Exercise 1

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Embry-Riddle Aeronautical University *

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Mechanical Engineering

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Dec 6, 2023

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AS 420 Flight Technique Analysis Exercise 1 Jet Transport Takeoff Factors as of 5-18-2021 Joseph T Gondek and Shubhanu Mukherjee OBJECTIVE: To be able to explain the various factors that impact takeoff distance considering such things as weight, flap setting, thrust setting, and density altitude. Further to be able to explain the factors that impact accelerate stop and accelerate go distances following an engine failure. PRE-EXERCISE QUESTIONS: 1. What do you think would happen to the distance to reach 35 feet AGL if a higher Vr is utilized? Longer take off run 2. What do you think would happen to the distance to reach 1000 feet AGL if a higher Vr is utilized? It would reach 1000AGL sooner 3. What do you think would happen to the distance to liftoff if a higher flap setting is utilized? Lesser distance used to reach V R 4. What do you think would happen to the distance to 1000 feet AGL if a higher flap setting is used? Lesser distance to reach 1000 AGL- more lift 5. Of the two incorrect choices to make the “go” decision 5 knots below V1 or to make the “abort” decision 5 knots above V1; which do you feel would be the better of the two? Abort 5knots above V1 READING:  Pilot Guide to Takeoff Safety Section 2  AC 91-79A  Air Florida Flight 90; January 13, 1982 https://www.faa.gov/about/initiatives/maintenance_hf/library/documents/media/aviation_mainten ance/airflorida_inc.pdf MANEUVERS: Maneuver 1.1 Normal takeoff. Initial Conditions Altitude Sea Level Weight 800,000 pounds Flaps 10 Gear Down EPR 1.52 Airspeed 0 KIAS

Procedure: With a V1 of 152 KIAS, Vr of 167 KIAS and V2 of 180, gear up at positive rate and climb to 1000. Maneuver 1.2 Enhanced climb at higher airspeed Initial Conditions Altitude Sea Level Weight 800,000 pounds Flaps 10 Gear Down EPR 1.52 Airspeed 0 KIAS Procedure: Rotate at Vr of 172 KIAS, gear up at positive rate and climb to 1000. Maneuver 1.3 Higher flap setting takeoff . Initial Conditions Altitude Sea Level Weight 800,000 pounds Flaps 20 Gear Down EPR 1.52 Airspeed 0 KIAS Procedure: With a V1 of 147 KIAS, Vr of 161 KIAS and V2 of 174 KIAS, gear up at positive rate and climb to 1000. Maneuver 1.4 Effect of reduced thrust takeoff Initial Conditions Altitude Sea Level Weight 800,000 pounds Flaps 10 Gear Down EPR 80% (1.42) Airspeed 0 KIAS Procedure: You’ll need to select -20% on your FMS to switch to reduced thrust. With a V1 of 160 KIAS, Vr of 171 KIAS and V2 of 180 KIAS, gear up at positive rate and climb to 1000.

Maneuver 1.5 Effect of weight on takeoff Initial Conditions Altitude Sea Level Weight 600,000 pounds Flaps 10 Gear Down EPR 1.52 Airspeed 0 KIAS Procedure: With a V1 of 133 KIAS, Vr of 143 KIAS and V2 of 163 KIAS, gear up at positive rate and climb to 1000. Maneuver 1.6 Accelerate Stop (Eng failure at V1 situ added) Initial Conditions Altitude Sea Level Weight 800,000 pounds Flaps 10 Gear Down EPR 1.52 Airspeed 0 KIAS Procedure: Accelerate to 152 KIAS (V1), wait 2 seconds, idle throttles, apply brakes until stopped. Maneuver 1.7 Accelerate Go (Eng failure at V1 situ added) Initial Conditions Altitude Sea Level Weight 800,000 pounds Flaps 10 Gear Down EPR 1.52 Airspeed 0 KIAS Procedure: Accelerate and continue after #1 Engine failure, rotate at 167 KIAS (Vr), follow

