Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Pierce, Idaho 83501
Thursday, September 23, 1993 8:15 PDT
NTSB Narrative Summary Released at Completion of Accident
WHILE MANEUVERING NEAR A REFUELING SITE IN HILLY/MOUNTAINOUS TERRAIN, THE 90 DEGREE GEARBOX SEPARATED FROM THE AIRCRAFT. THE PILOT THEN ATTEMPTED A RUN-ON FORCED LANDING ON A NEARBY LOGGING ROAD. DURING THE FLARE, THE AIRCRAFT LANDED HARD, RESULTING IN A COLLAPSE OF THE SKIDS, AND SEPARATION OF THE REMAINING PORTION OF THE TAIL BOOM. METALLURGICAL ANALYSIS REVEALED THAT ALL SIX GEARBOX ATTACH BOLTS HAD EXPERIENCED REVERSE-BENDING FATIGUE FAILURE. THE OPERATOR RECORDS INDICATED THAT THIS WAS A NEW SURPLUS PART WHICH HAD 136 HOURS OF OPERATION SINCE NEW. HISTORICAL RECORDS CONFIRMING THE UNIT'S TOTAL TIME SINCE BEING SHIPPED TO THE PHILIPPINES AS A NEW SURPLUS PART IN 1981 COULD NOT BE LOCATED.
NTSB Probable Cause Narrative
SEPARATION OF THE 90 DEGREE GEARBOX AFTER FATIGUE FAILURE OF THE GEARBOX ATTACH BOLTS. FACTORS INCLUDE HILLY/MOUNTAINOUS TERRAIN.
Event Information
| Type of Event | Accident |
| Event Date | 9/23/1993 |
| Event Day of the Week | Thursday |
| Time of Event | 815 |
| Event Time Zone | Pacific Daylight Time |
| Event City | PIERCE |
| Event State | IDAHO |
| Event Country | -- |
| Zipcode of the event site | 83501 |
| Event Date Year | 1993 |
| Event Date Month | 9 |
| 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 | -- |
| Weather Briefing Completeness | Unknown |
| Investigator's weather source | Witness |
| Time of the weather observation | 0 |
| Direction of event from weather observation facility (degrees) | 0 |
| Weather Observation Facility ID | |
| Elevation of weather observation facility | 0 |
| Distance of event from weather observation facility (units?) | 0 |
| Time Zone of the weather observation | |
| 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) | 0 |
| Air Temperature at event time (in degrees celsius) | 13 |
| Dew Point at event time (in degress fahrenheit) | -- |
| Wind Direction (degrees magnetic) | 0 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 0 |
| Wind Velocity Indicator | Calm |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | -- |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 1 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 2028 |
| NTSB Notification Source | -- |
| NTSB Notification Date | Sep 23 1993 12:00AM |
| NTSB Notification Time | 800 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Dec 11 2000 1:39PM |
| User who most recently changed record | dbo |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N3979C |
| NTSB Number | SEA93LA207 |
| Missing Aircraft Indicator | N |
| Federal Aviation Reg. Part | Part 133: Rotorcraft Ext. Load |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | -- |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BELL |
| Aircraft Model | UH-1B |
| Aircraft Series Identifier | UH-1B |
| Aircraft Serial Number | 62-2048 |
| Certified Max Gross Weight | 7200 |
| 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 | 7 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Aug 31 1993 12:00AM |
| Airframe hours since last inspection | 90 |
| Airframe Hours | 7922 |
| ELT Installed | Unknown |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | CLEARWATER MANAGEMENT CO. INC. |
| Aircraft Owner Street Address | P.O. BOX 1465 |
| Aircraft Owner City | LEWISTON |
| Aircraft Owner State | ID |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 83501 |
| Operator is an individual? | -- |
| Operator Name | CLEARWATER MANAGEMENT CO. INC. |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | P.O. BOX 1465 |
| Operator City | LEWISTON |
| Operator State | ID |
| Operator Country | |
| Operator Zip code | 83501 |
| Operator Code | YWQL |
| 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 | Unknown |
| Indicates Domestic or International Flight | Unknown |
| Operator carrying Pax/Cargo/Mail | Unknown |
| Type of Flying (Per_Bus / Primary) | Other Work Use |
| Second Pilot on Board | No |
| Departure Point Same as Event | Yes |
| Departure Airport Code | |
| Departure City | |
| Departure State | |
| Departure Country | |
| Departure Time | 810 |
| Departure Time Zone | PDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | |
| Destination City | |
| Destination State | |
| 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 | -- |