The crane was an American 8470. The operator first attempted to pick the panel of the slab at 47 feet. He then repositioned the crane twice more and finally got the panel off the slab and was attempting to boom it up and the crane would not boom up. The next thing the crew said they heard a loud noise from the back of the crane and then the boom buckled. This update report came in on 5/1/99: The American 8470 accident in San Diego was an Anthony crane and the panel hit the boom causing it to buckle.
The loud pop that job crew heard coming from back of crane was boom wire stacking up on itself next to boom winch drum flange which caused a severe shock on boom transition section located next to hammerhead when it fell off itself . Boom wire was brand new and this being first job in service. Consequently bottom cords of transition section buckled (open throat) causing boom to fail . After accident it was also noticed that transition section was also a hi-reach taper tip section (4″ chords) instead of Hammer head transition section (4/1/2″ chords ) which could have possibly added slightly to failure of boom. Thanks again!
Operator: Chris Taylor
P. S. The panel NEVER touched the boom, not even close!!!
Category: Accident Report