What happened
On July 8, 2003, a SUD-AVIATION Gardan Horizon GY-80-160, registration HB-DCI, departed from the Prangins airfield for a flight to Geneva. During the takeoff roll on runway 04, the aircraft appeared to perform normally. However, once the aircraft reached an altitude of approximately ten meters while crossing a road at the end of the runway, the engine experienced a significant drop in RPM. This power loss was observed by several witnesses, including experienced pilots. Following a brief moment of regained power, the engine stopped completely. The aircraft maintained a straight path before striking trees at the edge of a forest at a height of about twelve meters. The impact occurred at a steep 60-degree angle, causing the wings to be severed and the fuselage to break. The pilot was killed upon impact, and the passenger sustained serious injuries.
The investigation
Investigators examined the wreckage and the engine components. While the fuel was found to be compliant with specifications and no water contamination was detected, the investigation revealed that the aircraft had experienced two significant engine power drops during a previous takeoff from Geneva just days earlier. No technical inspections or repairs were performed following that incident. Technical analysis of the engine and carburetor showed no definitive mechanical cause for the failure. Additionally, investigators discovered that the aircraft's tachometer was incorrectly calibrated for the engine's RPM, resulting in a 10% underestimation of actual flight hours. The investigation also noted that the pilot had not refueled the aircraft at Prangins or Geneva prior to the accident.
Findings
- The primary cause of the accident was a loss of engine power during the takeoff phase.
- It is probable that the aircraft's nose-high attitude after takeoff prevented the remaining fuel in the tanks from being properly drawn into the engine.
- The pilot did not initiate any technical inspections or maintenance following engine fluctuations observed during a flight from Geneva a few days prior.
- The aircraft's weight and center of gravity were within permissible limits, and weather conditions were favorable for flight.