M.9

Precision

Knowledge and Skill

Timeframe

Experience

Outside Control

Fitness and Health

Environmental

Emotional State

mental

...Contributing Factors

Yourself...

PERFORMANCE LEVEL

OVER AROUSAL


IDEAL

UNDER AROUSAL Figure 36

Workload


HUMAN FACTORS M9.4 FACTORS AFFECTING PERFORMANCE Overload If you recall the factors of workload − namely the task itself, the accompanying conditions and yourself − it quickly becomes clear where overload starts. Imagine an activity which you find easy and enjoyable. Now reduce the time allowed for it by 50%. What has happened to your load? Under certain circumstances you are no longer able to complete the task. What do you do if an electrical system is overloaded? You reduce the load before the fuse blows. It sounds simple, but that is exactly the solution for human overload. Why is it so difficult to reduce this load? Just think which actions are necessary..  It is important to find agreement within your team.  It is better to assess the situation correctly before an overload develops.  Early intervention, for example in time schedules and job planning, helps to prevent overload. Good ideas and short−cuts often result from an overload. Such ideas should be discussed among the team in a low−stress environment. Underload Do workers usually complain about underload? Not usually, but it is a potential problem. Underload is undemanding work.


The risky combination of bordom and no challenge can lower your attention to the quality of the task. Be careful in such cases. Find additional responsibilities matched to your knowledge and abilities. The greatest risk of underload is that attention deteriorates. Along with boring routine activities this can happen extremely quickly. Another risk is declining motivation. If you are always given tasks which demand too little of you − physically as well as mentally − you can easily have the feeling: ”They don’t think I’m up to it!”. Real teamwork can help, in the same way as with overload. For example, talk in the group about:  Training, gaining experience,  Improvements  and sensible short−cuts and Completing unfinished tasks. In short: Use the time and team resources to get fit for the next ’big load’. It is sure to come!


M.9




M.9 PERFORMANCE MOTIVATION

LOAD

UNDERLOAD

OVERLOAD

UNDERLOAD

find agreement within your team.  assess the situation correctly before an overload develops.  Early intervention in time schedules and job planning 


Training, Gaining experience, Improvements  and sensible short−cuts and Completing unfinished tasks.  

Figure 37

Over- and Underload




M.9

FATIGUE General Former US President, William Clinton, once said that every bad decision he ever made was made when he was tired. Even the famous playwrite William Shakespeare drew attention to the importance of sleep: ”O sleep, O gentle sleep, nature’s soft nurse.” This unit is about fatigue, which is often a result of lack of sleep. But there are many additional factors that affect your levels of ”Alertness”. The airline industry operates around the globe, where it is always somewhere morning, afternoon, and nighttime. The industry does not rest! That is a fact!

It is also a fact that humans need sleep. Sleep is like a logistical supply. If you lose it or disrupt it, you must pay for it. All humans need rest! This requirement does not vary among cultures of the world. Some cultures sleep more that others. The US is an example of a culture that does not sleep enough. For example, a recent survey by the National Sleep Foundation showed that 2 of 3 Americans from the US do not get 8 hours of sleep. 1 in 4 Americans say that they are sleepy at work a few days each week. And, it is estimated that 20% of U.S. auto accidents are related to fatigue. Think about that the next time you drive home from the night shift! Effects We list here some of the effects of fatigue.

First of all, it degrades your work performance. Fatigue can affect the quality of your judgement.  Fatigue slows your reaction time.  Fatigue affects your ability to solve problems.  Your memory is not as good when you are tired.  Fatigue can affect you mood and your general attitude about the job and you co−workers.  Fatigue and loss of sleep have much the same effect as alcohol. In fact, scientists have demonstrated that driving while fatigued can be compared to driving while drinking. 20 hours of wakefulness has the same effect on driving performance as drinking 2 beers or 2 wines!  Excessive Fatigue can affect your long−term health. Fatigue is a serious matter for you and for your safe and efficient work.  





M.9

Lack of Sleep

?

approx. 20% of U.S. auto accidents are related to fatigue

FATIGUE

! y l n O s e s o p r u P g n i n i a r T r o F

Figure 38

Fatigue - Introduction

Breaks


HUMAN FACTORS M9.4 FACTORS AFFECTING PERFORMANCE Alertness ”Alertness” is a term that encompasses all aspects of rest and readiness for work. Alertness may be seen as a range. On one end you can be well−rested, highly alert and ready for work. Your safety margin is increased. At the other end of the range is Fatigue. You may have insufficient sleep. You may be physically and mentally tired. You are not fully fit for duty. And, you may be unsafe. ”Fatigue” is a lack of energy, a weariness or tiredness.

Fatigue is a normal and important human response to physical exhaustion, emotional stress, or to lack of sleep. It can lead to error and other unsafe conditions.


Circadian Clock The Circadian Clock is like an automatic clock in the brain. It affects all humans. Some scientists say that it is in our chromosomes. The word Circadian comes from two Latin words: ’Circa’, meaning about, and ’Dias’, meaning a day. The clock therefore affects our level of alertness over about one day, about 24 hours. You can see that we are most alert around 9 in the morning and around 7 at night. Our lowest level of alertness is around 2 in the afternoon and even lower between 1 and 3 am. It is probably not a coincidence that many of the worst human error−related disasters of this century started between 1 and 3 am. That includes the shipwreck of the Exxon Valdeeze Oil Tanker in Alaska, the nuclear powerplants of Chernobol, in Ukraine and Three−Mile Island, in the U.S., and the terrible chemical plant leak in Bhopal, India. You should consider the implications of the Circadian Clock on your work schedule.


M.9




M.9

CIRCADIAN CLOCK 1 A.M.




 

- fully alert

15

- lightly affected

s s e 10 n t r e 5 l A

SAFE

E L A C S S S E N T R E L A

3 A.M.

20

well rested alert fit for duty

0

- degraded alertness - dangerously sleepy 09

12

15

18

21

24

03

06

09

Time

UNSAFE   

exhausted physical and mental tired unfit for duty

Three-Mile-Island, USA

Figure 39

Alertness / Circadian Clock

Tschernobyl, Ukraine


HUMAN FACTORS M9.4 FACTORS AFFECTING PERFORMANCE Types of Fatgue

There are two types of fatigue: Acute Fatigue and Chronic Fatigue. Acute Fatigue is associated with temporary loss of sleep or temporary exhaustion from brief periods of too much physical or mental work. It is temporary and of short duration. Sometimes acute fatigue many be associated with too much partying the night before. The party causes you to stay awake throughout the night and, sometimes, there may be too much alcohol. The alcohol causes disturbed sleep. Thus, you suffer from a morning or day of acute fatigue.  The cure for acute fatigue is simple − get some rest and sleep. On the average you should have 8 hours of sleep each night. Treat sleep like money in the bank. If you borrow from the bank you must eventually pay it back. If you sleep only 5 hours one night you have to sleep a bit more the subsequent nights. Chronic fatigue is more serious than Acute fatigue. Chronic Fatigue is long term, and the recovery is slow. The symptoms are the same as Acute fatigue but they reoccur daily. You are always fatigued. The causes of Chronic Fatigue are not as straightforward as Acute fatigue, often resulting from physical sickness or some ongoing emotional stress. If you are always tired, you may have Chronic Fatigue.  When Chronic fatigue is a likely problem one must seek the advice of a professional in sleep disorders. Many General Practice Doctors do not have the specialized training to properly diagnose and treat Chronic Fatigue.


Fatigue: ’Routine Maintenance’ Most maintenance personnel underestimate the seriousness of fatigue and its effects on performance. In turn, they overestimate their ability to overcome fatigue. It is relatively easy to avoid fatigue. Here is a list of Guidelines.  Strive to obtain 8 hours of sleep per night. Keep a sleep record for 2 weeks and see how you do.  Set a routine for going to bed and for waking up.  Quality exercise prevents fatigue. It keeps your body in good condition and it helps you rest.  Sleep experts suggest to avoid caffeine and excessive alcohol before going to bed.  You should eat a balanced diet throughout the day.  

Put the correct ’fuel’ in your tank! (Mineral water, fruit drinks) Turn off the lights and the television. A dark and quiet room promotes sleep.


M.9 

Regarding shift work, it is best to sleep before your work shift rather than after the shift.

Fatigue: „Non-Routine Maintenance“ Although you may take all the appropriate steps to avoid fatigue, there are occasions when you cannot avoid it. In those cases you must work smart to avoid fatigue−related errors.  Often you may get so tired that you are too stubborn to admit your fatigue. Face the fact that fatigue is a normal human response to physical and/or mental exhaustion.  It is good to remain physically active when you are fatigued. Move around, exercise and stretch (best in fresh air) when you feel tired.  Conversation and caffeine are both good ways to stay awake.  There are many things that you can do to promote alertness at work. Take ’good breaks’. A small amount of exercise, like a walk, will help during a break. Working with a partner helps promote alertness. Eat your balanced meals on a regular schedule and drink water and fruit drinks.  Caffeine is a legal drug that works to keep you alert, but don’t overstrech it! Drink caffeine before you are tired.  When it is hard to remain alert, try to schedule the tedious/boring tasks early in the shift when you are most alert.  Remember that alertness is a ”Fitness for Duty” issue.  It is a requirement that you come to work fit for duty. When you have alertness challenges, ask your co−workers to assist you. In turn, you should help co−workers who have an occasional lapse in alertness.




M.9

CHRONIC FATIGUE 

THE SYMPTOMES ..........

  

Develops over Time Period Recover takes a long time Symptoms reoccur on a daily base Often caused by emotional Stress, Sickness!

ACUTE FATIGUE    

Lack of Sleep Temporay Breaks will Help Short Duration

......... ARE NEARLY THE SAME!

