What happened
On July 20, 2007, a Socata TB 200 aircraft, registration CS-DEH, operated by the Academia Aeronáutica de Évora (AAE), was conducting a solo flight training mission. While flying at a very low altitude over the Vigia Dam area near Redondo, the aircraft struck medium-voltage electrical cables suspended approximately 30 meters above the ground. The impact caused the cables to snap and fall near nearby fishermen, resulting in power outages for local residences and the interruption of a national road.
The student pilot, who was performing a Simulated Forced Landing (SAF) maneuver, managed to maintain control of the aircraft despite the impact. Although the collision caused a rupture in the left fuel tank and subsequent fuel leakage, the pilot declared an emergency and successfully executed an emergency landing at the Évora Aerodrome. The pilot sustained no injuries.
The investigation
The GPIAAF investigation examined the flight path, the aircraft's condition, and the operational procedures established by the flight school. Investigators noted that the aircraft was flying in a designated training area known as "K," which had a vertical division extending from the ground up to 3,500 feet.
The investigation found that the aircraft was performing the maneuver in a north-to-south direction, which, combined with a 12-knot wind from 340 degrees, created a tailwind component. This tailwind made the recovery of the maneuver more difficult, as the school's manual recommended performing such maneuvers with a headwind. Furthermore, the investigation revealed that the student pilot had deliberately delayed the recovery to perform a low pass over the dam. The investigation also identified that the electrical poles were difficult to detect from the cockpit due to one being obscured by vegetation and the other being positioned far from the water level.
Findings
- The primary cause of the accident was the collision with electrical cables due to a violation of the Rules of the Air.
- The aircraft was flying below the minimum safety altitude required by ICAO VFR rules, which mandate a minimum of 500 feet AGL over terrain/water (unless otherwise authorized).
- The flight school's training syllabus allowed for the practice of simulated forced landings during solo missions, which contributed to the risk.
- The designation of the training area's lower limit as the ground level was inadequate for fixed-wing instruction, as it encouraged unsafe low-altitude flight practices.
- The school's established minimum descent altitude for the maneuver (100 feet AGL in certain areas) was lower than the standard VFR safety minimums.