Airworthiness Directives; Boeing Model 727 Series Airplanes Modified in Accordance With Supplemental Type Certificate ST00015AT

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 727 series airplanes that have been converted from a passenger to a cargo-carrying (``freighter'') configuration, that requires limiting the payload on the main cargo deck by revising the Limitations Sections of all Airplane Flight Manuals (AFM), AFM Supplements, and Airplane Weight and Balance Supplements for these airplanes. This amendment also provides for the submission of data and analyses that substantiate the strength of the main cargo deck, or modification of the main cargo deck, as optional terminating action for these payload restrictions. This amendment is prompted by the FAA's determination that under certain conditions unreinforced floor structure of the main cargo deck is not strong enough to enable the airplane to safely carry the maximum payload that is currently allowed in this area. The actions specified by this AD are intended to prevent failure of the floor structure, which could lead to loss of the airplane.