Aviation Accident Summaries

Aviation Accident Summary CHI90LA276

MORRISON, IL, USA

Aircraft #1

N7197U

MOONEY M20E

Analysis

THE ACCIDENT AIRPLANE EXPERIENCED AN INFLIGHT FAILURE OF A PROPELLER BLADE DURING CRUISE FLIGHT. ACCORDING TO THE PILOT'S STATEMENT THE AIRPLANE STARTED A SEVERE VIBRATION AND REDUCING THE ENGINE POWER HAD NO EFFECT ON IT. THE VIBRATION STOPPED AFTER HE SHUT DOWN THE ENGINE AND RAISED THE NOSE IN ORDER TO STOP THE WINDMILLING PROPELLER. DURING THE FORCED LANDING THE LANDING GEAR COLLAPSED AND THE AIRPLANE SLID INTO A DIRT BANK. EXAMINATION OF THE REMAINING PORTION OF THE FAILED PROPELLER BLADE FRACTURE SURFACE SHOWED A FATIGUE CRACK EXTENDING FROM THE LEADING EDGE TO A POINT 3-1/4 INCHES MEASURED IN THE CHORDWISE DIRECTION. THE LEADING EDGE HAD BEEN REWORKED BY FILING OR GRINDING.

Probable Cause and Findings

IMPROPER MAINTENANCE OF THE PROPELLER BLADE BY UNKNOWN PERSONS AND THE SUBSEQUENT FAILURE OF THE BLADE IN FATIGUE DURING CRUISE FLIGHT. A FACTOR WAS: UNSUITABLE TERRAIN.

 

Source: NTSB Aviation Accident Database

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