Investigators released this image of the wreck of the Cougar Helicopters aircraft, which was raised from the floor of the Atlantic Ocean last March. (Transportation Safety Board of Canada)

The families of passengers who died in the crash of a Sikorsky helicopter off Newfoundland and the sole survivor of the tragedy have shifted their lawsuit against the U.S. company into confidential negotiations.

Seventeen people died when the chopper went down March 12.

The families of 15 victims and the lone survivor launched a lawsuit in June in the Philadelphia court of common pleas, alleging that Sikorsky, Keystone Helicopters and its parent company, United Technologies Corp., made false claims about the aircraft's safety.

Since then, one victim's family was added to the suit.

The plaintiffs had originally alleged the U.S. firms hadn't correctly indicated how long pilots could safely fly if oil leaked from the helicopter's gearbox.

But in court documents filed recently, the plaintiffs say they have "voluntarily discontinued" the lawsuit "to engage in alternative dispute resolution before further litigation."

The Cougar Helicopters flight was carrying 16 passengers and two crew members when it crashed in the North Atlantic as it was ferrying workers to two offshore oil platforms.