Aviation Accident Summary CHI90FA118

SOUTHFIELD, MI, USA

Aircraft #1

N871

SIKORSKY S-58F

Analysis

THE HELICOPTER WAS HOVERING IN PLACE DURING A ROOFTOP EQUIPMENT REMOVAL OPERATION WHEN IT ABRUPTLY DESCENDED ONTO THE STRUCTURE FROM WHICH THE LIFT WAS BEING MADE. IT THEN NOSED OVER THE STRUCTURE & IMPACTED APRX 10 FT BELOW ON THE ROOF OF THE 15TH FLOOR. THE WORKERS HEARD NO VERBAL WARNING FROM THE PILOT. ACOUSTICAL ANALYSIS OF A VIDEO REVEALED THAT DURING THE DESCENT THERE WAS A STEADY INCREASE IN ENGINE, M/R, AND T/R RPM. POST MORTEM EXAM OF THE PILOT REVEALED FOCAL ATHEROSCLEROSIS 50% LEFT AND RIGHT CORONARY ARTERY, LEFT ANTERIOR DESCENDING, AND LEFT CIRCUMFLEX. THE PILOT & CREW HAD OPERATED TOGETHER AS A TEAM FOR 18 YRS & THE CREW STATED THAT THE PILOT, WITH NO EXCEPTIONS, HAD ALWAYS NOTIFIED THEM BY RADIO WHEN UNEXPECTED OCCURRENCES CAUSED PREMATURE RELEASES.

Probable Cause and Findings

A LOSS OF CONTROL DUE TO PHYSICAL INCAPACITATION FOR UNKNOWN REASON(S).

 

Source: NTSB Aviation Accident Database

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