Aircraft Accident/Incident Report

Farewell, Alaska 99695
Saturday, July 14, 1990 9:00 AKD

NTSB Narrative Summary Released at Completion of Accident

WHILE APPROACHING A REMOTE MOUNTAINTOP SITE TO LAND, AT ABOUT 100 FT AGL AND 40 MPH, THE ENGINE LOST ALL POWER AS A RESULT OF A CONTAINED ENGINE FAILURE, AND THE HELICOPTER MADE A HARD LANDING. ENGINE TEARDOWN REVEALED THAT THE 1ST STAGE TURBINE WHEEL HAD FAILED DUE TO THERMAL FATIGUE WHICH ORIGINATED ON THE TRAILING EDGE O.D. RIM SURFACE. IN ADDITION, BOTH THE 1ST AND 2ND STAGE TURBINE WHEEL AIRFOILS EXHIBITED EVIDENCE OF OVERTEMPERATURE OPERATION. THE FUEL CONTROL WAS PROPERLY SET. THERE WAS NO EVIDENCE OF AN INTERNAL ENGINE OIL FIRE. FAST ENGINE SHUTDOWNS CAN ALSO RESULT IN OVERTEMPERATURES IF SUFFICIENT COOL DOWN TIME AT IDLE POWER IS NOT ALLOWED BEFORE THE ENGINE IS SHUTDOWN. THE TURBINE OUTLET TEMPERATURE GAUGE DID NOT INCORPORATE THE 'OVERTEMPERATURE LIGHT' FEATURE.

NTSB Probable Cause Narrative

AN INTERNAL ENGINE FAILURE DUE TO A THERMAL FATIGUE FAILURE OF THE 1ST STAGE TURBINE WHEEL AS A RESULT OF OVERTEMPERATURE. THE HIGH ROUGH/UNEVEN TERRAIN PREVENTED A SUCCESSFUL AUTOROTATION.

Event Information

Type of Event Accident
Event Date 7/14/1990
Event Day of the Week Saturday
Time of Event 900
Event Time Zone --
Event City FAREWELL
Event State ALASKA
Event Country --
Zipcode of the event site 99695
Event Date Year 1990
Event Date Month 7
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID NONE
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles 0
Degrees magnetic from airport 0
Airport Elevation --
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 800 Atlantic Daylight Time
Direction of event from weather observation facility (degrees) 117
Weather Observation Facility ID MCG
Elevation of weather observation facility 337
Distance of event from weather observation facility (units?) 55
Time Zone of the weather observation ADT
Lighting Conditions Day
Lowest Ceiling Height 6500
Lowest Non-Ceiling Height 5000
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling Overcast
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 40
Air Temperature at event time (in degrees celsius) 11
Dew Point at event time (in degress fahrenheit) 9
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) 0
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Serious
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None --
Injury Total Serious 5
Injury Total All 5
Investigating Agency NTSB
NTSB Docket Number (internal use) 1606
NTSB Notification Source --
NTSB Notification Date Jul 14 1990 12:00AM
NTSB Notification Time 904
Fiche Number and/or location -used to find docket information 42876
Date of most recent change to record Dec 12 2000 5:08PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N300AH
NTSB Number ANC90FA117
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 135: Air Taxi & Commuter
Type of Flight Plan filed Company VFR
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire Ground
Aircraft Explosion None
Aircraft Manufacturer's Full Name BELL
Aircraft Model 206L-1
Aircraft Series Identifier 206L-1
Aircraft Serial Number 45519
Certified Max Gross Weight 4150
Aircraft Category Helicopter
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? Unknown
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 100 Hour
Date of Last Inspection Jul 7 1990 12:00AM
Airframe hours since last inspection 12
Airframe Hours 6380
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name
Aircraft Owner Street Address
Aircraft Owner City
Aircraft Owner State
Aircraft Owner Country
Aircraft Owner Zipcode
Operator is an individual? --
Operator Name ALASKA HELICOPTERS, INC.
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address 6400 SOUTH AIRPARK DR.
Operator City ANCHORAGE
Operator State AK
Operator Country
Operator Zip code 99502
Operator Code ERCA
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 Non-scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Passenger/Cargo
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code SVW
Departure City SPARREVOHN AFS
Departure State AK
Departure Country
Departure Time 800
Departure Time Zone ADT
Destination Same as Local Flt crash at destination city
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Landing
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:35AM
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 --