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ASN Wikibase Occurrence # 40772
Last updated: 5 June 2020
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Date:30-JUL-1994
Time:18:50
Type:Silhouette image of generic H500 model; specific model in this crash may look slightly different
Hughes OH-6A
Owner/operator:Utah Dept Of Public Safety
Registration: N12UT
C/n / msn: 0038
Fatalities:Fatalities: 1 / Occupants: 1
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:Duchesne, UT -   United States of America
Phase: Landing
Nature:Unknown
Departure airport:Salt Lake City , UT (SLC)
Destination airport:
Investigating agency: NTSB
Narrative:
WHILE RETURNING TO SALT LAKE CITY FROM THE SOUTHEAST, THE PILOT REPORTED SEEING THUNDERSTORMS IN THE AREA. AT ABOUT 1843 MDT, THE HELICOPTER CHANGED COURSE AND PROCEEDED OVER MOUNTAINOUS TERRAIN WITH A MODE C ALTITUDE READOUT OF 9600 TO 9800 FEET MSL. THE TERRAIN ELEVATION ALONG THE FLIGHT PATH CHANGED FROM 7700 TO ABOUT 10,000 FEET. SHORTLY AFTER PASSING OVER TERRAIN NEAR 10,000 FEET, THE PILOT RADIOED A MAYDAY AND DECLARED THAT THE ENGINE WAS LOSING POWER. THE HELICOPTER BEGAN A DESCENT, ROUGHLY FOLLOWING A CANYON DRAINAGE AREA. SUBSEQUENTLY, IT CRASHED AT AN ELEVATION OF APPROXIMATELY 8850 FEET AFTER IMPACTING TREES. THE LONGITUDINAL WRECKAGE DISTRIBUTION WAS MINIMAL, INDICATING SLOW FORWARD VELOCITY AT TREE IMPACT. AN EXAM OF THE ENGINE REVEALED EVIDENCE OF POWER PRODUCTION DURING IMPACT; NO PREIMPACT PART FAILURE/MALFUNCTION WAS FOUND. THE DENSITY ALTITUDE WAS ESTIMATED TO BE ABOUT 12,000 FEET, AND THE HELICOPTER'S GROSS WEIGHT AT THE TIME OF THE ACCIDENT WAS ESTIMATED TO BE 1977 POUNDS. PERFORMANCE EVALUATION SHOWED THAT WITH THESE CONDITIONS, THE HELICOPTER WOULD HAVE BEEN UNABLE TO MAINTAIN A HOVER OUT OF GROUND EFFECT. THE ROTOR BLADES SHOWED ROTATIONAL ENERGY IMPACT SIGNATURES. CAUSE: THE PILOT'S IMPROPER IN-FLIGHT PLANNING/DECISION AND FAILURE TO MAINTAIN SUFFICIENT ALTITUDE/CLEARANCE FROM THE SURROUNDING TERRAIN. FACTORS RELATED TO THE ACCIDENT WERE: THUNDERSTORMS IN THE AREA (REQUIRING THE PILOT TO DEVIATE FROM THE DESIRED COURSE), HIGH MOUNTAINOUS TERRAIN, AND HIGH DENSITY ALTITUDE,

Sources:

NTSB: http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001206X01866


Revision history:

Date/timeContributorUpdates
24-Oct-2008 10:30 ASN archive Added
21-Dec-2016 19:23 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]

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