What happened
On September 14, 1998, an HB-350B Esquilo helicopter departed Uiramutã, Roraima, bound for the summit of Monte Roraima. The mission involved filming the border marker between Brazil, Venezuela, and Guyana. The aircraft was carrying a pilot and five passengers.
Upon reaching the summit at 8,200 feet, the pilot began flying at low altitude over the rocky, irregular terrain to locate the border marker. During a left-hand turn, the aircraft experienced a loss of lift and began to descend. In an attempt to regain control, the pilot pushed the cyclic forward to increase airspeed. However, the aircraft entered a depression in the terrain, causing the main rotor to strike a rock wall. The impact led to a loss of control and the subsequent crash of the aircraft.
The accident resulted in one fatality among the passengers, four serious injuries, and one minor injury to the pilot. The aircraft sustained extensive damage.
The investigation
CENIPA's investigation focused on the operational planning and the aircraft's performance capabilities at high altitude. Investigators found that the pilot was qualified but lacked experience operating in the specific critical conditions of Monte Roraima.
Technical analysis revealed that the aircraft's Airworthiness Certificate was suspended due to an expired annual maintenance inspection. Furthermore, the investigation determined that the aircraft was likely operating above its maximum takeoff weight. While the estimated weight at the time of the accident was approximately 1,932 kg, the inclusion of unrecorded filming equipment likely pushed the total weight beyond the 1,950 kg limit.
Crucially, the investigation established that while the aircraft could maintain hover within ground effect at 8,200 feet, it could not maintain level flight outside of ground effect at that altitude. By flying at low speeds (approximately 40 knots) over uneven terrain, the aircraft transitioned out of ground effect, leading to the loss of lift.
Findings
- Inadequate flight planning: The pilot failed to calculate minimum safety speeds for operations both within and outside of ground effect at high altitude.
- Operational weight limits: The aircraft was likely operating above its maximum allowable takeoff weight.
- Lack of experience: The pilot was inexperienced with the specific environmental challenges of the Monte Roraima summit.
- Environmental factors: The low air density at high altitude contributed to the loss of lift.
- Deficient supervision: A lack of operational oversight from the Roraima State Government allowed the aircraft to operate with a suspended airworthiness certificate and without proper flight planning oversight.