Airworthiness Directives; Boeing Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, 747SR, and 747SP Series Airplanes Equipped With Pratt & Whitney JT9D-3, -7, -7Q, and -7R4G2 Series Engines

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-100, -100B, -100B SUD, -200B, - 200C, -200F, -300, 747SR, and 747SP series airplanes equipped with Pratt & Whitney JT9D-3, -7, -7Q, and -7R4G2 series engines. This amendment requires drilling witness holes through the cowl skin at the cowl latch locations in the left-hand side of the cowl panel assembly of each engine. This action is necessary to prevent improper connection of the latch, which could result in separation of a cowl panel from the airplane. Such separation could cause damage to the airplane, consequent rapid depressurization, and hazards to persons or property on the ground. This action is intended to address the identified unsafe condition.