Accident Overview
On 2 July 1964, at Geneva-Cointrin Airport, a Piper Colt HB-ORR (PA-22-108) occupied by a pilot and a passenger was holding on holding area 05, facing into the wind. A Sud Aviation SE-210 Caravelle III, F-BLCZ, operated by Air Algerie as flight AH 186 from Geneva to Algiers, was aligning on runway 05 after being cleared to taxi to the runway and then to line up and wait.
Sequence of Events
The Piper Colt had received taxi clearance to runway 05 and then switched to tower frequency. After reaching the holding area, the pilot elected to position the aircraft as far back as possible on the western edge of the holding area to avoid the Caravelle's jet blast. The Caravelle, having stopped at the holding point while a departing Iberia Caravelle used the runway, increased power to resume taxiing and enter the runway. During this maneuver, the Caravelle made a quarter turn to the right, directing its jet exhaust toward the holding area where the Piper was parked.
The Piper, with its engine running at 1200 rpm and brakes set, oscillated and tipped onto its right side. The right wingtip and propeller struck the ground.
Damage and Injuries
Neither occupant of the Piper Colt was injured. The Piper sustained damage including a twisted propeller, distorted nose landing gear geometry, and damage to the right wing tip. Repair costs amounted to 2,200 Swiss francs, approximately 8% of the aircraft's value.
Weather Conditions
At the time of the accident, weather was characterized by a northeasterly wind (bise) at 18 knots. The wind was blowing parallel to the jet blast, acting as an additional vector to the turbulence generated by the Caravelle's engines.
Statements
The pilot of the Piper stated he followed tower instructions and moved the aircraft as far back as possible as a precaution. The Caravelle commander noted that during the alignment phase, he did not expect to blow the light aircraft, believing he had passed it sufficiently. The tower controller indicated that such situations were not uncommon and no prior incidents had occurred.
Discussion
The holding area 05 is located outside the turn that aircraft make when aligning on the runway, making it susceptible to propeller or jet blast from larger aircraft. In this case, the Caravelle's pilot, after stopping at the holding point, increased engine power to resume taxiing, which amplified the jet blast. The distance between the two aircraft at the critical moment was over 80 meters. The minimum lift-off speed of a Piper Colt is around 46 knots; the wind and jet blast combined produced a relative wind speed exceeding one-third of that, reducing wing loading and making the aircraft more vulnerable to the disturbed air.