Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2020-03-20, which applies 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 requires 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 multi-mode receiver (MMR) with certain software installed. Since the FAA issued AD 2020-03-20, the agency received reports from Boeing of simultaneous MMR resets related to an error in calculating Coordinated Universal Time (UTC). This proposed AD would continue to require the actions in AD 2020-03-20 and would also require installing certain MMR operational software (OPS). The FAA is proposing this AD to address the unsafe condition on these products.