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, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes; and certain Model 757-200, -200PF, and -300 series airplanes. The existing AD currently requires replacing the control switches of the forward, aft, and nose cargo doors for certain airplanes, and replacing the control switches of cargo doors 1 and 2 for certain airplanes. Since we issued that AD, we have determined that additional airplanes are affected by the identified unsafe condition. This proposed AD would continue to require replacing the control switches of the forward, aft, and nose cargo doors of Model 747 airplanes; and the control switches of cargo doors 1 and 2 of Model 757 airplanes; this proposed AD also adds airplanes to the applicability and revises the initial compliance times. We are proposing this AD to preventinjuries to persons and damage to the airplane and equipment.