„Non-Routine Maintenance“

’Routine Maintenance’




      

Aprox. 8 hr. Sleep/Night Standard Sleep Routine Excercises (Sports) No Caffein and Alcohol before Sleep Balanced Diet Sufficient Drinks Sleep before the Shift

     

Figure 40

Accept the Fact that you are tired! Physical excercises (e.g. streching)... ...in Fresh Air Take ’Good Breaks’ / Caffein maybe a ’booster’ for a short time Plan ’boring’ Task in the Beginning Conversate! -About the Fact that you are tired Teamwork / Mutual Support

Fatigue: Acute vs. Chronic





M.9

ALCOHOL, MEDICATION AND DRUG ABUSE This chapter is about alcohol, medicines and illegal drugs. We are not raising our finger in warning here. This chapter will attempt to show the characteristics of various substances and their effects on the body. We will also point out current legislation. You must draw your own conclusions from the facts!

Alcohol Alcohol has a calming effect on the central nervous system, but it dulls the senses and reduces mental and physical reaction time. Even small amounts of alcohol reduce human performance. The amount of alcohol in the blood depends on the amount of alcohol consumed, body weight, and sex. The effects of alcohol the morning after are often underestimated. An example:  If you finish drinking at 1 am with a blood alcohol level of 1.6 per mil, there is still 0.85 per mil in the blood at 6 am, since the body breaks down about 0.1 − 0.15 per mil per hour.

So far no blood alcohol level ( x.x per mil) has been set by the EASA, but EASA Part-66.B.500 quotes: ’...under the negative influence of alcohol...’ Look at the blood alcohol level scale and set your own limit.  A blood alcohol level of only 0.2 per mil affects performance and awareness. Perception and coordination suffer.  Spatial judgement begins to decline at 0.5 − 0.8 per mil. Also at this level, the eyes adapt more slowly to changing light conditions. Vision deteriorates by about 25% and concentration decreases.  At 0.8 per mil it takes 50% longer to react.  Between 0.8 and 1.2% a state of euphoria sets in, you begin to lose your inhibitions and to overestimate your abilities. Your vision narrows, and so−called ”tunnel−vision” sets in.  At 1.2 per mil there is a drastic reduction in the ability to judge space. You overestimate yourself to the extreme, feel more euphoric and lose more of your inhibitions, but your reactions become slower and slower. Balance and co−ordination are severely affected. It should now be clear why you should not position the pointer within the scale. It seems likely that the ’EASA limit’ for blood alcohol for maintenance personnel will be much lower than the one for the roads!




M.9

Per Mil Level

Typical Reactions

0,0 First reactions

Where do you set your „personal margin“?


Figure 41

0,3

You start to feel the alcohol

0,5

You feel ’tipsy’ and a clear sense of warmth

0,8

Limited reactions

1,0

Concentration and coordination problems, depreviation of balance and muscle control, starting speech disorder

1,5

Strong drunkenness

2,0

Uncontrolled staggering, drunken stupor, vomit

2,5

Here starts mortal danger

3,0

You are unable to keep up, you lose your consciousness

4,0

Lethal dose

Alcohol and its Effect


HUMAN FACTORS M9.4 FACTORS AFFECTING PERFORMANCE Medicines Medicines are routinely used in the treatment of illness. Ask yourself seriously if you are not already ’unfit for duty’. All medicines − including ’over the counter ones’ − can have side effects which impact our ability to work. If you are taking a medicine for the first time, be sure to take it at least 24 hours before you must report to work.

Here are a few typical medicines along with their effects on our work:  Pain killers, for example aspirin, should be quite safe if taken correctly.  Antibiotics, such as penicillin, are quite safe in themselves, but should only be taken if you have a serious infection!  Antihistamines, as often found in allergy or cold preparations, often cause drowsiness. Consult your doctor!  Over−the−counter cough mixtures are probably quite safe, as long as they do not contain substances such as antihistamine.  Preparations to reduce swelling of the nasal passages sometimes have side−effects such as a feeling of apprehension, shivering, racing pulse or headaches. You may be unfit for a time.  Stimulants are, of course, out! - If you need these to stay awake, you are definitely unfit. This list is not comprehensive. Speak to your doctor or pharmacist about the effects of medicines.



M.9




M.9

Do You have to take medicine on a regular base? If the answer is yes, do you know their effects? Check the description and discuss the this subject with your doctor.

My Medicin:


Figure 42

Medication


HUMAN FACTORS M9.4 FACTORS AFFECTING PERFORMANCE Cannabis Cannabis products such as hashish and marihuana are usually smoked in the form of joints. The ”high” begins within a few minutes, and reaches a maximum after about 15 minutes. The ”high” lasts for three to four hours, but the medical effect lasts longer − about nine to ten hours. The following effects are known:  The brain can no longer distinguish between relevant and irrelevant information,  

Movements slow down, lethargy may set in, speech becomes slurred and reaction time becomes longer and The thought process and perceptions of space and time are distorted, i.e. distances and speeds are judged wrongly. The effects may be particularly severe if even a small amount of alcohol is consumed at the same time.

Cocain Cocaine or ”crack” is usually ”snorted” or smoked. The effect starts almost immediately and lasts for about four hours. There are three phases:  Euphoria: this lasts about 30 minutes. The user becomes sociable, likely to take risks and feels ”omnipotent”.  Possible Hallucination: this lasts one to two hours and the user may suffer from illusions, restricted vision and paranoia. 


Possible Depression: fatigue, irritability, sleeplessness, and headaches may occur. In all three phases there are strong mental and physical changes, such as aggressiveness, increased pulse rate and blood pressure with the risk of blackouts, dilated pupils, with increased sensitivity to dazzling and blurred vision, and possibly convulsions. Certainly not ’Fit for duty’!


M.9


HUMAN FACTORS M9.4 FACTORS AFFECTING PERFORMANCE „Designer Drugs“ & LSD Speed, Extasy and ’Adam and Eve’ are amphetamines or designer drugs. They are usually swallowed in the form of a small pill. The effect lasts from about four to eight hours, depending on the drug. If taken frequently, there is the danger of mental addiction, resulting in a need to increase the dosage.  Subjectively increased performance leads to a greater willingness to take risks, to restlessness, irritability, nervousness and loss of inhibitions, possibly to delusions, optical and acoustic hallucinations, paranoia and panic. 

There may also be an increase in pulse rate and blood pressure, with the possibility of convulsions and a loss of muscular control.

LSD is found in various forms and is usually swallowed or sucked. The effects start within minutes, and lasts for up to eight hours.

There are four phases:  Coming up. This takes about 45 minutes, with effects that may include dizziness, anxiety, and increased pulse rate.  The high. This lasts for about eight hours, with possible hallucinations and reduced muscular control.  Coming down. Depression, exhaustion and anxiety may result  Flashback. This can last for days! The effects could be: hallucinations, distorted perception, and illusions, with paranoia and a tendency to violent acts, extremely dilated pupils with extreme sensitivity to light, increased pulse rate and may be convulsions, confusion and disorientation.



M.9 Opiates Opiates include opium, morphine and heroin. Opium is usually smoked, morphine and heroin usually injected. When injected, the effect is immediate. The effect lasts for a maximum of five to six hours, but in the case of heroin addiction this becomes shorter and shorter. There are three phases:  The flash or rush. There is a strong feeling of happiness, euphoria and subjectively increased performance.

Stoned. Apathy, indifference and blankness of expression, even virtual unconsciousness are the symptoms and  Coming down. The fear of coming down itself sets in, and the mind concentrates on finding more dope. Opiates are extremely addictive, with a high degree of tolerance leading to an increase in dosage. The risk of an overdose is great. Physical effects are: Pin−point pupils with no reaction to light and complete night blindness, drowsiness, slow physical movements, including stumbling, slurred speech and loss of muscular control. 


HUMAN FACTORS M9.5 PHYSICAL ENVIRONMENT

CAT A/B1/B2

M.9

M9.5 PHYSICAL ENVIRONMENT Noise and fumes; Illumination; Climate and temperature; Motion and vibration; Working environment.

INTRODUCTION The subject ”work environment” can be divided into two main sections: 1. The social environment and The social environment includes: motivation, responsibility, peer pressure, cultural issues, teamwork and management, supervision and leadership. This subject is covered under Chapter M 9.3 Social Psychology 2. The direct physical environment. Physical environment includes: noise, fumes, lighting, climate and temperature, movement and vibration and confined spaces.


EASA PART 66




M.9

See: M9.3 Social Psychology

NOISE

Social Environment/ Motivation

FUMES

Responsibilities

ILLUMINATION

Peer Pressure PHYSICAL ENVIRONMENT

CLIMATE & TEMPERATURE

Culture Issues MOTION & VIBRATION

Teamwork Supervision

CONFINED SPACES DIRECT WORK ENVIRONMENT

SOCIAL ENVIRONMENT


Figure 43

Work Environment



CAT A/B1/B2

M.9 NOISE Noise at the workplace can distract, disturb communication (if not make it totally impossible), and camouflage warning sounds. Noise can cause stress, with all its negative effects on the human being. Noise can be thought of as any unwanted sound, and may be annoying and unpleasant, especially if it is loud. Noise is subjective and perceived differently by different people. The brain can filter out much of the background noise. But this activity leads to a reduction in concentration. This explains why the ticking of a watch can be annoying (noisy!). Typical Noise Zones In aircraft maintenance we can expect noise levels  from 85 dB(A) to 90 dB(A) on the apron  and 70dB(A) to 75 dB(A) in the hangar. (During some maintenance Tasks , the noise levels exceed these figures.)

