What happened
On August 24, 2015, at approximately 15:00 UTC, a Cessna A188B, registration PT-WHY, was performing a ferry flight from Rio Brilhante, MS, to Gabriel Monteiro, SP. After roughly two hours of flight, the pilot reported a loss of power followed by a total engine failure. To avoid further complications, the pilot executed a forced landing in a pasture located near the Centro de Progress and Progressão Penitenciária in Pacaembu, SP.
The impact caused substantial damage to the aircraft's wings, landing gear, engine, and fuselage. The pilot survived the occurrence without injuries.
The investigation
CENIPA investigators examined the fuel management and flight planning procedures used during the mission. The investigation revealed that the aircraft's fuel quantity indicators (float gauges) were inoperative, and the fuel flow meter was not providing reliable indications. Consequently, the pilot had performed a visual check to confirm the aircraft was filled to its total usable capacity of approximately 52 US gallons.
While the pilot intended to fly for 2 hours and 20 minutes, the aircraft's average fuel consumption is approximately 23 gallons per hour, providing an estimated endurance of 2 hours and 15 minutes under standard conditions. Investigators found that the pilot relied on a routine planning method, assuming a fixed 2.5-hour endurance based on full tanks, without accounting for variables such as weight, altitude, or power settings. Notably, a significant amount of extra fuel (approximately 210 liters) was found stored inside the aircraft, intended for later refueling.
Findings
- The most probable cause was fuel exhaustion due to inadequate flight planning.
- The pilot failed to properly evaluate risks by not considering how changes in weight, altitude, and power settings would affect fuel consumption.
- The pilot did not utilize the aircraft's Pilot's Operating Handbook (POH) to accurately calculate the required fuel for the mission.
- The aircraft's fuel quantity indicators were inoperative, and the fuel flow meter was unreliable.
- Flight planning was based on a fixed endurance assumption rather than real-time performance calculations.