German crane rental company Scholpp has issued a statement regarding the overturn of one of its cranes while lifting 16 people in a gondola on June 22nd.
The company says that the Tadano crane has now been fully tested and inspected, including a full analysis of the its ‘black box’ data recorder, although it also points out that the public prosecutor’s investigations have not yet been completed.
The test results, commissioned by independent experts – the crane manufacturer, Tadano Faun, the independent expert and the prosecutor – indicate that the crane and its load moment indicator were in perfect working order and had no technical defects.
The company statement added: “In the configuration on the 22nd June the crane had a boom length of 48.5 metres and a designated maximum load radius of 16 metres. These parameters combined with a seven tonne counterweight provided a safe load capacity of eight tonnes, with an actual weight of the platform, including occupants, of about 2.2 tonnes.
The crane could therefore carry more than 3.5 times the given load within the stipulated parameters for use.”
The investigation has discovered that the crane operator programmed a counterweight of 18 tonnes into the crane’s load moment system, even though only seven tonnes of counterweight were available.
“This is where – according to the current state of knowledge – the problem began with a setting error,” added Scholpp.
The crane simply overturned
“It remains unclear however, why the operator then extended the radius of the load beyond the 16 metres. With this counterweight the crane had a stability limit, with the load it was lifting, of around 22 metres radius.”
“If the stability limit had not been exceeded, the crane would not have overturned, in spite of the incorrect programming of the safety system.”
The Heilbronn prosecutor is continuing the investigation.
The boom landing on a nearby roof may have saved several lives