Aitchison handled a routine take-off at 08:20 local time (07:20 UTC), then handed control to Lancaster as the plane continued to climb.

Flight attendant Nigel Ogden was entering the cockpit when a loud bang occurred[4] and the cabin quickly filled with condensation.

His knees were caught on the flight controls and his upper torso remained outside the aircraft, exposed to extreme wind and cold.

Ogden rushed to grab Lancaster's belt, while the other two flight attendants secured loose objects, reassured passengers, and instructed them to adopt brace positions in anticipation of an emergency landing.

The plane was not equipped with oxygen for everyone on board, so Aitchison began a rapid emergency descent to reach an altitude with sufficient air pressure.

He then re-engaged the autopilot and broadcast a distress call, but he was unable to hear the response from air traffic control (ATC) because of wind noise; the difficulty in establishing two-way communication led to a delay in initiation of emergency procedures.

The crew believed him to be dead, but Aitchison told the others to continue holding onto him, out of fear that letting go of him might cause him to strike the left wing, engine, or horizontal stabiliser, potentially damaging it.

)[3]: 7 Investigators found that the shift maintenance manager responsible for installing the incorrect screws had failed to follow British Airways policies.

[4][7] Aitchison left British Airways shortly after the accident and joined Channel Express (later rebranded as Jet2) until he made his last commercial flight on a Boeing 737-33A from Alicante to Manchester on the day of his 65th birthday on 28 June 2015.