What happened
On June 25, 2019, a Cessna 152, registration PR-MLB, was conducting a local flight instruction mission at the Pará de Minas Aerodrome in Minas Gerais, Brazil. The flight, operated by Aeroclube de Pará de Minas, carried an instructor and a student pilot.
After approximately 45 minutes of normal flight operations, the aircraft performed a touch-and-go maneuver. During the subsequent climb, the engine suddenly failed. The instructor took control of the aircraft and executed an emergency landing in an open field near the end of the runway. During the landing, the aircraft's landing gear struck vegetation, causing the plane to nose over. Both occupants of the Cessna 152 escaped without injury, but the aircraft sustained substantial damage.
The investigation
CENIPA investigators examined the engine and fuel systems to determine the cause of the power loss. Technical analysis by engineers from the Department of Aerospace Science and Technology (DCTA) included cylinder compression tests and magneto inspections, all of which yielded results within manufacturer specifications. The engine was subsequently tested in another aircraft and functioned normally.
Investigators also analyzed the remaining fuel, finding approximately 5 to 6 liters in each tank. This volume was at or below the level of unuseable fuel specified in the manufacturer's manual. While there were initial concerns regarding potential fuel adulteration due to abnormal lead accumulation on spark plugs, laboratory analysis by the National Agency of Petroleum, Natural Gas and Biofuels (ANP) confirmed that the imported AvGas met all required physical-chemical standards.
Discrepancies were noted between the instructor's and student's accounts regarding the refueling process. The investigation found that pre-flight briefings were not being consistently performed, which hindered situational awareness and the verification of critical tasks, such as fuel quantity.
Findings
- The engine failure was caused by inadequate flight planning, which resulted in insufficient fuel levels in the tanks.
- The lack of standardized pre-flight briefings prevented the effective verification of the refueling process.
- Organizational culture and management supervision contributed to the lack of adherence to briefing protocols.