What happened
On April 30, 2009, an Aero Boero AB-115, registration PP-GON, was conducting a local flight instruction mission at the Taubaté Aerodrome in São Paulo, Brazil. The flight, intended to help a student pilot transition back to the aircraft after a four-year hiatus, involved a pilot and an instructor. After completing several successful landings and takeoffs, the crew attempted a go-around following a fourth landing.
During the climb, the crew reported a gradual loss of engine power at a low altitude, making it impossible to clear obstacles located at the end of the runway axis. The instructor took control and attempted a right-hand turn to return to the runway. During this maneuver, the aircraft struck a motorcycle parking area belonging to the Army Aviation Command (CAVEX), colliding with 1 and 6 motorcycles. The impact caused substantial damage to the airframe, landing gear, engine, wings, and propeller. Both occupants sustained minor injuries.
The investigation
CENIPA investigators examined the aircraft's configuration and engine performance following the accident. Although the crew reported a loss of power, engine tests conducted on a test bench showed the engine functioned normally. Investigators noted that the flaps were found at a 45-degree position, which would have created significant aerodynamic drag and hindered the climb. Additionally, the fuel mixture lever was found slightly retarded, which could have restricted power or caused an engine cutout.
The investigation also looked into the flight preparation and cockpit environment. It was noted that the aircraft had been fueled to its maximum capacity, which impacted performance. Furthermore, the checklist available in the cockpit only covered normal operations and lacked emergency procedures. The investigation also identified that the rear seat safety harness was improperly installed, which could have caused the instructor's head to strike the seat or control column during the impact.
Findings
- The instructor failed to conduct a specific flight briefing, which was critical given the student's need for aircraft readaptation.
- The flaps were left in a 45-degree position, likely due to a failure to retract them after the initial touchdown, contributing to the difficulty in maintaining climb speed.
- A potential reduction in power may have been caused by the fuel mixture lever being inadvertently moved to a retarded position.
- The aircraft was fueled to maximum capacity, which negatively affected the aircraft's performance during the emergency maneuver.
- The lack of emergency procedures in the onboard checklist hindered effective crew response.
- Improper installation of the rear seat safety harness increased the risk of injury during the impact.