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OH-6 Cayuse/66-17825
Hughes OH-6 Cayuse Loach
Serial #: 66-17825
Construction #: -
Civil Registration:
  N13SD
Model: NOH-6P
Name: None
Status: Airworthy
Last info: 2007
   History:
Snohomish County Sheriffs Office, Everett, WA, 1994-2007.
– Registered as N13SD.
— Fitted with FLIR camera, NightSun, Microwave Videw Downlink system, Moving map system.
— Used for Airborne Law Enforcement with a secondary S.A.R. role.
– Crashed and heavily damaged in non-fatal accident, Nov. 29, 2002.
— Forward strut replaced as well as main rotor.
— Returned to airworthy, June 2006.
NTSB Identification: SEA03TA014.
Accident occurred Friday, November 29, 2002 in Snohomish, WA
Probable Cause Approval Date: 6/25/03
Aircraft: Hughes OH-6A, registration: N13SD
Injuries: 2 Uninjured.

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.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
Loss of engine power for undetermined reasons while in cruise flight. A tree was a factor.

Source(s):
National Transportation & Saftery Board (NTSB), 2003.
Federal Aviation Administration, www.faa.gov, 2007.
 Photo Source(s):
Deputy Bill Quistorf, Chief Pilot
Snohomish County Sheriff's Office
Research Assistance:
Deputy Bill Quistorf, Chief Pilot
Snohomish County Sheriff's Office