The FAA is adopting a new airworthiness directive (AD) for certain Dassault Falcon 2000s, 2000EXs, 900s and 900EXs and all Falcon 50s. The AD was prompted by reports that collapse of the main landing gear could cause wing tank structure failure, which could result in fuel spillage and a fire hazard. This AD requires modification of the wing fuel tanks in the area of the wheel well.