Summary
We propose to adopt a new airworthiness directive (AD) for the products listed above that would revise an existing AD. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:
[S]everal cases of wing anti-ice piccolo duct failure reported on CL-600-2B19 (CRJ) aircraft. Although there have been no failures reported on Challenger aircraft, similar ducts are installed on the * * * [other] Challenger models. Cracking of the wing anti-ice piccolo ducts could result in air leakage, with an adverse effect on the anti-ice air distribution pattern and a possible unannunciated insufficient heat condition.
The unsafe condition is anti-ice system air leakage with a possible adverse effect on the anti-ice air distribution pattern and anti-ice capability without annunciation to the flightcrew, and consequent reduced controllability of the airplane. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.