ASN Wikibase Occurrence # 32273
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| Date: | Saturday 22 April 1995 |
| Time: | 09:50 LT |
| Type: |  Bell UH-1B |
| Owner/operator: | Blue Mountain Helicopter Inc. |
| Registration: | N39SD |
| MSN: | 63-8699 |
| Year of manufacture: | 1963 |
| Total airframe hrs: | 4810 hours |
| Engine model: | Lycoming T53-L13B-22 |
| Fatalities: | Fatalities: 0 / Occupants: 1 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Walla Walla, WA -
 United States of America
|
| Phase: | Manoeuvring (airshow, firefighting, ag.ops.) |
| Nature: | Unknown |
| Departure airport: | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
THE PILOT STATED THAT DURING AN EXTERNAL LOAD OPERATION, JUST AFTER THE LOAD CLEARED THE GROUND THE HELICOPTER SHUTTERED AND MADE A LOUD SCRAPING NOISE FOLLOWED BY LOW ROTOR RPM. THE PILOT RELEASED THE LOAD AND MANEUVERED FOR AN EMERGENCY LANDING. DURING THE MANEUVER, THE HELICOPTER COLLIDED WITH TREES. DURING THE POST CRASH INSPECTION, IT WAS FOUND THAT THE FREEWHEELING ONE-WAY CLUTCH ASSEMBLY HAD FAILED IN FLIGHT. THE CLUTCH ASSEMBLY APPEARED TO BE WORN AND THE INNER CLUTCH RACE DISPLAYED SIGNS OF BRINELLING.
Probable Cause: TOTAL FAILURE OF THE FREEWHEELING SPRAG UNIT. A FACTOR TO THE ACCIDENT WAS: SUITABLE TERRAIN WAS NOT AVAILABLE FOR LANDING.
Accident investigation:
 |
|
Sources:
NTSB SEA95LA078
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 27-Sep-2008 01:00 | ASN archive | Added |
| 05-Nov-2011 16:18 | Dr. John Smith | Updated [Time, Cn, Total fatalities, Total occupants, Other fatalities, Location, Country, Phase, Nature, Departure airport, Source, Damage, Narrative] |
| 07-Jun-2022 20:25 | Ron Averes | Updated [Location, Narrative] |
| 09-Apr-2024 15:37 | ASN Update Bot | Updated [Time, Cn, Operator, Other fatalities, Country, Phase, Nature, Departure airport, Source, Damage, Narrative, Category, Accident report] |
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