SANTA ANA, CA, USA
N1168U
SIKORSKY S-58ET
AFTER THE CARGO WAS LOADED, AND AS THE PILOT GROUND TAXIED OVER A CONCRETE DRAINAGE DEPRESSION IN THE RAMP, THE LEFT MAIN LANDING GEAR SEPARATED FROM THE GEAR TUBE AND THE HELICOPTER ROLLED OVER. METALLURGICAL EXAMINATION OF THE FAILED LANDING GEAR STRUT REVEALED PRE-EXISTING FATIGUE CRACKS IN THE INSIDE THE GEAR LEG EXTENDING FROM MULTIPLE ORIGINS. IN ADDITION, THERE WAS CORROSION PITTING AND REMNANT TOOLING MARKS ON THE SURFACE FINISH OF THE LOWER GEAR TUBE INSIDE DIAMETER. THE PITTED AND CORRODED CONDITION OF THE TUBE INSIDE DIAMETER INDICATED THAT ENVIRONMENTAL INTRUSION OF THE CORROSION PREVENTATIVE MATERIAL MAY HAVE OCCURRED DURING SERVICE. THE AIRCRAFT WAS 951 POUNDS OVER CERTIFICATED MAXIMUM GROSS WEIGHT.
FAILURE OF THE LANDING GEAR RESULTING FROM EXCESSIVE LOADING DURING GROUND OPERATIONS, AND FATIGUE CRACKING.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
