What happened
On May 31, 2020, at approximately 10:20 local time, a Tecnam P92 Echo S, registration I-8534, was performing a takeoff from the ARMA airfield in Nettuno, Italy. The aircraft was occupied by the pilot and one passenger. Shortly after departing runway 21, during the initial climb phase, the aircraft entered an uncontrolled descent. The aircraft impacted the ground approximately 350 meters from the airfield, and a post-impact fire broke out. Both occupants sustained fatal injuries upon impact.
The investigation
The ANSV investigation examined the wreckage, engine components, and cockpit environment. Investigators reviewed video footage from social media showing the pre-flight and engine start procedures. The investigation also analyzed the pilot's flight history, noting that while the pilot held a valid PPL(A), his recreational flight (VDS) qualifications and medical certificate were expired.
Technical examinations of the engine and fuel system were conducted. Using video-endoscopy, investigators found that both fuel shut-off valves were only approximately 10% open, meaning they were 90% closed. The investigation also looked into the design of the fuel valve labeling and the cockpit atmosphere during the start-up sequence.
Findings
The primary cause of the accident was a loss of control resulting from an asymmetric stall. This stall was triggered by an engine malfunction, which was likely caused by the failure to fully open the fuel shut-off valves.
Several contributing factors were identified:
- The pilot's limited flight experience.
- A lack of cockpit discipline, as the pre-flight and start-up procedures were conducted in a jovial atmosphere that did not adhere to the principle of a sterile cockpit.
- An ambiguous design of the fuel system selection interface, where the instructional labeling for the "ON" and "OFF" positions on the fuel shut-off valves could lead to incorrect interpretation due to expectation and confirmation bias.
- The aircraft's flight manual lacked a specific requirement to verify the correct opening of the fuel shut-off valves during the pre-takeoff checklist.