What happened
On March 22, 1973, a Jodel DR 1051, registration HB-EBZ, was conducting a recreational flight from Annemasse, France, to Geneva, carrying the pilot and three children. During the approach to Geneva-Cointrin, air traffic control instructed the pilot to use the concrete runway 23, as the grass runway was closed. Due to heavy commercial traffic, the pilot was directed to fly a specific pattern to allow a DC-9 to land first.
After the DC-9 landed and vacated the runway, the pilot of the HB-REB proceeded to taxi toward taxiway 4. While executing a wide turn onto the taxiway without applying brakes and relying solely on the rudder, the pilot felt a vibration and observed the aircraft swerving sharply to the left. Despite attempts to correct the direction with the rudder pedals, the aircraft entered a ground loop. The force of the maneuver caused the main landing gear to be torn from the airframe, resulting in the aircraft coming to rest on its belly.
The investigation
The investigation examined the mechanical condition of the Jodel DR 1051 and the environmental factors present at the time of the incident. The aircraft was found to be airworthy, with the weight and center of gravity within permissible limits. While the tailwheel locking mechanism showed slight wear that reduced the force needed to disengage the guidance device, the tires and brakes were in good working order.
Investigators also reviewed the sequence of traffic at the aerodrome. It was noted that a DC-9 had landed just one minute prior to the HB-EBZ and had also vacated the runway via taxiway 4. The weather conditions were reported as having 4/8 cloud cover at 3,000 feet, visibility of 6 km, and a wind from 110 degrees at 7 knots.
Findings
Several contributing factors were identified that led to the pilot's loss of control during the taxi maneuver:
- Jet blast turbulence from the preceding DC-9
- The presence of a crosswind
- Excessive taxi speed during the turn