What happened
On February 24, 2011, a student pilot was preparing for a local flight at Jerez de la Frontera Airport (LEJR) in Spain. The aircraft, a PIPER PA-28-161 Warrior with registration EC-IKF, was operated by Flight Training Europe.
Following standard pre-flight procedures, the pilot successfully started the engine using the primer. However, as the pilot reduced power to idle during the initial taxi, the engine stalled. The pilot attempted a second start for approximately 10 seconds without using the primer. During the subsequent wait for the engine to cool, smoke was observed emanating from the front of the aircraft, and an instructor in a nearby aircraft reported seeing fire. The pilot immediately retarded the throttle and evacuated the aircraft.
An intense fire broke out in the engine compartment, producing heavy white smoke. While bystanders attempted to suppress the flames with handheld extinguishers, the fire was only extinguished by airport firefighters. The aircraft sustained important damage to the entire area forward of the firewall, including the engine, the melted lower cowling, and the nose gear fairing.
The investigation
The investigation focused on the origin of the fire and the operational procedures used during the startup. Investigators examined the fuel system and found no leaks, loose lines, or faulty connections. The inspection revealed that the fire originated in the lower part of the engine, specifically in the carburetor area, and spread from there.
Post-fire inspections of the aircraft's configuration showed that the fuel pump was connected, the mixture was set to lean, the throttle was at idle, and the right fuel tank was selected. The investigation also reviewed the Pilot Operating Handbook (POH) regarding startup procedures for a flooded engine, which mandates that the electric fuel pump should remain disconnected and the throttle should be at maximum power.
Findings
- The investigation determined that the fuel overflow from the carburetor was the primary cause of the fire.
- During the second startup attempt, the electric fuel pump was left engaged, contrary to the POH instructions for a flooded engine scenario.
- It is believed that the engine was already sufficiently primed from the first attempt; the use of the fuel pump during the second attempt likely caused excess fuel to overflow the carburetor and contact a hot engine component.
- The pilot followed the manual's emergency procedures by retarding the throttle but was unable to cut the fuel supply due to the rapid spread of the fire and the need for immediate evacuation.