What happened
On February 9, 2009, a Piper PA-23, registration N2176P, was completing its second flight of the day when the left engine began to fail as power was reduced while passing the vertical of the runway at Pará de Minas (SNPA). The pilot attempted to shut down the failing engine and entered the traffic pattern for a landing on runway 12. During the emergency, the pilot attempted to manually extend the landing gear using a hand pump but was only able to reach a halfway position.
After failing to restart the left engine, the pilot attempted a go-around. However, due to insufficient power to maintain flight, the pilot was forced to perform an emergency landing in a rural area near the left side of the runway 1/12 takeoff strip. The aircraft struck bushes and a fence before coming to a stop. The pilot and two passengers were uninjured, while one passenger sustained minor injuries. The aircraft sustained severe damage to the fuselage, wings, engines, and propeller.
The investigation
CENIPA investigators examined the aircraft's fuel system and engine components. Analysis of the fuel from both carburetors revealed the presence of water and metallic oxides, with the left engine's fuel containing higher levels of impurities. Surface corrosion was found in the fuel filter bowls and inside the engine fuel pumps, suggesting water contamination.
Investigators also noted that the fuel tank filler caps had worn and dried-out seals, and adhesive tape had been used on the left wing filler cap to prevent leaks. Furthermore, the investigation found that the aircraft's maintenance was inadequate, as evidenced by the corrosion in engine components and the lack of proper fuel drainage procedures, as the system only featured one drain per wing despite having two tanks per wing.
Findings
- Improper emergency management: The pilot attempted to execute the landing pattern, extend the landing gear, and restart the engine simultaneously, which led to a high-workload situation and prevented the establishment of a stabilized single-engine flight.
- Failure to feather propeller: The pilot did not feather the propeller of the failed engine, which significantly increased drag.
- Maintenance deficiencies: Inadequate maintenance allowed for engine component corrosion and failed to address worn fuel tank seals.
- Fuel contamination: The presence of water and impurities in the fuel system contributed to the engine failure.
- Pilot experience: While qualified, the pilot had limited experience with this specific aircraft type, which influenced the decision-making during the emergency.