Q400 Manual

Q400 Fuel Efficiency Manual

S T N E T N O C

2

1. Introduction

3

2. Abbreviations

5

3. Summary of Techniques

8

4. Flight Planning

11

4.1 Aircraft Weight

12

4.2 Center of Gravity (CG)

14

4.3 Auxiliar Auxiliary y Power Unit (APU)

14

4.4 Taxi

15

4.5 Take-Off

17

4.6 Climb

17

4.7 Cruise

19

4.8 Descent

23

4.9 Optimum Cruise Altitude

25

4.10 Fuel Reserves and Contingency Fuel

27

4.11 Flight Planning Example

28

5. Higher Resolution of SAR Data Using Cost Index Tables

30

6. Flight Managemen Managementt

35

6.1 Enroute Winds

36

6.2 Performance Monitoring

37

6.3 Approach and Landing

38

6.4 Tankering

38

7. Maintenance

39

7.1 Airframe Maintenance

40

7.2 Engine Maintenance

40

7.3 Dispatch under MEL and CDL

42

8. Conclusion

45


3

INTRODUCTION


N O I T C U D O R T N I 0 . 2

B

ombardier’s Q400 NextGen turboprop NextGen turboprop aircraft has benefited from an ongoing program of investment and continuous improvement. Since 2000, when the Q400 Q400 entered entered service, the price of fuel has risen significantly. Airlines are continually seeking solutions to counter the impact of rising fuel costs and economic challenges. Bombardier has developed a broad range of solutions and countermeasures to the rising cost of fuel. The Q400 Fuel Efficiency Manual serves as a guide for airlines to maximize their operational and performance techniques, enabling them to generate significant fuel savings across all mission profiles and phases of flight.

The Q400 NextGen airliner, NextGen airliner, which is built at Bombardier’s Toronto, Canada facility, is the most recent development in the evolution of the Q400 Q400 aircraft, aircraft, and the advanced successor to Bombardier’s Dash 8/Q-Series family of aircraft. The Q400 Q400 airliner airliner was developed after the introduction of regional jets and is the only turboprop designed de signed to meet the modern mode rn definition of regional flying. Optimized for short-haul regional operations the 70-to-86seat Q400 NextGen aircraft NextGen aircraft is a large, fast, quiet and fuel-efficient turboprop. Now available with seating configurations up to 86 seats, the Q400 provides an un-matched combination of productivity, passenger comfort and operating economics with a reduced environmental footprint.

4


N O I T C U D O R T N I 0 . 2

The Q400 aircraft is most often used on routes of 200 to 500 NM. As a modern turboprop, it also has the speed and range to be deployed on routes up to 1000 NM. The Q400 aircraft’s maximum cruise speed of 360 knots TAS lets the aircraft fly on demand-driven interchangeable schedules with jets. But, throttle back to 280 knots TAS and the Q400 aircraft is the most fuel efficient turboprop on a per-seat basis, while providing advantages in operating cost, speed, passenger capacity and baggage capacity. The Q400 turboprop delivers the operational flexibility and operating economics to meet the needs of regional flying in the modern era. Setting new environmental standards, the Q400 aircraft uses 30 to 40 per cent less fuel and produces 30 to 40 per cent fewer emissions on routes where it has replaced similar-capacity, older jets. Importantly, the Q400 turboprops Auxiliary Power Unit (APU), located in the tail of the aircraft, vents its exhaust and noise upward, resulting in a better operating environment for ground crews. Overall, the Q400 aircraft is 15 decibels quieter than ICAO Chapter 4 noise standards; raising the bar for the entire industry. The Q400 aircraft is also participating in biofuel test programs that could make a significant contribution in reducing aviation’s carbon footprint. The Q400 aircraft’s high rate of climb, single-engine service ceiling, higher take-off weight (thus greater payload), optional drop down oxygen system and jetway-compatibile front air stair passenger door are important factors that contribute to its operational flexibility. In addition, the Q400’s industry leading navigation capabilities, such as WAAS/LPV, RNP AR, Heads-up guidance, Coupled VNAV etc contribute to the efficiency of operations and flight completion rates in challenging environments. The commercial aviation industry has gone through significant changes since the recent global recession. The industry’s unwavering focus on optimization and efficiency is the key reason for its resilience. Economic growth will drive the demand for more aircraft. Rising oil prices and continued price volatility will drive airlines to accelerate the retirement of older less efficient aircraft, thereby increasing the demand for new-technology and fuelefficient aircraft such as the Q400. The Q400 FEH will help airlines find the optimum fuel efficiency solutions for today’s challenges, and it provides the tools to adapt to tomorrow’s challenges as well.

5


6

ABBREVIATIONS


S N O I T A I V E R B B A 0 . 1

A/C AEO AFM AOM APU BA CG CI FPM FT, ft GPU HSC IAS IATA IFR ISC ISA KG, kg LB, lb LRC ME MCL MCR MIN, min MLG MMEL MRC MTOW NLG NM, nm OEI ROD RPM SAR SE TAS TOC TOD TOW USG

Aircraft All Engines Operating Airplane Flight Manual Airplane Operating Manual Auxiliary Power Unit BOMBARDIER AEROSPACE Center of Gravity Cost Index Feet Per Minute Feet Ground Power Unit High Speed Cruise Indicated Air Speed International Air Transport Association Instrument Flight Rules Intermediate Speed Cruise International Standard Atmosphere Kilogram Pound Long Range Cruise Maximum Endurance Maximum Climb Power Rating Maximum Cruise Power Rating Minute Main Landing Gear Master Minimum Equipment List Maximum Range Cruise Maximum Take-O ff Weight Nose Landing Gear Nautical Mile One Engine Inoperative Rate Of Descent Revolutions Per Minute Specific Air Range Single Engine True Air Speed Top Of Climb Top Of Descent Take-Off Weight U. S. Gallon

