Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Kooskia, Idaho 83539
Friday, January 8, 2010 12:20 MST
NTSB Narrative Summary Released at Completion of Accident
The pilot was maneuvering the helicopter for a wolf-capturing mission above rugged terrain densely populated by trees. As the pilot maneuvered the helicopter in a hover about 300 to 400 feet above the ground, a loud "bang" emitted from the engine compartment, followed by a loss of engine power and slight vibration. With the low rpm light illuminated, the pilot lowered the collective and entered an autorotation; the helicopter landed hard.
A postaccident examination of the engine revealed metal particles adhering to both engine chip detector plugs. Disassembly of the engine revealed that the No. 2 bearing failed. The damage identified on the bearing’s outer race was consistent with electrical arcing. The extensive wear and mechanical damage to the bearing raceways and the bearing balls precluded the identification of arcing damage on the raceways and ball surfaces. However, the arcing damage found was sufficient to precipitate a bearing failure such as was found on accident engine.
The bearings are a common source of electrical grounding between the case of a turbine engine and the rotating components. Hence, bearings are a probable location of electrical arcing if conditions are sufficient. Although the exact source of electrical arc could not be determined for the helicopter, it is possible that a lightning strike or stray electrical current could have precipitated such damage. The metal splatter deposits present on the oil slinger surfaces were approximately aligned in the same direction suggesting that the arcing associated with the oil slinger occurred when the engine compressor was not rotating.
Although the chip detector caution indicator was found to be inoperative, it is unknown whether it would have alerted the pilot soon enough to the impending engine failure for him to execute a precautionary landing.
NTSB Probable Cause Narrative
A complete loss of engine power due to the failure of the No. 2 bearing, which was precipitated by electrical arcing that occurred at an unknown time prior to the accident flight.
Event Information
| Type of Event | Accident |
| Event Date | 1/8/2010 |
| Event Day of the Week | Friday |
| Time of Event | 1220 |
| Event Time Zone | Mountain Standard Time |
| Event City | Kooskia |
| Event State | IDAHO |
| Event Country | -- |
| Zipcode of the event site | 83539 |
| Event Date Year | 2010 |
| Event Date Month | 1 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 464315N |
| Event Location Longitude | 1150509W |
| 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 | -- |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Pilot |
| Time of the weather observation | 1856 Mountain Standard Time |
| Direction of event from weather observation facility (degrees) | 270 |
| Weather Observation Facility ID | KLWS |
| Elevation of weather observation facility | 1442 |
| Distance of event from weather observation facility (units?) | 45 |
| Time Zone of the weather observation | MST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | -1 |
| Dew Point at event time (in degress fahrenheit) | -7 |
| Wind Direction (degrees magnetic) | 80 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 10 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.34 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | KLWS 081856Z 08010KT 10SM CLR M01/M07 A3034 RMK AO |
| Event Highest Injury | Serious |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | -- |
| Injury Total Serious | 3 |
| Injury Total All | 3 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 29158 |
| NTSB Notification Source | FAA Comm Center |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Oct 28 2011 2:02PM |
| User who most recently changed record | coos |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N500LW |
| NTSB Number | WPR10GA102 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Public Use |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | No |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | HUGHES |
| Aircraft Model | 369D |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 470120D |
| Certified Max Gross Weight | 3000 |
| Aircraft Category | Helicopter |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 4 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | 100 Hour |
| Date of Last Inspection | Dec 30 2009 12:00AM |
| Airframe hours since last inspection | 27 |
| Airframe Hours | 13167 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | QUICKSILVER AIR INC |
| Aircraft Owner Street Address | 2721 CORMORANT ST |
| Aircraft Owner City | FAIRBANKS |
| Aircraft Owner State | AK |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 99709-2565 |
| Operator is an individual? | No |
| Operator Name | Idaho Fish and Game |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | -- |
| Operator City | Boise |
| Operator State | ID |
| Operator Country | USA |
| 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 | External Load |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | -- |
| Indicates Domestic or International Flight | -- |
| Operator carrying Pax/Cargo/Mail | -- |
| Type of Flying (Per_Bus / Primary) | -- |
| Second Pilot on Board | No |
| Departure Point Same as Event | Yes |
| Departure Airport Code | -- |
| Departure City | Kooskia |
| Departure State | ID |
| Departure Country | USA |
| Departure Time | 1155 |
| Departure Time Zone | MDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | KS82 |
| Destination City | Kooskia |
| Destination State | ID |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Oct 28 2011 2:03PM |
| User who most recently changed record | coos |
| Since inspection or accident | Last Inspection |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |