What happened
On June 24, 2020, a Piper PA 28-140, registration PT-IZO, was conducting a flight instruction mission at Aeródromo Fazenda Irohy in Biritiba Mirim, Brazil. The flight, operated by Aeroclube de São Paulo, involved an instructor and a student pilot performing touch-and-go landings. During the flight, the crew performed a simulated engine failure as planned in their briefing.
After completing a landing on runway 31, the student pilot attempted a go-around. As the power lever was advanced, the engine failed to reach the required performance parameters, resulting in insufficient acceleration. The instructor took control and attempted to abort the maneuver by deviating to the right to reduce speed. However, the aircraft could not be stopped within the runway limits and exited the paved surface, coming to a stop in the vegetation within a ditch beyond the runway threshold. The aircraft sustained substantial damage, but both occupants were unharmed.
The investigation
CENIPA investigators examined the engine, fuel, and oil, finding no evidence of contamination or mechanical defects in the Lycoming O-320-E3D engine. Tests on the fuel and oil samples confirmed they met technical specifications. While the exact cause of the power loss could not be definitively determined through mechanical testing, investigators focused on the possibility of carburetor icing.
Environmental data indicated high humidity and temperatures conducive to icing. Specifically, the investigation noted that the aircraft was operating in an area with high relative humidity near the coast. The investigation also highlighted a discrepancy in the crew's checklists: while the pre-landing memory check instructed the carburetor heat to be closed, the emergency procedure checklist for engine failure required it to be opened. This nuance, combined with the high workload of a simulated emergency, may have impacted the crew's situational awareness.
Findings
- Inadequate engine power during the go-around maneuver prevented the aircraft from maintaining the runway centerline.
- Reduced crew coordination during the simulated emergency contributed to the event.
- Managerial supervision issues regarding the standardization of training materials and procedures were identified as a contributing factor.
- High probability of carburetor icing due to atmospheric conditions and potential improper use of the carburetor heat control.