What happened
On 5 March 1998, a Piper PA-3ly8-112, registration G-BSOU, was involved in an incident at Cumbernauld Airport involving damage to several other aircraft. Following refueling, the pilot performed a pushback procedure with the engine running, positioning the aircraft so that the tail was facing the open doors of a nearby hangar. After a ground handler warned that the propeller wash was blowing into the hangar, the pilot taxied to holding point Bravo to perform engine power checks.
While positioned in the westerly wind, the pilot aligned the tail of the aircraft directly with a line of parked planes. Upon opening the throttle for the power check, the resulting airflow caused a cowling to detach from a nearby Socata TB 10. This component drifted over the fuselage of another aircraft and struck an aerial, causing it to break off. The force of the wash also caused a Piper Cub to be blown backward, subsequently striking an Islander.
The investigation
The investigation was based on the aircraft accident report submitted by the pilot and subsequent telephone inquiries. The AAIB examined the sequence of the engine run-up and the positioning of the aircraft relative to the parked fleet. The investigation established that the pilot was alerted to the initial risk of propeller wash entering the hangar by a ground handler, which prompted the taxi to the holding point. However, the new position at holding point Bravo placed the aircraft's tail directly in line with a row of parked aircraft.
Findings
- The primary cause of the damage was the increased airflow from the propeller during the power check.
- The pilot's positioning at holding point Bravo placed the tail of the G-BSOU in direct alignment with a row of stationary aircraft.
- The propeller wash was powerful enough to detach a cowling from a Socata TB 10 and move a Piper Cub into an Islander.