FAA Airline Transport Pilot (ATM)Aircraft Performance and Weight and BalanceEasy
During a takeoff performance briefing, a first officer asks the captain to define V1. Which statement best describes V1?
- AThe speed at which the airplane becomes airborne under normal takeoff conditions
- BThe speed at which the pilot must retract the landing gear
- CThe speed at which the airplane reaches its best angle-of-climb performance
- DThe maximum speed at which a rejected takeoff can be initiated and the airplane stopped within the accelerate-stop distance available, and the minimum speed at which the takeoff can be continued after an engine failure
Show answer & explanationAnswer & explanation
Correct answer: D. The maximum speed at which a rejected takeoff can be initiated and the airplane stopped within the accelerate-stop distance available, and the minimum speed at which the takeoff can be continued after an engine failure
V1 is the critical decision speed: below V1 a rejected takeoff can be stopped within the accelerate-stop distance available, and at or above V1 the takeoff must be continued. It is not the liftoff speed (VR) or gear retraction speed.
Why the other options are wrong
- A. That describes VR (rotation speed), not V1.
- B. Gear retraction speed is a separate limitation unrelated to V1.
- C. Best angle-of-climb speed (VX) is unrelated to the V1 decision point.
V1 (Takeoff Decision Speed)
The speed by which a rejected takeoff must be initiated to stop within the accelerate-stop distance available, or the takeoff must be continued.
- Balances accelerate-stop and accelerate-go distances
- Determined by weight, runway, wind, and altitude
- Crew must decide go/no-go essentially at V1
Memory trick: 'V1—Vee decide, VR—Vee rotate, V2—Vee fly on one'