What happened
On August 12, 2017, an Excel Cargo aircraft, registration PU-MON, departed from the Brigadeiro Araripe Macedo Aerodrome (SWUZ) in Luziânia, Brazil, bound for Brasília. Approximately two minutes after takeoff, the aircraft experienced an engine failure.
GPS data indicated that after an initial climb, the aircraft's speed and altitude began to decrease, signaling a loss of power. The pilot attempted to execute a turn to return to the runway. During this maneuver, the pilot encountered another aircraft on final approach to the same runway. To avoid a mid-air collision, the pilot performed a low-altitude maneuver to the right of the runway. However, the aircraft struck the ground approximately 30 meters from the runway near the threshold of runway 11. The aircraft was destroyed, and the pilot sustained severe injuries, later passing away three days after the accident.
The investigation
CENIPA investigators examined the engine, the fuel system, and the flight trajectory. The investigation included a bench test of the Rotax engine and an analysis of the fuel selector valve. Investigators also reviewed the pilot's credentials, the aircraft's maintenance records, and the meteorological conditions at the time of the event.
Technical analysis of the fuel selector valve revealed a fatigue fracture in an internal polymeric component. This fracture caused the valve to produce a "false click" when moved to the left tank position. In this specific position, the fuel flow was restricted, blocking approximately 80% of the necessary fuel passage. As the engine consumed fuel from the carburetors, the restricted flow prevented adequate replenishment, leading to a gradual loss of power.
Findings
- The primary cause of the engine failure was a fatigue fracture in the internal polymeric component of the fuel selector valve, which significantly restricted fuel flow.
- The pilot attempted a return-to-runway maneuver at a low altitude and low speed, which increased the risk of a stall or spin.
- The pilot's decision-making and flight judgment contributed to the outcome of the maneuver.
- The aircraft was an experimental category aircraft (PET) with a valid flight authorization (CAVE).