What happened
On 31 January 2016, a Piper PA-28-161 Cherokee Warrior III, registration G-CEXO, was involved in an accident at Durham Tees Valley Airport during a private flight. Following the engine start sequence, witnesses observed flames emerging from the lower area of the engine cowling. Upon being alerted to the fire, the pilot immediately throttled back, shut down the engine, and instructed the passenger to evacuate the aircraft. During the evacuation, the pilot issued a MAYDAY call and deactivated the electrical master switch. A bystander managed to extinguish the flames using a handheld fire extinguisher, specifically targeting the fuel water drain access hole.
Prior to this incident, the aircraft had completed two successful flights that day. During the first flight, which involved a cold engine, the pilot had used the electric primer for 50 seconds following advice from a maintenance engineer to address recent starting difficulties. During the second flight, with a warm engine, a shorter 25-second priming period was used. However, during the climb phase of that second flight, a faint smell of fuel was noted by the pilot.
The investigation
The investigation examined the engine starting procedures and the recent maintenance history of the aircraft. It was established that while the Pilot's Operating Handbook (POH) does not specify a maximum duration for priming, it suggests priming only as necessary if an initial attempt fails. The investigation found that the aircraft had recently experienced difficulties starting, which had led to a deviation from standard club procedures. While the standard technique involved approximately six seconds of priming, some pilots had been priming for much longer periods, including up to 50 seconds, to ensure a successful start.
Findings
- The fire originated in the airbox and carburettor area, spreading to the engine cowling.
- The fire was caused by overpriming the engine.
- There were no injuries to the pilot or the passenger.
- The aircraft sustained minor damage to the engine cowling paint and the ADF aerial.