What happened
On May 4, 2010, a BINGO ultralight aircraft, registration EC-EG4, departed from Cerval aerodrome in northern Portugal for a local VFR flight. The aircraft was carrying a pilot and one passenger. Approximately 45 minutes into the flight, while cruising at 1,20 and feet AGL, the engine began losing power, accompanied by a sharp drop in the temperature of the right cylinder.
The pilot attempted to return to the Cerval runway, but the high rate of descent and headwind made reaching the strip impossible. The pilot identified a small field near a residence as an emergency landing site. During the final approach, the pilot encountered an overhead electrical cable and was forced to trade airspeed for altitude to avoid a collision, causing the aircraft's speed to drop to approximately 60 km/h.
At an altitude of roughly 100 feet AGL, the pilot activated the aircraft's ballistic parachute system. The parachute deployed effectively, but the aircraft descended in a steep nose-down attitude, impacting the ground on its engine assembly. Both the pilot and the passenger sustained minor injuries.
The investigation
The GPIAAF examined the wreckage and the engine components. The investigation focused on the sudden loss of power and the mechanics of the emergency descent. Investigators analyzed the engine'1s condition and the installation of the emergency parachute system.
Findings
- The engine failure was caused by the absence of the spark plug from the right cylinder head. It is believed the plug was improperly tightened during a recent maintenance inspection and subsequently vibrated out of the cylinder, leading to decompression and loss of ignition.
- The aircraft's nose-down attitude during the parachute descent was likely due to the parachute being installed too far from the center of gravity, specifically configured for a single occupant rather than two.
- The pilot's decision to delay parachute deployment until a low altitude was influenced by the fear of being drifted by the wind into nearby high-voltage power lines or trees.