Transport i infrastruktura · 08/08/2012

Airworthiness Directives; The Boeing Company Airplanes

We are superseding an existing airworthiness directive (AD) for all Model 747-100B SUD, 747-300, 747-400, and 747-400D series airplanes; and Model 747-200B series airplanes having a stretched upper deck. The existing AD currently requires repetitively inspecting for cracking or discrepancies of the fasteners in the tension ties, shear webs, and frames at body stations 1120 through 1220; and related investigative and corrective actions if necessary. That AD requires modifying the frame-to-tension-tie joints at body stations 1120 through 1220 (including related investigative actions and corrective actions if necessary), which provides a terminating action for the repetitive inspections. That AD also requires new repetitive inspections after the modification, corrective actions if necessary, and additional modification requirements at a specified time after the first modification. That AD also removed certain airplanes from the applicability. That AD was prompted by reports of cracked and severed tension ties, broken fasteners, and cracks in the frame, shear web, and shear ties adjacent to tension ties for the upper deck. This AD revises the existing AD by adding repetitive open hole