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ASN Wikibase Occurrence # 42573
Last updated: 19 March 2019
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Date:31-MAY-1986
Time:07:10
Type:Silhouette image of generic UH1 model; specific model in this crash may look slightly different
Bell UH-1L
Owner/operator:private
Registration: N4964N
C/n / msn: 157854
Fatalities:Fatalities: 1 / Occupants: 1
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:Wenatchee, WA -   United States of America
Phase: En route
Nature:Unknown
Departure airport:
Destination airport:
Investigating agency: NTSB
Narrative:
N4964N, A BELL UH-1L, WAS BEING OPERATED IN LOGGING OPS BY AN EXPERIENCED, MILITARY TRAINED PLT WHO POSSESSED 6000 HRS OF FLT EXPERIENCE IN MODEL. WHILE LIFTING A SLING LOAD GND CREW reported SMOKE FROM THE TAIL ROTOR AREA. PLT RELEASED SLING LOAD & ACKNOWLEDGED THE WARNING RADIOING HIS INTENTIONS TO LAND NEARBY. THE SUBSEQUENT LOSS OF TAIL ROTOR/DIRECTNL CNTRL PLACED ROTORCRAFT IN A CONDITION WHEREBY AN AUTOROTATION WAS NOT POSSBL & A RUN ON LNDG WAS NECESSARY. UNSUITABLE TERRAIN LEFT THE PLT WITH ONLY TWO FORCED LNDG OPTIONS, ONE ON CURVING, HILLY HWY WITH POTENTIAL FOR A COLLISION WITH AUTO TRAFFIC, OR THE OTHER INTO HEAVILY TREED TERRAIN. THE PLT APPEARS TO HAVE CHOSEN THE LATTER. IT IS NOT APPARENT WHY HE CHOSE THIS OPTION RATHER THAN DIVERTING TO A NEARBY AIRSTRIP OR SOME OTHER LEVEL FORCED LNDG AREA. THE 42 DEGREE GEARBOX, WHICH HAD BEEN OVERHAULED AND INSTALLED 195 HRS PREVIOUSLY IN ACFT, WAS FOUND TO HAVE FAILED WHEN THE INPUT PINION GEAR FRACTURED IN FATIGUE ORIGINATING FROM CORROSION. CAUSE:

Sources:

NTSB: http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001213X33699


Revision history:

Date/timeContributorUpdates
24-Oct-2008 10:30 ASN archive Added
21-Dec-2016 19:24 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]

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