Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede an existing airworthiness directive (AD) that applies to certain The Boeing Company Model 747-100, 747- 100B, 747-100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR series airplanes. The existing AD requires, for certain airplanes, inspection to determine the material of a main entry door (MED) reveal; repetitive inspections of certain reveals for cracking; a detailed inspection of certain reveals for a sharp edge and cracking; and corrective action if necessary. That AD also allows a certain replacement as an optional action for certain inspections of certain airplanes. Since we issued that AD, an operator reported a crack found in a 6061 machined aluminum one-piece corner reveal. This proposed AD would add, for certain airplanes, an inspection to determine material type of MED reveals, repetitive inspections for cracking of 6061 machined aluminum one-piece corner reveals, and replacement with 6061 machined aluminum two-piece corner reveals if necessary. This proposed AD would also allow replacement with two-piece corner reveals as an option for certain repetitive inspections. This proposed AD would also revise the applicability by removing a certain airplane. We are proposing this AD to detect and correct fatigue cracking of the lower forward corner reveal of the number 3 MEDs, which could lead to the door escape slide departing the airplane when the door is opened and the slide is deployed, and consequent injuries to passengers and crew using the door escape slide during an emergency evacuation.