Federal Aviation Administration November 15, 2010 – Federal Register Recent Federal Regulation Documents

We propose to adopt a new airworthiness directive (AD) for certain Model 747-200B, -300, -400, -400D, and -400F series airplanes. This proposed AD would require an inspection to determine the part number of the door and to determine if the correct mid-pivot access door is installed, and the installation of a marker on the mid-pivot access door, and if necessary, repetitive ultrasonic inspections for cracking of the mid-pivot bolt assembly and eventual replacement of the mid-pivot bolt assembly. This proposed AD results from a report that the left and right spring beam mid-pivot bolt assembly access doors for the No. 1 strut were inadvertently installed in the incorrect position during strut modification. We are proposing this AD to detect and correct incorrectly installed mid-pivot bolt assemblies on the spring beam on the outboard struts. Incorrectly installed bolt assemblies could lead to fatigue cracking and consequent fracturing of the mid- pivot bolt assembly, which could lead to loss of the spring beam load path and the possible separation of a strut and engine from the airplane during flight.

We propose to rescind an airworthiness directive (AD) for the products listed above. The existing AD, AD 98-09-27, resulted from aircraft certification testing which revealed that stresses on the thrust reverser hinge were higher than had been anticipated during engine certification, and the United Kingdom Civil Aviation Authority, issuing AD 008-03-97. Since we issued AD 98-09-27, we discovered that its requirements were duplicated in airplane-level AD 2001-09-14, issued by the FAA Transport Airplane Directorate. This proposal to rescind the engine- level AD allows the public the opportunity to comment on the FAA's determination of the duplication of requirements in another AD, before we rescind the engine-level AD.