What happened
On June 19, 2003, at approximately 17:30 UTC, a Quick Silver GT500 ultralight, registration CS-UCQ, was performing local flight maneuvers at the private Benavente aerodrome in Portugal. After departing from runway 33, the pilot performed several circuits of the airfield. While returning on a right downwind leg, the aircraft's engine suffered a sudden and complete failure.
Following the engine failure, the aircraft entered a steep dive and began rotating to the left. Despite the pilot's efforts to recover, the aircraft struck the ground approximately 50 meters north of runway 10/28 and 700 meters from the aerodrome facilities. The impact was extremely violent, occurring in a three-point horizontal position. Both the pilot and the passenger sustained fatal injuries due to multiple fractures and severe internal trauma, resulting in immediate death.
The investigation
The GPIAAF investigation focused on the mechanical state of the engine and the physical movement of the flight controls during the emergency. Investigators examined the wreckage, which showed significant structural deformation, including fractured landing gear, broken wing spars, and damaged engine mounts.
Technical analysis of the engine revealed that the cylinder on the magneto side had seized, which caused the sudden loss of power. Furthermore, the investigation examined the flight control columns. The control sticks for both the pilot and the passenger positions showed significant deformation, with the handles bent in opposite directions. This suggested that intense, opposing forces were applied to the controls during the descent.
Findings
- The primary cause of the accident was the sudden seizure of the engine cylinder, which led to a total loss of power.
- The pilot was unable to execute an emergency landing on the runway or adjacent clear terrain because the movement of the elevator control column was obstructed.
- It is believed that the passenger's leg prosthesis, combined with the limited space in the tandem cockpit, physically prevented the control column from moving backward, hindering the pilot's ability to pitch the aircraft up to maintain a glide slope.
- The aircraft was operating with a takeoff mass of 400 kg, which exceeded the local regulatory limit of 295 kg, although it remained within the manufacturer's certified limit of 454 kg.
- The pilot, while qualified to fly the aircraft, was not legally qualified to carry a passenger at the time of the occurrence.