Aircraft Accident/Incident Report

North Bend, Washington 98045
Friday, November 12, 1993 11:30 PST

NTSB Narrative Summary Released at Completion of Accident

THE PILOT HEARD LOUD GRINDING SOUNDS FROM THE REAR OF THE AIRCRAFT, FOLLOWED BY BANGING SOUNDS AND A LOSS OF DIRECTIONAL CONTROL. HE JETTISONED HIS LOGS, THEN HIS LONG LINE, AND EXECUTED A POWERED AUTOROTATION INTO THE TREES, SUBSTANTIALLY DAMAGING THE AIRCRAFT. THE 42 DEGREE INTERMEDIATE GEARBOX WAS EXAMINED AND MULTIPLE ORIGIN FATIGUE CRACKS WERE FOUND IN FRAGMENTS OF THE INPUT PINION GEAR.

NTSB Probable Cause Narrative

TOTAL FAILURE OF THE INTERMEDIATE GEARBOX. THE LACK OF SUITABLE TERRAIN FOR AN AUTOROTATION WAS A FACTOR.

Event Information

Type of Event Accident
Event Date 11/12/1993
Event Day of the Week Friday
Time of Event 1130
Event Time Zone Pacific Standard Time
Event City NORTH BEND
Event State WASHINGTON
Event Country --
Zipcode of the event site 98045
Event Date Year 1993
Event Date Month 11
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 Pilot
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) 2
Air Temperature at event time (in degrees celsius) 16
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Unknown
Wind Speed (knots) 0
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 1
Injury Total None --
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 2124
NTSB Notification Source --
NTSB Notification Date Nov 12 1993 12:00AM
NTSB Notification Time 1153
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 11 2000 1:46PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N91NW
NTSB Number SEA94LA030
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 HAWKINS & POWERS
Aircraft Model UH-1B
Aircraft Series Identifier UH-1B
Aircraft Serial Number 62-1915
Certified Max Gross Weight 8500
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 2
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection Nov 8 1993 12:00AM
Airframe hours since last inspection 25
Airframe Hours 10106
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name NORTHWEST HELICOPTERS, INC.
Aircraft Owner Street Address 7822 OLD HWY 99 SE
Aircraft Owner City OLYMPIA
Aircraft Owner State WA
Aircraft Owner Country
Aircraft Owner Zipcode 98501
Operator is an individual? --
Operator Name NORTHWEST HELICOPTERS, INC.
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address 7822 OLD HWY 99 SE
Operator City OLYMPIA
Operator State WA
Operator Country
Operator Zip code 98501
Operator Code WYFL
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 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 800
Departure Time Zone PST
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 --