ASN Wikibase Occurrence # 36061
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| Date: | Sunday 12 October 1997 |
| Time: | 11:13 |
| Type: |  Bell 206B JetRanger |
| Owner/operator: | Royale Helicopter Service |
| Registration: | N911RH |
| MSN: | 1583 |
| Year of manufacture: | 1975 |
| Total airframe hrs: | 5971 hours |
| Engine model: | Allison 250-C20B |
| Fatalities: | Fatalities: 4 / Occupants: 4 |
| Aircraft damage: | Destroyed |
| Category: | Accident |
| Location: | Sago, WV -
 United States of America
|
| Phase: | Manoeuvring (airshow, firefighting, ag.ops.) |
| Nature: | Passenger - Non-Scheduled/charter/Air Taxi |
| Departure airport: | Spruce Fork, WV |
| Sawmill Run, WV | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
On October 12, 1997, about 1113 eastern daylight time, a Bell 206B, N911RH, was destroyed as it impacted the terrain in a wooded area near Sago, West Virginia. The certificated commercial pilot and three passengers received fatal injuries. The helicopter was owned and operated by Royale Helicopter Services, Incorporated, Burgettstown, Pennsylvania. Visual meteorological conditions prevailed and no flight plan was filed for the flight conducted under 14 CFR Part 135.
The helicopter was transporting passengers to a remote site when it dropped in a flat attitude and impacted into trees. A witness said he watched as the helicopter approached and circled the local area. As the helicopter flew overhead for the second time, he waved his arms to attract the pilot's attention. As the helicopter continued past him again, he thought that they were taking aerial photographs of the site. He said that the helicopter appeared to be lower and slower on its second pass overhead. Examination of the engine revealed uncommanded engine shut downs. During bench testing, the power turbine governor failed to limit fuel flow, and during disassembly it was revealed that a machine self locking hex nut had backed off the muscles valve stem. Examination of the muscles valve components revealed that the threaded valve stem was below the minimum requirements for a UNJ thread, and the flank angle was too large. The turbine governor, with zero Time Since Overhaul, was installed on the engine in January 1997. The governor was last overhauled at the manufacturer's facility during May-June 1996.
Probable Cause: The improper overhaul of the turbine governor by the manufacturer, which resulted in the loss of power.
Accident investigation:
 |
|
Sources:
NTSB: https://www.ntsb.gov/ntsb/brief.asp?ev_id=20001208X09034
Images:
Photo: NTSB
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 24-Oct-2008 10:30 | ASN archive | Added |
| 21-Dec-2016 19:22 | ASN Update Bot | Updated [Time, Damage, Category, Investigating agency] |
| 18-Oct-2022 12:25 | Captain Adam | Updated [Nature, Narrative, Accident report, Photo] |
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