Aims To Prevent Widespread Fatigue Damage -- But Operators Would Have To Pay

Earlier this week, the FAA issued its Notice for Proposed Rulemaking (NPRM) on measures the agency intends to prevent fatigue damage in transport category aircraft. The proposal would require aircraft manufacturers and design approval holders to establish operational limits on transport category airplanes, in order to prevent widespread fatigue damage (WFD.) Those parties would also be required to determine if maintenance actions are needed to prevent widespread fatigue damage before an airplane reaches its operational limit.

Operators of any affected airplane would be required to incorporate the operational limit, and any necessary service information, into their maintenance programs. Operation of an affected airplane beyond the operational limit would be prohibited, unless an operator has incorporated an extended operational limit and any necessary service information into its maintenance program.

The FAA states the proposal should preclude WFD from occurring in transport category airplanes, by providing a "more proactive management" of WFD.

The proposal would also 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 incorporated an extended operational limit into their maintenance programs.

The FAA states that present value benefits of the proposal consist of $726 million of accident prevention benefits, and $83 million of detection benefits -- for total benefits of $809 million. The detection benefits the FAA cites are the benefits resulting from accidents averted by the measure if it is implemented -- accidents that haven't occurred yet, in other words -- and a reduction in unscheduled maintenance and repairs.

The present value cost of this proposal, estimated over 20 years, is $360 million. Here's the kicker, however: the FAA estimates that airplane manufacturers would incur approximately 10 percent of these costs -- while the remaining 90 percent of these costs would be borne by operators.

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. For future type certification, all TC applicants for transport category airplanes would be affected.

As far as existing type certificates, the 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.

FMI: www.faa.gov