What happened
On November 3, 2012, a Cessna 152, registration PR-BRO, was conducting a local flight training mission at the Aeródromo Nacional de Aviação in Goiânia, Brazil. The flight, operated by Aeroclube de Goiás, included an instructor and a student.
During the approach to runway 13, the instructor decided to execute a go-around in the air due to a tailwind that made the landing seem unsafe. As the aircraft reached approximately 70 knots and the pilot reduced the pitch angle, the engine experienced a loss of power. The instructor attempted to turn back to the runway, but the aircraft lacked sufficient altitude. While attempting to divert the aircraft toward a hangar access road to avoid a residential area, the plane struck high-voltage power lines. The impact caused a loss of control, and the aircraft subsequently collided with the ground. Both occupants sustained light injuries, and the aircraft suffered substantial damage.
The investigation
CENIPA investigators examined the engine, propeller, and fuel systems, as well as the carburetor (a Precision MA-3). Post-accident testing of the cylinders, fuel lines, ignition, and fuel supply showed no mechanical discrepancies or defects. Analysis of the fuel by the National Agency of Petroleum, Natural Gas and Biofuels (ANP) confirmed the fuel met all required specifications.
Witness accounts provided a different perspective on the maneuver than the instructor's report. Witnesses observed that during the go-around, the pilot applied an excessive pitch angle of approximately 70 degrees, followed by a high negative load factor during leveling. Laboratory simulations using the aircraft's actual carburetor demonstrated that such extreme pitch angles cause fuel to shift within the float chamber, leaving the discharge jet without sufficient fuel to be atomized by the venturi effect. This disruption of the air-fuel ratio led to the engine failure.
Findings
- Excessive pitch angle during the go-around maneuver caused insufficient fuel delivery to the engine cylinders.
- The pilot's application of flight controls exceeded the operational limits for the aircraft's maneuver envelope.