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command bars (magenta flight director queues) for climb, gear up at positive rate, climb through 35 feet. Maneuver 1.8 Making the abort decision 10 above V1 *use 10 kts above V1 situation Initial Conditions Altitude Sea Level Weight 800,000 pounds Flaps 10 Gear Down EPR 1.52 Airspeed 0 KIAS Procedure: Accelerate until #1 Engine fails, wait 2 seconds, idle throttles, apply brakes until stopped. Maneuver 1.9 Making the Go decision below V1 *use 10 kts below V1 situation Initial Conditions Altitude Sea Level Weight 800,000 pounds Flaps 10 Gear Down EPR 1.52 Airspeed 0 KIAS Procedure: Accelerate and continue after #1 Engine failure, rotate at 167 KIAS (Vr), follow command bars (magenta flight director queues) for climb, gear up at positive rate, climb through 35 feet. Maneuver 1.10 DO NOT DO THIS ONE BUT ANSWER ALL EXERCISE QUESTIONS Contaminated runway effect on V1 abort distance *haven’t figured out how to contaminate (numbers are for uncontaminated rnwy) Initial Conditions Altitude Sea Level Weight 800,000 pounds Flaps 10 Gear Down EPR 1.52 Airspeed 0 KIAS

Procedure: Accelerate to 152 KIAS (V1), wait 2 seconds, idle throttles, apply brakes until stopped. Maneuver 1.11 DO NOT DO THIS ONE BUT ANSWER ALL EXERCISE QUESTIONS Contaminated runway impact on V1 Go distance *haven’t figured out how to contaminate (numbers are for uncontaminated rnwy) Initial Conditions Altitude Sea Level Weight 800,000 pounds Flaps 10 Gear Down EPR 1.52 Airspeed 0 KIAS Procedure: Accelerate to 152 KIAS (V1), rotate at 167 KIAS (Vr), and climb at 180 KIAS (V2), gear up at positive rate, climb through 35 feet. Maneuver 1.12 Density altitude effect on takeoff Initial Conditions Altitude 8320 MSL Temperature 25°C Altimeter 29.92” Hg Weight 800,000 pounds Flaps 10 Gear Down EPR 1.63 Airspeed 0 KIAS Procedure: With a V1 of 160 KIAS, Vr of 174 KIAS and V2 of 182 KIAS, gear up at positive rate and climb to 1000. Note: Bogota, Columbia SKBO EVALUTION DISCUSSION: All of the below questions refer to your interpretation of the flight data of the above Maneuvers in the Excel Spreadsheet “Exercise 1 Takeoff”. Your responses should not just be limited to such

things as which one is higher or lower but should include how this relates to the relationships you know in aerodynamics and performance. You should also include your rationale of why these results were attained and what you can apply to practical applications in a jet transport environment. 1. When evaluating Maneuvers 1.1 and 1.2, what differences in takeoff runway distance and climb performance did you find when using the higher Vr in Maneuver 1.2? A higher rotation speed means the aircraft will be on the ground for longer. This leads to a longer takeoff roll. Compared to 1.1, 1.2 roll was about 300 feet longer. The climb performance was slightly better in 1.2 since there was extra speed. 2. When evaluating Maneuvers 1.1 and 1.3, what differences in takeoff runway distance and climb performance did you find when using the higher flap setting in Maneuver 1.3? With higher flap setting more lift is produced. The extra lift helps the aircraft get off the ground sooner. Compared to 1.1, the rotation speed is lower which led to a couple hundred feet shorter ground roll. The climb performance was worse in 1.3 due to the higher drag to 1000 feet. 3. When evaluating Maneuvers 1.1 and 1.4, what differences in takeoff runway distance and climb performance did you find when using the reduced EPR in Maneuver 1.4? The reduced thrust takeoff comes with the price of a longer takeoff roll. It is more efficient for the airline due to less fuel consumption but the penalty is a longer takeoff roll. Along with the takeoff roll, climb performance is worse due to not having full power. It will take longer to reach the desired altitude. 4. When evaluating Maneuvers1.1 and 1.5, what differences in takeoff runway distance and climb performance did you find when using the reduced weight in Maneuver 1.5? Less weight will always be an advantage when flying. Vr and V1 were significantly lower which drastically changes the takeoff roll. There was about a 2500-foot reduction in distance. Less weight is always preferred when flying. 5. When evaluating Maneuvers 1.6 and 1.7 what differences did you find in the runway distance to stop in Maneuver 1.6 and takeoff (to 35 feet AGL) in Maneuver 1.7? In 1.6, there was only a few feet remaining on the runway. I think there would 6. When evaluating Maneuvers 1.6 and 1.8, what differences in runway distance used to stop did you note in using the higher “abort” speed in Maneuver 1.8? When comparing the two situations, the distance to stop was about 600 feet longer. In 1.8 we overran the runway so the data stopped recording. Aborting over V1 is never a good idea and 9 times out of 10 leads to running off the runway. 7. When evaluating Maneuvers 1.7 and 1.9, what difference in runway distance used to continue did you find in using the lower “go” speed in Maneuver 1.9? 1.9 took a longer takeoff roll due to the loss of the number 1 engine. 10 knots below V1 should normally be aborted although it is still possible to get off the ground if there is enough runway remaining.

