September 18 is the comment deadline on a notice of proposed rulemaking (NPRM) to establish operational life limitations designed to prevent widespread fatigue damage primarily in large commercial transport aircraft (those with mtow of more than 75,000 pounds). The NPRM is one of several rulemaking actions that are part of the FAA’s aging-aircraft program. Currently manufactured jets operated under Parts 91 and Part 135 on-demand operations would be excluded from the retrofit requirement of the proposed rules (AIN, June).