7


8

SUMMARY OF

TECHNIQUES


S E U Q I N H C E T F O Y R A M M U S 0 . 3

A

lthough fuel price and emissions costs have become very important operational factors, it is important to remember that a minimum fuel optimized operation is not necessarily the best for every operator, since there are factors and situations that can diminish or negate the fuel saving benefits, such as: • • • • • • • • • • •

Ineffective use of the APU Start-up delays and taxi speeds High time-related costs (maintenance, flight and cabin crew, leasing, etc.) Missing or unfiled ATC clearances Missing slot times Airspace access or overflight costs Passenger related delay costs (missing connecting flights) Not taking advantage of en-route winds Reduced weather avoidance capabilities Poor scheduling Crew understanding and compliance

For these reasons many operators use a minimum cost strategy. All aspects of fuel efficiency, such as fuel price, cost of emissions, fuel weight and tankering can be included in a Cost Index method, which is a method to minimize total operational cost as a function of all or a selection of operating variables. As the purpose of this manual is to focus on fuel efficiency, it will first show the minimum fuel techniques for ground operations and for each flight segment (climb, cruise, descent, approach and landing), with the understanding that optimizing each flight segment does not always mean that the trip is optimized; this is further explained in the flight level selection section. It is up to the operator or flight planning provider to use this knowledge and data to optimize the overall flight profile. Next, a few Cost Index methods are explained, followed by practical flight management recommendations and maintenance implications on fuel burn.

9


S E U Q I N H C E T F O Y R A M M U S

10

Summary – Fuel Burn Reduction Techniques12

Technique Aircraft Weight Management

Block Fuel Saving Potential Up to 1%

C of G Management

Up to 0.5%

APU Usage

Up to 0.7%

Single Engine Taxi

Up to 3%

Climb Technique

Up to 6%

Cruise Technique

Up to 12%

Descent Technique

Up to 5%

FL270 Operation

Up to 3%

Fuel Reserves and Contingency Fuel

Up to 1%

Higher Resolution SAR data

Up to 2%

Enroute Winds

Up to 15%

Visual Approaches

Up to 0.5%

Tankering

Up to 1%

RNP AR Approaches

Up to 3.0%

Airframe Maintenance

Up to 1%

Engine Maintenance

Up to 0.5%

0 . 3

1 2

Individual techniques are not additive and results will vary according to particular conditions Based on 500 NM


11

FLIGHT

PLANNING


G N I N N A L P T H G I L F 0 . 4

A

flight plan that is accurate in all its components (ground operations, climb, acceleration, cruise, descent, approach & landing, reserves and contingency factors) is critical for fuel efficiency. Optimized routing must be examined, taking into consideration any en-route fees that may be charged as a result of specific routings. Any optimization benefit must be balanced against the need for accurate and e fficient on-time performance for passenger movements and connections. The impact of a non-optimal flight planning or carrying unnecessary fuel is multiple: • cost of additional fuel • more emissions (CO2, NO) • additional fuel weight leading to reduced performance, in turn leading to further limitations and additional fuel required • payload reduction – when limited by MTOW

4.1 Aircraft Weight Aircraft weight is one of the key factors in determining the fuel burn. Starting with an accurate weight on the ground and continuing to have a correct fuel consumption and aircraft weight estimate for all flight segme nts will allow the aircraft route to be planned and flown effectively. As much as possible, it is recommended to reduce the aircraft weight, as any excess weight is always detrimental to fuel efficiency. The chart below shows the Block Fuel3 increment associated with TOW increase, for a medium sector distance (450 nm).

3

Block Fuel includes: start , taxi-out, take-o ff , climb, cruise, descent , approach, landing, taxi-in

12



13

For example, if take-off weight is increased by 1% from 58,000lbs to 58,580lbs and with a HSC setting the block fuel will increase by 0.51%, which translates into 16lbs of fuel. When the take-off weight is increased, there will be an increase in block fuel. The table below offers some examples of the fuel increase with an additional take-off weight increase of 1000 lb.

300 nm

450 nm

600 nm

LRC

16 – 20 lb

25 – 29 lb

32 – 39 lb

HSC

6 – 10 lb

7 – 13 lb

9 – 15 lb

An aircraft weight reduction can be achieved by minimizing each of its components: Operating Weight Empty (OWE), payload and fuel. The OWE is the Manufacturer’s Empty Weight (MEW) plus operational items. This would include flight crew and their baggage, passenger service items, manuals, galley supplies, carts, supplementary equipment, and consumables – food, water, etc. An audit should be conducted to ensure only essential items are carried. The following items could be minimized or removed entirely: • • • • • • • • • •

Old magazines and newspapers Empty galley containers, extra supplies Excess duty free material (consider removing this entirely) Extra water in storage tanks Pillows and blankets Excessive flight crew baggage Extra magazines, seatback advertising Heavy seats, carpets, spare equipment Flight manuals and documentation (consider an Electronic Flight Bag Potable water weight implications under normal and MEL use

The MEW tends to increase during operational life due to repairs, upgrades and moisture accumulation. These weight increments should be monitored and kept to a minimum. • Consider drying out insulation • Keep the aircraft clean and free of dirt (inside and out) • Infrequent lavatory servicing



14

The Payload weight (passenger + carry-on baggage + checked baggage) should be accurately assessed by statistical or other methods. • Where feasible, use actual weights of passengers and baggage • Assumed or average weights may be limiting • Optimize weight and balance calculations • Avoid zonal calculations due to curtailment requirements • More zones provide a more precise calculation The total Fuel quantity on board is discussed in Section 4.11.