There is a useful rule−of−thumb to answer the question ”Do I need an ear protector?” . If you cannot understand a normal conversation within a radius of two metres, you should protect yourself from the noise.


EASA PART 66




M.9

NOISE CAN ...

..DISTRACT

..DISTURBS COMMUNICATION

..CAMOUFLAGE WARNINGS

..CAUSES STRESS

Typical Noise Zones in Maintenance Enviroment y l n O s e s o p r u P g n i n i a r T r o F





85dB(A) (Decibel) bis 90 dB(A)



Figure 44

Noise

70dB(A) (Decibel) bis 75dB(A) Caution: during some maintenance Tasks expect much higher levels!




M.9 FUMES In the maintenance environment there are many materials such as grease, oil, paint and solvent − that vaporise. The resulting fumes can be categorised as unpleasant and hazardous to health. In the case of health hazards, warning notices and safety regulations must be obeyed. Serious damage to health can otherwise result. You are only ”aware” of unpleasant fumes. They often smell nasty, and may irritate the eyes . Working under thoose conditions, the ’motivation’ is often lowered and you want to get the job done as soon as possible. Besides the health aspects, fumes lead to performance limitations.

FUMES

hazardous

’unpleasant’

one is ’only ’aware of

Warnings Safety Regulations Health Damages possible

Figure 45


Fumes




M.9 ILLUMINATION In order to carry out maintenance you need proper illumination. But what is proper illumination? Whether natural or artificial, light sources have very different light properties. This is clearly illustrated by our perception of colour under different light sources.  Natural light is best for recognising colours.  The ratings for artificial light are: − good for candescent light, − average for florescent tubes − and poor for mercury vapour lamps. In this case, a red cable appears as anything from orange to black.

ILLUMINATION

Artificial Light

Natural Light Colour Perception

GOOD

BEST

AVERAGE

Clearly, correct color recognition depends on proper illumination!

When the focus is on light efficiency, the rating changes completely. The mercury vapour lamps do best. Note: Mercury vapour lamps are often found as Hangar and Apron illumination, because of its efficency.

POOR

Artificial Light

Natural Light

Caution: Rotating parts quickly appear to be stationary when illuminated by florescent tubes. This is also called the stroboscope effect.

Efficiency POOR


AVERAGE

GOOD

BEST Figure 46

Ilumination




M.9 CLIMATE AND TEMPERATURE Humans can exist and work under various climatic conditions.

Optimum

Sunlight Strong Winds Precipitation

Arctic

Temperature Zones

Tropic

Desert

L E V E L E C N A M R O F R E P

18 - 25 Celsius 25 - 85 % relative Humidity

Cold & Humid

Figure 47

Climate and Temperature

Cold & Dry

CLIMATE

Hot & Dry

Hot & Humid

Extract from EASA Part 145.A.25 Facility requirements


Individual performance depends strongly on temperature, humidity and other climatic factors. Age also plays a role. The graph shows the connection between performance and climatic factors. Other factors include:  wind,  sunlight  and precipitation. Result: The Performance level further decreases! The authorities (EASA) has come to grips with the matter and applied regulations. We cannot change the weather − so work must be adjusted to suit the conditions.

5. ..... 6. the working environment for line maintenance is such that the particular maintenance or inspection task can be carried out without undue distraction. Therefore where the working environment deteriorates to an unacceptable level in respect of temperature, moisture, hail, ice, snow, wind, light, dust/other airborne contamination, the particular maintenance or inspection tasks must be suspended until satisfactory conditions are re−established.. 7. .....




M.9 MOTION AND VIBRATION Vibrations

Vibrations Of course, such scenes are rarely seen in aviation. Vibrations and motions reduce performance and lead to fatigue and distraction. Vibrations in maintenance stem mainly from the use of tools, such as rivet guns or grinding and polishing machines. Vibration can be a safety challenge. Fingers and hands can become numb as a result of using machines that vibrate strongly. It can take a long time for feeling to return to the hands. In the meantime, precise work, such as making fine ad justments, is virtually impossible.

Movements

Fatigue Distraction

Platforms

What comes to mind when you look at this picture? Physical activities which are not carried out on firm ground, can lead to sudden movement.

Working on wobbly grounds...

SAFETY...!

Height affects the reaction of a person more strongly than when on solid ground. y l n O s e s o p r u P g n i n i a r T r o F

At first he focuses on his safety, and as a result is distracted. In some circumstances a task cannot be completed safely.

Cheery Picker moves

Height will augment the sensation...

Figure 48

Motion & Vibration




M.9 DANGEROUS SONIC WAVES Engines are sources of sonic waves. When there is a danger there will proper labeling and warnings. Infra-Sonic Waves Some engines emit INFRA−SONIC WAVES, which you cannot hear (<20Hz), but which can damage internal organs (e.g. kidneys).  Going near a running engine will not harm you as long as you take the usual safety precautions. Ultra-Sonic Waves ULTRA−SONIC WAVES are above our hearing range (>20.000Hz). These sonic waves can damage nerve canals.

s e v a W c i n o S

Can damage intenal organs (internal bleeding!)

Infra-Sonic < 20 HERTZ

Ultra-Sonic > 20.000 HERTZ

NOT AUDIBLE!

Can damage nerve cells y l n O s e s o p r u P g n i n i a r T r o F

Figure 49

Dangerous Sonic-Waves




M.9 WORKING ENVIRONMENT Confined Spaces You do not have to suffer from claustrophobia to get an uneasy feeling at the thought of climbing into a fuel tank. Of course, apart from the ’classical example’ of the fuel tank, other areas, depending on the type of aircraft, can also lead to uneasy feelings and claustrophobia.

When working in confined spaces, especially if entry and exit is limited, good planning is recommended. Here are some tips:  Follow all safety regulations,  Let a colleague assist you,  Make sure that ventilation and lighting are good,  and make your job as comfortable as possible for yourself. Stay in contact with your colleagues. Should you still feel uneasy, it is nothing to be ashamed of. Speak openly about it and take a break. The time between feeling uneasy and having a panic attack can be very short, and is usually not under your control. There have been cases of working in tanks where people have had to be rescued by the emergency services. The build of the worker should be considered. It should not be necessary to send a six−foot−six mechanic into the smallest of tanks.

NARROW...? Do I suffer from Claustrophobia?

Uneasy...

NOT UNDER SELF-CONTROL!


PANIC!!!

Figure 50

Confined Spaces


HUMAN FACTORS M9.6 TASKS

CAT A/B1/B2

M.9

M9.6 TASKS Physical work Repetitive tasks Visual inspection Complex systems

INTRODUCTION Chapter M9.6 Tasks combines many topics of ”Human Factors” that have already been discussed previously. The ”SHELL” model of chapter M9.1 shows how these individual topics are interlocked.

PHYSICAL WORK Planning Thorough planning must precede all work procedures. The individual mechanic, a group of mechanics or process engineering − they all have to do their preparatory planning before starting with the actual job.


EASA PART 66

This planning includes:  exact analysis of the work to be performed  considerations concerning the required means and tools − are these available in the necessary numbers and in due time; which spare parts will be needed; what about the documentations, availability of hangars etc.  planning of personnel with respect to number of persons, required qualifications and skills  specific tasks must be detailed on ”Task Sheets”. The individual tasks have to be clearly specified as check, inspection, repair, replacement, or overhaul. Furthermore additional information like AMM references or part numbers must not be missing

In cases of doubt concerning the work to be performed, the mechanic has to refer to written documentations. To just ask a colleague for clarification is by no means sufficient, as wrong or improper information could be passed on. − On the other hand such a conversation is advisable should the documents provide no specific details or only imprecise information. Communication between colleagues can often help to eliminate ambiguities. In general the shift supervisor is responsible for the provision of the means and tools necessary to perform the work. The supervisor usually delegates individual jobs to the members of his team. As an alternative the supervisor of course can delegate a complete work procedure to a team. In this case the individual members of the team will perform those jobs which correspond to his/her qualifications (CAT A, B1/B2 etc.) and experiences that have been acquired in a specific field of work. It is in the responsibility of the management to ensure every mechanic receives the training necessary for the performance of the tasks required of him or her:  Every individual mechanic is responsible for his/her decision as to whether or not he/she has acquired the necessary training and experience to deal with the desired task. In case the mechanic is not absolutely sure of that, he should not hesitate to mention his doubts even if he is subjected to peer pressure and additional pressure from the management. A ”good mixture” of mental and physical activities is important to avoid various aspects of exhaustion and stress. At best this should already be considered when planning the task, but at the latest it must be accounted for when realising the work demands on the technical object.





M.9

Figure 51

Task-Planning



CAT A/B1/B2

M.9 Physical work Maintenance work is a rather energetic activity and it requires a relatively high amount of physical energy from the employees. This applies for both, precision work with a high demand on fine motor skills and work which requires physical strength and thus a high demand on gross motor skills. The physical properties of people are different of course.

The attempt to lift an extremely heavy object is usually beyond our physical properties and might even lead to injuries. Many tasks are only possible with the help of suitable tools and devices (e.g. lifting heavy structural components) or they are facilitated in this way. The older a person gets, the stiffer the body and the weaker the muscles become. This increases the risk of injury and prolongs the healing time. Exercise can minimize this process, but the effects of aging cannot be eliminated all together. In the long run intensive physical work will lead to exhaustion. If the body is granted sufficient time for relaxation and recovery, this will not create problems. But when break−times are ignored in order to finish a particular job within a certain time, the result may well be injury instead of productiveness, because exhausting our motor skills to the limit will decrease our faculty of perception, our awareness and our work standards.


