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ASN Wikibase Occurrence # 59985
Last updated: 6 November 2019
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Date:13-MAY-2009
Time:09:08
Type:Silhouette image of generic UH1 model; specific model in this crash may look slightly different
Bell UH-1B Iroquois
Owner/operator:Avag Inc
Registration: N843M
C/n / msn: 63-8676
Fatalities:Fatalities: 0 / Occupants: 1
Aircraft damage: Substantial
Category:Accident
Location:Richvale Airport (07CL), California -   United States of America
Phase: Unknown
Nature:Ferry/positioning
Departure airport:Richvale, CA (07CL)
Destination airport:Richvale, CA (07CL)
Investigating agency: NTSB
Narrative:
The helicopter had undergone a 100-hour inspection the day prior to the accident, which included a flushing of the hydraulic system. The pilot reported that as he lifted the helicopter into a hover, he initiated forward movement. The pilot stated that the controls felt "ratchety" and stiff, as if the helicopter had the hydraulic system turned off. He was not able to land the helicopter by lowering the collective, nor was he able to control direction with the cyclic. The helicopter had climbed about 15 feet above the ground and subsequently collided with a hangar about 160 feet away. The fuselage section remained embedded in the building, while the tail section came to rest on the ground below. A post accident examination revealed no mechanical malfunctions or failures that would have precluded normal flight. A representative for Bell stated that it is common during the "initial start up of all of these aircraft after assembly and/or reassembly or after first servicing," to cycle all of the controls for as long as 2 minutes to attain smooth and uninterrupted control motion. He further stated that during these initial run up exercises it would not be unusual to feel "ratcheting or binding in the cyclic that is generally accompanied by a howling noise" as the hydraulics purge air from the lines, pumps, and actuators. It is unknown if the pilot adequately cycled the controls through their full travel prior to flight.
Probable Cause: The pilot's failure to maintain control of the helicopter during takeoff for undetermined reasons.

Sources:

NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20090513X30919&key=1


Revision history:

Date/timeContributorUpdates
14-May-2009 04:10 slowkid Added
14-May-2009 04:15 slowkid Updated
21-Dec-2016 19:25 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
02-Dec-2017 14:52 ASN Update Bot Updated [Operator, Other fatalities, Departure airport, Destination airport, Source, Narrative]

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