Mass refers to the quantity of matter in a body as measured by its inertia
Holiday Charter
Mass & Mass & Balance Balance 1
Pax may be determined from from a verbal statement • Mass of individual Pax may
Other
< exceedi ng the the standard • Considerable amout of pax or baggage exceeding
Infant (0y ...2y) Child (2y ...12y)
masses: Operator should use individual masses or add an adequate mass increment graduations ations of 500g • Weighing machine for pax: Capacity !150kg; gradu liday Charter = 75kg • Max weight of cabin crew in 19-seat AC on Ho liday Charter Baggage = Personal belongings • Baggage = • Standard mass for baggage (15kg) may be used if >20 seats • If no carry-on baggage is carried: Subtract 6kg from standard masses
35kg; 1seat 83kg 69kg
Adult
84kg
or avg. of 76kg
Limitations Limitations Structural
Performance
Other
Limiting in “Hot & High” conditions
Regulated TOM = Lower of both structural and performance limited TOM
= MRM • Maximum certified Ramp (or Taxi) Mass • Mass an AC may be loaded prior to engine start • Fixed value listed in AC Flight Manual
Definitions Definitions
Ramp Mass - RM
Taxi Fuel
Takeoff Mass - TOM
= MTOM • = max. permissible total AC mass @ start of TO run • May not be exceeded on any TO • Normally the limiting factor on TL on long distance flights
Traffic Load (TL) TL)
• Trip Fuel (TF)
)
L U
Operating Mass - OM
Takeoff (useable) fuel (TOF ( TOF))
( d a o L l u f e s U
Takeoff (useable) fuel (TOF ( TOF))
• Usable TOM: Consider MLM + Fuel burn
Landing Mass - LM • Contingency • Alternate • Final reserve
• Passengers • Cargo
Traffic Load (TL) TL)
= MLM • If exceeded, undercarriage could collapse on LDG
Zero Fuel Mass - ZFM
= MZFM
• AC mass with no USEABLE fuel
• Structural limit due to max permissible bending moment
If AC < max. structural LM but > max. performance limited LM:
• Tire temperature limits could be exceeded • Runway may be too short • No go-around possible •Structural fatigue increased
•Limited by strength of runway •Amount of fuel to jettison: To a
safe level at or below regulated Landing Mass
@ wing root (on AC without central tank)
• Imposes fuel dumping from the inner wing tank first • Regulatorylimitation • Calculated for a LF of +2.5g • Fixed value stated in AC Operating Manual TL on short legs with minimum fuel •Limiting factor on TL on
• Operator must establish
TL by actual weighing or in accordance with standardmasses specified in JAR-OPS Part J
Responsibility for determination lies with the operator!
Aircraft must be weighed:
Specific equipment integral to the particular aircraft configuration
plus or minus 0.5% of the maximum landing mass
•
determined prior to initial entry into service and thereafter at intervals of 4y if 4y if no modifications have taken place. Where an operator uses "fleet masses" and provided that changes have been correctly documented, this interval is 9y for 9y for each aeroplane.
• It is not required to drain all engine tank oil or fuel tanks • Must take place in an enclosed, non-air conditioned hangar • With a minimum of three points of support • Aeroplane has to be clean and equipment complete for weighing
Basic Empty Mass - BEM • = Weighed Mass • Determined by manufacturer • Found in the latest version of the weighing schedule as corrected to allow for modifications
or modifiactions
• If the cumulative change in CG position exceeds 0.5% of the MAC • If individual masses are used the mass of an aeroplane must be
operation
• Crew baggage
• On initial entry into service alt eration ons s • If the mass and balance records have not been adjusted for alterati ass exceed • Whenever the cumulative changes to the dry operating m ass exceed
Mass & Balance 2 The Datum is the point on the aeroplane designated by the manufacturers from which all CG measurements and calcuations are made. Its position is given in the aeroplane Flight or Loading Manual. It is located at a convenient point which may not physically be on the aeroplane. The datum is a fixed vertical plane from which all the arm distances are measured
CG in %MAC
CG (MAC) =
is the location of CG in relation to the Mean Aerodynamic Chord of the wing. Loads must be adequately secured in order to avoid 0% unplanned CG movement and aircraft damage.
Center of Gravity (CG)
Changing tailplane incident angle does not change CG position!
Total MAC
MAC 50%
25%
75%
100%
CG
LE
CG location is calculated/measured along the longitudinal axis
Distance: Leading Edge (LE) - CG
range is between front and rear CG [ CG safelimits ] and includes both limits
A location in the aeroplane, identified by a number designating its distance from the datum = A Station
Standard CG Calculati on Walkthrough
•= the point of a body through which the sum of the forces of all
1.Calculate Moment = Arm * Force for all stations
masses is considered to act •= the point where all the aircraft mass is considered to be concentrated
2.Add up all moments => Total Moment (taking out weight = negative Moment!) 3.Add up all forces (weights) => Total Weight 4.Calculate CG position with Arm = Total Moment / Total Weight
Weight •Acts in a direction parallel to the gravity vector •On ground or in level, non accelerated flight vertically through CG
Units •If the actual fuel density is not known, conversion from volume to mass can be done by using std. fuel density according to the OM •1US.gal. = 3.785l = 0.833Imp.gal. = 6lbs AVGAS •1kg = 2.2lb
Moment • All moments turning clockwise arund datum are positive;
• If all moments given are positive, the datum must be at the nose or in front of the AC
=
Arm = Moment Arm = Balance Arm
*
Force use N or kg consistently!
= Horizontal distance from Datum to CG
Other •Once the mass and balance documentation has been signed prior to flight, acceptable last minute changes to the load must be documented •Index Method: In Mass and balance calculations the index is the moment divided by a constant
