NTSB Identification: LAX00FA136.
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Accident occurred Sunday, March 26, 2000 in VAN NUYS, CA
Probable Cause Approval Date: 07/17/2001
Aircraft: Aerospatiale AS350B, registration: N500WC
Injuries: 2 Serious.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

While hovering out of ground effect, the helicopter had a hydraulic system failure. The pilot shutoff the hydraulic accumulator pressure 5 seconds after the warning horn sounded. According to the onboard cameraman the helicopter began to spin. The pilot stabilized the helicopter, and reported to other news helicopters filming the night time event, that she had lost hydraulic pressure and was experiencing control problems. Another pilot suggested that the pilot consider two airports within 5 miles. The pilot elected to return to the home base, about 15 miles away. The pilot reported en route to escorting helicopters that her right leg was 'killing her.' A hover landing was attempted, and a loss of control resulted in spinning out of control to the ground. Postaccident examination revealed a failed hydraulic pump drive pulley bearing and subsequent drive belt failure. According to the rotorcraft flight manual, 'The pressure stored in the accumulators allows sufficient time to reach the 'refuge' area with hydraulic servo-assistance.' According to manufacturer representatives, that time is between 30 and 45 seconds, depending on control inputs. The pilot action is to 'Calmly reduce collective pitch and adjust the airspeed to between 40 and 60 knots in level flight. Cut off the hydraulic pressure, using collective lever pushbutton.' According FAA medical data, the pilot's last reported weight was 108 pounds and a height of 61 inches. According to pilots who are experienced in this model, body size and strength are important issues in handling this type of emergency. The manufacturer representative stated that it is an emergency, and the pilot should land as soon as practical. It was also stated that the accident pilot had recently completed the factory-training course successfully.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

the pilot's failure to land as soon as practical and to utilize the available accumulator pressure to transition from hover to flight. Contributing to the accident was the pilot's physical stature and strength, and the inadequate and incomplete emergency training and flight manual information.

Full narrative available

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