NTSB Identification: DEN02LA010
14 CFR Part 91: General Aviation
Accident occurred Friday, November 09, 2001 in Ogden, UT
Probable Cause Approval Date: 09/20/2002
Aircraft: Agusta A119, registration: N119RX
Injuries: 3 Minor.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
Prior to accepting delivery of the new helicopter, the pilot noticed a 4 percent decay in rotor rpm when the collective control was lowered after landing, activating the aural and visual LOW ROTOR RPM warnings. After a few seconds, engine and rotor speed returned to normal. The engine manufacturer said it should be of no concern as long as it operated normally during flight, but suggested adjusting the linear variable differential transducer after they ferried the helicopter home. On the day of the accident, the pilot intended to make a low pass and land at a hospital helipad. He lowered the collective control and noticed rotor rpm had decreased to 96 percent. The LOW ROTOR RPM warnings activated. He realized he was too low to attempt an autorotation. He reduced collective and pitch attitude further. RPM drooped to 90 percent, and stabilized. Approximately 20 to 30 feet above the helipad, the pilot raised the collective control to flare for landing. RPM rapidly deteriorated. The aircraft impacted the helipad in a tail-down position, rolled over, and came to rest on its left side. The operator found the rotary variable differential transformer rigged at 57.9 degrees of twist grip travel at the Flight Gate position. According to the A119 maintenance manual, the device is supposed to be rigged to achieve 60 degree (+ or - 1 degree). The operator said misrigging of the rotary variable differential transducer would cause incorrect fuel scheduling to the fuel control unit.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: improper rigging of the rotary variable differential transformer by the manufacturer, resulting in incorrect fuel scheduling to the fuel control unit. Full narrative available
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