4.2 Center of Gravity (CG) The Q400 AOM cruise data is produced based on the aircraft loaded to the Forward CG Limit. There is lower drag if the aircraft is loaded aft of the forward limit. The drag reduction improves the fuel burn by approximately 0.04% per 1% MAC change in CG position. That is approximately 0.76% fuel burn improvement in cruise for a CG shift from full forward (17%) to full aft (36%), for an aircraft weight of 28690 kg (63250 lb). The effect is reduced for lighter weights (linearly scaled by weight). For a 1 hour flight at MRC this translates in 3.6 kg (8 lb) fuel saved in cruise.

4.3 Auxiliary Power Unit (APU) The Q400 APU/Bleed combination uses an average 1.5 kg/minute (3.3 lb/minute) of fuel. The fuel burn is reduced by almost half when the Bleed Air is selected OFF. There is great potential to save fuel and reduce maintenance costs by reducing APU useage, and the useage of bleed air from the APU.

APU and Bleed Air (22 deg C)

103 kg/hr (227 lb/hr) or 1.7 kg/min (3.8 lb/min)

APU Only (22 deg C)

53.5 kg/hr (118 lb/hr) or 0.9 kg/min (2 lb/min)



4

Excessive use of the APU can be caused by the following: • • • • • • •

Inadequate SOP’s detailing the use of the APU Ground electrical power unavailable Ground air conditioning unavailable APU Bleed used on unattended aircraft APU Generator used on unattended aircraft Maintenance action using APU instead of Ground Power APU used for longer turnaround times (greater than 1 hour)

Consider reduction of APU usage when environmental conditions allow (sufficient ambient light and comfortable cabin temperature) and avoid early starting or running during extended turnarounds. Further, consider closing window shades/blinds to minimize thermal heating in the cabin . Ensure all vents are open in the flight deck and cabin to maximize the heating/cooling effects when the APU Bleed is operating. When available, the crew should consider the use of Ground Power Unit (GPU) and air carts when practical and economical, considering cost, time delays, and noise.

4.4 Taxi Engine Start Starting engines during the pushback phase, instead of at the gate may minimize the fuel burn. However, this would require the APU to be operating or would require a battery only start. Starting one engine at the gate while on ground power and then pushing back may be the best alternative and most efficient method. Delaying the start of the second engine until just prior to the completion of the pushback procedure will provide additional savings. Consider holding the start and pushback procedure if a departure delay is anticipated.

4

Sector distance: 274nm, cruise segment 197nm, fuel used in cruise: 1056lb

15



Single Engine Taxi The Q400 average fuel burn for Two Engine Taxi is approximately 12 lb/minute. The Single Engine Taxi Operations – Considerations and Procedures are presented in the Q400 AOM, Section 3.4.3.11. The potential fuel savings (for 1 engine operating, one engine shutdown) are on the order of 40% for the Start and Taxi fuel. For example, a standard departure that includes a two engine start followed by a 15 minute taxi will result in a fuel b urn of 92.5 kg (204 lb). A single engine start, followed by a 15 minute taxi and delayed second engine start will consume approximately 54.4 kg (120 lb) of fuel. Taxi-out When multiple runways are available, choose a runway that will minimize taxi and ground holding times. However, it may be more beneficial to choose a runway that is aligned with the initial en route heading, even though it may take longer to taxi. The fuel burn on the ground is much less than the fuel required to depart in the opposite direction and make the turn en route while airborne. Consider the use of intersection departures where applicable to minimize taxi time. Where possible, choose the most direct taxiing route from gate to runway. Taxi-in Single engine taxi operations could be employed during the taxi-in phase as well. A reduction in fuel consumption, pollution, noise and brake wear is possible. It is important that the flight crew consider taxiway surface conditions, taxi time, ramp and parking congestion before employing this strategy. When waiting excessively for a stand or gate after landing (after the AFTER LANDING checklist is complete), the crew may opt to select START/FEATHER on both Condition Levers. The loss of A/C power has no subsequent effect on the remaining taxi. The difference between DISC/1020 rpm and START/FEATHER is approximately 90 kg/hour (198.4 lb). Once the gate becomes available, return the Condition Levers to 1020 RPM and wait for the propellers to unfeather before continuing to taxi.



4.5 Take-Off Supplement 13 – “Reduced Power” take-off may result in lower overall engine operating costs as a result of the lower engine temperatures. The fuel burn benefits of the lower power settings become offset by the extra time required for acceleration on the ground and when airborne. The benefits of Supplement 13 are specific to the circumstances of individual airline operations.

4.6 Climb Q400 can continuously climb from SL to its maximum operational ceiling (25000 ft) for any combination of take-off weight, temperature and propeller RPM. No step climbs are required. The following climb techniques are currently provided in the Q400 AOM: • Climb Type 1 (High Speed): is using the most fuel but it takes more time and the longest distance to Top of Climb (TOC). • Climb Type 2 (Intermediate Speed): is a speed approximately halfway between Type 1 and Type 3 climb speeds, and the times, distances and fuel are approximately averages of the times, distances and fuel to TOC of Type 1 and Type 3. • Climb Type 3 (Low Speed): is using the least fuel, it takes the least time and the shortest distance to TOC (best climb gradient). • In addition, a Pitch Attitude climb (higher indicated speed, low pitch) is also considered, as some operators use this technique due to ATC/ operational considerations.

