AD FAA-2017-1023

We are superseding Airworthiness Directive (AD) 2017-19-17, which applied to certain Dassault Aviation Model FALCON 900EX and FALCON 2000EX airplanes. AD 2017-19-17 required revising the airplane flight manual (AFM) to include procedures to follow when an airplane is operating in icing conditions. AD 2017-19-17 also required a detailed inspection of the wing anti-ice system ducting for the presence of a diaphragm, and follow-on actions (replacement of ducting or re- identification of the ducting part marking). This new AD retains the actions required by AD 2017-19-17, and corrects the follow-on actions for certain airplanes. This AD was prompted by a determination that the follow-on actions specified in AD 2017-19-17 were incorrect for certain airplanes. We are issuing this AD to address the unsafe condition on these products.