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How is take-off performance affected by using flaps 10° instead of flaps 5°?
  • A

    Ground roll is decreased, drag is increased, climb performance is decreased.

  • B

    Ground roll is decreased, drag is decreased, climb performance is increased.

  • C

    Ground roll is decreased, drag is increased, climb performance is increased.

  • D
    Ground roll is increased, drag is increased, climb performance is decreased.

Refer to figure.

EFFECT OF FLAPS ON LANDING/TAKE-OFF RUN AND CLIMB GRADIENT
The use of high life devices (Flaps) will have an impact on the take-off and Landing roll and climb gradient.


For a given runway length and airplane weight, selecting a greater flap setting will increase the lift coefficient, which reduces the stalling speed.
  • As a consequence, the take-off speeds are reduced (the same lift will be created at smaller air speed due to greater lift coefficient). This will reduce the take-off run.
  • Flap extension during landings provides several advantages by:
producing greater lift and permitting lower landing speed;
producing greater drag, permitting a steep descent angle without airspeed increase.
=> Reducing the length of the landing roll.

The down side of the use of flaps is that it generates more parasite drag:
We get our best angle of climb and, therefore, our best gradient where there is the biggest gap between the thrust available and thrust required. The parasite drag from the extended flap closes the gap and the climb angle and climb gradient will reduce => go around performance is deteriorated. Hence as soon as we can after take off we accelerate and retract the flap and climb clean.

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