AD NUMBER: 2017-23-10

PRODUCT: Certain Dassault Aviation Model FALCON 900EX and FALCON 2000EX airplanes.

ACTION: Final Rule.

SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2017-19-17, which applied to the products listed above.

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 antiice 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.

COST: The FAA estimates that this AD affects 52 airplanes of U.S. registry. The action required by AD 2017-19-17, and retained in this AD, takes about 5 work-hours per product, at an average labor rate of $85 per work-hour. Based on these figures, the estimated cost of the action that is required by AD 2017-19-17 is $425 per product.

This AD adds no new economic burden to AD 2017-19-17.

The FAA also estimate that any necessary follow-on actions will take about 19 work-hours and require parts costing $24,000, for a cost of $25,615 per product. The agency says it has no way of determining the number of aircraft that might need these actions.

DATES: This AD is effective December 1, 2017.

FMI: AD