UK contractor St James Group has reported a serious incident - a near miss - with a 40 tonne Hitachi-Sumitomo SCX400T telescopic crawler crane on a London job site in January.

The crane was lifting a compressor when the boom dropped rapidly until it bottomed out in the horizontal position. Fortunately no one was hurt or injured. On inspection it became clear that a fitting connection to a pressure gauge on the pressure side of the lift cylinder had fractured, allowing hydraulic oil to escape, causing the boom to descend.

Watch the Video : - "Hitachi Sumitomo SCX 400 crawler crane"

The incident was reported to the Health & Safety Executive and a joint investigation launched by the crane owner Eagle Crawler Cranes Hire and Hitachi distributor NRC. All parties confirmed the failure of an adapter that connected the pressure transducer and gauge to the cylinder. The adapter was fitted as original equipment by Hitachi Europe. An independent report by Penenden Engineering indicated that the failure was due to fatigue, although the part does not have a given service life.

The contractor is now bringing it to the wider attention of crane owners and users to highlight the fact that a misconception exists that in the event of such a failure the cylinder’s Holding/Lock/Check valves will still support the boom in the event of such a failure.

We hope to have a video of the incident shortly, however it is unlikely to show any further detail, but will show the speed that the boom descended.