AAIB Report: Boeing 737-800 (G-JZHL), Insufficient Thrust During Takeoff

During takeoff at Kuusamo Airport in Finland, a Boeing 737-800 (G-JZHL) climbed slowly due to insufficient thrust, 1 December 2021

During takeoff, the flight crew inadvertently left the thrust set at the 70% engine run-up setting rather than the 89% required for takeoff. This caused the aircraft to become airborne with only 400 m of runway remaining and climb slowly. At 250ft agl, the flight crew realised they had insufficient thrust and applied the correct power. The flight continued with no further incident and no injuries to the crew.

This incident was caused by the thrust not being set correctly, due to the Takeoff Go-around (TOGA) button not being pressed. This happened because the co-pilot was startled by the aircraft starting to move as he commenced the run-up against the brakes, and this occurred because the co-pilot applied insufficient brake pressure. The commander was distracted by a radio call and did not check to see if the thrust was correctly set.

The AAIB has investigated several takeoff performance incidents across the industry, and this incident is further evidence that the current barriers designed to prevent events like these are not fully effective. Therefore, two Safety Recommendations have been made to develop technical specifications and certification standards for a technical solution, and to improve the detection of takeoffs with compromised performance.

Read the report