Aviation Accident Summaries

Aviation Accident Summary LAX90LA015

BORREGO SPRINGS, CA, USA

Aircraft #1

N9330L

GRUMMAN AA-1A

Analysis

THE 23-YEAR-OLD RECENTLY CERTIFIED PRIVATE PILOT PURCHASED AN 18-YEAR-OLD FLYING CLUB AIRPLANE. THE AIRCRAFT AND ENGINE HAD BEEN OPERATED FOR A TOTAL OF 2093 HOURS. NO RECORD WAS FOUND OF THE ENGINE HAVING BEEN OVERHAULED. DURING THE AIRCRAFT'S LIFE, IT HAD BEEN INACTIVE FOR TWO PERIODS TOTALING 8 YEARS. DURING CRUISE FLIGHT, THE ENGINE LOST ALL POWER. THE PILOT MADE AN EMERGENCY LANDING IN THE DESERT, AND THE AIRCRAFT COLLIDED WITH A BERM AND NOSED OVER. EXAMINATION OF THE ENGINE, WHICH HAD A TBO OF 2400 HOURS IF KEPT IN CONTINOUS SERVICE, REVEALED THAT THE NO. 1 EXHAUST VALVE HEAD HAD SEPARATED FROM THE STEM WHICH WAS NECKED DOWN AT THE POINT OF FAILURE. THE ENGINE'S THREE OTHER EXHAUST VALVE STEMS WERE ALSO FOUND NECKED DOWN IN THE SAME GENERAL AREA.

Probable Cause and Findings

THE FAILURE OF THE ENGINE EXHAUST VALVE.

 

Source: NTSB Aviation Accident Database

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