The Federal Aviation Administration is rethinking a controversial 1959 rule that required commercial airline pilots to retire at 60. The age limit was adopted because certain physiological and psychological functions deteriorate with age, but some pilots have argued the rule amounts to age discrimination.

In response, Congress three years ago directed the National Institutes of Health to examine whether the rule was warranted. NIH's National Institute on Aging concluded last summer that age-related health changes can endanger safety and that there now is no way to sort out safe pilots from potentially dangerous ones.

The institute suggested that the FAA or some other agency establish a program to monitor the health and performance of older pilots to determine if the rule should be relaxed. In the meantime, it said, the 60-year limit should be kept. Meanwhile, on the other side of the fence, United Airlines has asked the FAA to extend the rule so that flight engineers and other crew members have to retire at 60.

To accommodate all parties, the FAA has issued an advance notice of proposed rulemaking, seeking comments on which federal agency should run the evaluation program, how it should be conducted, whether flight engineers also should be forced to retire at 60, and, if so, what the economic consequences would be.