Summary
We propose to adopt a new airworthiness directive (AD) for all Airbus Model A318, A319, A320, and A321 series airplanes. This proposed AD was prompted by a determination that the maintenance actions for airplane systems susceptible to aging must be mandated. This proposed AD would require revising the maintenance or inspection program to incorporate more restrictive maintenance requirements and airworthiness limitations. We are proposing this AD to mitigate the risks associated with aging effects of airplane systems. Such aging effects could change the characteristics leading to an increased potential for failure, which could result in failure of certain life limited parts, and could reduce the structural integrity or reduce controllability of the airplane.