Crawford-Gordon THORP T-18 N111GC

Summary

On 16 December 1989 at about 01:56 local time, a Crawford-Gordon THORP T-18 registered N111GC was involved in an accident near Austin, Nevada, United States. One person was on board and one died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

16 December 1989 at 01:56

Classification

Accident

Location

Austin, Nevada, United States

Coordinates

39.5407, -117.1895

Aircraft

Crawford-Gordon THORP T-18

Registration

N111GC

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Autsin → Sun Valley

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

SEA90FA030

1 person died.

AN IMPROPER MAJOR ALTERATION PERFORMED BY THE PILOT. AS A RESULT OF THIS MODIFICATION, THE PROPELLER FAILED IN FLIGHT.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB 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.

Quoted verbatim from the NTSB record.