Ely, NV, USA
N8353F
Hughes 369D
The single engine helicopter experienced a loss of engine power after the oil was inadvertently pumped overboard. A company mechanic replaced the torque gauge prior to the accident flight due to needle "bounce." The mechanic bled the torque system and reinstalled a radio that was removed to facilitate the work. During the radio installation, he inadvertently engaged the bleed valve, which is located behind the instrument panel, allowing oil to flow out of the engine from behind the instrument panel. While at 9,500 feet, the engine lost power and the pilot performed an autorotation landing to a field at the base of mountains. The pilot said he touched down smooth and light; however, the main rotor blades flexed and severed the tail boom. As a result of the accident, the operator rerouted the torque system bleed line toward the pilot's feet so that they could detect an inadvertent oil leak.
On January 23, 2001, approximately 0745 Pacific standard time, a Hughes 369D single-engine helicopter, N8353F, impacted terrain during an autorotation landing following a loss of engine power while in cruise flight near Ely, Nevada. The helicopter was registered to and operated by Hawkins & Powers Aviation, Inc., Greybull, Wyoming, under the provisions of 14 CFR Part 91 as a business flight. The helicopter sustained substantial damage, and the commercial pilot and three passengers were not injured. The business flight departed Ely about 0730, and was destined for private property near Ely. Visual meteorological conditions prevailed, and a company flight plan had been filed. According to the pilot's written statement, the torque gauge was showing a "bounce" in its reading. The pilot notified a company mechanic, who elected to replace the torque gauge with a new one. The mechanic replaced the torque gauge and bled the system at the torque gauge bleed valve behind the instrument panel. He removed the radio located below the torque gauge to facilitate the work. He tested the system, noted no leaks, and replaced the radio. The flight departed to ferry company personnel to a job site. Approximately 1.5 miles from the planned destination, the pilot noticed the needle "bounce" on the torque gauge, and illumination of the "engine chip" caution light. The pilot notified his passengers and told them that they would be landing early. Approximately 30 seconds after noticing the chip light, at an elevation of 9,500 feet, the engine lost power. The pilot entered an autorotation and attempted to land at the base of mountains at the 7,500-foot level. The pilot stated the helicopter touched down "very smooth and light;" however, during the landing roll, the main rotor blades flexed down and severed the tail boom. According to the operator, the bleed valve is located in a confined area behind the instrument panel. When the mechanic conducted the system bleed, and reinstalled the radio, he inadvertently hit the bleed valve. Oil seeped out of the engine through the bleed valve and down behind the instrument console. Examination of the engine after the accident revealed it had no oil, and metal covered the upper chip detector. The bottom of the helicopter was coated with oil.
The mechanic's inadvertent activation of the bleed valve, which resulted in a loss of engine oil and loss of engine power while in cruise flight.
Source: NTSB Aviation Accident Database
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