On 10 November, the rotor sheared off a Repower MD77-1500kW turbine at Menil-la-Horgne, in the Meuse department of north-east France.
According to investigations so far, the cause of the accident is presumed to be "a slag inclusion in the shaft", explained a spokesperson at Wpd Windmanager, which took over operational management of the plant from French project operator Theolia in early November.
In other words, it appears a fault in the main shaft connecting the rotor with the gearbox cracked open as the shaft became fatigued.
Senvion, which was known as Repower when the turbines were installed, said that it could not comment until the full investigation to identify the exact cause was completed.
The project, comprising seven Repower MD77 turbines, was commissioned in 2007. It was developed by Wpd and built by ABOWind, and is now owned by Eoliennes Suroit SNC, based in Colmar, north-east France.
The remaining six turbines are still out of service, waiting for permission from the French authorities to restart them, Wpd Windmanager said.