Aircraft and Personnel
The incident involved two light aircraft: a Cessna 182F Skylane, registration G-WARP, manufactured in 1963 (serial no. 182-54633), and a Grumman AA-5 Traveller, registration G-BBSA, manufactured in 1974 (serial no. AA5-0472). Both aircraft were powered by single piston engines: the Cessna had a Continental Motors Corp O-470-R, and the Grumman had a Lycoming O-320-E2G. Both flights were private, each with one pilot. The Cessna carried three passengers, and the Grumman carried one passenger. No occupants were injured.
Background
At the time of the accident, it was Race Day on the Isle of Man, resulting in a high number of aircraft movements at Ronaldsway Airport. Taxiway D had been reclassified as an apron, with approximately 70 light aircraft parked on the grass on either side. All aircraft were required to obtain clearance to taxi, but only IFR flights needed clearance to start engines. Both G-WARP and G-BBSA had been parked on the grass north of Taxiway D.
Sequence of Events
The pilot of G-BBSA, concerned about taxiing on uneven grass, had been advised by ground staff several days earlier to pull the aircraft onto the taxiway before starting the engine. Just before the collision, he moved the aircraft forward until the nosewheel was on the taxiway and the mainwheels were at the edge. He then started the engine and waited to contact the Tower for taxi and departure clearance. He heard an aircraft receive clearance and watched G-WARP taxi along Taxiway D towards him. Initially, he believed the right wing of G-WARP would clear his aircraft, but at the last moment realized a collision was imminent and attempted to shut down the engine. The outer section of the wing struck his propeller while the engine was rotating at approximately 1,000 rpm.
The pilot of G-WARP reported being aware of a parked aircraft with an engine running on the left side of the taxiway and G-BBSA, with its nosewheel on the taxiway, on the right side. He positioned his aircraft two meters left of the centerline, judging that there was sufficient clearance. He stated that the engine of G-BBSA was not running as his cabin passed the other aircraft.
Damage
Approximately 0.3 meters of the outer right wing and aileron of G-WARP were severed. The propeller of G-BBSA sustained slight damage, and the engine was suspected of having been shock-loaded.