What happened
On October 26, 2017, a homebuilt JARMAN SIMON GLASTAR GS-1, registration F-PHIM, was parked at the general aviation apron of San Sebastián Airport (LESO) in Spain. The pilot, intending to fly to Auch Gers, France, had moved the aircraft from its parking stand to the engine testing area by pushing it manually with an assistant. During this process, the pilot did not place chocks under the wheels.
Because the aircraft's battery was depleted, the pilot used an external battery connected via jumper cables to initiate the start. The engine was started by the assistant, who pressed the starter button from outside the cockpit while the cabin remained unoccupied. Upon starting, the aircraft began to move unexpectedly, striking the assistant. In an attempt to regain control, the pilot tried to board the moving aircraft but failed, falling to the ground and being briefly dragged. The aircraft continued to roll for approximately 254 meters across the apron without a pilot on board, eventually striking a perimeter fence. The impact caused the nose wheel to collapse, and the aircraft overturned, striking a meteorological station belonging to AEMET. The pilot sustained minor injuries, while the aircraft suffered substantial damage.
The investigation
The investigation examined the sequence of events leading to the uncontrolled movement of the aircraft. Investigators noted that the pilot had not contacted the control tower to announce the intention to move the aircraft to the engine area, which is required by local procedures. While the parking brake was engaged, the investigation found that the brake's effectiveness was negligible because the hydraulic circuit had not been pressurized by pumping the pedals. Furthermore, the absence of wheel chocks and the decision to start the engine while the cockpit was empty created a high-risk scenario.