Aircraft Accident/Incident Report

Rainier, Washington 98576
Thursday, April 4, 1996 8:20 PST

NTSB Narrative Summary Released at Completion of Accident

While preparing to sling a load of logs, the pilot noticed several changes in engine noise level followed by two loud bangs and a total loss of power. He executed an autorotation/landing into a small clearing directly beneath the rotorcraft as no other suitable site was available. During the forced landing, the helicopter was damaged. Disassembly of the ex-military, Allied Signal (Lycoming) T53-L-13BA turboshaft engine revealed that the number 21 forward bearing (P/N 1-300-082-01B) had disintegrated. The engine had a total of 4202.4 operating hours of which 199.4 were accrued since entering the civilian operating environment. Nonmandatory Service Bulletin No. 0056 provided procedures for replacing this bearing with an improved bearing (P/N 1-300-082-03), within 400 hours after receipt of the bulletin.

NTSB Probable Cause Narrative

failure of the forward power shaft (number 21) bearing. A factor relating to the accident was: the lack of suitable, unobstructed terrain for an emergency landing.

Event Information

Type of Event Accident
Event Date 4/4/1996
Event Day of the Week Thursday
Time of Event 820
Event Time Zone Pacific Standard Time
Event City RAINIER
Event State WASHINGTON
Event Country --
Zipcode of the event site 98576
Event Date Year 1996
Event Date Month 4
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 Weather Observation Facility
Time of the weather observation 818 Pacific Standard Time
Direction of event from weather observation facility (degrees) 280
Weather Observation Facility ID OLM
Elevation of weather observation facility 206
Distance of event from weather observation facility (units?) 22
Time Zone of the weather observation PST
Lighting Conditions Day
Lowest Ceiling Height 300
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 0.75
Air Temperature at event time (in degrees celsius) 6
Dew Point at event time (in degress fahrenheit) 6
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) 30
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) 922
NTSB Notification Source --
NTSB Notification Date Apr 4 1996 12:00AM
NTSB Notification Time 1113
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 9:57AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N6166R
NTSB Number SEA96FA076
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-1H
Aircraft Series Identifier UH-1H
Aircraft Serial Number 157199
Certified Max Gross Weight 9500
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 Mar 29 1996 12:00AM
Airframe hours since last inspection 7
Airframe Hours 5020
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site No
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
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 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 745
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 Emergency landing
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 --