During the night, one of the 4 turbines of a wind farm inaugurated in May 2002 lost a blade, followed by two others. The mast broke at mid-height and the nacelle fell. One blade was found nearby, while the two others drifted out to sea as far as Wimereux (8 km away). The operator claimed in the press that a subcontractor had failed to perform the monthly retightening of the blade attachment bolts. A technical report attributed the cause to be a design fault. The blades installed were different from those specified by the hub manufacturer: the insufficient connection between the composite material of the blade and the attachment lag screws caused a crack in the ejected blades. The beginnings of this same phenomenon were detected on the blades of the farm’s three other wind turbines. All of the blades were replaced by a suitable model and the destroyed wind turbine was completely rebuilt.
According to the operator, the damage amounted to over €450,000.