What happened
On January 7, 2014, a Cessna 172 A, registration PT-BHF, was performing a private flight from Rondonópolis (SWRD) to Primavera do Leste (SWPY) in Mato Grosso, Brazil. The flight was conducted under visual flight rules (VFR) with the pilot maintaining an altitude of 3,500 feet during the cruise phase.
As the aircraft approached the base leg for the landing at SWPY, the engine failed. The pilot attempted to glide the aircraft toward runway 19; however, there was insufficient altitude to reach the runway threshold. Consequently, the pilot performed a forced landing into a soybean plantation. The aircraft struck the ground approximately 660 meters from the runway threshold, resulting in substantial damage to the airframe. The pilot sustained minor injuries.
The investigation
The investigation established that prior to the flight, the pilot had conducted a verification flight to check for any discrepancies following a recent 50-hour inspection. During the preparations for the subject flight, the pilot measured the fuel levels using a ruler, noting 12 liters in the left tank and 26 liters in the right tank. Following this, the pilot refueled the left tank with 32 liters, bringing the total fuel load to approximately 58 liters (42 liters in the left tank and 16 liters in the right tank).
The investigation analyzed the fuel consumption requirements based on the aircraft's Owner's Manual. For a flight duration of approximately 55 minutes, including taxi, takeoff, climb, and cruise, the estimated consumption was approximately 40.65 liters. However, the investigation noted that the 16 liters available in the right tank placed the fuel level within the red arc of the indicator (indicating 1/4 tank or less), which, according to the manual, is a condition where takeoff is not recommended.
Crucially, the investigation determined that by the time the aircraft reached the traffic pattern at SWPY, the remaining fuel was approximately 17.65 liters, which essentially consisted only of the unuseable fuel. The engine failure was confirmed to be a fuel exhaustion event.
Findings
- Fuel exhaustion caused the engine failure.
- Inadequate flight planning regarding fuel reserves.
- Errors in pilot judgment regarding takeoff with low fuel levels in one tank.