What happened
On July 28, 2023, at approximately 09:25 UTC, a Piper PA-36-375 aircraft, registration EC-DMO, was performing agricultural spraying operations near Brunhós, Coimbra, Portugal. The aircraft was operating from the Quinta da Foja agricultural runway.
During the second circuit over several rice field parcels, the aircraft experienced a sudden right-wing drop while aligned with a swath. The pilot reported a loss of engine power prior to reaching the swath line, which prompted an emergency release of the chemical hopper load. Following the loss of control, the aircraft struck vegetation and then the ground, rotating 180 degrees on its right wingtip. The impact caused the aircraft to catch fire, which subsequently spread to a small area of nearby forest. The pilot was able to egress the aircraft on his own and sustained minor injuries due to the protection provided by the seat belts during the abrupt deceleration.
The investigation
The GPIAAF conducted a safety investigation to gather evidence at the site. The investigation focused on the pilot's experience, the aircraft's configuration, and the operational procedures. Investigators noted that while the pilot held a valid commercial pilot license and had recently transitioned to agricultural work, there was no documented practical training program for specific or emergency maneuvers in high-risk agricultural operations. Additionally, there were no records of mass and balance calculations for the flight, though the pilot reported taking off with approximately 640 liters of product.
Findings
- The pilot had relatively limited experience in agricultural flight, having only begun training in tailwheel aircraft and agricultural operations in early 2023.
- There was no evidence of a practical training program for specific or emergency maneuvers consistent with the pilot's lack of experience in high-risk agricultural operations.
- The aircraft, a 1978 model, featured a high wing loading of approximately 100 kg/m², a design characteristic that requires precise control of aerodynamic stall speeds, particularly during turns.
- The aircraft was destroyed by the impact and the post-collision fire.
- An unexpected factor in the pilot's survival was that the emergency release of the hopper load was incomplete; the spilled liquid flowed through the cockpit, creating a protective barrier against the intense fire.