What happened
On September 26, 2005, a Piper PA-34-220T (registration CS-DID) was performing a visual flight rules (VFR) flight from Tires to Évora. The pilot, who was flying solo to complete a flight review, had previously performed maneuvers near Montemor-o-Novo.
During the approach to runway 01 at Évora Aerodrome, the pilot configured the aircraft for landing by deploying 10 degrees of flaps and extending the landing gear. The pilot confirmed the gear was down and locked via the three green cockpit lights and noted no audible warnings.
At 12:2DH UTC, the aircraft touched down on runway 01. While the main gear made contact with the pavement, the nose gear unexpectedly retracted. As the nose gear moved upward, the propellers struck the runway surface, causing the aircraft to lose stability. This impact triggered a sudden collapse of the right main landing gear, causing the right wing to scrape the asphalt. The aircraft subsequently veered 90 degrees to the right, exiting the runway and coming to rest with its tail across the landing strip. The pilot escaped the aircraft without injury.
The investigation
The GPIAAF examined the aircraft's maintenance history and performed functional tests on the landing gear retraction system. The aircraft had been maintained according to its scheduled inspections and complied with applicable Airworthiness Directives (ADs) and Service Bulletins (SBs).
Investigators placed the aircraft on jacks to simulate flight conditions and tested the landing gear extension and retraction cycles. During these tests, the system functioned normally, and all warning lights and audible alerts operated as designed. The investigation also reviewed the manufacturer's history, noting that the Piper PA-34 model had a known history of issues regarding the involuntary retraction of the nose gear and the collapse of main gear components, which had previously led to various FAA directives.
Findings
- The pilot had a valid license and the aircraft possessed a valid Certificate of Airworthiness.
- The pilot had correctly selected the gear down position and verified the gear was locked.
- The aircraft's landing gear warning systems (red lights and audible alerts) were fully functional and did not trigger during the landing roll.
- The exact cause of the nose gear retraction and the subsequent right main gear collapse could not be determined.
- The aircraft's maintenance records showed compliance with relevant safety directives, though some historical directives from its previous Swedish registration were only identified after reviewing the original logbooks.