What happened
On July 2, 1964, a Piper Colt (HB-ORR) was positioned at the holding bay for runway 05 at Geneva-Cointrin Airport. The pilot and a passenger were preparing for a VFR flight to Prangins. While the light aircraft was stationary and facing into the wind, an Air Algerie SE-210 Caravelle (F-BLCZ) was taxiing to the runway.
After having previously stopped at the holding point to wait for an Iberia aircraft to depart, the crew of the Caravelle increased engine power to 6,000 RPM to proceed to the runway. As the jet aircraft performed a right-hand turn to align with the runway, its engine exhaust swept across the holding bay. The force of the jet blast, combined with existing wind conditions, caused the Piper Colt to oscillate and eventually tip onto its right side, resulting in damage to the propeller, nose gear, and right wing tip.
The investigation
The investigation examined the movements of both aircraft, the meteorological conditions, and the airport procedures in place at the time. Investigators reviewed the radio communications between the aircraft and Geneva Ground and Tower controllers. The inquiry also assessed the physical layout of the holding bay 05, noting its position relative to the taxiway turn and the path of aircraft aligning with the runway.
Findings
- The primary cause was the combined effect of the jet blast from the Caravelle's engines and the prevailing wind.
- At the time of the incident, the wind was blowing from the northeast at approximately 18 knots.
- The Caravelle's maneuver required an increase in engine thrust to complete the turn, which directed the exhaust directly toward the stationary light aircraft.
- The wind was blowing parallel to the jet exhaust, acting as an additional force that pushed the light aircraft.
- Because the Piper Colt was light and the wind speed was significant, the aerodynamic lift and turbulence created by the jet engines made the aircraft highly vulnerable to being overturned.
- The holding bay is located outside the turning radius of aircraft aligning with the runway, making it inherently susceptible to engine wash.