17


G N I N N A L P T H G I L F

The climb speed profiles are shown below, in Indicated Air Speed. The Constant Pitch Attitude climb and Type 1 climbs overlap or exceed (in some areas) the LRC speed. This suggests that for those conditions these high climb speeds are not the best for a minimum fuel technique, since the climb is performed at MCL (Maximum Climb power), a power rating which is higher than any cruise power.

6 . 4

In order to minimize fuel burn for the climb segment, the most fuel efficient is Climb Type 3. For example, using Type 3 climb instead of Type 1 from SL to FL 160 will save 217 kg (478.4 lb) – 206 kg (454.1 lb) = 11 kg (24.3 lb) which represents 5% in the climb segment. However, upon reaching the Top Of Climb, the cruise segment will have to be extended to reach the same point downstream of the Type 1 Top Of Climb. The overall impact of climb/ cruise fuel burn will have to be assessed when optimizing the flight profile. In addition, climbing at 900 RPM instead of 850 RPM saves fuel by an average 0.5% for the climb segment. The climb time, distance, and fuel data for all climb types are presented in the AOM for both 850 and 900 propeller RPM. With the same example conditions as above, but using 900 propeller RPM instead of 850 RPM, using Type 3 climb instead of Type 1 will save 213 kg (469.6 lb) – 201 kg (443.1 lb) = 12 kg (26.5 lb) which represents 5.6% in the climb segment.5

5

ISA, 850 RPM, 28000kg (61730 lb)

18



19

4.7 Cruise The Q400 AOM presents fuel flow, speed and torque in tabular format for specific weight, altitude and temperature increments for the following: • • • • • •

Maximum Endurance cruise (ME) Maximum Range Cruise (MRC) Long Range Cruise (LRC) Intermediate Speed Cruise (ISC) High Speed Cruise (HSC) Maximum Cruise Rating (MCR)

The tabular data in the AOM is derived from charts similar to the example provided below. This chart highlights the Specific Air Range (nm/lb of fuel) for 3 different weights, and is valid specifically for ISA temperatures at FL250. The various cruise speed options (listed above) have been added to the chart for convenience.

Weights

18000 kg (39683 lb)

24000 kg (52911 lb)

29574 kg (65200 lb)



20

The best cruise SAR (best fuel efficiency) is achieved at MRC speed as highlighted below. Simply put, it will provide the furthest distance traveled for a given amount of fuel burned. LRC has been historically defined as the speed above MRC that will result in 1% SAR reduction. The benefit of using LRC is that 1% of SAR is traded for 3% to 5% higher cruise speed. The minor fuel burn increase is offset by the increase in speed and cruise time reduction.

18000 KG (39683 LB)

Cruise Setting

Speed (KTAS)

SAR (nm/lb)

MRC

252

0.2107

LRC

271

0.2086

In contrast, the least fuel efficient but fastest jet-like operation is at MCR (minimum time). Flying at HSC will trade a small speed reduction (20 kt) for a significant SAR improvement (7%). The ISC makes a compromise b etween a fuel efficient operation and time efficient operation, and is defined as the average speed between LRC and HSC.



21

29574 KG (65200 LB)

Cruise Setting

Speed (KTAS)

SAR (nm/lb)

MCR

355

0.1426

HSC

335

0.1527

For a relatively short trip, Toronto (CYYZ) to Montreal (CYUL), the fuel savings achieved in cruise when using MRC instead of MCR is 24.2%6, for an increase in cruise time of 11.6 minutes (35.3%). Similarly, on a relatively long route, Toronto (CYYZ) to Halifax (CYHZ), the fuel savings achieved when using MRC instead of MCR is also 24%7. The increase in cruise time is 33.5 minutes (35.3%).

6 7

ISA , FL250 , 24000 kg cruise weight, 274 nm total distance (cruise portion 197 nm), Type 3 climb/descent ISA , FL250 , 24000 kg cruise weight, 697 nm total distance (cruise portion 569 nm), Type 3 climb/descent



If saving fuel in cruise is most important and overall flight time is not a concern8, the flight crew can use speeds even lower than MRC, leading to further fuel burn reductions. This is illustrated in the following chart, which is showing the same data as above, but presented in terms of fuel flow (lb/hr).

For flight planning (cruise segment only, or the climb/cruise/descent profile) it is important to remember that fuel consumption has to be continuously interpolated and integrated along the flight path using appropriate soft ware as the aircraft weight, speed, engine power and ambient conditions are continuously changing. The final results are not always intuitive or comparable when checking against discrete fuel consumption values or hand calculations. The data and discrete values are provided by Bombardier in the AOM. Bombardier has developed and is offering additional & refined performance data in our cost index data package.

8

Factors may include favorable enroute tailwinds, fixed arrival time, unavailable/early arrival slots; short sectors and short cruise sections; flight schedules; or to provide slower speeds, similar to competition turboprop aircraft.

