AD 2021-07-09 Requires Repetitive Inspections Of All TADD Material

The FAA is superseding Airworthiness Directive (AD) 2007-07-03, which applied 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. AD 2007-07-03 required repetitive tests to detect hot air leaking from the trim air diffuser ducts or sidewall riser duct assemblies (collectively referred to as TADDs), related investigative actions, and corrective actions if necessary. AD 2007-07-03 also provided an optional terminating action for the repetitive tests. This AD requires repetitive inspections of all TADD material for damage and applicable oncondition actions. This AD w