# Accident 19971012030609A: Bell 206B, Sago, WV, October 12, 1997

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: October 12, 1997, 11:13 local time
- Place: Sago, WV
- Damage: Destroyed
- Phase of flight: Fcd/Prec Ldg From Cruise
- Operating rules: Air taxi and commuter (Part 135)
- Operator: BATA
- Location: 38.9807° N, 80.2208° W: From the FAA, an estimate near the named town, within about 3 miles
- Nearby events: https://openairdocs.org/map.md?lat=38.9807&lon=-80.2208&mi=10
- Aircraft: N911RH, a cancelled registration (https://openairdocs.org/deregistered/N911RH-2017-05-23) (OpenAirDocs)
- Registry model: Bell 206B (registry code 1181511, https://openairdocs.org/model/bell-206b) (OpenAirDocs)
- Registry engine: Allison 250 SER 400HP (registry code 03013, https://openairdocs.org/engine/allison-250-ser-400hp) (OpenAirDocs)
- Reported make and model: BELL 206B
- Reported engine: ALLSN 250C20B
- People aboard: 4
- Fatal injuries: 4
- Pilot flight hours: 14,000 total, 9,200 in this make and model
- NTSB investigation: [NTSB IAD98FA005](https://openairdocs.org/ntsb/IAD98FA005) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/19971012030609A

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

BELL 206B CRASHED IN WOODED AREA ALL 4 POB SUFFERED FATAL INJ, ACFT WAS DESTROYED, SAGO, WV (.4) A 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 DU RING MAY-JUNE 1996.

## The NTSB's investigation of this event (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB IAD98FA005](https://openairdocs.org/ntsb/IAD98FA005), Oct 12, 1997: Bell 206B (N911RH), Sago, WV, destroyed, 4 fatal. Probable cause: The improper overhaul of the turbine governor by the manufacturer, which resulted in the loss of power.

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.