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ASN Wikibase Occurrence # 31047
Last updated: 23 October 2020
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Time:12:15 PDT
Type:Silhouette image of generic UH1 model; specific model in this crash may look slightly different
Bell UH-1B
Owner/operator:Grizzly Mountain Aviation
Registration: N22753
C/n / msn: 1109
Fatalities:Fatalities: 0 / Occupants: 2
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:Dayville, Oregon -   United States of America
Phase: En route
Departure airport:Prairie City, Oregon
Destination airport:Prineville, Oregon
Investigating agency: NTSB
While cruising at 2,000 feet above ground level and 100 knots, the helicopter's right transmission door separated from the aircraft, striking the tail rotor and 90-degree gearbox and knocking them off the aircraft.

The pilot entered an autorotative descent to a forced landing in a field, but was unable to raise the collective for touchdown without inducing undesirable yaw. The aircraft landed hard in the forced landing.

An FAA inspector found that the two rear cowl latch blocks (which attach the aft end of the separated door to the engine firewall) were missing and did not appear to have been installed, and that the cowl top latch was also unlocked. This enabled the door to lift enough to slide aft out of the front latches and separate from the aircraft.

The FAA inspector subsequently found that the company mechanic who removed the latch blocks had not entered the work in the helicopter maintenance records, and that another company mechanic who reinstalled the cowls did not notice the blocks were missing and also improperly locked the top latch.


Revision history:

27-Sep-2008 01:00 ASN archive Added
31-Oct-2011 12:29 Dr. John Smith Updated [Time, Total fatalities, Total occupants, Other fatalities, Location, Country, Phase, Nature, Departure airport, Destination airport, Source, Damage, Narrative]

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