FAA Aircraft Dispatcher (ADX)Flight Planning and PerformanceMedium
A turbojet is being dispatched from a runway with a 1% upslope. Compared to a level runway, how does this affect the takeoff distance required?
- ATakeoff distance decreases because gravity assists acceleration.
- BTakeoff distance increases because the upslope reduces the rate of acceleration during the takeoff roll.
- CTakeoff distance decreases due to reduced rolling friction on an upslope runway.
- DTakeoff distance is unaffected; runway slope only influences landing performance.
Show answer & explanationAnswer & explanation
Correct answer: B. Takeoff distance increases because the upslope reduces the rate of acceleration during the takeoff roll.
An upslope runway works against the aircraft's forward acceleration, requiring more distance to reach takeoff speed. Performance charts include slope corrections, typically increasing required takeoff distance for positive (upslope) gradients.
Why the other options are wrong
- A. Gravity works against acceleration on an upslope, not for it.
- C. Rolling friction is not reduced by slope; the opposing component of gravity increases required distance.
- D. Runway slope is a standard correction applied to takeoff performance, not just landing.
Runway Slope Effect on Takeoff
Runway gradient affects acceleration during takeoff roll; upslope increases takeoff distance required, downslope decreases it.
- Upslope opposes acceleration, increasing TODR
- Downslope aids acceleration, decreasing TODR
- Slope correction factors are found in aircraft performance manuals
Memory trick: Uphill takeoff = uphill battle — more runway needed.