The New York Cranes Favco 440 collapsed while it was being fitted with a third collar. The prosecution case argued that Rapetti had used less slings to lift the collar than he should have done, had fitted them incorrectly, and had used one that was worn. When one sling failed, the prosecution said, the collar was dropped, starting a chain reaction that brought the crane crashing down, destroying a building across the street and killing seven people.

Rapetti’s defence argued that he had followed industry norms, and that the straps were not necessarily the root cause of the accident.

The defence argued that other components may have played a role in the accident. Electronics on the crane had a history of problems, they said. Peter Stroh, the engineer who planned the erection of the crane, told the court that tie-ins used on the job had not initially met his specifications. The defence also argued that the friction foundations used on the crane may have played a role, an issue first raised in Cranes Today in February 2009, in a letter from one of the first ironworkers on the scene, Terence Soebel of Ironworkers Local 40.

As well as suggesting other possible causes for the accident, the defence put the prosecution’s explanation of the accident to the test, showing the judge video of an experiment that attempted to replicate the conditions of the accident, conducted by former New York City department of buildings employee Leo Lee. An identical collar, fitted with three new and one worn sling, in the configuration used by the riggers that day, was subjected to similar stresses. Lee testified that, even when the worn strap was cut, the collar held, slipping only a few inches.

Rapetti chose to be tried by a judge sitting without a jury. The judge cleared him of all charges.

Back in February 2009, when Rapetti was first charged, Cranes Today’s leader column asked if, when questions remain about the root causes of an accident, it can be right to conduct a criminal prosecution of a single individual. Currently, New York prosecutors are pursuing a second criminal case, against two men involved in the mass fatality collapse of a Kodiak crane in May 2008. New York City is facing court action from the Steel Institute of New York, which is attempting to block crane regulations that, it argues, were rushed out in response to both accidents, and exceed the city’s regulatory powers.