What happened
On December 30, 2000, a RANS S-14 ultralight aircraft, registered EC-YPD, was conducting a local flight test at the Cerval aerodrome in Valença, Portugal. The pilot intended to evaluate the aircraft's performance for a potential purchase. Shortly after takeoff from runway 34, at an altitude of approximately 30 meters, the engine failed.
In an attempt to return to the airfield, the pilot initiated a 180-degree turn to land on runway 16. However, due to the low altitude and the reduced airspeed following the engine failure, the aircraft lost lift and entered a stall. The aircraft subsequently plummeted into the ground near the threshold of runway 16, resulting in the death of the pilot and the total destruction of the aircraft.
The investigation
The GPIAAF investigation examined the aircraft's condition, the pilot's experience, and the operational environment. Investigators found that the engine had been subjected to bench testing after the accident, which revealed no mechanical deficiencies that would explain the failure. While witnesses noted fuel spilled at the site, the presence of fuel in the right wing tank suggested the failure was not due to fuel exhaustion, though a blockage or rupture in the fuel line remained a possibility.
The investigation also noted significant regulatory irregularities. The Cerval aerodrome was not certified by the national aviation authority, and the operations conducted there were considered unauthorized. Furthermore, there was a lack of maintenance and flight time records for the aircraft, and the aircraft's insurance had expired prior to the accident.
Findings
- The primary cause of the accident was the engine failure following takeoff, which led to a stall during an attempted turn at insufficient altitude and airspeed.
- The pilot's lack of experience contributed to the accident, as the decision to attempt a 180-degree turn contradicted flight manual recommendations, which advise landing straight ahead when altitude is insufficient for a return to the runway.
- A lack of flight discipline and aeronautical knowledge was evident, characterized by the execution of a flight in an unfamiliar aircraft without proper safety precautions.
- Negligence regarding maintenance and flight log documentation meant the operational status of the engine and airframe could not be verified.
- The pilot's experience was extremely limited, with only 11.5 hours of flight time recorded 18 days prior to the accident.