ASN Wikibase Occurrence # 87462
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| Date: | Friday 31 August 2001 |
| Time: | 09:05 |
| Type: |  Kawasaki Vertol 107-II (CH-46) |
| Owner/operator: | Columbia Helicopters Inc |
| Registration: | N186CH |
| MSN: | 4005 |
| Year of manufacture: | 1963 |
| Total airframe hrs: | 41559 hours |
| Engine model: | General Electric CT 58-140-1 |
| Fatalities: | Fatalities: 3 / Occupants: 3 |
| Aircraft damage: | Destroyed |
| Category: | Accident |
| Location: | Emigrant, MT -
 United States of America
|
| Phase: | Manoeuvring (airshow, firefighting, ag.ops.) |
| Nature: | Test |
| Departure airport: | Emigrant, MT |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
On August 31, 2001, approximately 0905 hours mountain daylight time, a Kawasaki KV-107 II rotorcraft, N186CH, registered to and operated by Columbia Helicopters Leasing, Inc., and being flown by two commercial pilots, was destroyed when it collided with terrain following a loss of control in flight during a cruise/climb phase of operation. The crash site was approximately three miles south of Emigrant, Montana. Both pilots and the onboard mechanic were fatally injured. A post-crash fire destroyed much of the rotorcraft. Visual meteorological conditions existed and no flight plan had been filed. The flight, which was a non-mandatory maintenance check flight following a phase five inspection, was to have been operated under 14CFR91, and originated from the Fridley Helibase staging site approximately eight nautical miles north of the crash site and slightly north of Emigrant, Montana. The rotorcraft was estimated to have departed on the check flight approximately 0845. The aircraft was under contract with US Forest Service and was engaged in firefighting operations in support of the Fridley Fire centered approximately eight nautical miles north and west of Emigrant, Montana.
The Kawasaki Vertol KV-107 II rotorcraft had departed the helibase on a non-mandatory test flight requested by the pilot-in-command (PIC) to 'tweak' the rotorcraft's engine synchronization system. The test flight was conducted with the bucket and 150 foot long line attached to facilitate the test procedure. Witnesses reported observing the rotorcraft between 300 and 1,000 feet in altitude and beginning a climb when it began to pitch/roll and descend rapidly. Several witnesses reported seeing the bucket horizontal to the rotorcraft and also caught up in one of the rotors. The aircraft impacted on its right side intact with the exception of its rotor blades. Two of the three forward rotor blades were found 600-900 feet from the ground impact site. The third forward rotor blade, which was broken in half, was found with its outboard section at the ground impact site and the inboard half approximately 100 feet away. All three aft rotor blades were found in close proximity to one another and approximately 400 feet distant from the primary ground impact site. All six blades separated from their root sections in about the same place and a post crash fire destroyed much of the rotorcraft. Post crash examination established control continuity from the cockpit area through the control closet and on to all the associated hydraulic actuators as well as the continuity of the entire synchronization drive shafting. Examination and disassembly of all major components revealed no evidence of any fatigue propagation, disconnects, or characteristics of other time dependent failure mechanisms. All hydraulic actuators underwent an X-ray examination and disassembly and there was no evidence of any blockage or jamming within any of the actuators. The engines were examined and disassembled and the gas generator speed range for both was determined to be between 64.3% and 69.7%, or about 10% above ground idle. There was evidence that the long line cable encountered/impacted the nose gear strut, as well as an aft strut, the forward left side of the fuselage, the forward rotor head rain shield and all three forward rotor blades. It could not be determined whether the cable to rotor interaction was an initiating event or the result of a previous occurrence which allowed the cable to become entangled with the forward rotor blades. The PIC had more than 1630 hours of V-107 rotorcraft time of which more than 670 hours were logged as PIC time. The co-pilot had more than 150 hours of V-107 rotorcraft time none of which was PIC time.
Probable Cause: The loss of control during cruise/climb flight for undetermined reasons.
Accident investigation:
 |
|
Sources:
NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20010907X01903&key=1
History of this aircraft
Other occurrences involving this aircraft
| 30 April 1992 | 11311 | Canadian Armed Forces (CAF) | 1 | near Bella Coola, Vancouver Island, BC |  |
w/o |
Location
Images:
An aerial view looking north shortly after the accident showing thenortheasterly smoke drift. Note the forward green rotor blade in theforeground (arrow).
Photos: NTSB
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 10-Jan-2011 09:15 | TB | Added |
| 10-Jan-2011 10:12 | TB | Updated [Aircraft type] |
| 10-Jan-2011 14:06 | TB | Updated [Source] |
| 21-Dec-2016 19:25 | ASN Update Bot | Updated [Time, Damage, Category, Investigating agency] |
| 10-Dec-2017 12:23 | ASN Update Bot | Updated [Cn, Operator, Nature, Departure airport, Source, Narrative] |
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