22



4.8 Descent A properly planned and executed descent profile can offer some of the greatest fuel savings. The ideal profile would include an uninterrupted descent from cruise altitude without the use of any power. This is often unachievable in busy airspace. Descents that begin too early or late can also increase the fuel burn. If given a choice, it would be better to begin the descent early, rather than late. An early (shallow) descent affords the opportunity to regain the optimal profile and find savings in fuel. A late descent will require in increased rate of descent from the optimal profile, and this added energy would eventually have to be dissipated through alternative means – increasing drag, increasing propeller RPM, or a premature level off. The following descent types are currently provided in the Q400 AOM: • Descent Type 1, limited by a/c ROD=2000fpm and/or cabin ROD=300fpm • Descent Type 2, limited by a/c ROD=1500fpm and/or cabin ROD=300fpm • Descent Type 3, limited by a/c ROD=1000fpm and/or cabin ROD=300fpm • Descent Type 4, limited by a/c ROD=2000fpm and/or cabin ROD=500fpm • Descent Type 5, limited by a/c ROD=1500fpm and/or cabin ROD=400fpm The aircraft ROD and cabin ROD limitations are shown on the illustration below.

23



The actual descent speeds are shown below in Indicated Air Speed. The most fuel efficient descent segment is achieved with a Type 5 descent, followed sequentially to Type 1. Descent Types 4 and 5 provide an overall higher ROD and significant fuel savings, compared with Types 1 and 2 respectively (up to 40% when descending from FL250). However, these savings are reduced by a longer cruise portion as a result of the shorter descent segment. This is very similar to the “climb - cruise trade off discussed earlier.

In summary, various descent techniques can save up to 5% on fuel burn on a 500nm sector flight.

24



4.9 Optimum Cruise Altitude From a fuel efficiency perspective, the most important aspect is the block fuel optimization, not the individual flight segments optimization. For a fixed sector length, optimizing the individual flight segments does not translate into overall flight profile optimization. Similarly, when flying jet-like speeds and profiles, the most important aspect is the block time. For a given sector length, temperature and wind condition, the most important factor that impacts the block fuel and block time is the cruise altitude, as that defines TOC position, the cruise segment length and TOD point. To determine the optimum cruise altitude for each technique, the block fuel/block time charts are plotted for all sector lengths, altitudes, temperatures and winds, and the optimum altitudes for each technique (minimum block time, minimum block fuel) are selected for each combination of sector length, wind and temperature. The AOM optimum cruise altitudes for a minimum time technique are based on HSC. The minimum fuel techniques are based on LRC. The related performance is presented in Q400 AOM Section 5.2. As mentioned before, the only way to accurately perform these calculations and to integrate the optimum cruise altitudes is by using specialized route analysis software. To illustrate this concept (block fuel versus block time), data for different techniques related to the same cruise speed regimes as presented in the Cruise section (4.7) are shown below. The chart, for demonstration purposes only, shows a sector length of 600 nm and three possible cruise altitudes (FL180, FL220, and FL250) 9. • “High speed, short time” technique • ISC or HSC • CL1 / DC1 • “Fuel saving” technique • MRC or LRC • CL2 / DC2

9

Both chart assumptions consist of: ISA, 0 wind, IFR Reserves, 100 nm diversion, High TOW

25



26

•

From the chart above: For a 600 nm sector at FL180, it is possible to complete the “high speed” flight as follows:

Time

Fuel

Climb 1, ISC and Descent 1

133.7 minutes

2163 kg (4768 lb)

Climb 1, HSC and Descent 1

124.7 minutes

2358 kg (5198 lb)

However, for the same distance and altitude, the “fuel saving” flight results are:

Time

Fuel

Climb 2, MRC and Descent 2

157.3 minutes

2017 kg (4447 lb)

Climb 2, LRC and Descent 2

150.0 minutes

2035 kg (4487 lb)



Cruise at FL270: The Q400 maximum operational cruise altitude was recently increased f rom FL250 to FL270. The following chart shows the fuel savings that can be achieved when flying long sector distances at FL270.

For a typical 500 nm sector, fuel savings will equate to approximately 3%.

4.10 Fuel Reserves and Contingency Fuel Fuel reserves consist of holding fuel, diversion (alternate) fuel, contingency fuel and extra fuel. On many occasions reserve fuel estimates are conservative; in some cases the pilots will take extra fuel due to lack of confidence in the flight planning data, although most of the time the flight planning providers apply their own safety factors to cover various operational unknowns. The overall result is that too much reserve fuel is carried. Holding fuel should be estimated based on Maximum Endurance speed (ME) since this speed provides the minimum fuel flow. The holding fuel estimate should also be based on the expected weight at arrival, as the fuel burn for holding is less at lower aircraft operating weights. The expected holding altitude may not necessarily be at the standard 1500 ft ASL. If applicable, calculating the fuel burn at a higher assumed holding altitude will allow for less fuel to be carried. Holding data (including holding in icing with minimum speed required in icing) are provided in Q400 AOM Chapter 5.10.

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28

G N I N N A L P T H G I L F

Diversion fuel10 can be minimized in a similar manner to the sector fuel. This would include using a minimum fuel technique, and optimum cruise altitude selection for the distance and ambient conditions. Depending on the jurisdiction, choosing appropriate alternates (enroute alternates) allows a reduction of the contingency factor.

0 1 . 4

An accurate fuel reserve estimate should be tailored to route specific operational and weather conditions, and be very close to the minimum required by regulations.

Contingency factors are designed to account for meteorological variations and unforeseen operational constraints. One method to reduce the contingency factor is to take into account seasonal variations and statistical data obtained from performance monitoring for specific routes and flight profiles. Another method is to consider decision / diversion points along the route. Overall, contingency factors can be reduced from very conservative 5% or 6% to more accurate and realistic 2% to 3%. Extra (discretionary) fuel should not be added without a good reason, as it might duplicate reserve fuel components already accounted for in the flight planning, and unnecessarily increase to overall aircraft weight11 .

