FAA Aircraft Dispatcher (ADX)Flight Planning and PerformanceMedium
A dispatcher is reviewing turbojet takeoff performance data. Which statement best defines V1?
- AThe calculated speed at 35 feet above the runway at the end of the takeoff distance.
- BThe maximum speed at which the pilot must take the first action to reject the takeoff, and the minimum speed at which the takeoff must be continued following an engine failure.
- CThe speed at which the aircraft is rotated for takeoff.
- DThe minimum speed at which the aircraft can be safely flown with the critical engine inoperative.
Show answer & explanationAnswer & explanation
Correct answer: B. The maximum speed at which the pilot must take the first action to reject the takeoff, and the minimum speed at which the takeoff must be continued following an engine failure.
V1 is the takeoff decision speed: the maximum speed at which the crew can initiate a rejected takeoff and stop within the accelerate-stop distance, and the minimum speed at which the takeoff must be continued following recognition of an engine failure.
Why the other options are wrong
- A. This describes V2 achieved at the screen height, not V1.
- C. This describes VR (rotation speed), not V1.
- D. This describes VMC (minimum control speed), not V1.
V1 (Takeoff Decision Speed)
The critical speed during takeoff roll at which the decision to continue or reject the takeoff must be made.
- Balances accelerate-stop and accelerate-go distances
- Below V1: reject; at/above V1: continue takeoff
- Determined by weight, runway, wind, and obstacle data
Memory trick: V1 = 'the point of no return' on the runway.