Flight History
The pilot departed Vannes aerodrome for Toussus-le-Noble. During approach, after lowering the landing gear, the right main gear indicator remained red and a "gear unlocked" message appeared. The pilot cycled the gear again without change. A low pass was performed; the tower controller reported the gear appeared extended. The pilot then manually cranked the gear until the stop, but the red light persisted. The pilot executed a precautionary landing on runway 25L, attempting to minimize loads on the gear. During the landing roll, the right main gear retracted, causing the aircraft to tilt right and veer laterally off the runway into the grass. The right wing and propeller were damaged.
Investigation Findings
Examination revealed that the actuation rod of the right main gear mechanism had failed at the spherical ball joint connected to the bellcrank. The fracture was consistent with overload in tension and likely occurred during gear extension. No geometric defects, pre-existing damage, or material anomalies were found. Maintenance records showed no work on that part since 2000. The aircraft manufacturer was unaware of other similar failures. The pilot reported that on a previous flight, one green landing gear indicator light had illuminated a few seconds later than the others, but he did not recall if the "gear unlocked" light was on. He had landed without incident. A preflight inspection before the accident flight revealed no abnormalities.
Conclusion
The side runway excursion resulted from a loss of control during the landing roll due to the retraction of the right main landing gear, which had not locked because of a failed actuation rod. The manual gear extension crank, which operates the same mechanism, was unable to secure the gear. The investigation did not determine the cause of the rod failure.