What happened
On an unspecified date in 2025, a Bell 206B helicopter, registration YV3004, was performing a flight from the Uruyen Camp to Canaima. During the initial climb phase, the aircraft experienced a significant decrease in main rotor RPM. In response to this power loss, the pilot initiated an emergency landing.
During the descent and subsequent impact with the terrain, the tail boom separated from the fuselage due to inertial loads and the force of the impact. The loss of the tail rotor led to a total loss of aircraft control, causing the main rotor blades to strike the ground near a roadway. The two crew members on board, a pilot and a mechanic, were uninjured, though the aircraft was destroyed.
The investigation
Investigators examined the wreckage and reviewed maintenance records, which showed that the aircraft had undergone scheduled inspections as recently as September 202 and was fully airworthy at the time of the accident. A visual inspection had been performed at the Uruyen Camp on November 22, 2025, following a report of RPM fluctuations on the previous day.
The physical examination of the wreckage revealed catastrophic failure of the landing gear due to overstress, with one skid completely detached and the other severely deformed. The impact was forceful enough that the landing gear crosstube penetrated the lower fuselage skin. While the main rotor blades showed only superficial abrasions—consistent with low RPM at the time of contact—the transmission experienced a sudden stoppage. The investigation also confirmed that the tail boom separation was caused by the impact and subsequent torsion rather than contact with the main rotor blades.
Findings
- A failure in the power regulation system occurred during takeoff, resulting in low rotor RPM.
- Despite the crew's attempt to execute an autorotation, the loss of rotor energy resulted in insufficient lift for a controlled touchdown.
- The investigation identified that the pneumatic lines connecting the Governor to the Fuel Control Unit (FCU) were in good operational condition with no leaks.
- Based on maintenance manual fault localization diagrams regarding "excessive droop," physical evidence points toward an internal failure within the N2 Turbine Governor mechanism as the primary cause of the inability to maintain revolutions during high-torque demand.