Accident Hughes OH-6A N13SD,
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ASN Wikibase Occurrence # 296388
 
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Date:Friday 29 November 2002
Time:14:50 LT
Type:Silhouette image of generic H500 model; specific model in this crash may look slightly different    
Hughes OH-6A
Owner/operator:Snohomish Co Sheriff's Office
Registration: N13SD
MSN: 66-17825
Year of manufacture:1968
Fatalities:Fatalities: 0 / Occupants: 2
Aircraft damage: Substantial
Category:Accident
Location:Snohomish, WA -   United States of America
Phase: Unknown
Nature:Unknown
Departure airport:Snohomish, WA
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The pilot reported that about five minutes after departure, in cruise flight, at 100 knots and 1,000 feet msl, the engine rpm fluctuated with a noticeable engine noise reduction. Subsequently N2 rapidly decelerated and the helicopter yawed to the left. The pilot initiated an autorotation, however, due to heavily wooded terrain, the pilot had to maneuver around obstructions to a landing site. During the maneuver, the helicopter collided with a tree branch which broke the chin bubble. At approximately 100 feet agl, the pilot started the deceleration. Approximately 30 feet agl, the forward airspeed was at or near zero. The helicopter descended faster than the pilot anticipated as he pulled in collective to slow the descent and then a significant amount of collective to cushion the landing. The helicopter landed with more force than normal and the helicopter rolled to the right after landing. The right side fore and aft skid legs collapsed at the mid point of the struts and the helicopter came to rest on its right side. The engine was inspected and subsequently removed for an engine test cell run. During the engine test cell run, the engine was found to be making more than rated horsepower at all points.

Probable Cause: Loss of engine power for undetermined reasons while in cruise flight. A tree was a factor.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: 
Status: Investigation completed
Duration: 6 months
Download report: Final report

Sources:

NTSB SEA03TA014

Revision history:

Date/timeContributorUpdates
14-Oct-2022 05:51 ASN Update Bot Added
30-May-2023 07:18 Ron Averes Updated

Corrections or additions? ... Edit this accident description

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