The aircraft’s left main landing gear failed shortly after it landed on Runway 20 at Doncaster Sheffield Airport. The left main landing gear detached from its mounts and the aircraft slid along the runway on its remaining landing gear, left wingtip and baggage pannier, before veering off the runway and coming to rest on the adjacent grass. The single passenger and the flight crew vacated the aircraft without injury. The failure occurred as a result of stress corrosion cracking in the forward pintle housing, at the top of the left landing gear cylinder.
The same aircraft, operating under a different registration, was involved in a similar accident in 2012 during which the right main landing gear failed in the same location, also due to stress corrosion cracking.
This investigation determined that a design solution implemented by the aircraft manufacturer following the 2012 accident, which introduced a protective washer on the forward pintle housing, had not met its original design intent. A fouling condition, not identified when the design solution was first implemented, caused rotational movement of the protective washer on G-GAVA resulting in degradation of the surface protection on the forward pintle housing. This created conditions conducive to the formation of corrosion pits, from which a stress corrosion crack initiated and propagated to failure. This report follows publication of AAIB Special Bulletin S5/2014, in which two Safety Recommendations were made. One additional Safety Recommendation is made.