What happened
On December 15, 2007, an Aero Boero AB-115, registration PP-GPC, was conducting a training flight from Juiz de For and Minas Gerais, Brazil. The flight was operated by the Aeroclube de Juiz de Fora, carrying a flight instructor and a student pilot.
While flying over the Dr. João Penido reservoir, the aircraft struck high-voltage power lines. The impact caused the right fuel tank to rupture and the engine cowling to sustain significant damage. Following the collision with the electrical cables, the aircraft struck the ground and was destroyed by a post-impact fire. The two fatalities involved were the instructor and the student.
The investigation
CENIPA investigators examined the wreckage and determined that the aircraft struck the lines while flying at an altitude of approximately 30 meters (100 feet) above the reservoir level. This altitude was in violation of established minimum height requirements for the type of operation being conducted.
Physical evidence from the wreckage showed that the impact with the ground occurred with the engine at low power, suggesting a possible stall condition following the collision. The investigation also noted that the electrical lines involved were part of a primary distribution network, which, at the time, did not require the same warning signage or markers as high-voltage transmission lines.
Furthermore, the investigation looked into the organizational structure of the flight school. It was noted that the instructor was a recent hire and had been previously evaluated with a specific restriction regarding flight instruction for certain student profiles, a restriction that was not being strictly adhered to during this flight.
Findings
- Flight Indiscipline: The crew failed to maintain the minimum required altitude over the reservoir, which led to the collision.
- Inadequate Risk Assessment: The crew failed to properly evaluate the risks associated with low-altitude flight over the water.
- Lack of Obstacle Marking: The primary distribution power lines lacked adequate warning signals, which prevented the crew from identifying the hazard.
- Organizational Deficiencies: The flight school lacked standardized instruction manuals for new instructors and had weaknesses in its selection and supervision processes.
- Operational Oversight: There was a lack of management supervision regarding the instructor's adherence to flight doctrines and pre-flight procedures.