What happened
On September 20, 2015, at 09:15 UTC, a Land Africa Impala ultralight aircraft, registration CS-USI, was conducting a private leisure flight at Valdonas Airfield in Tomar, Portugal. The aircraft was operated by a private individual and carried a crew of one pilot and one passenger.
After departing from runway 33, the aircraft climbed into a left downwind pattern, leveling off at approximately 600 feet AGL. While positioned over the runway, the aircraft suddenly pitched down and entered a left spin. The aircraft completed two and a half turns before impacting the ground. The collision resulted in two fatalities and the total destruction of the aircraft.
The investigation
The GPIAAF investigation established that the flight was properly authorized and the pilot was duly qualified. There were no reported pre-existing technical issues with the aircraft, and the engine was producing power at the moment of impact. The investigation focused on the aerodynamic sequence leading to the crash, specifically examining the aircraft's transition from a left turn into a spin.
Investigators also noted ambiguities in existing regulations regarding training syllabi, specifically pointing out that certain wording regarding high-speed maneuvers was contradictory and that training programs lacked explicit instruction on stall-induced wing drops during turns.
Findings
- The primary cause of the accident was loss of control in flight due to a spin caused by a low-speed turn.
- The loss of control occurred at a very low altitude of approximately 600 feet AGL.
- The pilot possessed little or no experience in spin recovery techniques.