Airworthiness Directives; Aerospatiale Model ATR42-200, -300, -320, and -500 Series Airplanes; and Model ATR72 Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to all Aerospatiale Model ATR42-200, -300, -320, and - 500 series airplanes; and all Model ATR72 series airplanes; that currently requires revising the Airplane Flight Manual (AFM) to modify procedures for calculating takeoff performance when Type II or IV de- icing or anti-icing fluids have been used. This amendment requires revising the existing AFM revision to correct the performance values for Model ATR-72 series airplanes and to provide an additional method of compliance for all airplanes. This amendment is prompted by issuance of mandatory continuing airworthiness information by a civil aviation authority. The actions specified by this AD are intended to ensure that the flightcrew is advised of the potential effects of Type II or IV de- icing or anti-icing fluids on the airplane's performance during takeoff, and to ensure that the flightcrew is advised of the revised performance calculations for takeoff to address these effects.