What happened
On July 18, 2007, a Piper PA-23 Aztec, registration EC-AZV, was conducting a private flight from Sabadell Aerodrome to Requena Aerodrome. The aircraft, operated by Aeroclub de Sabadell, was carrying one pilot and two passengers when the cabin door opened while cruising at an altitude of 4,000 feet.
The sudden opening of the door caused intense vibrations throughout the airframe. To mitigate these forces, the pilot attempted to stabilize the aircraft by transitioning from a low-cruise configuration to a slow-flight configuration. Due to the loss of normal flight control caused by the vibrations, the pilot executed an emergency landing in the municipality of Cabanes, specifically near a construction area adjacent to the CV-157 road.
During the landing, the aircraft traveled approximately 100 meters along the soft, irregular ground before veering left and coming to a stop in a roadside ditch. The aircraft sustained important damage, but all three occupants were uninjured and able to exit the aircraft on their own.
The investigation
Investigators examined the door's locking mechanism, which utilizes a complex system of levers, bars, and cables. While the post-accident inspection found no mechanical defects and confirmed the door could be locked and unlocked normally, the investigation focused on the possibility of improper engagement.
The investigation also reviewed maintenance records, noting that the door had undergone several maintenance actions, including one specifically related to a malfunction reported in June 2007. Additionally, the investigation noted that the pilot's training for multi-engine ratings included specific procedures for managing this exact emergency, which involves reducing speed to 90 mph and attempting to close the door from the left window.
Findings
- The primary cause of the accident was the in-flight opening of the door, likely due to an incorrect locking of the mechanism.
- The resulting vibrations prevented the pilot from maintaining normal control of the aircraft.
- The choice of an emergency landing site on soft and irregular terrain contributed to the aircraft veering off course during the landing roll.