AD FAA-2017-0494

We are superseding Airworthiness Directive (AD) 2016-17-02, which applied to certain Dassault Aviation Model FALCON 900EX and FALCON 2000EX airplanes. AD 2016-17-02 required revising the airplane flight manual (AFM) to include procedures to follow when an airplane is operating in icing conditions. AD 2016-17-02 also provided optional actions after which the AFM revision may be removed from the AFM. Since we issued AD 2016-17-02, we have determined additional actions are necessary to address the identified unsafe condition. This new AD retains the requirement of AD 2016-17-02, and also requires a detailed inspection of the wing anti-ice system ducting (anti-ice pipes) for the presence of a diaphragm, and replacement of ducting or re- identification of the ducting part marking. We are issuing this AD to address the unsafe condition on these products.