What happened
On 9 December 2010, a Cessna 750 Citation X, registration G-CDCX, was performing a private positioning flight from Luton to Doncaster Airport for scheduled maintenance. The weather conditions were favorable, with a light crosswind well within landing limits.
During the landing on Runway 20, the aircraft touched down smoothly, though slightly before the left mainwheel. Shortly after touchdown, the right main landing gear trailing link failed, causing the right mainwheels to detach from the aircraft. As the nose began to drop, the aircraft rolled to the right and the crew experienced a significant vibration through the control yoke.
Despite the crew's efforts to maintain directional control using the left brake and rudder, the aircraft began to veer right and eventually came to a halt just off the paved edge of the runway. The incident resulted in damage to the right mainwheels, flaps, outboard wing skin, and a puncture to the right elevator. There were no injuries to the two crew members on board.
The investigation
The AAIB examined the aircraft and the wreckage at Doncaster Airport. Investigators analyzed the flight data recorder (FDR) and cockpit voice recorder (CVR), noting that the aircraft's descent rate and approach parameters were normal until the gear failure.
Metallurgical examination of the failed trailing link was conducted in the presence of a specialist from Cessna Aircraft Company. The analysis revealed a 27 cm longitudinal crack on the upper surface of the link. The investigation also looked into the maintenance history of the landing gear, specifically regarding previous inspections and repairs related to corrosion and plating thickness.
Findings
- The primary cause of the accident was the failure of the right main landing gear trailing link due to a long stress corrosion crack.
- The crack originated from an area of severe corrosion and pitting on the upper surface of the link.
- Evidence suggested the crack pre-existed the final failure and was likely exacerbated by the loss of protective cadmium plating and primer.
- The investigation noted that the left main landing gear link also showed signs of corrosion and could have been susceptible to a similar failure.
Safety action
- The AAIB made a safety recommendation to the Cessna Aircraft Company to amend the maintenance schedule for the Model 750 Citation X to include more frequent external visual inspections of the main landing gear trailing link upper surface for cracks.