What happened
On December 8, 1970, a Piper PA-18 Super Cub, registration HB-OPW, was prepared for a pleasure flight at the Eplatures aerodrome. The pilot positioned the aircraft on the tarmac, parallel to runway 06, with a passenger already seated in the rear.
To facilitate a manual engine start, the pilot requested that the passenger apply the brakes. However, the pilot failed to place wheel chocks in front of the tires. Upon starting the engine by hand, the aircraft began to move, turning right and rolling toward a nearby hangar. In an attempt to reach the cockpit and shut off the engine, the pilot moved under the right wing, causing the left wingtip to strike a hangar door frame. The impact caused the aircraft to pivot, leading the rotating propeller to strike and damage the hangar door.
The investigation
The investigation examined the aircraft's mechanical condition, the environmental factors, and the procedures used during the start sequence. Investigators found that the brakes were fully functional and the aircraft was well-maintained with valid airworthiness certificates.
While the tarmac was covered in a layer of ice and approximately 5 cm of snow, tire tracks in the snow confirmed the aircraft rolled under its own power rather than sliding. The investigation also looked into the passenger's method of applying the brakes. It was discovered that the passenger, who lacked aviation experience, was not instructed on the correct technique for braking and was pressing with the tips of his shoes rather than his heels, which compromised braking effectiveness.
Findings
Several contributing factors led to the collision:
- The pilot performed a manual start without using wheel chocks.
- The engine was running at an excessively high RPM (approximately 1500 RPM) because the throttle was set too far forward.
- The tarmac possessed a slight slope directed toward the hangar.
- The passenger's lack of training resulted in an ineffective application of the brakes.
There were no injuries to the pilot or the passenger, though the Piper PA-18 Super Cub sustained significant damage, estimated at 70% of its value.