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8. Although both 1.8 and 1.9 choices would be incorrect, which was the better of the two incorrect choices between Maneuver 1.8 (aborting at V1+10kts) and Maneuver 1.9 (continuing the Takeoff at V1-10kts), in your opinion, and why? I think that continuing the takeoff with the engine failure before V1 is safer because assuming there is extra runway, the pilot can still get off the ground and circle back to land. If they were to abort after V1 there is a very high chance of running off the runway and striking a object causing more damage and possibly fatalities. 9. When considering Maneuvers 1.6 and 1.10, what differences in runway distance to abort do you hypothesize ? The runway distance to stop would be greater due to the contaminated runway surface. If the runway is wet or icy, then the plane could hydroplane or start slipping on the ice. This could cause a lot more damage if it were to slide off the side and strike another plane or a building. 10. When considering Maneuvers 1.7 and 1.11, what differences in runway distance to continue the takeoff do you hypothesize ? I think the runway distance would increase with the contaminated runway due to the plane having to work harder to push through the contaminants. If there is standing water on the runway then the plane has to push it out of the way which creates more drag. 11. When evaluating Maneuvers 1.1 and 1.12, what differences in runway distance did you note when using the higher altitude in Maneuver 1.12? There was not a very big difference in the data. The takeoff distances were about the same. The climb performance was worse in 1.12. 12. What factors from the above comparisons might have had an impact in the Air Florida Flight 90 accident? The biggest factor leading to the crash of Air Florida flight 90 was that they had a lot of built up ice and did not notice that they had reduced power. This is similar to how 1.4 used less thrust and how they had extra drag like 1.3. They were also a lot heavier due to the ice build up which increases the takeoff distance a lot more. 13. Discuss how BFL is derived and what environmental/runway conditions may both positively and negatively affect it. BFL is when the accelerate stop and the takeoff distance is the same. It is based on aircraft weight, thrust setting, runway condition, and aircraft configuration. 14. Other than raising density altitude, discuss how temperature above ISA will affect takeoff performance with specific reference to turbine engine operations. A higher ISA will increase takeoff distances and decrease climb performance. This is due to hot air being less dense which means the turbine needs to pull in more air to produce the same amount of thrust. 15. Discuss how the use of conventional crosswind correction techniques in high winds will affect takeoff performance. Using crosswind correction increases the surface are over parts of the wing where the ailerons are. This creates more drag which would increase the takeoff roll.

16. Explain your overall conclusions relative to the Exercise 1 Objective listed above. Aircraft configuration is extremely important when trying to takeoff in a certain distance. Having the correct flaps with the correct thrust setting is crucial in case of an emergency. There needs to be adequate planning before each takeoff to ensure that if there is an emergency the aircraft will not overrun.