What happened
On May 17, 2007, a Cessna 210L, registration PR-LHN, departed Anápolis, Brazil, bound for Luziânia. During the initial climb, the aircraft experienced a significant drop in engine RPM, falling to approximately 800 RPM, and the pilot lost effective control of the throttle lever.
The pilot attempted an emergency landing on a roadside area adjacent to the GO-437 highway. During the approach, the aircraft's right wing struck six concrete fence posts, and the nose collided with an embankment. The impact caused the aircraft to overturn, and a fire immediately broke out, consuming the cabin. The pilot managed to escape through the baggage compartment door, sustaining minor injuries and burns.
The investigation
CENIPA investigators examined the maintenance history and the mechanical state of the throttle system. The investigation revealed that the aircraft had recently undergone maintenance at an aeronautical workshop. Specifically, a maintenance attempt to replace the throttle cable had been performed the day before the accident.
Investigators found that the throttle cable was disconnected from the engine acceleration rod at the time of the accident. The hardware used to secure the connection—including the bolt, nut, and cotter pin—was missing from the wreckage. Testing demonstrated that the type of cotter pin used was prone to fatigue and breakage after multiple uses. Furthermore, the investigation found that the maintenance service order had not been properly closed or signed by a qualified inspector, and the aircraft had been released for flight without official certification of airworthiness following the recent work.
Findings
- Reused hardware: The reuse of a fatigued cotter pin likely led to its failure due to engine vibration, allowing the throttle cable to disconnect.
- Inadequate maintenance supervision: The workshop and the operator demonstrated complacency by allowing the aircraft to operate without a completed and inspected service order.
- Unqualified personnel: An unlicensed mechanic participated in the maintenance tasks performed prior to the flight.
- Improper maintenance oversight: The lack of a formal inspection by a qualified inspector meant the use of fatigued hardware and the incomplete service records went unnoticed.
- Emergency procedures: The pilot did not perform standard emergency procedures, such as turning off the master switch, which may have contributed to the post-crash fire.