AD FAA-2020-0848

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 on-condition actions. This AD was prompted by reports that high temperature composite material TADDs installed as specified in AD 2007-07-03 have also failed. The FAA is issuing this AD to address the unsafe condition on these products.