NTSB Identification: LAX98LA021.
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Accident occurred Sunday, October 26, 1997 in LONG BEACH, CA
Probable Cause Approval Date: 05/29/1998
Aircraft: Revolution MINI-500, registration: N7234Y
Injuries: 1 Serious.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
After taking off, the helicopter had climbed about 250 to 300 feet, when the engine abruptly lost power. The pilot attempted an autorotation, but said he was able to maintain only 80 percent rotor rpm, which was insufficient to prevent a hard landing. The pilot reported that the main rotor low pitch stop had recently been changed from -1.8 degree to -0.5 degree, as recommended by a factory representative. Also, the pilot stated that he was aware of a phenomenon called 'cold-freeze' (engine seizure without over temp) that (according to him) had occurred with other engines of this make/modle. He believed there was a possible engine seizure and that reduced settings of the rotor low pitch stops could have resulted in low rotor rpm. No preimpact mechanical problem was found that would have resulted in loss of engine power.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: loss of engine power and low rotor rpm for undeterminted reasons. The factory representative's recommendation to reduce the main rotor low pitch stop (from -1.8 degree to -0.5 degree) may have been a related factor. Full narrative available
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