Aircraft Accident/Incident Report

Thorne Bay, Alaska 99903
Saturday, May 8, 1993 9:30 AKD

NTSB Narrative Summary Released at Completion of Accident

THE HELICOPTER WAS BEING USED TO MOVE LOGS IN A LONG-LINE LIFT OPERATION. THE PILOT REPORTED THAT AS HE INCREASED COLLECTIVE TO LIFT A LOG, HE HEARD A LOUD NOISE, WHICH WAS FOLLOWED BY A LOSS OF POWER. AN AUTOROTATION WAS MADE TO A LANDING ON ROUGH, DOWNHILL TERRAIN, DOWNSLOPE FROM WHERE THE LOG WAS BEING LIFTED. A TEARDOWN OF THE ENGINE REVEALED EVIDENCE OF FOREIGN OBJECT DAMAGE AT THE 6TH AND 7TH STAGES OF THE N1 (GAS PRODUCER) COMPRESSOR. SELF-LOCKING NUTS (PN STD3064-4) WERE MISSING FROM 2 COMPRESSOR CASE BOLTS (PN MS9566-36), WHICH WERE LOCATED OVER A BLEED PORT, LEADING TO THE 6TH STAGE OF THE GAS PRODUCER. METALLURGICAL EXAM REVEALED NUT FRAGMENTS OF A CHEMICAL COMPOSITION, CONSISTENT WITH THE MATERIAL SPECIFIED IN STD3064-4 NUTS. THE ENGINE HAD BEEN IN OPERATION ABOUT 283 HOURS, AFTER BEING REASSEMBLED WITH A NEW COMPRESSOR SECTION.

NTSB Probable Cause Narrative

FOREIGN OBJECT DAMAGE TO THE COMPRESSOR ASSEMBLY, PROBABLY DUE TO LOOSE NUTS FROM THE COMPRESSOR CASE AFTER IMPROPER MAINTENANCE (INSTALLATION) BY MAINTENANCE PERSONNEL.

Event Information

Type of Event Accident
Event Date 5/8/1993
Event Day of the Week Saturday
Time of Event 930
Event Time Zone --
Event City THORNE BAY
Event State ALASKA
Event Country --
Zipcode of the event site 99903
Event Date Year 1993
Event Date Month 5
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 Unknown
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 4000
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 20
Air Temperature at event time (in degrees celsius) 4
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 20
Variable Wind Indicator Unknown
Wind Speed (knots) 8
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 2
Injury Total None --
Injury Total Serious --
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 1152
NTSB Notification Source --
NTSB Notification Date May 8 1993 12:00AM
NTSB Notification Time 1100
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 11 2000 1:17PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N314CR
NTSB Number ANC93FA061
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 133: Rotorcraft Ext. Load
Type of Flight Plan filed Company VFR
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name BELL
Aircraft Model 214B1
Aircraft Series Identifier 214B1
Aircraft Serial Number 28055
Certified Max Gross Weight 16000
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 AAIP
Date of Last Inspection May 6 1993 12:00AM
Airframe hours since last inspection 9
Airframe Hours 5647
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name CRI HELICOPTERS, INC
Aircraft Owner Street Address 19378 CENTRAL ROAD
Aircraft Owner City APPLE VALLEY
Aircraft Owner State CA
Aircraft Owner Country
Aircraft Owner Zipcode 92307
Operator is an individual? --
Operator Name CHET RASBERRY
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address 19378 CENTRAL ROAD
Operator City APPLE VALLEY
Operator State CA
Operator Country
Operator Zip code 92307
Operator Code EEYA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? Yes
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) Unknown
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code
Departure City
Departure State
Departure Country
Departure Time 0
Departure Time Zone
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 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 --