What happened
On December 21, 2011, an Aero Boero AB-115, registration PP-FAX, was conducting a local flight instruction mission departing from the Belém Novo aerodrome in Porto Alegre, RS. The aircraft was operated by Aeroclube do Rio Grande do Sul with an instructor and a student pilot on board.
During the landing roll, the crew experienced intense vibrations originating from the tail of the aircraft. In an attempt to manage the situation and maintain the runway centerline, the instructor applied power and used pitch controls to lift the tail. However, the increased engine torque likely induced a leftward yaw, causing the aircraft to veer off the left side of the runway. The aircraft subsequently entered a ditch and collided with an embankment. The impact caused substantial damage to the propeller, landing gear, and windshield. The instructor sustained a minor injury, while the student remained uninjured.
The investigation
CENIPA's investigation examined several operational and administrative aspects of the flight school. Investigators reviewed the instructor's flight training records and found significant lapses in supervision, noting that many evaluation forms lacked grades, comments, or required signatures from the course coordinator. Furthermore, it was discovered that some student missions lacked defined objectives, and certain students were permitted to proceed to subsequent flight phases despite receiving deficient grades, bypassing mandatory review flights required by regulations.
Regarding the flight itself, investigators noted that the aircraft had departed with an estimated weight of 797 kg, which was 27 kg above the maximum takeoff weight of 770 kg. While the weather was generally favorable, the landing was performed with a 6-knot tailwind. The investigation also noted that the aircraft's flight manual did not provide specific guidance for landing with a tailwind component, only for crosswind conditions.
Findings
- Improper application of flight controls and lack of effective crew coordination during the landing roll.
- Deficient flight planning, specifically regarding the aircraft's takeoff weight exceeding maximum limits.
- Inadequate management supervision of the flight training program and student progress.
- The occurrence of a tailwind component during landing.
- The use of simultaneous engine power and pitch inputs which likely contributed to the loss of directional control.