What happened
On November 19, 2016, a Cessna 172A, registration PT-BHB, departed from Tupi Paulista, São Paulo, bound for São Sebastião do Paraíso, Minas Gerais. The flight, operated by Aeroclube Tupi Paulista, was carrying a pilot and three passengers.
During the initial approach to the destination aerodrome, the engine experienced a flameout. The pilot attempted to restart the engine but was unsuccessful. Consequently, the pilot performed an emergency landing in an open field approximately 7km from the destination. During the landing sequence, the aircraft's landing gear struck a farm fence, causing the nose to pitch down. While the aircraft sustained substantial damage, all four occupants escaped the wreckage without injury.
The investigation
CENIPA investigators examined the flight planning, aircraft maintenance records, and environmental conditions. The investigation confirmed that the pilot held valid commercial and flight instructor licenses, and the aircraft possessed a valid airworthiness certificate. Maintenance logs for the airframe, engine, and propeller were up to date, and the aircraft was within weight and balance limits.
Investigators analyzed the fuel consumption parameters based on the aircraft's owner's manual. While the pilot maintained a rich mixture setting to manage engine temperatures, this significantly increased fuel consumption. The investigation also noted that the flight encountered a 15-knot headwind, which further increased the duration of the flight.
Findings
- The engine flameout occurred because the aircraft had exhausted its usable fuel.
- Inadequate flight planning failed to account for the high fuel consumption rate caused by operating with a rich mixture at 3,500ft.
- The presence of a 15-knot headwind reduced the aircraft's ground speed and increased the time required to reach the destination.
- The pilot's estimation of a 4.5-hour endurance was inconsistent with the actual operational parameters used during the flight.