What happened
On December 8, 2021, a Cessna 152, registration CP-2667, was conducting a local instructional flight near Peji, Santa Cruz, when the engine experienced a loss of power. The aircraft, operated by CIAC Sky Team and carrying an instructor and a student pilot, had departed at 13:54 UTC for training maneuvers. During a right-hand turn while returning to the area, the crew noted fluctuating power and a loss of altitude.
To avoid a more serious accident, the crew performed an emergency landing in an irregular open field. During the landing sequence, the nose gear struck a ditch, causing the aircraft to skid 10 and then overturn. The impact resulted in significant damage to the airframe, including a broken nose gear, damaged engine mount, bent propeller, and structural deformations to the fuselage, wings, and doors. Both occupants exited the aircraft without injuries.
The investigation
The investigation by the Bolivian AIG authority established that the aircraft had not been refueled since its previous flight eight days prior. At the time of the accident, the total fuel on board was approximately 13 gallons. Based on the engine's consumption rate and the fuel remaining after takeoff and taxiing, only about 9.5 gallons of usable fuel were available for the flight.
The investigation revealed that the aircraft had been modified via STC SA4795SW with a larger Lycoming O-320 engine, which requires a Supplemental Flight Manual (SFM) for proper operation. The investigators found that the operator did not possess this required SFM, leaving the pilots without accurate performance and endurance data. Furthermore, the student pilot had incorrectly recorded an endurance of five hours in the flight logs, based on manual values rather than actual fuel levels.
Findings
- Fuel exhaustion was the probable cause of the engine power loss.
- Inadequate fuel management by the crew.
- Lack of necessary operational documentation (Supplemental Flight Manual) for the modified aircraft.
- Incorrect calculation of flight endurance during pre-flight planning.