4.11 Flight Planning Example The flight planning example below illustrates the impact of using the fuel saving methods described in this manual. A typical high speed operation12 can be optimized for minimum fuel13 with the following procedures:

Fuel Saving Action

OWE reduction Payload estimate TOW

Typical High Speed Optimized for Operation Minimum Fuel

Savings kg/(lb)

Savings % of Block Fuel

17819 kg (39284 lb)

17690 kg (39000 lb)

-

-

8489 kg (18715 lb)

8339 kg (18385 lb)

-

-

29574 kg (65200 lb)

28476 kg (62780 lb)

-

-

10

Using the flight planning standard of 100 nm or actual diversion/alternates

11

Operators employing a Flight E ffic iency program highlight this topic as one of the most di ffi cult to convince Flight Crew to adhere to, but result in large savings. Flight Crew awareness and compliance is critical.

12 13

Sector length – 500nm, ISA, IFR Reserve – 45 min “Typical High Speed Operation” and “Optinized for Minimum Fuel” calculations are perfor med with the same route analysis program and database.


G N I N N A L P T H G I L F 1 1 . 4

Fuel Saving Action

APU Bleeds (ON/ OFF)

29

Typical High Speed Optimized for Operation Minimum Fuel

Savings kg/(lb)

Savings % of Block Fuel

34 kg (76 lb)

18 kg (39 lb)

16.8 kg (37 lb)

0.7%

93 kg (204 lb)

54 kg (120 lb)

38 kg (84 lb)

1.6%

Take-Off

42 kg (93 lb)

42 kg (93 lb)

Air Manoeuvre

28 kg (62 lb)

-

28 kg (62 lb)

1.2%

324 kg (715 lb)

375 kg (827 lb)

50 kg ( – 112 lb)

-2.2%

Cruise altitude

23000 ft

27000 ft

-

Cruise Speed/ Winds/CG

1335 kg (2944 lb)

897 kg (1977 lb)

439 kg (967 lb)

18.8 %

Descent Type/ ROD

318 kg (703 lb)

166 kg (365 lb)

153 kg (338 lb)

6.6 %

App./Landing/ RNP

89 kg (196 lb)

22 kg (49 lb)

67 kg (147 lb)

2.9%

Taxi-in (SE/AE Taxi)

93 kg (204 lb)

54 kg (120 lb)

38 kg (84 lb)

1.6%

Reserve altitude

5000 ft

10000 ft

817 kg (1802 lb)

Diversion fuel Contingency factor

Taxi-out (SE/AE Taxi)

Climb Type/RPM

-

-

-

-

-

532 kg (1172 lb)

286 kg (630 lb)

-

413 kg (912 lb)

362 kg (799 lb)

47 kg (103 lb)

-

6.00%

2.00%

Total Reserves

1359 kg (2997 lb)

924 kg (2038 lb)

Block Fuel

2329 kg (5135 lb)

1628 kg 700 kg (3590 lb) (1545 lb)

30.1%

Trip Fuel

2138 kg (4713 lb)

1502 kg 636 kg (3311 lb) (1402lb)

29.7%

Reserve fuel

-

-

-

-


30

HIGHER RESOLUTION OF SAR DATA USING

COST INDEX TABLES


X E D N I T S O C

The Flight Planning section presented fuel efficient methods for ground operation, and each individual phase of flight. These methods can be used either separately, or for trip optimization, within a simple (static) or a dynamic Cost Index solution.

0 . 5

Total Cost = Fixed Costs + Time Dependent Costs + Fuel Cost Cost Index is a concept or a tool used to minimize the total operational cost, not necessarily isolated to minimize fuel burn. Cost Index is defined as the ratio of time-related costs to fuel-related costs, and is specific to each operating environment and each operator, since every operator has different routes, marketing strategies and cost structures. Cost Index can be measured in: Cost ($)/minute : Cost ($)/kg fuel = kg fuel/minute For example, the ratio of “100 kg fuel : 1 minute” shows that from a cost perspective 100 kg of fuel can be traded for 1 minute of flight, or vice versa, while maintaining the same operational cost.

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X E D N I T S O C

The fuel related cost is really just the price of fuel on board; however the time dependent cost is influenced by many factors. The most important time dependent costs are related to: • • • •

flight crew salary and benefits maintenance and overhaul intervals missed connecting flights late flight charges and expenses

Each of these costs can be further analyzed and quantified. For example, the cost of an arrival delay (missing connecting flights): • can rise sharply in discrete steps and raise sharply to high amounts as more and more people lose connections • can be quantified and it can help to determine the recovery plan, and be modeled in a (dynamic) Cost Index, when fuel savings are negated by arrival delay costs

0 . 5

A modern, efficient and safe flight planning requires consideration of many operational aspects (weather, navigational data, airspace rules and restrictions) and advanced flight management (optimum vertical and horizontal flight profile, at optimum speed), as the optimum altitude and speed change with time, weight and weather. All the operational aspects c an be correlated with costs by using a dynamic Cost Index method. IATA14 identified that the main impediment for fuel efficient operations is the lack of sophisticated Flight Planning tools (i.e. Cost Index methods). Using Cost Index methods has the biggest savings potential once it is developed, understood and correctly implemented at each level/department in the organization (management/accounting, maintenance, flight planning, dispatch, flight crew) and continuously monitored and adjusted. With various Cost Index methods and other fuel saving initiatives, there is always a risk of confusion with regards to “who” is saving either fuel o r money, at what level and how, which can lead to conflicting strategies and overall inefficiencies. Flight crews need to be aware that a properly implemented Cost Index takes into account not only operational, but more importantly business decisions, and that they do not always have visibility to all the factors considered when required to fly a specific Cost Index.

