1 December 2021 – Kuusamo Airport, Finland

“During takeoff from Kuusamo Airport in Finland the flight crew of a Boing 737-800 inadvertently left the thrust set at the 70% engine run-up setting rather than the 89% required for takeoff.

The thrust was not set correctly because the TOGA button was not pressed. It was not pressed because the co-pilot (Pilot Flying) was startled by the aircraft starting to move when he set 70% power against the brakes.

The meteo conditions required a pre-takeoff engine run-up to clear any ice from the engines. This required the engines to be accelerated to 70% N1 on the runway for 30 seconds whilst the aircraft was held on the brakes.”

The co-pilot felt the aircraft sliding and released the brakes with 70% N1 without push the TOGA button.

“During takeoff the co-pilot felt the aircraft “heavy” in pitch and say “we need more power”. At this stage the commander realised they did not have takeoff power set and manually advanced the thrust levers to 89% N 1.”

The remainder of the flight to Stansted continued without further incident.

Source

AAIB Field Investigation

https://assets.publishing.service.gov.uk/media/633d3bcfe90e07440ca13208/Boeing_737-800_G-JZHL_11-22.pdf