EASA PART 66

The amount of aircraft maintenance work has to be physically manageable for the staff. The Boeing company uses a computer program that is based on human performance data (average body size, strength etc.) and on the force that is necessary to create for example a certain leverage. The aim of the Boeing Company is to facilitate maintenance of modern aircraft by incorporating data on the physical abilities and capabilities of its staff.





M.9

Figure 52

Physical Work



CAT A/B1/B2

M.9 REPETITIVE TASKS

VISUAL INSPECTION

Monotonous activities may have a tiring effect and can decrease stimulation ( see chapter M9.4). Most scientific research on that topic has been done in the field of manufacture (assembly line) and thus is not easily transferable to aircraft maintenance. In maintenance the monotony is usually created by repetitive activities that have to be performed when doing a certain check, during shift−work, or during any other short period of time. The level of complexity of the respective tasks is of minor importance. The task ”checking life vests for completeness” during a night stop may prove as ”monotonous” as the fiftiest special check of a certain engine type. Routine is created by frequency and repetition. A positive development one may think. You can fully concentrate on the job (for instance an inspection) without having to think about the way it has to be done. But when routine arrives at the level that ”you feel like being able to do the work in your sleep” the danger of complacency is not to be disregarded.  Work procedures are consciously or unconsciously ”modified” in order to break away from the monotony.  The documentation is not used anymore or only in a superficial way.  Facts are being replaced by assumptions (we have never had a problem with that, so why should there be one today?)  ..............................................................................

Visual inspections are one of the primary methods to ensure the airworthiness of an aircraft. Visual inspections include simple pre−flight and post−flight checks, visual checks of components during large inspections up to detailed examinations using equipment like boroscopes. In addition to vision, the other senses are usually also required. Here is a simple practical example. Please find out which of your sensory organs you will need to use.




EASA PART 66

..............................................................................

Maybe you can think of similar reactions. In chapter M9.8 we deal with the problem of complacency in more detail. Monotonous activities are one source for this type of mistake.

Checking Point 1: examination of the elevator for... 

obvious damage



........................................................................... Clearance of mountings



........................................................................... Delamination of panels ...........................................................................

It is obvious that you will need functioning sensory organs (  see chapter M9.2) apart from other necessary gear (lights, mirrors, boroscopes) Visual inspections are a question of concentration. Similar to physical work, exhaustion will result sooner or later. Concentration decreases, perception and vision are limited. As a matter of fact a thorough inspection does not take place any more, although the respective area is still being looked at. A sensible change between physical and mental work can improve matters ( see task planning). A further aspect of visual inspections is assessment. Training, experience and common sense are important here. Those topics are also called ”situation awareness”.




M.9

Monotonous Tasks? Boroscope Check


Figure 53

Monotonous Tasks / Visual Inspections




M.9 Situation Awareness Situation awareness is an important topic in ”Human Factors” and is a complicated process that takes place in the attention, awareness and decision reaching areas in our brain. In the past the term for situation awareness was used only for cockpit personnel. Today it is also recognized in aircraft maintenance. Situation awareness can be divided into three stages:

SITUATION

Sensing

AWARENESS

Attention

The first stage is Perception − for example loose bolts and missing parts. This stage may involve listening attentively.  The 2nd stage of Situation Awareness is understanding: Why is it so? Is it the way it should be?  The third stage is Prediction: How will it develop? What effects can it have? ’Prediction’ can also look back and ask − What was the reason? Situation awareness in the technical field means: − recognizing the state of the system, − forming a relationship between defect and modification and − predicting the possible effect on other systems. 

Awareness

Short Term

Example The following example should help clarify the three stages of situation awareness. Look carefully at the picture and go consciously through the three stages.


1. Perception recognizes a blue−green smear along the side of the fuselage, beginning at the service panel and ending in the middle of the wing. 2. Our knowledge tells us that the service panel belongs to the forward toilet facilities. The aircraft is obviously losing a considerable amount of liquid. The pipe seal or the ”donut” is defective or completely missing. 3. The prediction is that the liquid could freeze and then blocks of ice could hit the engine or other components. Often it was only the ”donut” that was replaced. The nicks remained in the fan blades!

Decision

Memory Motor

Action

Neuron

Feedback

Long Term Memory

PERCEPTION

Situation

UNDERSTANDING: Why is it so? Is it the way it should be?

Awareness

PREDICTION How will it develop? What effects can it have?

Figure 54

Situation Awareness - Model




M.9

PERCEPTION

UNDERSTANDING


PREDICTION

Figure 55

Situation Awareness - Real Life



CAT A/B1/B2

M.9 COMPLEX SYSTEMS All modern aircraft can be seen as ”complex systems”. Within this system there are many individual systems and components which are complex themselves. This complexity will increase even more in the future, as the trend goes from mechanical operation towards advanced electronic systems. The future will be dominated by integrated mechatronics, which will be even more complex, although trouble shooting will be far easier. Operation of the elevator is used here to clarify this trend. Basic System Purpose, configuration and function of a basic system are usually easy to comprehend for an aircraft technician. Routine work, trouble shooting and diagnosis should be relatively simple − but the respective manuals must be consulted nevertheless.


EASA PART 66

Complex Systems When dealing with complex systems the aircraft technician must be familiar with the purpose of the system at least. Configuration and function are usually quite difficult to understand completely. In order to maintain such systems you need a specific training. Here it is important to observe a balance of detailed technical knowledge and analytic proceeding during trouble shooting. Manuals and released procedures are of an even greater importance than in the case of comparable basic systems. Today the documentation of the manufacturers is put together according to the most advanced standards. They enable the technician to perform his work or to facilitate it. Due to the linkage of individual systems one cannot be sure to understand everything in detail anymore. Thus we have to follow manufacturers’ instructions, but not without a critical attitude. Another aspect of this complexity is the necessary specialization of the technicians. In our example ”elevator operation” knowledge in the areas airframe/engine (EASA CAT B1) and avionics (EASA CAT B2) is required. Teamwork is absolutely necessary and its importance will be increased even more in the future. A single modern aircraft is usually complex enough − nevertheless the aircraft technicians are normally qualified for more than one aircraft type.

It will not be practicable to achieve the same level of familiarity with all these aircraft types − one more reason to adhere to the manufacturers’ instructions. Different ”philosophies” of the manufacturers have quite a share in the hazard potential as well. Here an example: In order to be able to lift a spoiler for maintenance purposes, a maintenance unlocking device (hex drive) is turned. This is almost identical on Airbus and Boeing airplanes. B757/767:  The cylinder is internally unlocked and hydraulically isolated and bypassed  The spoiler can then be lifted manually

Resetting of the cylinder is effected automatically when the spoiler is retracted again. A320:  The cylinder is hydraulically isolated and bypassed permanently.  The spoiler can be lifted manually  Resetting the cylinder has to be effected via the maintenance unlocking device (hex drive). 

Several incidents on A320 airplanes have been reported worldwide where the spoiler(s) where suction during approach (airspeed/ landing flap position) has caused the spoilers to lift. Sudden changes in the lateral attitude of the aircraft in proximity to the ground were the result (!) In almost all cases the technicians had achieved ”several years of experience with Boeing aircraft and had only recently finished an A320 training” (quote from the incident report).




M.9

? „Complex System“

Elevator Electronic Flight

Yoke „Sidestick“

(Boeing) (Airbus)

EFCS

Electrical Signal Aircraft Systems

Control

Hydraulic

System

Actuator (Servo)

Yoke

Elevator Autopilot Cables/Push-pull Rods Hydraulic Actuator (Servo)


„Simple System“

Yoke

Elevator

Cables/Push-pull Rods

Figure 56

Complex Systems


HUMAN FACTORS M9.7 COMMUNICATION


M.9

M9.7 COMMUNICATION Within and between teams; Work logging and recording;

Which of these methods is most important in aviation maintenance? Check the correct box.

Keeping up to date, currency;

Reading and Writing

Facial expresions

Speaking and Listening

Leg-, Arm-, Eyeand Head movements

Dissemination of information.

INTRODUCTION General Communication is a critical component of safe and efficient maintenance work. Communication issues are the number one type of cause of events in aviation maintenance. Therefore, this unit is very important. In it, we will discuss communication by offering a small amount of theoretical explanation and a number of practical ways to minimize communication−related issues. The list of results of poor communication is endless. A few examples are: Lower quality and performance, loss of time and money, unnecessary revisions, maintenance error, frustration, delays, personnel conflicts, and many more. Why is communication difficult? How do communication errors lead to so many errors in maintenance?


What does Communication mean? Communication is the exchange of informations between two or more persons. Among the many ways that humans communicate:  Writing and Reading;  Speaking and Listening;  Facial Expressions; 

Leg, Arm, Eye, and Head movements; and Body posture.

All of these methods are critical for effective communication. In each conversation we use wording, tone of voice and body language as so called ’non-verbal elements’. Assume a ’normal’ conversation. How much is transported by words and how much by non−verbal signals Your guess Words

%

Tone of voice

%

Body language

%

(Answer see next page)

100%




M.9 Communication model As a rule, communication is performed from  a sender (speaker, author, artist)  to a receiver (listener, reader, spectator). In order to make communication possible the sender has to translate his thoughts, messages or his knowledge into recognizable signals.  He has to encode them. The receiver has to understand the meaning.  He has to decode. The receiver is left to his own devices when doing so. The meaning he gives to what he hears depends on his former experience, his expectations and apprehensions. This way, some messages may be misunderstood. Some may not be understood at all. This makes it very important for the sender to make sure his messages are correctly understood. In every day life we can usually tell from the receiver’s reactions whether or not he or she has understood correctly what we tried to get across. But if we are dealing with information whose correct comprehension is vital.  We have to give or demand feedback.

Answer (from previous page)


Percentage (approx.)