14

Guidance Material and Best Practices for Fuel Management, 1st Edition 2004

32


X E D N I T S O C 0 . 5

If a Cost Index solution is developed, or the flight profile is already optimized either for minimum time, optimum cost or minimum fuel, it is detrimental if the flight crew deviates from the plan. However, the flight crew need to be aware of the plan, and be able to make good and safe decisions when operational restrictions or weather changes require deviations. Ideally, the crew should have the Cost Index tools (FMS, EFB , in-flight support from ground stations, etc.) and the capability to re-optimize when flight milestones or enroute changes occur. A sophisticated, dynamic Cost Index solution is a software solution that can access and use performance, financial, weather and operational data in real time. Bombardier has made available a detailed Cost Index performance data package to support flight planning/cost index solutions. The Q400 Cost Index Data package consists of detailed high resolution climb, cruise and descent performance digital data (AEO and OEI) in small increments of weight, altitude, temperature and speed, in a generic, easy to use and implement format.

33


X E D N I T S O C

For example, with reference to the SAR chart below, the Cost Index Data is provided in additional speed increments of 7 kt, additional weight increments of 227 kg (500 lb), temperature increments of 2 degrees C, and altitude increments of 500 ft. This Cost Index data set has vastly more information as opposed to the AOM, which for practical reasons, shows only the six cruise regimes described earlier in this document

0 . 5

Therefore, the Q400 Cost Index Data allows for a higher accuracy in all optimization calculations, eliminating linear interpolation and other related errors, which will result in a more accurate cruise fuel burn es timate by 2% to 10%.

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35

FLIGHT

MANAGEMENT


T N E M E G A N A M T H G I L F 1 . 6

6.1 Enroute Winds The effect of predicted enroute winds (tailwinds or headwinds) are considered in the dispatch flight planning and eventually can be reconsidered in flight, when advantageous. Cruise altitudes can be changed, either to take advantage of tailwinds or to alleviate the effect of headwinds. For example, the chart below shows the influence of headwinds on SAR, for a LRC cruise segment at different altitudes. The chart illustrates how it is possible to estimate if a cruise altitude change would be beneficial.

In this specific example, in order to maintain the original SAR of 0.1300 nm/lb fuel planned for FL210, zero wind, an unpredicted headwind of 25 kt would be alleviated by climbing to FL230 . Or, reading left to right in the chart, the same SAR of 0.1300 nm/lb can be achieved if climbing to FL250 with a 50 kt headwind. The effect of en-route winds is best accounted for within a flight planning or a Cost Index software program, since the winds are dynamic and frequently changing.

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6.2 Performance Monitoring Aircraft and engine performance monitoring (airspeed, torque, RPM, fuel flow, fuel quantity on board, correlated with the aircraft weight and the actual ambient conditions) is highly recommended, as it allows to identify trends in engine fuel flow, airframe drag and overall trends at aircraft level. Performance monitoring also allows the statistical assessment of the flight planning accuracy and the potential reduction or customization of fuel contingency factors. Performance monitoring is often a regulatory audit requirement for IATA Operational Safety Audit (IOSA). It is very useful to have a record of fuel on board at critical points: Take-Off, TOC, TOD, and fuel remaining at destination. This data will help identify specific areas of flight planning or Cost Index methods that need to be further addressed or refined. This data should be recorded from the actual fuel indications, and not be taken from the FMS.

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6.3 Approach and Landing Whenever possible and safe, shorten the approach procedure. When practical and permitted, the flight crew can choose to fly a visual approach in order to save both time and fuel. Properly programming the FMS and aligning the descent with the approach will also help reducing the fuel burn. The advantages of new technology, including RNP, can offer significant savings by shortening approaches and reducing track miles, which equate to fuel savings. Operators have reported saving anywhere between 5 – 40 track miles with the advent of SID’s or STAR’s. The savings can amount to over 3% of block fuel.15 A decelerated approach (low noise, low drag) can lower fuel consumption and reduce noise. Keeping the aircraft clean, delaying flap and gear selections will help increase the fuel savings. Consideration should be given to the flap setting used on landing. Maximum flap will have increased drag, and may not be optimum on approaches or runways that do not require their use. Reduced flap landings, where applicable, can offer savings.

6.4 Tankering For each type of operation, especially for return routes, a specific tanker/ transport coefficient should be derived. Using route analysis or flight planning software, it will be easy to determine the ratio of fuel price at the origin airport compared to the fuel price at the destination airport, and whether it is economical to transport (tanker) fuel. This data can be further refined to determine the optimal tankered f uel quantity. When tankering, always remember to consider the impact on TOW, payload and landing weight limitations. The cost of tankering can be determined using the chart presented in 4.1.

15

34 nm savings on approach due to RNP capabilities can equate to roughly 180 lb of descent/ approach fuel. Assuming a block fuel of 2610 lb, this equates to 6.9% total savings.

