Aircraft Accident/Incident Report

Sago, West Virginia 26201
Sunday, October 12, 1997 11:13 EDT

NTSB Narrative Summary Released at Completion of Accident

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 during May-June 1996.

NTSB Probable Cause Narrative

The improper overhaul of the turbine governor by the manufacturer, which resulted in the loss of power.

Event Information

Type of Event Accident
Event Date 10/12/1997
Event Day of the Week Sunday
Time of Event 1113
Event Time Zone Eastern Daylight Time
Event City SAGO
Event State WEST VIRGINIA
Event Country --
Zipcode of the event site 26201
Event Date Year 1997
Event Date Month 10
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation 1760
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1051 Eastern Standard Time
Direction of event from weather observation facility (degrees) 95
Weather Observation Facility ID EKN
Elevation of weather observation facility 1987
Distance of event from weather observation facility (units?) 16
Time Zone of the weather observation EST
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 13
Dew Point at event time (in degress fahrenheit) 11
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Variable
Wind Speed (knots) 0
Wind Velocity Indicator Calm
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Fatal
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal 4
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 4
Investigating Agency NTSB
NTSB Docket Number (internal use) 1852
NTSB Notification Source --
NTSB Notification Date Oct 12 1997 12:00AM
NTSB Notification Time 1245
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 12:37PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N911RH
NTSB Number IAD98FA005
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 135: Air Taxi & Commuter
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Bell
Aircraft Model 206B
Aircraft Series Identifier 206B
Aircraft Serial Number 1583
Certified Max Gross Weight 3200
Aircraft Category Helicopter
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 6
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection Oct 9 1997 12:00AM
Airframe hours since last inspection 3
Airframe Hours 5971
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name ROYALE HELICOPTER SERVICE, INC
Aircraft Owner Street Address PO BOX 127
Aircraft Owner City BURGETTSTOWN
Aircraft Owner State PA
Aircraft Owner Country
Aircraft Owner Zipcode 15021
Operator is an individual? --
Operator Name
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Non-scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Passenger Only
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code NONE
Departure City SPRUCE FORK
Departure State WV
Departure Country
Departure Time 1100
Departure Time Zone EST
Destination Same as Local Flt --
Destination Airport Code NONE
Destination City SAWMILL RUN
Destination State WV
Destination Country
Specific Phase of Flight Maneuvering
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:34AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --