Following the issue of an AD for the 747classic and -400 aircraft, the worldwide 747 freighter fleet will have to be inspected before October 05th 2021'
The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -400D, -400F, 747SR, and
747SP airplanes. This AD was prompted by reports of cracks found in the front spar shear tie and at the intercostal lug fitting at certain locations. This AD requires repetitive detailed and surface high frequency eddy current (HFEC) inspections of the front spar shear tie and intercostal lug fitting at certain locations for any cracking, and applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products.
The FAA reviewed Boeing Alert Requirements Bulletin 747-53A2904 RB, dated December 16, 2020. This service information specifies procedures for repetitive detailed and surface HFEC inspections of the station 1000 front spar shear tie at the left and right side buttock line (BL) 11.33, BL 33.99, BL 57.50, and BL 75.92, and of the intercostal lug fitting at the left and right side BL 11.33, for any cracking, and applicable on-condition actions. On-condition actions include repair, installing a new front spar shear tie, and installing a new intercostal lug fitting
The FAA is issuing this AD to address any cracking in these areas that could result in the loss of limit load capability in a principal structural element, the potential inability to restrain the cargo for certain cargo configurations, and the potential for a center fuel tank rupture for certain cargo configurations under limit load conditions, which could adversely affect the structural integrity of the airplane.
See : https://rgl.faa.gov/Regulatory_and_Guid ... -17-06.pdf
Although ADs are routinely issued, the current unavailability of repair kits and the fast-approaching effective date of October 05th could cause a lot of (planning) issues with the 747 cargo operators, except the 747-8 series.