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39

MAINTENANCE


E C N A N E T N I A M 1 . 7

7.1 Airframe Maintenance As airframe deterioration is expected over the aircraft operational life16, it is important to efficiently maintain the aircraft operational efficiency by performing regular airframe inspections and performing repairs or adjustments when required. The following represent items with the highest potential to have a negative impact on aerodynamic performance and therefore on fuel efficiency: • rough surfaces • paint condition • dents, blisters, gaps • surface mismatches • door seals, panel seals and wheel well doors • fairings, engine nacelle • flight controls rigging • dirt, oil leaks, other contamination • airframe asymmetry (following ground or other impacts) Bombardier has created an Aircraft Economics Working Group to further reduce the per hour operating cost of the aircraft. To date, the hourly operating cost has been reduced by over $75 with various maintenance related initiatives.17

7.2 Engine Maintenance Monitoring engine performance allows for the determination of fuel consumption degradation. This will help in determining the savings expected from maintenance performance improvements versus the cost to perform these activities or refurbishments. All these aspects should be reviewed in detail with the engine manufacturer. The best plan for maintenance of good engine performance is to maintain the engine gas path as close to original condition as possible, in terms of parts surface condition and compressor and turbine running clearances. This involves cleaning, repairing and replacing components as required, and accepting certain conditions in accordance with AMM and Engine Manuals and CIR. Defining the extent of a work scope is a decision between cost and engine turn time versus expected gains in performance.

16 17

Airfr ame components include but are not limited to doors, panels, flight control surfaces, fairings, seals, engine nacelle, etc. AEWG improvements since 2005 can be found on www.iflybom bardier.com

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The following elements have a negative impact on fuel burn: • • • •

FOD dirty compressor shroud rubbing HP and LP turbine blade increased tip to shroud clearances.

General recommendations are: • The LPC1 rotor should be examined for leading edge foreign object damage and erosion. In situ repairs may be carried out in accordance with approved manuals • Perform a performance recovery wash on a routine schedule • Engine shop visit for HSI or overhaul will re-establish the proper clearances and parts condition to improve on engine performance hence lower fuel burn. Performance recovery wash is a detergent wash which has significant performance recovery potential, hence direct fuel savings. Detergent washing is recommended to be performed on a routine schedule; the interval is to be optimized based on visual inspection of the compressor rotors. An engine wash can recover 0.5% in terms of fuel efficiency.

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42

7.3 Dispatch under MEL and CDL The Master Minimum Equipment List (MMEL) allows for higher dispatch reliability. However, some of the MMEL items have significant impacts and impose additional restrictions on flight planning (either altitude, temperature, speed or weather limitations). These limitations bring fuel consumption penalties by not allowing optimum flight planning, for example by not flying at the optimum altitude, or by having to fly above/below/around icing conditions. In the context of maximizing fuel efficiency, these MMEL items should be fixed or replaced as soon as possible:

Component

Condition

Limitation

21-30-1 CABIN PRESS Warning Light

Inoperative

Max altitude: 10000 ft

21-30-2 CABIN ALT Indicator

Inoperative


21-30-3 CABIN DIFF Press. Indicator

Inoperative


21-30-4 CABIN RATE Indicator

Inoperative


21-30-5 Cabin Pressure Control System

AUTO & Max altitude: 10000 ft MAN modes Inoperative

21-30-6 Aft Valves Indicator

Inoperative


27-30-2 Stick Shaker

Inoperative

No flight in icing

27-30-3 Flap Discrepancy

Inoperative

No flight in icing

27-30-4 Stall Warning

Inoperative

No flight in icing

27-30-5 Stick Pusher

Inoperative

No flight in icing

28-40-2 Fuel Tank Temperature Indication, if using Jet B/ JP-4 fuel

Inoperative


30-10-1 TAIL De-Ice Boots Advisory Lights

Inoperative

No flight in icing

30-10-2 DEICE PRESS Caution Light

Inoperative

No flight in icing

30-10-3 DEICE PRESS Indicators

Inoperative

No flight in icing

30-10-4 Low Pressure Warning Switches

Inoperative

No flight in icing



Component

43

Condition

Limitation

30-10-6 Timer Monitor Unit

Inoperative

No flight in icing

30-10-7 Airframe De-Icing

Inoperative

No flight in icing

30-20-2 ENGINE INTAKE HTR Advisory Lights

One Inoperative

No flight in icing

30-20-4 Engine Intake Adapter Heater Assemblies

One Inoperative

No flight in icing

30-30-1 Pitot/Static Heaters

Two Inoperative

No flight in icing

30-30-2 Pitot HEAT 1, 2, STBY Caution Lights

Inoperative

No flight in icing

30-40-2 Windshield Heaters

One Inoperative

No flight in icing

30-60-1 Propeller De-Icing

Inoperative

No flight in icing

30-80-2 Ice Detector Probes

Inoperative

No flight in icing

32-30-1 Landing Gear

Inoperative

Max speed: 215 KIAS Retraction System AFM Supp. 94 Max altitude: 20000 ft

35-20-1 Passenger Oxygen System (APPOS)

Inoperative


36-10-1 Bleed Systems

One Inoperative


52-10-2 Door Seal Drain Valve Open

Inoperative


71-60-1 Engine Intake Bypass Doors

Doors Inoperative

No flight in icing

71-60-1 Engine Intake Bypass Doors

Inoperative Open

Max Temp. = ISA+25



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Similarly, the Q400 AFM Supplement 41 Configuration Deviation List (CDL) allows the airplane to be operated with certain missing parts that cause a performance degradation or limitation. In the context of optimum flight planning and fuel efficiency, the following should be replaced as soon as possible:

Component

Condition

Limitation

30-1 Wing Root Cold Bonded Leading Edge De-ice Boot

One Inoperative

No flight in icing

30-2 Engine Intake De-ice Boot

One Inoperative

No flight in icing

32-1 MLG Shock Strut Performance limited

Fairings All Inoperative

weight reduced by 450 kg

32-1 NLG Aft Doors

One Inoperative

Maximum Speed = 190 KIAS


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CONCLUSION

Q400 Manual

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