Aircraft Accident/Incident Report

Coolin, Idaho 83821
Wednesday, September 7, 1994 13:00 PDT

NTSB Narrative Summary Released at Completion of Accident

THE PRIVATE PILOT WAS FORCED TO LAND THE AIRPLANE ON UNSUITABLE TERRAIN BECAUSE OF A LOSS OF ENGINE POWER. DURING THE FORCED LANDING, THE AIRPLANE IMPACTED A TREE STUMP, NOSED OVER, AND WAS SUBSTANTIALLY DAMAGED. AN EXAMINATION OF THE ENGINE REVEALED THAT THE ROCKER ARM FOR THE NO. 1 CYLINDER EXHAUST VALVE HAD FAILED. AN EXAMINATION OF THE ROCKER ARM REVEALED THAT THE ARM HAD FAILED DUE TO FATIGUE, AND THAT THE FATIGUE CRACKING WAS INITIATED AT ROUGH TOOL MARKS PRODUCED DURING THE CHAMFERING OF THE ARM'S OIL HOLE. THE CHAMFERING WAS PERFORMED BY THE ENGINE MANUFACTURER DURING REMANUFACTURE OF THE ENGINE.

NTSB Probable Cause Narrative

THE FAILURE OF THE ENGINE MANUFACTURER TO PROPERLY REMANUFACTURE AND ADEQUATELY INSPECT THE NO. 1 ROCKER ARM PRIOR TO ITS INSTALLATION ON THE ENGINE. THIS RESULTED IN FATIGUE CRACKING OF THE ROCKER ARM AND A SUBSEQUENT LOSS OF ENGINE POWER.

Event Information

Type of Event Accident
Event Date 9/7/1994
Event Day of the Week Wednesday
Time of Event 1300
Event Time Zone Pacific Daylight Time
Event City COOLIN
Event State IDAHO
Event Country --
Zipcode of the event site 83821
Event Date Year 1994
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 Weather Observation Facility
Time of the weather observation 1252 Pacific Daylight Time
Direction of event from weather observation facility (degrees) 200
Weather Observation Facility ID GEG
Elevation of weather observation facility 2372
Distance of event from weather observation facility (units?) 25
Time Zone of the weather observation PDT
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 25000
Sky/Lowest/Cloud Conditions Thin Overcast
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 30
Air Temperature at event time (in degrees celsius) 28
Dew Point at event time (in degress fahrenheit) 3
Wind Direction (degrees magnetic) 170
Variable Wind Indicator Unknown
Wind Speed (knots) 4
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
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 2
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 1858
NTSB Notification Source --
NTSB Notification Date Sep 7 1994 12:00AM
NTSB Notification Time 1400
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 6 2000 12:18PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N61838
NTSB Number SEA94LA235
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name CESSNA
Aircraft Model 172M
Aircraft Series Identifier 172M
Aircraft Serial Number 17264832
Certified Max Gross Weight 2400
Aircraft Category Airplane
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 0
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection May 4 1994 12:00AM
Airframe hours since last inspection 15
Airframe Hours 2263
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name NETT, EUGENE A.
Aircraft Owner Street Address EAST 551 JOSEPH
Aircraft Owner City SPOKANE
Aircraft Owner State WA
Aircraft Owner Country
Aircraft Owner Zipcode 99207
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 None
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 --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Personal
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code 66S
Departure City CAVINAUGH BAY
Departure State ID
Departure Country
Departure Time 1215
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 Climb
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 --