Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200F, 747-200C, 747-300, 747SR, and 747SP Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to all Boeing Model 747-100, 747-100B, 747-100B SUD, 747- 200B, 747-200F, 747-200C, 747-300, 747SR, and 747SP series airplanes. This AD requires repetitive inspections for discrepancies of the structure near and common to the upper chord and splice fittings of the rear spar of the wing, and repair if necessary. This AD also provides for an optional modification that, if accomplished, terminates the repetitive inspection requirement, but would necessitate eventual post- modification inspections. This action is necessary to find and fix fatigue cracking of structure near and common to the upper chord and splice fittings of the rear spar of the wing, which could result in loss of structural integrity of the airplane. This action is intended to address the identified unsafe condition.