What happened
On June 26, 2003, a Piper PA-34-200T, registration EC-CTK, was conducting a flight training session involving multiple takeoffs and landings at the Casarrubios del Monte airfield in Toledo. After an initial series of maneuvers and a refueling stop, the crew performed two additional takeoff and landing cycles. During the third landing attempt of the final sequence, the nose gear collapsed.
The aircraft slid approximately 250 meters along the runway, supported by the nose of the fuselage and the main landing gear, before exiting the left side of the runway. The impact caused significant damage to the engines, propellers, and the lower section of the forward fuselage. The two occupants, an instructor and a student, were uninjured and evacuated the aircraft without assistance.
The investigation
The investigation focused on the landing gear's hydraulic extension and retraction system, which utilizes an electric pump to provide pressure. Investigators examined the aircraft's maintenance records, which showed the plane had been maintained according to its authorized program.
During the inspection of the wreckage, investigators found that while the nose gear could be extended, the left main gear collapsed while attempting to move the aircraft off the runway. Subsequent ground tests performed on jacks demonstrated that the landing gear system was functioning correctly, with the gear extending and locking as designed. The tests also revealed that the three green lights indicating the gear was down and locked were difficult to see from the instructor's seat on the right side of the cockpit.
Findings
- The investigation determined that the landing gear was likely in transition toward the fully extended position during touchdown. While the main gear may have reached the overcenter locking position, the nose gear had not yet fully locked.
- The crew likely performed the final approach checklist without realizing the gear was not fully locked. It is probable that due to the repetitive nature of the training maneuvers, the crew inadvertently attempted to retract the gear instead of verifying its extension, or they failed to notice the gear was still in motion.
- The decision not to retract the gear during the preceding takeoff may have been due to an oversight or an intentional effort to reduce strain on the hydraulic pump after multiple consecutive cycles.
- The landing gear was in the process of extending but had not yet reached the fully locked position at the moment of touchdown.