LONGVIEW, WA, USA
N26631
Fairchild Hiller FH-1100
SEVERAL PERSONS SAW THE HELICOPTER FLYING AT A CRUISING ALTITUDE OF ABOUT 200 TO 300 FT, THEN ENTER A LOOP TYPE OF MANEUVER. THEY LOST SIGHT OF THE HELICOPTER NEAR THE BOTTOM OF THE MANEUVER BEFORE IT CRASHED. THE PLT RECEIVED SERIOUS HEAD INJURIES & COULD NOT RECALL WHAT HAD HAPPENED. AN EXAM OF THE AIRFRAME REVEALED THAT THE TRANSMISSION & MAIN ROTOR HUB ASSY HAD REMAINED PARTIALLY ATTACHED TO THE AIRFRAME THRU THE LEFT & RIGHT LONGITUDINAL TRANSMISSION STRUTS. BOTH THE LEFT & RIGHT VERTICAL AS WELL AS BOTH LEFT & RIGHT LATERAL TRANSMISSION STRUTS HAD SEPARATED NEAR THEIR ATTACH POINTS. A METALLURGICAL EXAM OF THESE PARTS REVEALED THAT FITTING ASSEMBLY, PN 24-61022-6 HAD FAILED AT A FATIGUE CRACK. ADDITIONALLY, CORROSION WAS FOUND WITHIN THE LEFT VERTICAL & LATERAL (ADJUSTABLE) TRANSMISSION STRUTS. PREIMPACT CONTINUITY OF THE CYCLIC PITCH CONTROL WAS VERIFIED.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
