What happened
On 8 March 2012, a BAE Systems Jetstream 31, registration G-CCPW, was performing a commercial passenger flight from Leeds Bradford International Airport to Isle of Man Airport. During the landing on Runway 26, the aircraft's right main landing gear failed immediately upon touchdown. The collapse caused the right engine propeller blades to strike the runway surface, creating an unusual noise and causing the aircraft to lean heavily to the right.
As the aircraft'ed speed decreased, the rightward lean intensified. The crew attempted to maintain control using left aileron and rudder inputs, but the aircraft eventually departed the paved surface, yawing to the right and sliding sideways before coming to a stop 90 degrees from the runway heading. The aircraft left debris and marks on the runway, including sections of the landing gear yoke pintle. There were no injuries to the 12 passengers or the 2 crew members on board.
The investigation
The investigation examined the aircraft's flight data, cockpit voice recordings, and the physical wreckage. Analysis of the Digital Flight Data Recorder (DFDR) and Terrain Avoidance Warning System (TAWS) confirmed that the descent rate at touchdown was within design limits and that the landing weight was below the maximum allowable limit.
Metallurgical examination of the right main landing gear focused on the forward yoke pintle. Investigators found that the failure originated at the top outer edge of this component. Scanning Electron Microscopy (SEM) revealed evidence of stress corrosion cracking (SCC) in the initial 10 mm of the crack. Furthermore, heavy corrosion and the presence of cadmium leached from the steel spigot into the crack suggested the damage had been present for some time.
Findings
- The right main landing gear detached from its trunnions due to the failure of the forward yoke pintle.
- The failure was initiated by stress corrosion cracking at the top edge of the pintle.
- Significant corrosion and the presence of cadmium indicated the crack was likely present during the most recent visual inspection, which had occurred 29 cycles prior to the accident.
- The landing forces during the flight were within the aircraft's design specifications, meaning the gear should not have failed under these conditions.
Safety action
Safety Recommendation 2012-008
It is recommended that the European Aviation Safety Agency review the effectiveness of Airworthiness Directive G-003-01-86 in identifying cracks in the yoke pintle housing on landing gears fitted to Jetstream 31 aircraft.