What happened
On December 28, 2016, at approximately 13:55 local time, a ground collision involving three aircraft occurred at Birrfeld Aerodrome (LSZF). The incident began while the pilot of a Rutan VariEze, registration HB-YBL, was attempting to start the engine. Because this specific aircraft requires manual engine starting, the pilot had to hand-prop the propeller.
During this manual starting process, the parking brake of the HB-YBL unexpectedly released. This caused the aircraft to begin rolling toward a nearby fuel station. In its path, the moving aircraft struck two other stationary planes: a HB-UCT (Gyroflug SC 01 Speed Canard) and a HB-YLB (Votec 322).
The investigation
An investigation by the Swiss Transportation Safety Investigation Board (SUST) established that the collision involved three separate aircraft. The investigation focused on the mechanical sequence of the engine start and the subsequent movement of the HB-YBL. The inquiry confirmed that there were no injuries to any persons involved in the incident, though all three aircraft sustained damage.
Findings
- The primary cause of the movement was the release of the handbrake during the manual engine starting procedure.
- The Rutan VariEze (HB-YBL) rolled toward the fuel station after the brake failed to hold the aircraft in place.
- The collision resulted in light damage to all three aircraft involved.