What happened
On April 19, 1964, at the Eplatures airfield in La Chaux-de-Fonds, a pilot was conducting training maneuvers to obtain an extension to his license for glider towing operations. The flight was performed under the direct supervision of a flight instructor. During the second towing exercise of the session, the pilot prepared to release the tow rope and proceed immediately to landing without performing an additional circuit.
As the pilot approached the grass runway, he experienced a sudden loss of altitude and airspeed. The pilot reported a moment of hesitation while attempting to manage the aircraft's energy. The DH-824 Tiger Moth, registration HB-UBL, struck the ground approximately 150 meters from the start of the runway. The impact occurred on the landing gear and the lower left wing, causing the aircraft to tilt onto its right wing and capsize. The pilot emerged from the wreckage without injury, though the aircraft sustained heavy damage to the propeller, engine cowling, landing gear, and wings, leading to its total loss.
The investigation
An investigation established that the pilot had recently completed transition training on the DH-824 Tiger Moth only one day prior to the accident. While the pilot was physically fit and had no prior history of violations, he lacked extensive experience with this specific aircraft type. The investigation examined the flight procedures used at the airfield, specifically the practice of releasing the tow rope and landing during the same approach. Investigators also reviewed the instructions provided by the flight instructor prior to the flight.
Findings
- The primary cause of the accident was a loss of airspeed during the final approach.
- The pilot, being relatively unfamiliar with the aircraft, likely became preoccupied with the task of releasing the tow rope.
- This preoccupation led to a lack of attention to the aircraft's flight parameters, causing the plane to sink.
- The instructor failed to explicitly instruct the pilot to separate the rope release from the landing maneuver.
- The practice of attempting to land immediately after a release is a high-risk maneuver that requires significant experience and training.