Pontiac, MI, USA
N9390F
Hughes 269B
The helicopter impacted terrain during a simulated autorotation by the operator's pilot during training conducted by the operator's flight instructor. The helicopter experienced a total loss of engine power during the recovery from the autorotation. The aircraft checklist stipulates procedures to be used in checking engine idle speed to verify that it is in the range of 1,400-1,600 rpm. These checks, which are to be performed at the end of the last flight each day and prior to shutdown, were not being conducted by the operator. Inspection of the engine idle speed revealed it to be 700-800 rpm.
On August 26, 2001, at 1530 eastern daylight time, a Hughes 269B, N9390F, operated by Oakland Helicopters Incorporated, was substantially damaged during a simulated autorotation on runway 27R (5,000 feet by 100 feet, asphalt) at the Oakland County International Airport near Pontiac, Michigan. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 instructional flight was not operating on a flight plan. The airline transport pilot and instructor pilot were uninjured. The local flight originated at 1430. The pilot reported in a written statement, "Engine failed during power-recovery phase of autorotational descent. After touchdown, (1) main rotor blade contacted tailboom..." Inspection of the engine idle speed by a mechanic revealed that the engine idle speed was 700-800 rpm. The Schweizer 269C Pilot's Flight Manual (PFM) states under Normal Procedures, Pilot's Check of Idle Mixture, Idle Speed, and Fuel Boost Pump, "NOTE: This check of idle mixture, idle speed, and fuel boost pump shall be accomplished at the end of the last flight each day, prior to shutdown." According to the Federal Aviaiton Administration, this check was not being conducted by the operator. The PFM also states, ...NOTE: The first check (throttle into full override) should produce an idle speed no less than 1400 rpm. The second check (throttle at normal idle stop) should produce an idle speed no greater than 1600 rpm."
the checklist not compiled with by the operator and not verified by the operator’s pilot and the operator's flight instructor. An additional cause was the improper autorotation by the pilot in command. The out of calibration engine idle speed was a contributing factor.
Source: NTSB Aviation Accident Database
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