Words

only 8 − 10%

Tone of voice

40%

Body language

50 − 52% = 100%

Sender

Receiver Feedback

Idea

Idea

encode

decode

Words

Words

Sender/Receiver Communication model



CAT A/B1/B2

M.9 Oral Communication Each verbal Communication process has three areas where you can actively make improvements: 1. Speaking (transmitting) 2. Listening (receiving) 3. Feedback (give and receive) Proper communication is important to each of us. Thus, as we are responsible for our communication, we need to make every effort to optimise it. There is a good rule for optimal communication. It is the rule of the ’Three C’s’. The ’Three C’s’ represent the three main principles of every communication: Clear − Correct and Complete.

An example: Mike: ”Hey, you over there, did you see the cut in the propeller?” Was that clear? No! At least 3 kinds of information are missing:  Which aircraft?  Which propeller?  Which blade? Clear communication is concrete and easily understandable. Was this correct? No! At least 2 questions remain:  Who is ”Hey, you over there?“ and,

at which part of the propeller is the cut? At the leading edge? At the trailing edge or at the blade tip? Correct communication is precise, and provides exact information without mistakes. Was this complete? No! Complete communication is thorough and explicit. So, when you meet Mike the next time, tell him to say: 


EASA PART 66

”John, on the aircraft ABC, did you see the cut in the Number 2 propeller, blade Number 3 at the blade tip?”

Whenever you communicate: keep it clear, correct and complete.





M.9

Rules for Speaking  Speak using the first person singular. This stresses that you take responsibility for what you say.  Be self confident. Express your thoughts and feelings clearly.  Speak for a purpose and make sure that everybody knows what your purpose is.  Consider the knowledge of your listeners and adapt your speech to it.  Use a positive body language. Address your listeners not only orally, but also with your gestures.

Rules for listening  Turn to the speaker.  Concentrate. What the speaker has to tell you should be important enough for you to listen to it closely.  Don’t interrupt. Don’t wait for the ”catchword” you always use to make your point.  Listen actively. Ask questions.

Figure 57

Transmitting and Receiving





M.9 Rules for feedback Feedback can be given and received. It is important that nobody tries to use the feedback procedure to get the better of others. If you do this, the person you are talking to will probably refuse to communicate with you any further.  Be conscious of place and time. It’s no use to show your feelings about something four weeks after the incident happened. People will not even remember the incident, leave alone understand your hurt feelings.  In addition to that you might have worked yourself in a rage over four weeks. This can make a matter of fact conversation difficult for you. You would have made the previous four weeks easier for you if you had reacted immediately.  When you are giving feedback you should be together with only those you are offering the feedback to and you should have enough time at your disposal. Don’t choose the breakfast break in the canteen when you are surrounded by the other colleagues.  Feedback is a personal process.




M.9

FEEDBACK

FEEDBACK

(IDEAL)

ASK FOR FEEDBACK


Message

Receiving feedback  Clarify the facts. Ask, if anything remains unclear.  Listen to the end before you answer. Don’t start preparing your answer before the other person has finished speaking.  Check if there is anything in the answers you can learn from.  Thank the person who gives you feedback It shows that you are important enough to him or her to care about you and your problems.

Figure 58

Giving feedback  Be precise. If you are vague you might not be understood.  Use the first person singular. You can only give your impressions, not those of others.  Speak for yourself only, do not generalize. It is unfair and will cause your partner to take up a defense position anyway.  Criticize behavior, not persons.  Be constructive. Try to make suggestions.  Show respect. Check on your motivation. Do you intend to help or to hurt?

Feedback





M.9 DISSEMINATION OF INFORMATION. Written communication - General In your work area the written word is as important as the spoken word. Job−cards, work plans, instructions for work procedures and log book entries are some examples for a communication that’s based on writing and reading. When writing a message you should observe the following: The text has to...  be readable  include all necessary information  be formulated clearly  be easily understandable  be free of emotions (at least in business matters) You shouldn’t neglect the following considerations:  What is the reader’s level of knowledge?  Is the reader familiar with the subject?  Does the reader understand your language?  What is the reader’s attitude? Written communication is more difficult than verbal communication. This is true for several reasons: There is limited feedback between the transmitter and the receiver. There are no spoken words or body language to provide critical feedback. The receiver cannot ask the transmitter to clarify. Therefore, you must be aware of these challenges when you write a message to someone.

The rules for written communication also apply to electronic communication. First of all, treat an E−mail as if it was a written letter that will be printed and sent for many to see. Never write an E−mail when you are angry. Cool off before you send a message that you may later regret. Be careful to check the addressee so as not to send the message to the wrong person. E−mail messages should be short and to the point. Again, when you write an E−mail it is good to remember the 3 Cs: Correct, Clear, and Complete.



CAT A/B1/B2

M.9 Shift Turnover & Log Book-Entries Communication is critical to safe and efficient shift turnover.  Create an organized routine for shift change.  Try to meet in the same location each day.  Know the persons who are responsible for communication of information.  Complete all job card written documentation so that all information is available.  Describe what has been done and what must be completed.

Make special note of any tasks that may not be documented on the job card, such as installing a warning flag on components or switches.  When an uncompleted task crosses shifts it is especially important to communicate the status of the job. Thus, shift turnover is not only a time to say hello to colleagues, but also to communicate critical job−related information. 


EASA PART 66

Another important form of written communication is the log book entry. This document is the ”Medical History” of the aircraft. The captain will rely on it to assess the condition of the airplane. Maintenance uses the documentation to determine whether the airplane can be released to service again.  It must be clear, correct and complete.  Do your very best to follow the company procedure on log book completion.  Take your time, and complete the logbook with attention to detail. Most of the errors are caused by carelessness. The common mistakes are: illegible handwriting, imprecise or incomplete descriptions or citation of incorrect ATA chapter. Safety is dependent on all of your work tasks including the ”Paperwork”. Treat written communication as a critical safety item.


HUMAN FACTORS M9.8 HUMAN ERROR


M.9

M9.8 HUMAN ERROR Error models and theories; Types of error in maintenance tasks; Implications of errors (i.e accidents) Avoiding and managing errors.

ERROR MODELS AND THEORIES General To err is human. As humans we make mistakes. No matter how we try, that will never change! However, as aviation maintenance personnel you must take the proper steps to minimize error.  It is a matter of safety!  It is also a matter of pride in your work and a matter of cost control for your company.

Concept developed by Gordon Dupont

To minimize error, it is necessary to understand error. This unit will first define error. Then, the section will offer graphical models to help you visualize error. Finally, the section will show you the 12 most common errors that humans make, and will offer guidelines for minimizing such errors.


Throughout the human factors training you may hear the words ”Dirty Dozen.” The Dirty Dozen is a listing of the 12 most common causes of human error in maintenance. The concept was developed by Mr. Gordon Dupont at Transport Canada.

Gordon Dupont, Transport Canada




M.9

To Err is Human!

MAINTENANCE ERRORS COST MONEY!!

SAFETY FACTOR minimise Error

As humans we make mistakes - that will never change!

Error containment

1 2 y l n O s e s o p r u P g n i n i a r T r o F

3 4 5 6

EXAMPLE: Look at this easy example of one bolt with many nuts. This nut and bolt assembly can only be disassembled one way. However, there are over 40,000 combinations for reassembly, of which only one is correct! This is a good example of the complexity, and chance of error, in aviation maintenance environments.

Figure 59

Human Error





M.9 SWISS CHEES - MODELL Professor James Reason, a Psychology Professor at the University of Manchester in the United Kingdom, uses Swiss cheese to explain safety. His ”Swiss Cheese” model is shown. The holes represent ”gaps” in the safety system.  The gaps may be caused by individuals or by the organisation.  With Swiss cheese, and with airline maintenance, it is very rare that all of the holes align. The holes in the Swiss cheese can also be called ”Contributing Factors” that lead to an event. The solid, more substantial portion of the cheese represents the many safety systems or ”defences” that stop the danger arrow.  The solid portion of the cheese can be called the ”preventative or corrective actions” that prevent the danger arrow from penetrating the pile of cheese. Remember this model as you learn about minimizing human error.




M.9

Gaps Preventive or Corrective Actions Contributing Factors Defences - inadequate

Individual

Interactions with local factors

Organisation

Productive Activities - unsafe acts


Preconditions - „psychological“ precursors of unsafe acts Line Management - deficencies

Event (Arrow)

Figure 60

Management - failable decisions

„Swiss Cheese“ Model



CAT A/B1/B2

M.9 TYPES OF ERROR How is ERROR defined? There are many definitions of error, only a few of which are offered here. Generally an error is ”an unsafe act unintentionally committed”. In other words, we don’t err on purpose! An error can be a slip or a mistake. Think about it.  A slip (and lapse) is merely a good plan poorly executed. For example, you read a torque value from the job card and you transposed 26 to 62.  A mistake is a ”bad plan”. For example, you select the wrong work card to conduct a specific job. Much of the information on the card may not apply to the work task.  

Activer Error

Latent Error

A violation is a very serious mistake. Contrary to mistake or slip, a violation is always conducted willingly (on purpose or intentionally) NOTE: ’good intentions’ - may have the same result as ’bad intentions’!

A violation occurs when you deviate from; − safe practices, − procedures, − standards, − or regulations. What are the different kinds of error? The first type is active error, or the specific individual activity that is an obvious event. The second type is latent error, or the company issues that lead up to the event. In this example the active error was falling from the ladder. y l n O s e s o p r u P g n i n i a r T r o F

EASA PART 66

The latent error was the broken ladder. Someone should have replaced the broken ladder, or the mechanic should have chosen not to use it. When you see latent conditions that may lead to error you should report them.

