Aviation Accident Summaries

Aviation Accident Summary CHI91LA097

NORTH MANKATO, MN, USA

Aircraft #1

N8955F

HUGHES 269C

Analysis

THE PILOT REPORTED THAT DURING THE AERIAL OBSERVATION FLIGHT HE HEARD A LOUD NOISE FROM THE BACK OF THE HELICOPTER. THE HELICOPTER THEN BEGAN ROTATING CLOCKWISE AND DESCENDED TO IMPACT WITH THE TERRAIN IN A WOODED AREA. POST ACCIDENT IMSPECTION REVEALED A FATIGUE FAILURE OF THE TAIL BOOM SUPPORT STRUT CLUSTER FITTING (LEFT SIDE). AN AIRWORTHINESS DIRECTIVE ISSUED IN 1976 CALLED FOR A DAILY VISUAL INSPECTION AND A 200 HOUR DYE PENETRANT INSPECTION OF THE FITTING. A LOGBOOK ENTRY DATE AUGUST 15, 1990, STATED ALL AD'S HAD BEEN COMPLIED WITH.

Probable Cause and Findings

THE FATIQUE FAILURE OF THE TAIL BOOM SUPPORT STRUT ATTACHMENT CLUSTER AND THE IMPROPER INSPECTION OF THE CLUSTER ATTACHMENT.

 

Source: NTSB Aviation Accident Database

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