FAA Proposes Rule to Put Operational Time Limits on Air Transports

The FAA is proposing a new rule intended to prevent what it describes as "widespread fatigue damage," or WFD, on transport category airplanes, by requiring that design-approval holders establish their operational time limits.

Design-approval holders would also be required to determine if maintenance actions are needed to prevent widespread fatigue damage before an airplane reaches its operational limit.  Beyond that, operators of any affected airplane would be required to incorporate the operational limit and any necessary service information into their maintenance programs.  Operating an affected airplane beyond the operational limit would be prohibited without specific approval, and possible changes in the aircraft's maintenance program.

Those wishing to comment on the proposed rule need to submit them on or before July 17, 2006.

The FAA says its rationale for the rule is to preclude WFD from occurring in transport category airplanes by being more proactive on WFD management.

For existing type certificates, this proposal would affect only airplanes with maximum takeoff gross weights (MTGW) over 75,000 pounds, including airplanes that have had the MTGW increased to greater than 75,000 pounds.  For future type certification, all TC applicants for transport category airplanes would be affected.

The proposed rule would require type certificate (TC) holders to establish an initial operational limit on certain airplanes.  Operation of these airplanes beyond the initial operational limit would be prohibited, unless operators have incorporated an extended operational limit into their maintenance programs. Type certificate holders would be required to develop the initial operational limits based on an evaluation of WFD susceptibility, both for existing airplanes and for proposed future certifications.

STC (supplemental type certificate) holders for these airplanes would be required to evaluate their certificates for WFD susceptibility and the ability of the airplane to remain free of WFD up to the initial operational limit established by the TC holder.

Once the proposed initial operational limits are developed, operational rules in parts 121 and 129 of the Federal Air Regulations would require operators to incorporate initial operational limits into their maintenance programs.

While the proposed operational rules would prohibit operation beyond its established limit, there would be means to extend the initial operational limit under certain circumstances, and with possible additional maintenance procedures and restrictions.  In addition, the proposed operational rules would address repairs, alterations, and modifications to airplanes operating with an extended operational limit.  04-30-2006.

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