What happened
On October 6, 2020, a Piper PA-25-235, registration LV-LXM, departed from a private airfield in Los Toldos, Buenos Aires, for a local training flight. Shortly after rotating from runway 09, the engine suffered a sudden loss of power. The pilot attempted an emergency landing, but the aircraft struck the ground near Provincial Route 65. The initial impact occurred at the tailwheel, after which the aircraft slid and rotated approximately 180 degrees until the left main landing gear struck the terrain, bringing the aircraft to a stop. There were no fatalities or injuries to the pilot during the event.
The investigation
The investigation focused on the engine's performance and the fuel system. While the air intake was clear, investigators found that the carburetor bowl was empty of fuel. Physical evidence at the scene and laboratory analysis revealed traces of a polymeric material—likely Teflon tape used for sealing threads—inside the fuel connection valve and obstructing the carburetor nozzle. This blockage prevented the necessary flow of fuel to the engine.
Furthermore, the investigation looked into the aircraft's maintenance and operational status. It was discovered that the main fuel tanks were disconnected, and the aircraft was operating solely on a supplementary nose tank. Additionally, the oil sampled from the crankcase sump was found to be unsuitable for use due to excessively high viscosity. The investigation also noted that the aircraft's records had not been updated since October 2019, and the operator's Air Operator Certificate (CETA) had expired earlier that year.
Findings
- The engine power loss was caused by fuel starvation resulting from polymeric material obstructing the fuel nozzle and connection valve.
- The aircraft was utilizing only a supplementary nose tank for the flight, as the main tanks were disconnected.
- The pilot was operating with an expired medical certificate.
- Fuel at the base was stored in a drum labeled as lubricant oil, posing a risk of contamination.
- The aircraft's maintenance documentation and the operator's certification were both out of date.