What happened
On 31 January 2022, a privately operated Bombardier CL-604 Challenger 604, registration N999PX, was performing a landing at London Stansted Airport following a flight from Cairo. During the final approach, the aircraft encountered strong gusting winds. As the aircraft flared, it floated for several seconds above the runway. During this period, the airspeed dropped significantly, leading to a sudden left wing drop and a rapid roll.
The aircraft struck the runway surface multiple times, with the left wingtip making contact with the pavement and subsequently the grass verge. The impact was severe enough to trigger the aircraft's stick pusher, resulting in a hard landing on the nosewheel. The nose landing gear assembly was damaged, and the aircraft eventually exited the paved surface. The crew subsequently initiated a go-around and diverted to London Gatwick Airport, where the aircraft's damage was further inspected.
The investigation
The AAIB investigation examined the flight data, cockpit voice recordings, and the physical condition of the aircraft and runway. Investigators found that the aircraft was flying at an airspeed lower than the recommended VREF +X for the prevailing wind conditions. The investigation also looked into the crew's fatigue levels, noting they had been awake for over 17 hours and were operating during their circadian low.
Furthermore, the investigation reviewed the relationship between the crew members and the lack of standardized crew resource management training within the operator's structure. The aircraft manufacturer's documentation was also analyzed, specifically regarding the guidance provided for crosswind landing techniques.
Findings
- The aircraft experienced a rapid roll and yaw following a long float at an insufficient airspeed.
- The left wingtip and nose landing gear sustained substantial damage during the sequence of impacts.
- Plan continuation bias likely influenced the commander's decision to continue the landing despite the deteriorating conditions.
- The effective crosswind component exceeded the commander's personal safety limit.
- The aircraft's stall protection system (stick shaker and pusher) activated due to the high angle of attack during the landing attempt.
- The crew's communication and decision-making may have been impacted by fatigue and a strained professional relationship.