What happened
On November 26, 2003, a Bell 206B helicopter, registration PT-HKM, was performing a flight from Fortaleza to Paracuru, Brazil. During the mission, the pilot requested a change in destination to São Benedito to pick up two passengers. While en route, the pilot heard a loud noise, immediately followed by the activation of the low rotor RPM alarms.
In response to the engine failure, the pilot initiated an emergency autorotation procedure. The pilot attempted to reach a nearby access road to perform a controlled landing; however, unable to reach the intended site, the aircraft performed a flare over irregular, undulating terrain. The helicopter struck the ground, resulting in severe damage to the aircraft. The pilot sustained minor injuries, while the two passengers remained uninjured.
The investigation
CENIPA's investigation focused on the mechanical failure and the operational decisions leading to the impact. Technical analysis of the engine compressor conducted by the Aerospace Technical Center (CTA) revealed that the failure likely originated in one of the blades of the second stage. The investigation also examined the organizational structure of the operator, a small family-owned company, and the pilot's flight planning.
Findings
- The primary cause of the engine failure was identified as a failure in a second-stage compressor blade.
- Inadequate flight planning contributed to the accident, as the pilot selected a low altitude and a route over rugged terrain, which limited options for a safe emergency landing.
- The pilot's judgment was a contributing factor, specifically regarding the failure to maintain a flight level that would allow for a safer landing site selection during the emergency.
- The investigation noted a culture of informality within the operator's organization, which lacked structured emergency training and formal supervisory oversight.
- The pilot exhibited excessive confidence in the aircraft and the routine nature of the flight, which may have hindered an adequate risk assessment.