What happened
On January 20, 2007, a Texan Top Class ultralight, registration I-6SB, departed from Benavente, Portugal, bound for the Palma aerodrome in Alcácer do Sal. The flight was operated by a pilot and one passenger. Following a social gathering in Benavente, the pilot decided to return directly to the Palma aerodrome.
During the final stages of the flight, the aircraft performed a low-level pass along the arm of the Venda Nova Dam. At approximately 15:56 UTC, the aircraft struck three medium-voltage electrical cables that crossed the waterway. The impact severed two of the aluminum-steel conductors, causing a power outage in the nearby village of Casebres. The collision caused the aircraft's tail section to break away, severing the elevator control cables and causing the parachute system to deploy due to the structural failure. The aircraft subsequently plunged into the waters of the dam, where the wreckage was found semi-submerged. The impact and subsequent submersion resulted in two fatalities.
The investigation
The GPIAAF investigation utilized GPS data to reconstruct the flight profile. The data revealed that the aircraft had been maintaining a steady altitude before initiating a descent and a right-hand turn during the final minute of flight. The investigation established that the pilot was flying at a height between 7.00 and 7.50 meters above the water level at the time of the collision.
Investigators examined the wreckage and the electrical infrastructure, noting that the cables were positioned perpendicularly to the aircraft's path. The investigation also reviewed the pilot's credentials, finding that his ultralight license had expired. Furthermore, the investigation analyzed the aircraft's fuel levels, estimating that the aircraft had sufficient fuel for the flight, and ruled out engine failure due to fuel exhaustion.
Findings
- The primary cause of the accident was the collision of the aircraft with medium-voltage electrical cables.
- The pilot violated air regulations by flying at an altitude of less than 150 meters (500 feet) above the water.
- The pilot's ability to detect the wires was likely hindered by the sun being directly in his line of sight during the low-level pass.
- The structural failure of the tail section was caused by the impact with the wires, which also triggered the accidental deployment of the parachute.
- The pilot was operating with an expired ultralight license.