Accident Thorp T-18 N111GC,
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ASN Wikibase Occurrence # 34775
 
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Date:Friday 15 December 1989
Time:17:56
Type:Silhouette image of generic T18 model; specific model in this crash may look slightly different    
Thorp T-18
Owner/operator:private
Registration: N111GC
MSN: 387
Total airframe hrs:1602 hours
Engine model:LYCOMING O-320-E2A
Fatalities:Fatalities: 1 / Occupants: 1
Aircraft damage: Destroyed
Category:Accident
Location:Austin, NV -   United States of America
Phase: En route
Nature:Private
Departure airport:Autsin, NV (9U3)
Destination airport:Sun Valley, ID (TWF)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
DURING A CROSS COUNTRY FLIGHT, THE PILOT MADE AN UNSCHEDULED LANDING AT AN AIRPORT TO CHECK ON A NOISE. SHORTLY AFTER LANDING, THE FLIGHT CONTINUED. RADAR RETURNS INDICATE THAT THE AIRPLANE DEPARTED THE AIRPORT ON A NORTHERLY HEADING AND CLIMBED TO 11,900 FEET THEN BEGAN TO DESCEND, TURNING WESTERLY AWAY FROM RISING TERRAIN. THE AIRPLANE COLLIDED WITH HILLY TERRAIN APRX 14 MILES FROM THE AIRPORT. ONE PROPELLER BLADE HAD SEPARATED AND WAS NOT LOCATED. A METALLURGICAL TEST REVEALED THAT THE BREAK WAS DUE TO HIGH CYCLE BENDING STRESSES INDUCED BY RESONANT VIBRATION. RESEARCH OF THE AIRPLANE'S HISTORY REVEALED THAT ANOTHER ENGINE (DIFFERENT FROM WHICH THE AIRCRAFT WAS ORIGINALLY CERTIFICATED) HAD BEEN INSTALLED ON THE AIRPLANE AND THAT THE PROPELLER (ORIGINAL FROM THE FIRST ENGINE) AT SOME TIME HAD BEEN CUT AND REPITCHED. CAUSE: AN IMPROPER MAJOR ALTERATION PERFORMED BY THE PILOT. AS A RESULT OF THIS MODIFICATION, THE PROPELLER FAILED IN FLIGHT.

Sources:

NTSB: https://www.ntsb.gov/ntsb/brief.asp?ev_id=20001213X30013

Revision history:

Date/timeContributorUpdates
24-Oct-2008 10:30 ASN archive Added

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