Summary
We propose to adopt a new airworthiness directive (AD) for the products listed above. 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:
Wing anti ice telescopic tubes (P/N [part number] 5035-400 and 5035-500) ball joints were originally designed with high temperature polymer (Kynel TM) sealing rings. Temperature induced cracking of these rings associated with long term wear has been encountered in a small number of cases. This degradation may lead to binding of the ball joint and high swiveling forces which may result in improper operation of the leading edge slats and also in failure of the ball joint mounting bracket with possible friction on the aileron control rod, which could lead, if combined with a failure of the aileron emergency actuator, to an aileron jamming.The unsafe condition is a jammed aileron, which results in reduced controllability of the airplane. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.