Thomson Airways Flight 1526

On 21 July 2017, a Boeing 737-800 belonging to and operated by Sunwing Airlines Inc. and operating as Thomson Airways Flight 1526 from Belfast International Airport and bound for Corfu, Greece with 185 people aboard, suffered a "serious incident" during takeoff, colliding with a runway approach light during departure. The incident was investigated by the Air Accidents Investigation Branch and determined to be the result of an incorrect temperature input into the aircraft's flight computer resulting in underperformance at take-off. The area beyond the runway and the terrain beyond were largely unobstructed, and the aircraft eventually climbed away undamaged. The remainder of the flight to Corfu was uneventful. The "serious incident" at take-off was realized and reported when airport staff subsequently observed minor ground damage. The investigation report concluded that the crew could not reasonably have been expected to recognize the anomalously low speed sooner or intervene more effectively. The report listed several examples of aircraft underperformance at takeoff, reviewed the history of relevant industry efforts, and recommended that a Takeoff Acceleration Monitoring System and associated certification standards should be developed without further delay.

Incident

The outside air temperature was 16 C, but the operating crew entered incorrect figures (variously -47 C and -52 C) for the airport outside air temperature, into the flight management computer, resulting in miscalculation of the required N, the engine fan speed (low-pressure compressor speed) required on the take-off run.<ref

</ref> (Both incorrect figures appeared as OATs on the flight plan: -47 °C at the first waypoint after top-of-climb, -52 °C at top-of-climb.<ref

name=":0" /> Delays around reporting the incident meant that the Cockpit Voice Recorder information was not available for the investigation.<ref

As the aircraft departed Runway 07, the crew noticed unusually slow acceleration as well as a low climb rate, a fact noted by witnesses on the ground. Shortly after lifting off the runway one of the aircraft's landing gear collided with a supplementary runway approach light. The light was knocked loose from its mounting and crushed while the 737 suffered no damage. Crewmembers were not made aware of the incident until ATC personnel at Belfast airport filed an incident report with the AAIB.