Bristow Helicopters is suing Sikorsky and its parent company, United Technologies, for negligence over a crash in which a Sikorsky S-76A plunged into the North Sea last July, killing all 11 people on board. In a lawsuit brought before a London court, Bristow alleges that faulty repair work was performed on a main rotor blade three years before, when that blade was hit by lightning while on another S-76A, also operated by Bristow. The S-76A was ferrying workers between a gas-production platform and a drilling rig when it crashed into the sea off Norfolk. Two pilots and nine passengers were killed. Bristow alleges that the rotor blade, which had been approved as airworthy following the lightning strike, fractured catastrophically because of fatigue, the result of intense thermal damage caused by the lightning strike. For its part, Bristow is being sued by families of the 11 victims. Bristow is further asking the court to rule that Sikorsky and United Technologies are liable to indemnify it against the cost of any compensation Bristow might have to pay to the surviving families, including sums already distributed to dependents of the crash victims. Bristow is also suing another company, Composite Technology, for damages, claiming negligence and breach of contract over the inspection and safety certification of the rotor blade.