What happened
On June 2, 2007, a Piper PA 24-180, registration CS-ALT, operated by AEROPILOTO, was performing a flight from Cascais Municipal Aerodrome (LPCS) to Évora (LPEV). The flight was requested by a co-owner of the aircraft. After departing Cascais, the pilot noticed an irregular indication regarding the landing gear position. Upon consulting Air Traffic Control, the pilot was informed the gear appeared to be retracted. Shortly after, the pilot noted discrepancies in the transponder's altitude and heading indications, leading the decision to fly outside controlled airspace.
During the return flight to Cascais, the pilot noted a strong smell of fuel. While approaching runway 35, the pilot reduced speed to maintain separation from preceding traffic. Upon touchdown, the propeller tips struck the runway surface, creating several impact marks. The aircraft continued to float for approximately 30 meters before the propeller struck the ground again, causing the aircraft to settle on its belly. The aircraft slid approximately 70 meters along the runway before coming to a halt, obstructing the centerline.
The investigation
The GPIAAF investigation examined the aircraft's maintenance history and the pilot's operational procedures. It was established that the aircraft had previously been involved in an accident in February 2006. At the time of the incident, the aircraft's Certificate of Airworthiness was suspended, as the necessary documentation had been submitted to the authorities for renewal and was not yet finalized.
Investigators analyzed the physical evidence on the runway, including the propeller blade deformation and the scrape marks on the asphalt. The investigation also reviewed the aircraft's electrical system, specifically the circuit breaker for the landing gear actuator, which had tripped during the event. The investigation further looked into the operational oversight by the airport's flight operations services in both Cascais and Évora, which had accepted flight plans without verifying the presence of mandatory aircraft documentation.
Findings
- The primary cause of the incident was the failure to extend the landing gear prior to touchdown.
- The pilot had not flown this specific aircraft for over a year and was not sufficiently familiar with its cockpit layout and procedures.
- The absence of mandatory onboard documentation, including essential checklists, prevented the pilot from verifying all landing configurations.
- The pilot elected to continue the flight despite noticing gear position irregularities and transponder malfunctions.
- The aircraft was operating without a valid Certificate of Airworthiness and without required documents on board.
- The landing gear actuator motor tripped its circuit breaker because the pilot attempted to manually extend the gear while the aircraft was already settling on the runway, preventing the mechanism from moving.
- The airport operations services at both the departure and arrival aerodromes failed to ensure the aircraft was carrying the required flight documents.