What aircraft was involved and where did it happen?

The accident on 2006-11-25 involved a aircraft, registration PTOYF, at BAURU, SP, BR.

What was the probable cause of the accident?

The engine shutdown was caused by the instructor's excessive reduction of the mixture control during a simulated emergency. This was compounded by poor pilot judgment regarding wind conditions and a lack of proper flight briefing and supervision.

Simulated Engine Failure Leads to Emergency Landing in Bauru

A flight instructor's attempt to simulate an engine failure during a training flight resulted in an actual engine shutdown and an emergency landing in a field near Bauru, Brazil.

What happened

On November 25, 2006, a Cessna C150, registration PT-OYF, was conducting a training flight departing from Bauru Aerodrome (SBBU). The flight was intended to be a navigation exercise for a student pilot, but the instructor altered the mission profile to conduct emergency procedure training during the traffic pattern.

While on the downwind leg, the instructor questioned the student regarding procedures for a power lever cable failure. As the aircraft transitioned to the base leg, the instructor intentionally reduced the mixture control to a level that caused the engine to shut down. Due to the high wind conditions and the aircraft's position, the crew was unable to return to the runway. The instructor attempted to restart the engine without success, necessitating an emergency landing in an unprepared field. During the landing, the aircraft's nose gear failed, and the plane struck an embankment, resulting in severe damage to the airframe. The instructor sustained minor injuries, while the student was uninjured.

The investigation

CENIPA's investigation focused on the sequence of events leading to the engine shutdown and the decision-making process of the crew. Investigators examined the aircraft's maintenance logs, which showed the engine and propeller were in good condition, and reviewed the flight school's training records. The investigation also looked into the meteorological conditions, noting significant winds that complicated the recovery attempt. Furthermore, the investigation scrutinized the flight school's supervisory practices, finding inconsistencies in student evaluation records and a lack of standardized briefing procedures.

Findings

The instructor's excessive reduction of the mixture control was the primary cause of the engine shutdown.
The instructor failed to properly assess the environmental conditions, specifically not accounting for how the wind would affect the aircraft's ability to reach the runway after the simulated failure.
There was a lack of adequate flight planning and briefing, as the mission profile was changed last minute without a specific briefing for the student.
Inadequate management supervision at the flight school was identified, evidenced by poor documentation of student progress and a lack of standardized emergency training protocols.
The instructor's decision to perform a high-risk, non-standard emergency simulation in flight, rather than using a flight simulator, contributed to the accident.