What happened
On April 25, 2009, an Aero Boero AB-115, registration PP-FLL, departed from the Imperatriz Aerodrome in Maranhão, Brazil, for a flight intended to verify the functionality of the engine's ignition system following maintenance on the magnetos and spark plugs. The flight involved a pilot and a passenger, both of whom held leadership positions within the local aero club.
During the flight, which included a series of touch-and-go maneuvers, the aircraft experienced a loss of engine power. The pilot attempted an emergency landing in an unprepared area outside the airfield. During the landing sequence, the aircraft struck the ground with significant force, causing the aircraft to capsize. Both occupants sustained light injuries, and the aircraft suffered substantial damage.
The investigation
The CENIPA investigation examined several technical and operational aspects of the occurrence. Investigators analyzed the carburetor bowl, discovering the presence of water and settled debris, which likely caused a momentary engine failure by reducing the fuel mixture. Additionally, the investigation found that the aircraft had taken off at a weight exceeding the manufacturer's maximum allowable limit, a factor that was not identified during flight planning.
Technical inspection of the control systems revealed that while the elevator was functioning, the trim compensator was inefficient. Investigators determined that a control cable clip had detached during flight, likely due to an improper cold-pressing procedure performed during previous maintenance. The investigation also noted that the passenger had assumed control of the aircraft at certain intervals, which may have led to improper control inputs during the emergency.
Findings
- The presence of water and contaminants in the carburetor bowl likely caused the power loss.
- The aircraft was operated above its maximum takeoff weight.
- Improper maintenance of the control cable clip contributed to control surface inefficiency.
- Inadequate flight planning regarding weight and balance.
- Improper use of flight controls during the emergency phase.
- Deficiencies in maintenance supervision and management oversight.