AD FAA-2023-1993

The FAA is superseding Airworthiness Directive (AD) 2020-03- 20, which applied to certain The Boeing Company Model MD-11, MD-11F, and 717-200 airplanes; all Model 737-8 and 737-9 airplanes; all Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes; certain Model 747-400 and 747-400F series airplanes; certain Model 757 and 767 airplanes; and all Model 777 airplanes. AD 2020-03-20 required revising the existing airplane flight manual (AFM) to include a limitation to prohibit operations that require less than 0.3 required navigational performance (RNP) within a specified area for airplanes having a certain multimode receiver (MMR) with certain software installed. This AD was prompted by reports from Boeing of simultaneous MMR resets related to an error in calculating Coordinated Universal Time (UTC). This AD requires the actions in AD 2020-03-20, removes an airplane model from the applicability, and would also require installing certain MMR operational software (OPS). The FAA is issuing this AD to address the unsafe condition on these products.