What happened
On June 22, 2001, at approximately 17:50 LT, a mid-air collision occurred south of the Yverdon-les-Bains aerodrome in Switzerland. The aircraft involved were a Piper PA-28-181 Archer II, registration HB-PKL, carrying a pilot and three passengers, and a Schleicher ASW 15 glider, registration HB-1013, operated by a single pilot.
The HB-PKL had departed from Blécherette aerodrome and was approaching Yverdon for landing. At the same time, the HB-1013 glider was entering the glider descent zone for runway 23. During the approach, the HB-PKL performed a left turn, which placed it on a collision course with the glider. The aircraft collided at an altitude of approximately 230 to 280 meters. The impact struck the tail and fuselage of the glider and the tail section of the airplane. Following the collision, the engine of the HB-PKL stopped, and the aircraft entered a left-hand spin, eventually striking trees before hitting the ground. The glider lost its tail section and part of its right wing, landing inverted in a field.
The collision resulted in three fatalities: the pilot of the glider and two passengers from the HB-PKL. A third passenger from the HB-PKL sustained serious injuries during the impact with the ground. Both aircraft were destroyed.
The investigation
An investigation was launched by the Swiss Transportation Safety Investigation Board (SUST) in collaboration with the Vaud cantonal police. Investigators examined the flight paths, radio communications, and the wreckage of both aircraft.
Radio logs indicated high levels of aerial activity at the aerodrome that day, including motor flight, gliding, and parachuting. The investigation confirmed that both pilots were properly licensed and that neither was under the influence of alcohol or drugs. Technical inspections of both the HB-PK0 and HB-1013 revealed no mechanical failures or defects that contributed to the accident. The investigation also noted that the pilot of the HB-PKL had used 10 degrees of flaps during the approach.
Findings
- The primary cause of the accident was that the pilot of the HB-PKL failed to see the glider.
- High levels of air traffic and intense radio communications at the aerodrome may have created a stressful environment for the pilot of the HB-PKL.
- It is possible the pilot of the HB-PKL confused the HB-1013 glider with another glider that had recently completed its radio calls and landed.
- The pilot of the HB-PKL likely initiated a left turn to reposition for the downwind leg after hearing another aircraft announce its position, which inadvertently directed the plane into the path of the glider.