What happened
On September 14, 2006, at 17:45 UTC, an Aeroboero AB115, registration PP-GMV, was performing a local flight training mission at the Juiz de Fora aerodrome (SBJF) in Minas Gerais, Brazil. The flight was part of a private pilot training program, with an instructor and a student on board.
During the takeoff roll, once the aircraft reached approximately 40 MPH, the aircraft veered sharply to the left. The instructor attempted to regain control and steer the aircraft back toward the center of the runway, but was unsuccessful. As the aircraft left the paved surface, it struck an embankment at the edge of the runway area. The aircraft continued to slide for approximately 10 meters, striking small trees before rotating on its axis and coming to a stop with the propeller spinner touching the ground.
To mitigate the impact, the instructor attempted to reduce power, but was unable to move the throttle due to the student's grip on the lever. Consequently, the instructor had to shut down the engine using the magnetos to stop the propulsion. The aircraft sustained substantial damage to the engine and propeller, though both occupants escaped the wreckage uninjured.
The investigation
The CENIPA investigation focused on the cockpit coordination and the adherence to established training protocols. Investigators found that the takeoff procedure deviated from the standards set in MCA 58-3, which stipulates that for this stage of training, the instructor should execute the takeoff while the student observes and accompanies the maneuver. Instead, the instructor had planned for the student to take the lead during the takeoff roll.
During the investigation, it was noted that the student applied excessive left rudder pressure. The instructor's attempts to counter this input were insufficient to keep the aircraft on the runway. Furthermore, the investigation highlighted a lack of coordination in the cockpit, as the instructor could not manipulate the throttle because the student was holding it.
Findings
- Excessive rudder input by the student pilot caused the initial deviation from the runway centerline.
- Improper cockpit coordination, specifically the student's physical interference with the throttle, prevented the instructor from reducing engine power.
- Deviation from training standards, as the instructor allowed the student to perform the takeoff instead of following the prescribed instructional protocol.
- Inadequate management supervision regarding the oversight of flight instruction practices at the aero club.