Accident Synopsis
On 10 September 2018, at approximately 1200 hours local time, a Tecnam P92 JS Echo (registration 9H-MSF) experienced a left main landing gear failure after landing on Runway 23 at Malta International Airport. The aircraft came to rest on the runway to the left of the centerline on a heading of 195° magnetic, at the end of the second touchdown zone. No injuries were reported.
Aircraft and Crew Information
The aircraft, manufactured in 2013, was a single-engine airplane with a tricycle landing gear configuration. It was operated by Malta School of Flying Company Ltd., an approved training organization. The total airframe time was 2699 hours. The pilot in command held an EASA CPL (A) with instructor rating and had 928 flight hours. The student pilot occupied the right seat and had 82 hours total flight time. A VFR flight plan was filed for the cross-country training flight from Reggio Calabria, Italy, to Malta.
Events During Landing
The flight departed Reggio Calabria and landed on Runway 23. The instructor reported that the approach, flare, and initial rollout were normal. When brakes were applied, a vibration resembling nose-wheel shimmy was felt, which became severe. The aircraft then tilted left-wing down and came to rest. The braking was described as not hard.
Post-Accident Examination
Examination of the runway revealed tyre marks consistent with a failed landing gear. The left main landing gear had collapsed, with the leaf spring rotated backwards. The attachment system showed that the nut on the front outer bolt was missing. The bolt shank had swarf on its thread, consistent with a nut being stripped under tension. The rear outer and inner bolts were bent but still had their nuts secured. The clamp was scraped and the front hole widened. A search for the missing nut on the runway and in the airframe did not locate it.
Maintenance records indicated that the undercarriage bolts were checked and re-tightened during a 100-hour inspection on 6 September 2018, 26 flight hours before the accident. The maintenance company noted that the aircraft type experienced compression of leather liners, which could leave play in the undercarriage, but no evidence linked this to the accident.
Probable Cause
The Bureau of Air Accidents (Malta) determined the probable cause of the accident to be: collapse of an undercarriage leg during roll-out due to failure of a retaining nut. The exact reason for the nut failure could not be ascertained.