What happened
On February 17, 2008, an Aero Boero AB-115, registration PP-GJZ, was performing a flight training mission at Estância Santa Rita Aerodrome (SJCY) in Cuiabá, Mato Grosso. The flight, operated by Aeroclube de Várzea Grande, involved an instructor and a student pilot. After a successful initial flight and landing, the crew prepared for a second departure from runway 30. However, the mission involved a specific training maneuver: a ground run starting from runway 12 to practice maintaining a straight path.
During the ground run, the aircraft reached a speed of approximately 50 MPH. As the crew reduced power to idle to lower the tail and prepare for the subsequent takeoff, the aircraft began to deviate from the centerline. At a point approximately 600 meters into the run, the aircraft entered a sharp left turn. The aircraft subsequently exited the left side of the runway and struck a ditch located 20 meters from the runway edge. Both occupants of the aircraft were unharmed, though the aircraft sustained light damage.
The investigation
The CENIPA investigation examined the aircraft's mechanical condition, the flight crew's experience, and the environmental conditions at the time of the incident. Investigators verified that the aircraft's maintenance records, including the engine and propeller, were up to date, and that the aircraft was within weight and balance limits. The braking system was also inspected, and no evidence of tire lock-up was found.
Regarding the crew, the investigation noted that while the student pilot had demonstrated good performance in previous missions, the instructor was relatively new to the role, having completed flight instructor training only a few months prior and possessing only 14 hours of instruction time in this specific aircraft type. Meteorological data from a nearby station (SBCY) showed light winds, though the investigation could not definitively confirm if a localized gust occurred at the incident site.
Findings
- Inadequate control inputs: The instructor's intervention to correct the deviation occurred too late, as evidenced by tire marks on the runway indicating effective braking and rudder use only began when the aircraft was already significantly off-course.
- Potential environmental or mechanical factors: A sudden wind gust or a sharp reduction in engine torque during the power reduction phase may have contributed to the loss of directional control.
- Pilot experience: The instructor's limited experience in the aircraft type may have hindered the ability to anticipate and correct the deviation more effectively.