If autothrottle is not engaged during takeoff, you should not engage above which speed until which altitude?

If autothrottle is not engaged during takeoff, you should not engage above which speed until which altitude?

• A. 60 kt until 1000' AGL
• B. 65 kt until 400' AGL
• C. 70 kt until 200' AGL
• D. 75 kt until 800' AGL

Answer: (B)

When you’re not using autothrottle during takeoff, you’re manually managing thrust, so there’s a safety-limiting point for how aggressively you increase power. The restriction to not advance thrust beyond a certain speed until you’re higher gives you time and altitude to verify the engine response and establish a stable climb without surprise throttle changes. The recommended limit is to keep thrust from being increased beyond 65 knots indicated airspeed until you reach 400 feet above the ground. This provides a safe buffer: you stay under a controlled power increase during the critical low-altitude phase, while still allowing you to transition smoothly into a normal climb once you’re above the altitude where you can safely manage engine performance and configuration. Other speed/altitude combinations would push the throttle changes too early or too late, either constraining timely climb progression or risking abrupt thrust changes in the most demanding portion of takeoff.

When you’re not using autothrottle during takeoff, you’re manually managing thrust, so there’s a safety-limiting point for how aggressively you increase power. The restriction to not advance thrust beyond a certain speed until you’re higher gives you time and altitude to verify the engine response and establish a stable climb without surprise throttle changes.

The recommended limit is to keep thrust from being increased beyond 65 knots indicated airspeed until you reach 400 feet above the ground. This provides a safe buffer: you stay under a controlled power increase during the critical low-altitude phase, while still allowing you to transition smoothly into a normal climb once you’re above the altitude where you can safely manage engine performance and configuration.

Other speed/altitude combinations would push the throttle changes too early or too late, either constraining timely climb progression or risking abrupt thrust changes in the most demanding portion of takeoff.