Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Bombardier Model CL-600-2C10 (Regional Jet Series 700 & 701) series airplanes, that currently requires a revision to the Airplane Flight Manual (AFM) to prohibit operations into known or forecast icing conditions under certain conditions. That AD also requires an inspection to detect damage of the wing anti-ice (WAI) ducts to determine if the external shrouds of the ducts are open or cracked, and replacement of any damaged duct with a new duct or a duct with the same part number, and an optional terminating action. This action would require accomplishment of the previously optional terminating action for the AFM revision and inspection. The actions specified by the proposed AD are intended to prevent the WAI ducts from collapsing, cracking, or rupturing, which could cause leakage of hot air in the under-floor pressurized area of the fuselage when the anti-ice system is turned on. Such leakage of hot air results in insufficient heat for the anti-ice system and consequent aerodynamic degradation. This action is intended to address the identified unsafe condition.