Figure 61

Active vs. latent Error




M.9

SLIP (LAPSE)

MISTAKE Unintended actions Transposed numbers

Error Type

Root cause

SLIP

Awareness

LAPSE

Memory

Rule based MISTAKE

Routines / Patterns of behaviour

Knowledge based MISTAKE

Knowledge and problemsolving strategies

VIOLATION

Motivation - good / - bad intentions

VIOLATION

Used wrong Task Card


Did NOT use a Task Card at all!

(SABOTAGE) Intended actions

Figure 62

Error Types

Motivation



CAT A/B1/B2

M.9 DIRTY DOZEN We all make the same kind of errors and we are all human. ”To Err is Human.” Throughout the human factors training you may hear the words ”Dirty Dozen” many times. If we could eliminate or control these 12 causes of error we would eliminate a very high percentage of maintenance−related events. We will look at each factor that contributes to an error, and offer possible corrective actions to prevent such error. By the end of your Human Factors training you should remember many of these errors, and also know the best methods for preventing them. The following is a listing of the Dirty Dozen:            


EASA PART 66

Lack of communication Lack of teamwork Norms Pressure Complacency Lack of knowledge Lack of awareness Lack of ressources Distraction Assertiveness Fatigue Stress




M.9

Lack of Communication Lack of Teamwork Norms Pressure Complacency Lack of Knowlegde Lack of Awareness Lack of Resources Distraction y l n O s e s o p r u P g n i n i a r T r o F

Lack of Assertiveness Fatigue Stress

Figure 63

Dirty Dozen




M.9 LACK OF COMMUNICATION Communication errors are the most common type of error. There are many opportunities to fail in communication. You must be continuously aware of the communication challenge, therefore a whole chapter (M9.7 Communication) deals with this factor exclusively. Tips What are some of the corrective actions that can be taken?  First of all: Be aware of the challenges.  Remember that complete communication requires a transmitter, a receiver and feedback. All three are important!  When you communicate, remember the 3 C’s: Correct − Clear − Complete.  Assumptions are dangerous. Try to avoid assuming that your message was understood. Be sure by looking for the feedback.

LACK OF COMMUNICATION

YES! I checked the oil

BILL! Are the screws tightened

Continental Express - EMB120 - 1994






M.9

Figure 64

Lack of Communication





M.9 LACK OF TEAMWORK Maintenance requires teamwork. ”Lack of Teamwork” is another of the Dirty Dozen. Lack of teamwork is the failure of a group to work together to achieve a common goal. Tips What are the Corrective Actions for Lack of Teamwork?  Communicate the group goal. − Make sure that everyone understands what is going on. − The team leader should promote this understanding.  Recognize that the team’s success is a shared success.  Recognize that each person must contribute to the team goal.  Do you give your best effort to serving your customers? You must remind yourself to treat your teammates the same as your most important customers.  A good team should communicate the challenges. When something goes wrong it should be discussed, not ignored.

LACK OF TEAMWORK





M.9

Figure 65

Lack of Teamwork





M.9 NORMS Norms are the commonly accepted work practices within an organization. Norms are not usually written down − they are simply the methods by which the organization works. Often „norms“ are bad practices, bypassing „inconvenient procedures“ but there are examples of „good norms“ as well. Here is an example of a good norm for shift turnover.  (Klaus): ”Hi Stefan, let me tell you what we did today and what are the next tasks. We also wrote this information on the job cards”  (Stefan): ”Thanks Klaus, I want to be sure I understand this so I can explain it to the team. By the way, are the lock pins and power−on warnings installed as usual?”  (Klaus): Also Stefan, remind everyone that the lock pins for the thrust reverser are hard to see, and must be removed before the aircraft is ready for service. I also wrote that down.”  (Stefan):”OK Klaus, have a good evening and I will see you the same time tomorrow.” Tips Now let’s look at some of the corrective actions for bad norms. Remember that a violation was defined as a disregard of regulations and operating procedures. Often the difference between a norm and a violation is based on whether or not there is an incident. If you do something merely ”because everyone does it that way” you may be subject to legal action.  Therefore, a corrective action may be finding proper documentation for the norm.  It is OK to ask why a procedure is not documented. There should be a reasonable answer or you should not follow the action.  Pressure from your co−workers can force you to follow undocumented procedures.  Assume leadership. Be assertive and push for converting the good norms to good written procedures. Finally, adopt the ”Good Norms”.

NORMS

Chickago, 1979 American Airlines DC10





M.9

Figure 66

Norms



CAT A/B1/B2

M.9 PRESSURE There is often pressure in maintenance, which can come from many sources. Often, you put the greatest pressure on yourself. You You press yourself for high quality performance in minimal time. Your managers may apply pressure. Pressures to meet a deadline are the most common. And, your co−workers may also apply pressure. They can create a sense of urgency that forces you to work at a pace faster than you are comfortable with. Conditions cause pressure. The closer it gets to departure the more pressure builds up to get the task completed quickly. quickly. So, pressure is one of the dirty dozen. It is a possible contributing factor to an event. Tips We have established that negative pressure can have negative consequences on your maintenance work. It can lead to error, but you can control it. What are the Corrective Actions for Pressure?  First, when pressured, stop and assess the situation. Be rationale. Cool down - ”Chill”.  Remind yourself of the consequences of error.  As the saying goes, ”If you do not have time to perform the job correctly the first time, how will you have time to redo the task?” Haste makes waste. waste.  Don’t let pressure become the norm. If there is always undue pressure, it becomes a condition that is setting you up to fail.  Bring the situation to management attention.

The Airline industry will always have daily pressures, but you must do your best to ensure that the pressure does not affect system safety or efficiency. y l n O s e s o p r u P g n i n i a r T r o F

EASA PART 66

PRESSURE





M.9

Figure 67

Pressure



CAT A/B1/B2

M.9 COMPLACENCY

COMPLACENCY

Complacency can contribute to a maintenance event when the mechanic is overconfident about a task. This is usually a result of performing the tasks repeatedly. Psychology experts say that many tasks become ”Automatic”. Like driving to work, you sometimes can forget the trip. That is because you were on ”Automatic.” You may have been inattentive. You have been ”unsafe.” Most likely you were Complacent! Tips What are the Corrective Actions needed to avoid errors of complacency?  You should remind yourself to be aware of complacency.  Continued use of Job Cards is a good way to avoid complacency.

Ask for check by colleagues. Rather think:“...today I will detect something...“ The error of Complacency can be minimized. You must remind yourself, or an unsafe event may be the grim reminder of complacency.  


EASA PART 66

...LIKE ALWAYS...





M.9

Figure 68

Complacency



CAT A/B1/B2

M.9 LACK OF KNOWLEDGE Lack of knowledge is one of the 12 common mistakes that contribute to events, but is rather rare. However, the Lack of Knowledge factor is usually compounded by a worker’s failure to consult the manual, or failure to work as a team, or failure to communicate the lack of knowledge. Fatigue may also contribute to a Lack of Knowledge error type. Tips

Lack of knowledge should not be an error in today’s aviation maintenance. There are many ways to avoid such error. What are the Corrective Actions for Lack of Knowledge?  First of all, strive to recognize what you do not know. When something is unfamiliar, acknowledge that you need assistance.  Often your co−workers are the best source of new knowledge. They can offer explanations and can show you how to do a task.  Use the manual. If you have the appropriate type training you can read the manual to learn how to do a job.  If you have many situations where you lack appropriate knowledge, you may request additional training.  Don’t let lack of knowledge become a company norm. If many people lack knowledge, then additional training is necessary.


EASA PART 66

LACK OF KNOWLEDGE





M.9

Figure 69

Lack of Knowledge



CAT A/B1/B2

M.9 LACK OF AWARENESS Lack of Awareness is an error that is often combined with other errors in the dirty dozen. Quite simply it can be called ”Failure to Pay Attention.” All too often, an event investigation will result in quotes like the following: ”I was not paying attention,” ”I did not see the obstacle,” ”I did not notice the wing tip was so close to the hangar door.” Whatever the confounding excuse, usually the person acknowledges that there was a lack of awareness. Tips Lack of Awareness is a challenge that can be overcome. What are the Corrective Actions?  First of all, and most simply, remain alert to workplace conditions. Maintain situation awareness by observing conditions, knowing what they mean, and project to the impact of the conditions.  For example, if you recognize a close clearance between equipment, buildings, and aircraft then you should project the potential danger and remain aware of it.  Cooperate with colleagues to maintain awareness. Help one another.

Lack of awareness does not have to be a common error. However, you must work hard to maintain constant awareness of the maintenance work environment.


EASA PART 66

LACK OF AWARENESS





M.9

Figure 70

Lack of Awareness



CAT A/B1/B2

M.9 LACK OF RESOURCES Lack of Resources is often cited as a reason for error. Resources can mean many things: tools, manuals, computers, people, time, and more. Lack of Resources is likely to become a problem when it is combined with other errors in the Dirty Dozen. For example, if you need a part or a tool that is not available, then you must speak up. You must be assertive, you cannot be complacent, and you must not become a victim of pressure or of schedules. You must do the job correctly. When there is a lack of resources you must be realistic about the situation and find the best legal and safe way to get the aircraft back in the air. Tips What are the corrective actions for lack of resources?      


EASA PART 66

First of all, you must be realistic and accept that resources are not unlimited in any organization. However, you have the responsibility to decide which resources are imperative for safety. That minimum cannot be compromised. Good job planning can reduce resource challenges. Order stock and special tools before you start the job. Have a means to pool parts and to get them quickly. Work the resource logistics with planners. Don’t let lack of resources become your workplace norm.

