AD NUMBER: 2007-23-18
MANUFACTURER: Boeing
SUBJECT: Airworthiness Directive 2007-23-18
SUMMARY: The FAA is superseding an existing airworthiness directive (AD) that applies to all Boeing Model 747-100B SUD, 747-300, 747-400, and 747-400D series airplanes; and Model 747-200B seriesairplanes having a stretched upper deck. The existing AD currently requires repetitively inspectingfor cracking or discrepancies of the fasteners in the tension ties, shear webs, and frames at bodystations 1120 through 1220, and performing related investigative and corrective actions ifnecessary. This new AD reduces the repetitive interval for certain inspections. This AD resultsfrom new reports of multiple severed adjacent tension ties, in addition to the previous reports ofcracked and severed tension ties, broken fasteners, and cracks in the frame, shear web, andshear ties adjacent to tension ties for the upper deck. We are issuing this AD to detect andcorrect cracking of the tension ties, shear webs, and frames of the upper deck, which could resultin rapid decompression and reduced structural integrity of the airplane.

FMI: www.faa.gov/regulations_policies/airworthiness_directives/