APACHE JUNCTION, AZ, USA
N6624N
Bell 206B
While in cruise flight about 600 feet agl, the pilot noticed that the engine oil pressure was high and the torque gauge was exceeding the high limits. The engine chip light became illuminated. As the pilot descended to make an immediate landing, the engine quit about 75 to 100 feet agl. The pilot autorotated to the ground. The main rotor blades severed the tail cone aft of the horizontal stabilizer after the toe of the left skid became entangled in a large bush and separated. A teardown examination of the engine was conducted. The mechanic reported that the Nos. 6 and 7 bearings displayed evidence of heat distress and oil starvation. When he blew through the oil jet for the Nos. 6 and 7 bearings, he heard something pop out. He opined that it might have been a piece of carbon, which could have prevented the flow of oil into the turbine. He stated that all other components of the lubrication system were intact and functional. No other discrepancies were found.
On October 7, 1999, at 1015 hours mountain standard time, a Bell 206B, N6624N, experienced a loss of engine power and collided with high vegitation during a forced landing near Apache Junction, Arizona. The helicopter, operated by Arizona HeliServices, Inc., of Chandler, Arizona, sustained substantial damage. The commercial pilot and two passengers were not injured. The local personal flight, conducted under the provisions of 14 CFR Part 91, originated from the Cochise County Airport, Willcox, Arizona, about 0905, and was en route to Falcon Field, Mesa, Arizona. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that while in cruise flight about 600 feet agl, he noticed that the engine oil pressure was "exceedingly high," and the torque gauge was exceeding the high limits (120+). The engine chip light became illuminated. The pilot lowered the collective with no apparent effect on the torque gauge reading. As he descended to make an immediate landing, the engine quit about 75 to 100 feet agl. The pilot autorotated to the ground with a slight aft skid touchdown and minimum forward airspeed. The left skid toe became embedded in a creosote bush and the helicopter turned left 90 degrees. The left skid separated from the crossmember and the left side of the nose dipped. The main rotor blades severed the tail cone aft of the horizontal stabilizer. The right skid separated but the helicopter remained upright. A teardown examination of the engine was conducted. The mechanic reported that the Nos. 6 and 7 bearings displayed evidence of heat distress and oil starvation. He blew through the oil jet for the Nos. 6 and 7 bearings and thought it seemed to be partially blocked. He then blew compressed air through the oil jet and heard something pop out. He opined that it might have been a piece of carbon, which could have clogged the jet and blocked the flow of oil. He stated that all other components of the lubrication system were intact and functional. No other discrepancies were found.
Oil starvation and seizure of the engines Nos. 6 and 7 bearings due to a clogged oil jet, which resulted in a total loss of engine power.
Source: NTSB Aviation Accident Database
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