What happened
On June 8, 2010, an Aero Boero AB-115, registration PP-GOZ, was performing a flight instruction mission at the Campo de Marte Aerodrome (SBMT) in São Paulo. The flight involved an instructor and a student pilot who was in the early stages of a Private Pilot License (PPR) course.
During the takeoff roll, the aircraft experienced a sudden and strong leftward yaw. The student pilot, attempting to correct what he perceived as a slight deviation to the right of the runway centerline, applied left rudder pedal. This input, combined with the engine torque of the single-engine aircraft, caused the plane to veer sharply to the left. The aircraft exited the left side of the runway, where the right wing tip struck the ground due to irregularities and ditches in the terrain adjacent to the paved surface. The aircraft came to a stop after rotating approximately 210 degrees. Both occupants were uninjured, though the aircraft sustained minor damage to the right wing tip.
The investigation
CENIPA's investigation focused on the flight instruction procedures and the student's proficiency at the time of the incident. The investigation established that the instructor, despite having sufficient experience and valid certifications, had deviated from the established flight training mission plan. While the curriculum intended for the instructor to handle the takeoff during this specific phase of training, the instructor allowed the student to take the lead due to high confidence in the student's performance during a previous flight.
Investigators also examined the airfield conditions, noting that the presence of ditches and uneven terrain near the runway contributed to the wing tip striking the ground. The investigation reviewed the student's control inputs, noting that the application of the left rudder, and potentially inadvertent braking, triggered the loss of directional control.
Findings
- Improper control input: The student pilot applied left rudder to correct a perceived deviation, which, when coupled with engine torque, induced a sharp left yaw.
- Deviation from training syllabus: The instructor allowed the student to execute the takeoff, a task that the training mission plan had reserved for the instructor during this stage of instruction.
- Inadequate instructor intervention: The instructor failed to intervene effectively with the controls to prevent the aircraft from exiting the runway.
- Lack of student experience: The student had not yet reached the level of proficiency required to manage the aircraft's directional control during the high-torque takeoff phase.
- Airfield conditions: Irregularities and ditches in the grass area adjacent to the runway facilitated the contact between the wing tip and the ground.