DEN06LA080

On May 29, 2006, at 1815 mountain daylight time, a Garlick Helicopters Inc. OH-58C, N16JD, owned and piloted by a commercial pilot, sustained substantial damage during a forced landing near Muddy Gap, Wyoming. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under the provisions of Title 14 Code of Federal Regulations Part 91 without a flight plan. The pilot was not injured. The local flight originated at Split Rock Ranch, Wyoming, approximately 1700.

According to the Pilot/Operator Aircraft Accident/Incident Report (NTSB Form 6120.1) submitted by the pilot, he was approaching his ranch for landing. The pilot stated that he "lifted up on [the] collective to add power" but "no power [was] present." The "horn and low rotor" lights were immediately activated. The pilot stated that he lowered the collective and lowered the nose of the helicopter to gain some forward speed. The pilot stated that he "elected to keep forward speed to the ground" to aid in the impact. The helicopter impacted sagebrush and sloping terrain. It slid for a distance and came to rest on its right side. Both skids were bent out laterally and the main rotor blade contacted the tail boom, crushing and separating the tail boom at mid span.

The helicopter was recovered to a hangar in Fort Collins, Colorado, for further examination. The Safety Board Investigator-In-Charge and a representative from Rolls-Royce examined the wreckage on July 13, 2006. The tail rotor blades, gearbox assembly, and vertical fin separated from the tail boom. Both tail rotor blades separated at midspan and the main rotor blades exhibited slight cordwise wrinkling along the entire span and impact damage at the blade ends. The main rotor mast was bent and the upper and lower main rotor mast stops exhibited signatures of mast bumping.

External examination of the engine and transmission revealed a fractured drive shaft and extensive damage to the drive tunnel area. The first and second stage compressor blades and vanes exhibited foreign object damage. The freewheeling unit drive coupling was found fractured. Examination of the remaining systems revealed no anomalies.

The freewheeling unit was removed and sent to the NTSB lab for further examination. Examination of the fracture revealed torsional overstress with no indication of preexisting cracking. Examination of the sprag clutch revealed normal and correct function and no noticeable damage to the clutch or bearings.

The engine was removed from the helicopter and sent to Rolls-Royce for further examination. The engine was examined by a Rolls-Royce investigator under the auspices of a Federal Aviation Administration (FAA) principal maintenance inspector from the Indianapolis Flight Standards District Office (FSDO) on August 16, 2006. Disassembly and examination revealed that the first and second stage compressor blades were bent opposite the direction of rotation. The third, fourth, and fifth state compressor blades exhibited foreign object damage. The sixth stage was without damage. According to Rolls-Royce, the "damage discovered in the engine compressor section is consistent with engine operation at the time of impact."

The main fuel control and power turbine governor were sent to Honeywell in South Bend, Indiana, for further examination. The controls were examined and functionally tested on October 6, 2006, under the auspices of the FAA inspector from the South Bend FSDO. No condition was found to prevent either unit from functioning normally.