What happened
On February 7, 2004, a Cosmos Chronos 14 ultralight, registration CS-UDF, departed from the Tavira airfield for a local flight. The aircraft was carrying a pilot and one passenger. During the initial climb, upon reaching an altitude of approximately 180 feet, the engine ceased operation.
Faced with low altitude and low airspeed, the pilot attempted an emergency landing in a nearby field used for model aircraft flying. During the approach, the aircraft's right main landing gear struck a 40 cm high earthen embankment. The impact caused the aircraft to rotate 90 degrees to the left of its approach path and subsequently roll over approximately 15 meters from the point of impact. The pilot sustained a fractured right wrist, while the passenger remained uninjured.
The investigation
The GPIAAF investigation focused on the mechanical failure and the landing execution. Investigators examined the engine and the aircraft's maintenance history. The investigation revealed that the aircraft was frequently transported in a trailer and assembled/disassembled for each flight. This repetitive process led to the degradation of the insulation on an electrical cable supplying the engine.
Furthermore, the investigation found that the manufacturer's established maintenance plan had not been followed. While the pilot, a former Air Force aircraft electrician, performed much of the maintenance himself, the engine logbook lacked records of periodic inspections required by the manufacturer and did not include the engine's installation details.