Airworthiness Directives; Boeing Model 747 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes. This action requires repetitive detailed visual inspections to find discrepancies of the installation of the midspar fuse pins of the inboard and outboard struts, and follow-on actions, if necessary. This action also provides for an optional terminating modification for the repetitive inspections. This action is necessary to find and fix discrepancies of the installation of the midspar fuse pins, which could result in loss of the secondary retention capability of the fuse pins, migration of the fuse pins, and consequent loss of the strut and engine from the airplane. This action is intended to address the identified unsafe condition.