What conditions must be met for the autobrakes to engage during a rejected takeoff?

What conditions must be met for the autobrakes to engage during a rejected takeoff?

• A. Thrust Levers IDLE or REV, wheelspeed above 60 kt, and brake pedals not pressed
• B. Thrust Levers at MAX, wheelspeed below 10 kt
• C. Thrust Levers IDLE, wheelspeed above 100 kt, and brake pedals pressed
• D. Thrust Levers at MID, wheelspeed below 20 kt

Answer: (A)

Autobrakes are intended to take over braking automatically when a takeoff is rejected, to bring the airplane to a controlled stop. For this to happen, the engines must be in a state where they aren’t contributing forward thrust, the aircraft must be moving fast enough to allow effective braking, and the crew must not be manually applying the brakes. Specifically, the thrust levers need to be at IDLE or in reverse so there’s no thrust fighting the brakes, the wheels must be turning faster than about 60 knots so the system can sense and control the deceleration, and the brake pedals must not be pressed, otherwise manual braking overrides or disables the autobrake. That combination exactly matches the conditions described, making it the correct answer.

Autobrakes are intended to take over braking automatically when a takeoff is rejected, to bring the airplane to a controlled stop. For this to happen, the engines must be in a state where they aren’t contributing forward thrust, the aircraft must be moving fast enough to allow effective braking, and the crew must not be manually applying the brakes. Specifically, the thrust levers need to be at IDLE or in reverse so there’s no thrust fighting the brakes, the wheels must be turning faster than about 60 knots so the system can sense and control the deceleration, and the brake pedals must not be pressed, otherwise manual braking overrides or disables the autobrake. That combination exactly matches the conditions described, making it the correct answer.