Airworthiness Directives; The Boeing Company Airplanes

We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes. This AD was prompted by reports of fuselage skin cracks at the lower forward corner of the main entry door (MED) 1 cutout. This AD requires repetitive inspections of the fuselage skin of the MED 1 cutout for cracking, and repair if necessary; and also provides an optional terminating modification, including post-repair or post-modification fuselage skin inspections for cracking, and corrective actions if necessary. We are issuing this AD to detect and correct skin cracking, which can become large and could adversely affect the structural integrity of the airplane.