The first officer of a Jet2 Boeing 737-800 inadvertently set the wrong thrust setting for take-off after being startled by the unexpected movement of the aircraft during an engine run-up procedure, a report by the Air Accidents Investigation Branch (AAIB) has found.
The captain subsequently failed to catch the error because he was distracted by a radio transmission during the take-off roll.
The jet, G-JZHL (c/n 63568), which was departing Kuusamo Airport in Finland bound for London/Stansted on December 1, 2021, climbed slowly after becoming airborne with 400m (1,312ft) of runway remaining.
The thrust was left at the 70% engine run-up configuration rather than the 89% required for take-off. The AAIB concluded the power was not set correctly because the take-off go-around (TOGA) button had not been pressed.