What happened
On September 24, 2021, a Piper Aircraft PA-32R-301 operated by a local flying club was conducting a recreational local flight at the Eulogio Sánchez Aerodrome (SCTB) in La Reina, Chile. The flight, which included the pilot and one passenger, proceeded normally until the pilot initiated landing preparations. Upon deploying the nose landing gear, the pilot noticed that the green indicator light, signifying the gear was down and locked, failed to illuminate.
Following standard operating procedures, the pilot attempted to cycle the gear multiple times. To verify the gear's status, the pilot requested a low pass to allow air traffic control to visually inspect the aircraft. The controller confirmed that the nose gear was in an abnormal position and was not fully extended. The pilot then attempted the emergency gear extension procedures specified in the flight manual, but the nose gear remained unsecure. Consequently, the pilot declared an emergency and performed a landing on runway 1 and 9, relying solely on the main landing gear. Both the pilot and the passenger remained uninjured, though the aircraft sustained damage.
The investigation
DGAC Chile investigators examined the aircraft's maintenance records and performed functional tests on the landing gear system. The investigation confirmed that the aircraft's maintenance was up to date, with the last annual inspection completed approximately 6,500 flight hours prior to the event. The aircraft's documentation, including the airworthiness certificate, was valid.
During post-accident inspections in a hangar, investigators found that while the hydraulic pump and electrical warning lights were functioning correctly, the nose gear would not lock in the down position. A detailed teardown of the nose gear actuator revealed a deformed rod end (terminal) and a misaligned piston rod. The inspection of the actuator cylinder showed that the internal walls had been scored by the piston, and the end cap had been subjected to significant torsional stress.
Findings
- The primary cause of the accident was the abnormal contact of the aircraft with the runway surface during an emergency landing, resulting from the failure of the nose gear to extend and lock.
- A deformed rod end on the nose gear actuator prevented the gear from securing in the down position.
- The deformation of the rod end and the subsequent misalignment of the piston rod were likely caused by a heavy or hard landing during a previous flight.
- The investigation found no evidence of recent hard landings recorded in the pilot's logbook, suggesting that previous structural stresses had gone unreported.
- The aircraft's maintenance program was compliant with regulations, and the mechanical failure was not related to any recent maintenance actions.