What happened
On June 27, 2017, a privately owned Piper PA-46-310P, registration JA4010, was conducting a familiarization flight from Honda Airport to Fukushima Airport. After performing an ILS approach and touching down on runway 01, the pilot began the landing roll. To maintain the centerline, the pilot utilized the rudder pedals without immediately applying brakes, as there was significant runway remaining before the intended taxiway exit.
During the roll, the aircraft began to drift toward the right side of the runway, and the nose began to pitch downward. Despite the pilot's attempt to pull up the control column, the nose continued to descend until the propeller blades struck the runway surface. The aircraft subsequently slid along the runway, with the lower forward fuselage making contact with the pavement, before coming to a stop near the intersection of runway 01 and taxiway T4. There were no injuries to the pilot or passenger.
The investigation
Investigators examined the wreckage and the mechanical components of the nose landing gear assembly. The inspection revealed significant damage, including a bent piston rod, a cracked engine mount frame, and bent propeller blades. The nose landing gear door had also been forced open wider than its normal range.
Technical analysis focused on the rod end bearing of the nose landing gear actuator. Metallurgical testing conducted by the National Institute for Materials Science determined that the failure was not due to metal fatigue, but rather a ductile fracture resulting from excessive bending and compression loads. The investigation also reviewed maintenance records, noting that while 100-hour inspections were up to date, there was no specific record of the rod end bearing being replaced recently.
Findings
- The primary cause of the incident was the rupture of the rod end bearing on the nose landing gear actuator, which led to the unintended retraction of the nose gear.
- This failure was likely triggered by a longitudinal compression load applied to the actuator because the nose landing gear strut was not in its proper, fully extended position.
- The investigation suggests the strut may have leaned backward from its normal position due to improper adjustment of the extended position or restricted movement within the sliding interface of the actuator.
- The mechanical failure caused the nose of the aircraft to drop, leading to the propeller strike and subsequent inability to taxi.