What happened
On 24 January 2004, a Piper PA 28, registration EI-BSO, was conducting a private training flight near Ramsgrange, Co. Wexford. While the crew was performing aircraft stall maneuvers at approximately 3,200 ft AS to perform the third flight of the day, the engine lost power.
Upon the loss of power, the pilot identified a suitable landing site in a field located 50 ft above mean sea level. The pilot performed several emergency procedures, including switching fuel tanks and applying carburettor heat, but the engine failed to recover power. The aircraft landed in a field used for grazing cattle, striking two wires in the process. The crew, consisting of two individuals, evacuated the aircraft safely within 15 seconds. The landing resulted in minor damage to the engine air intake scoop, but there were no injuries to the crew or passengers.
The investigation
Investigators examined the aircraft and the engine components following the incident. While fuel samples were found to be satisfactory, the carburettor was removed and sent to a specialist contractor in the United Kingdom for a detailed strip-down and inspection.
During the examination of the carburettor, technicians discovered a small "centipede" type insect inside the bowl. The investigation also noted that ten days prior to the accident, the engine had experienced intermittent power issues during an approach to Waterford, which had been investigated but not resolved.
Findings
It could not be definitively determined whether the engine failure was caused by carburettor icing or an obstruction. While the ambient temperature of 8°C and a dewpoint of 4°C created conditions favorable for serious carburettor icing, the presence of the insect in the carburettor bowl suggested a potential blockage. It is possible that the insect blocked a fuel jet, thereby interrupting the fuel supply to the engine.