LACK OF RESOURCES TIME

TOOLS COMPUTERS

MANUALS

PEOPLE

MONEY





M.9

Figure 71

Lack of Resources



CAT A/B1/B2

M.9 DISTRACTION Jobs and life are full of distractions! That is why ”Distraction” is another of the Dirty Dozen. Distraction can come in the form of thoughts, noise, bright lights, people, radio messages or telephone calls. Since you cannot easily eliminate distractions, you must accept them and find ways to cope with them. Tips

”Keep your mind on the job.” ”Concentrate to avoid distractions”. That is easier said than done. Whatcan be done to overcome Distractions?  Beware of other dirty dozen errors. If you are pressured, fatigued, or lack assertiveness, then you are more likely to be bothered by distractions.  To avoid error, finish a task before you attend to the distraction.  If you leave a task unfinished, mark the task as incomplete.  Try to avoid stopping before the final step.  When you return to a task that was interrupted, go back a few steps in that task to check that everything was completed.  When you know that you have mental distractions, then ask a colleague to check on you, and you can also check on yourself. Recognize that mental distractions can cause work problems.  Again, use the checklists and the job cards to help ensure that you completed the job correctly, in spite of the complications.


EASA PART 66

DISTRACTION





M.9

Figure 72

Distraction



CAT A/B1/B2

M.9 LACK OF ASSERTIVENESS Assertiveness is a good thing! It means that you speak up when you believe it is necessary. When an assertive worker sees an opportunity, they bring it to the attention of their co−workers or the management. There are times when assertiveness is an absolutely necessary part of aviation safety. Tips What are the corrective actions needed for assertiveness?

Usually you must speak up to assert your opinion. Do it politely and at the right time. − If you speak too soon you may be embarrassed. − However, if you wait too long you may not be able to properly influence the situation.  When you do speak up, follow the ’3 Cs’: Clear, Correct, and Complete.  Sometimes your actions show your assertiveness. That is demonstrated when you insist on doing a job properly, or by refusing to do a job in a manner that is unacceptable to your standards.  Sometimes you must document situations to show assertiveness. For example, you write in the logbook only the items that you believe to be air worthy. Assertiveness is a good thing. It is not to be confused with stubbornness, aggressiveness, bossiness or other negative characteristics. 


EASA PART 66

LACK OF ASSERTIVENESS





M.9

Figure 73

Lack of Assertiveness



CAT A/B1/B2

M.9 FATIGUE ’Fatigue’ is one of the dirty dozen errors that we make in maintenance. It is a potential problem for many. Fatigue can be a serious on−going ’chronic’ problem or it may be ’acute’ − just caused by a few nights of missed sleep. Usually you make errors because you are fatigued. For example, you may forget to complete a task, you may be unclear in your communication, or you may be temporarily too lazy to do the job correctly. But fatigue is the real problem. When you are fatigued, your physical strength and mental ability are impaired. Fatigue can be managed, but first you must be aware of the risks. Tips What are the corrective actions for fatigue?  If you are fatigued you may not admit it, so be careful!  Remain physically active. When tired, get up and walk around, stretch at frequent intervals and engage in conversation if possible, take breaks, drink caffeinated beverages and lots of water, avoid the most tedious work when fatigued.  Work with colleagues and let one another know when fatigue may be a problem.  To minimize fatigue, review this list: − Get 7−8 hours of sleep every night. − Eat properly. − Exercise regularly. − If you are always tired you should seek professional medical care.


EASA PART 66

FATIGUE





M.9

Figure 74

Fatigue





M.9 STRESS Stress is a psychological and sometimes physical condition caused by some kind of ”stressor.” The stressor can be a once−only situation or it can be an ongoing one. For example, a short−term stressor may be a very difficult repair that must be done quickly. Once the repair is completed the stress goes away. An example of long−term stress could be a divorce situation or other personal problems. Like fatigue, there is short−term stress, called acute stress, and long−term stress, called chronic stress. Whether acute or chronic, stress can affect your life and your work performance. You must deal with it. What are the symptoms of stress? Different individuals may have different symptoms; however, many behaviours are reliable indications of stress. Usually you know when you are stressed. Stress may make you irritable. It may affect your memory, your ability to pay attention, or your ability to make rational decisions. Stress affects health. It may cause loss of appetite, headaches, stomach problems, and inability to sleep. Stress causes one to be nervous or restless. Stress can lead to alcohol or drug abuse. Obviously, all of these conditions may put at risk the quality of your work. Stress is often a part of daily life and therefore a part of work. While stress is not an error, it can lead to error. What can you do about it?  First of all, always be aware that stress can impact the quality of your work.  When stressed, you should slow down, or stop, and regain your composure. You should try to think rationally, not emotionally, about the situation. Sometimes you may want a ”TIME OUT” − a short break to think over the stressful situation. It is often helpful to discuss the conditions that are causing the stress.  You should ask your colleagues to monitor your work if you are stressed out.  Engage in physical activity − exercise relieves stress. Do not let a stress compound itself by performing poorly in your maintenance responsibilities.

STRESS





M.9

Figure 75

Stress





M.9 ERROR MANAGEMENT General Airlines are the safest mode of transportation. That is a FACT! However, incidents, accidents and events happen, albeit to a minute percentage of flights. The ”Event Investigation” describes a process that was introduced by the Boeing Company in the early nineties. The process is called Maintenance Error Decision Aid or MEDA for short. The prime philosophy is that we can learn a lot from our errors. MEDA helps us to document, classify, understand, and minimize our errors. There are other investigation programs available, which have a structured design to evaluate incidents. Which of the many programs is used within a maintenace organistation is rather secondary. MEDA is widely spread throughout the MRO community, therefor we will give a brief overview of its operation. We use the word ”Event” to include accidents and incidents where maintenance is a contributing factor. Iceberg Model The ”Iceberg Model” provides a rationale for recording and understanding human error using processes like MEDA. On a large iceberg, the tip of the iceberg is above the water level. The tip of the iceberg represents the one human error that causes a serious airliner event. At the large base of the iceberg are the multitudes of minor human errors that are committed daily within an airline maintenance organization. Most of these errors do not compromise safety but can cause large expenses of wasted time and resources. However, some are ”operationally significant” causing delays, cancellations or in−flight shutdowns. We must reduce the number of errors below the water level to reduce the serious events above the water level. By understanding our current errors we can prevent future errors.

MEDA MEDA - Philosophy: LEARN FROM ERRORS!




M.9

ICEBERG MODELL

Inflight loss of a Cowling (Exemplary): - Cowling was not locked properly!

1

Visible

Statistics How many delays in the past where caused by unlocked Cowlings?

? Please guess?


Unkown How many Cowlings were (resp. are) NOT properly closed?

0 0 6 . x o r p p a / 0 4 / 1 : r e w s n A

? Please guess?

Figure 76

Iceberg Model



CAT A/B1/B2

M.9 MEDA Prozess ”Maintenance Error Decision Aid” or MEDA is a process used to investigate human error. Many airlines and MRO customers support the development of the MEDA system with Boeing. The process is quite simple.  It starts with an identified error.  Then the ”Contributing Factors” will be identified. Usually there is more than one contributing factor.  In the last step you have to determine corrective actions. Thus, the combination of contributing factors and corrective actions are the basis for understanding and minimizing human error.

After the error is identified, you must identify the factors that contributed to causing it. Boeing offers 10 categories on the MEDA form. While the MEDA form is an excellent way to identify Contributing Factors, you may also choose to list any of the Dirty Dozen as contributing factors. An incident is usually a chain of events, and there is seldom one contributing factor. Therefore, you are likely to choose many factors. Consult the MEDA form to see all the contributing factors. Once you become familiar with these contributing factors you will be more aware of them when they appear in your work environment.


EASA PART 66

Each contributing factor has a reasonable set of corrective actions. Many of the corrective actions were described in the Dirty Dozen. Corrective actions are often specific to the individual workplace and are best determined once the contributing factors are identified. Your event investigation practice during the classroom training will help you practice ways to identify corrective actions.




M.9

Maintenance Error Decision Aid (MEDA)

indentified Error


Contributing Factors

Dirty Dozen

Figure 77

MEDA Process- simplified

Corrective Actions


HUMAN FACTORS M9.9 HAZARDS IN THE WORKPLACE

CAT A/B1/B2

M.9

M9.9 HAZARDS IN THE WORKPLACE Recognising and avoiding hazards; Dealing with emergencies.

INTRODUCTION General The Chapter 9.9 Hazards in the Workplace has many overlapping items with the subject ’Safety at Work’. ’Safety at work’ is a subject that puts the emphasis on the health and safety of the employee. The EASA/JAA requires that this topic be discussed in a ”Human Factors” course. We will only mention a few important points here, as there are a large number of training courses elsewhere on this subject. Safety at Work is not the absence of accidents, but the recognition of potential risks and the eliminating of those. The following possible hazards can be expected in Aviation Maintenance: (Hangar, Apron, Power Plant Testcell)  Noise (Fuel Tank)  Confined Spaces (Docks, Platforms, ’Cherry Picker’)  Heights (Liquids, Gases, other Materials)  Harmful Substances (supercool and hot Components)  Excessive Temperatures  Taxiing and towing of aircrafts  Propeller- and Jet-wash Many of these issues are discussed in Chapter M9.5 Physical Environment.


EASA PART 66

Responsibilities Safety at work is the responsibility of two parties:  the employer and the employee.

The Employer...  The employer must recognise potential hazards. If possible, he must remove them or limit them. In addition, he must inform the employees about them though suitable instructions or notices, and provide the necessary aid and protection. The employee...  The employee must report hazards when he sees them, take note of safety information and make use of the safety measures provided. This is controlled by national regulations and standardised in accordance with European harmonisation.

