Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 747-100, -100B, -100B SUD, -200B, - 200C, -200F, -300, -400, -400D, -400F, and 747SR series airplanes. This proposed AD was prompted by reports of cracking at the aft upper corner of the main entry door (MED) 5 cutout. This proposed AD would require inspecting for the presence of repairs and measuring the edge margin at certain fastener locations around the upper aft corner of the door cutout, inspecting for any cracking of the fuselage skin assembly and bear strap in the aft upper corner area of the door cutout, and repairing or modifying the fuselage skin assembly and bear strap if necessary. We are proposing this AD to detect and correct cracking of the skin and bear straps at the aft upper corner of the MED 5 cutout, which could result in in-flight depressurization.