The families of those killed when a pilot crashed a Germanwings passenger plane into the French Alps are suing the American flight school where he was trained.
The lawsuit claims the Airline Training Center of Arizona failed to properly screen Andreas Lubitz's medical history.
He had long suffered from mental health problems and in March last year locked the captain out of the cabin before crashing the aircraft into the Alps, killing all 150 people on board.
Investigators found that weeks before the crash a doctor had urged him to attend a psychiatric hospital but his employer was never alerted.
A spokeswoman for Lufthansa said the action had "no chance of success". The school was yet to comment.