At most airlines, the people responsible for keeping the rules are: the safety engineer, the safety representatives, the works council, and the technical supervisory committee of the occupational insurers. Good question: Who is the safety representative in your field?



CAT A/B1/B2

M.9 RECOGNISING AND AVOIDING HAZARDS Typical accidents in Maintenance These points are at the top of the accident statistics at Lufthansa Technik and other maintenance companies. > The Head tossed against the Engine Cowling...    

> Tripping of a Platform, Ladder or Dock...    

> Various cuts in the handplam (e.g. working with sheet metal)...    

> Hydraulic Fluid irritates the eyes...  


EASA PART 66

 

Look at the four examples of accidents and think what could have been done to prevent them. If you put your knowledge into practice, you can avoid such accidents.



CAT A/B1/B2

M.9 DEALING WITH EMERGENCIES Dealing with Emergencies How would you behave in an emergency? Probably − run away. But where? It would be a good idea to memorise the alarm plan for your area. It shows the escape routes and the assembly points. It also includes a checklist for rules of behaviour. The most important points for general emergencies are: 1. Try to stay calm and think: What has happened? What are the dangers dangers for others and myself? 2. Report Report the emergency emergency.. 3. Make things safe: that means, among other things, the hazard, e.g. switch off the power source, rescue the person in danger, and think about yourself at the same time. Don’t try to be a hero. 4. Take care care of the victim victim and 5. Make yourself yourself available available,, and help in any way you can. Caution: Die recommndations here reflect on the Maintenance environment. Probably you may (or will) recall other priorties from general First Aid Training!


EASA PART 66





M.9

Figu Figure re 78

Deal Dealin ing g with with Eme Emerg rgen enci cies es

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TABLE OF CONTENTS M9 HUMAN FACTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

M9.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DISCIPLINES OF HUMAN FACTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . HISTORICAL REVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STATISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ACCIDENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INFLUENCE OF MAINTENANCE (3 STUDIES) . . . . . . . . . . . . . . . . . . EXAMPLES OF ACCIDENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SHELL - MODEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MURPHY’S LAW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2 2 4 6 8 10 12 14 20 22

M9.2 HUMAN PERFORMANCE AND LIMITATIONS . . . . . . . . . . . . . . . . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . THE FIVE SENSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SIGHT / THE HUMAN EYE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HEARING / THE HUMAN EAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INFORMATION PROCESSING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LIMITATIONS OF INFORMATION PROCESSING . . . . . . . . . . . . . . . . PHOBIAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24 24 24 26 28 30 34 36

M9.3 SOCIAL PSYCHOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MOTIVATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RESPONSIBILITIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PEER PRESSURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CULTURE ISSUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TEAMWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MANAGEMENT, SUPERVISION AND LEADERSHIP . . . . . . . . . . . . .

38 38 42 46 50 52 54 58

M9.4 FACTORS AFFECTING PERFORMANCE . . . . . . . . . . . . . . . . . . . . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STRESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WORKLOAD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FATIGUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ALCOHOL, MEDICATION AND DRUG ABUSE . . . . . . . . . . . . . . . . . . .

60 60 62 66 70 76

M9.5 PHYSICAL ENVIRONMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

82

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NOISE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FUMES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ILLUMINATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CLIMATE AND TEMPERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MOTION AND VIBRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DANGEROUS SONIC WAVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WORKING ENVIRONMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

82 84 86 87 88 89 90 91

M9.6 TASKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PHYSICAL WORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REPETITIVE TASKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VISUAL INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . COMPLEX SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

92 92 92 96 96 100

M9.7 COMMUNICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DISSEMINATION OF INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . .

102 102 108

M9.8 HUMAN ERROR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ERROR MODELS AND THEORIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . SWISS CHEES - MODELL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TYPES OF ERROR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DIRTY DOZEN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LACK OF COMMUNICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LACK OF TEAMWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NORMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PRESSURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . COMPLACENCY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LACK OF KNOWLEDGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LACK OF AWARENESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LACK OF RESOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DISTRACTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LACK OF ASSERTIVENESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FATIGUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STRESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

110 110 112 114 116 118 120 122 124 126 128 130 132 134 136 138 140

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TABLE OF CONTENTS ERROR MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

142

M9.9 HAZARDS IN THE WORKPLACE . . . . . . . . . . . . . . . . . . . . . . . . . . . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RECOGNISING AND AVOIDING HAZARDS . . . . . . . . . . . . . . . . . . . . . DEALING WITH EMERGENCIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

146 146 147 148

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TABLE OF FIGURES Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 2 2 Figure 23 Figure 2 4 Figure 25 Figure 26 Figure 27 Figure 28 Figure 29 Figure 30 Figure 31 Figure 32 Figure 33 Figure 34 Figure 35

Introduction to Human Factors (HF) . . . . . . . . . . . . . . . . . Disciplins of Human Factors . . . . . . . . . . . . . . . . . . . . . . . . Historical Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acident Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Accident Statistics - Boeing Study . . . . . . . . . . . . . . . . . . . 80 / 20 Rule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reasons for Accidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maintenance Influence on Incidents and Accidents . . . . . Aircraft Accidents/Incidents - Examples . . . . . . . . . . . . . . SHEL(L) Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Murphy’s Law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction / 5 Senses . . . . . . . . . . . . . . . . . . . . . . . . . . . Sight - The Human Eye . . . . . . . . . . . . . . . . . . . . . . . . . . . SIGHT - Negative Influences . . . . . . . . . . . . . . . . . . . . . . Typical Noise Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hearing - The Human Ear . . . . . . . . . . . . . . . . . . . . . . . . . Information Processing (1) . . . . . . . . . . . . . . . . . . . . . . . . Information Processing (2) . . . . . . . . . . . . . . . . . . . . . . . . Information Processing - Limitations and Tips . . . . . . . . Phobias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Social Psychology - Introduction . . . . . . . . . . . . . . . . . . . Organisational Influences on Employees . . . . . . . . . . . . Maslow’s Hierachy of Needs . . . . . . . . . . . . . . . . . . . . . . . Motivation (Maslow’s Hierachy of Needs) . . . . . . . . . . . . Motivation / De-Motivation . . . . . . . . . . . . . . . . . . . . . . . . . Individual Responsibility . . . . . . . . . . . . . . . . . . . . . . . . . . . Group Responsibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Peer Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Safety Culture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Group vs. Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maintaining a Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Leadership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Factors Affecting Performance . . . . . . . . . . . . . . . . . . . . . Stress - General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Negative Stress - Reactions and Counter Measures . .

Page: 3 Page: 5 Page: 7 Page: 8 Page: 9 Page: 10 Page: 11 Page:13 Page: 19 Page: 21 Page: 23 Page: 25 Page: 26 Page: 27 Page: 28 Page: 29 Page: 31 Page: 33 Page: 35 Page: 37 Page: 39 Page: 4 1 Page: 42 Page: 4 3 Page: 45 Page: 47 Page: 49 Page: 51 Page: 53 Page: 55 Page: 57 Page: 59 Page: 61 Page: 63 Page: 65

Figure 36 Figure 37 Figure 38 Figure 39 Figure 40 Figure 41 Figure 42 Figure 43 Figure 44 Figure 45 Figure 46 Figure 47 Figure 48 Figure 49 Figure 50 Figure 51 Figure 52 Figure 53 Figure 54 Figure 55 Figure 56 Figure 57 Figure 58 Figure 59 Figure 60 Figure 61 Figure 62 Figure 63 Figure 64 Figure 65 Figure 66 Figure 67 Figure 68 Figure 69 Figure 70

Workload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Over- and Underload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fatigue - Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Alertness / Circadian Clock . . . . . . . . . . . . . . . . . . . . . . . . Fatigue: Acute vs. Chronic . . . . . . . . . . . . . . . . . . . . . . . . Alcohol and its Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Medication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Work Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ilumination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Climate and Temperature . . . . . . . . . . . . . . . . . . . . . . . . . Motion & Vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dangerous Sonic-Waves . . . . . . . . . . . . . . . . . . . . . . . . . . Confined Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Task-Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Physical Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Monotonous Tasks / Visual Inspections . . . . . . . . . . . . . . Situation Awareness - Model . . . . . . . . . . . . . . . . . . . . . . . Situation Awareness - Real Life . . . . . . . . . . . . . . . . . . . . Complex Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transmitting and Receiving . . . . . . . . . . . . . . . . . . . . . . . . Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Human Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . „Swiss Cheese“ Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . Active vs. latent Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . Error Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dirty Dozen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lack of Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . Lack of Teamwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Norms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Complacency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lack of Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lack of Awareness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Page: 67 Page: 69 Page: 71 Page: 73 Page: 75 Page: 77 Page: 79 Page: 83 Page: 85 Page: 86 Page: 87 Page: 88 Page: 89 Page: 90 Page: 91 Page: 93 Page: 95 Page: 97 Page: 98 Page: 99 Page: 101 Page: 105 Page: 107 Page: 111 Page: 113 Page: 114 Page: 115 Page: 117 Page: 119 Page: 121 Page: 123 Page: 125 Page: 127 Page: 129 Page: 131

P66 A/B M9 E

TABLE OF FIGURES Figure 71 Figure 72 Figure 73 Figure 74 Figure 75 Figure 76 Figure 77 Figure 78

Lack of Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Distraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lack of Assertiveness . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fatigue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Iceberg Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MEDA Process- simplified . . . . . . . . . . . . . . . . . . . . . . . . . Dealing with Emergencies . . . . . . . . . . . . . . . . . . . . . . . . .

Page: 133 Page: 135 Page: 137 Page: 139 Page: 141 Page: 143 Page: 145 Page: 149

P66 A/B M9 E

TABLE OF FIGURES

P66_A_B_M9_E

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