Federal Aviation Administration March 10, 2023 – Federal Register Recent Federal Regulation Documents

The FAA is adopting a new airworthiness directive (AD) for certain MHI RJ Aviation ULC Model CL-600-2C10 (Regional Jet Series 700, 701 & 702); CL-600-2C11 (Regional Jet Series 550); CL-600-2D15 (Regional Jet Series 705); CL-600-2D24 (Regional Jet Series 900); and CL-600-2E25 (Regional Jet Series 1000) airplanes. This AD was prompted by laboratory tests that showed that the oxygen tubes of the crew oxygen system may be contaminated with lubricants, as a result of the manufacturing and cleaning procedures used. This AD requires cleaning and flushing the crew oxygen system. The FAA is issuing this AD to address the unsafe condition on these products.

In accordance with the Paperwork Reduction Act of 1995, FAA invites public comments about our intention to request the Office of Management and Budget (OMB) approval to renew an information collection. The Federal Register Notice with a 60-day comment period soliciting comments on the following collection of information was published on September 29, 2022. The FAA's Fuel Tank Flammability Safety rule requires manufacturers to report to the FAA every 6 months on the reliability of the fuel tank flammability reduction systems of their fleet. The data is needed to assure system performance meets that predicted at the time of certification. This collection of information supports the Department of Transportation's strategic goal of safety.

The FAA is superseding Airworthiness Directive (AD) 2021-07- 09, which applies to all 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 2021-07-09 required repetitively inspecting all trim air diffuser ducts or sidewall riser duct assemblies (collectively referred to as TADDs) for damage, including repetitive structural inspections of the center fuel tanks for damage, and performing applicable on-condition actions. Since the FAA issued AD 2021-07-09, the agency has determined that the existing requirements do not adequately address the unsafe condition. This AD continues to require repetitive inspections of the TADDs for damage, with revised compliance times, and repair if applicable. This AD also requires repetitive replacement of the TADDs and removes the structural inspections of the center fuel tanks. This AD also prohibits the installation of affected parts. This AD removes certain airplanes from the applicability. The FAA is issuing this AD to address the unsafe condition on these products.

The FAA is superseding Airworthiness Directive (AD) 2020-12- 01, which applied to certain Rolls-Royce Deutschland Ltd. & Co KG (RRD) Trent XWB-75, Trent XWB-79, Trent XWB-79B, and Trent XWB-84 model turbofan engines. AD 2020-12-01 required initial and repetitive inspections of the low pressure compressor (LPC) outlet guide vane (OGV) outer mount ring assembly and, depending on the results of the inspections, possible replacement of the LPC OGV outer mount ring assembly. Since the FAA issued AD 2020-12-01, the FAA determined that these inspections are also necessary for RRD Trent XWB-97 model turbofan engines. This AD was prompted by analysis by the manufacturer of the LPC OGV assembly and LPC OGV outer mount ring assembly which predicted that when the front engine mount is in the fail-safe condition, the most highly stressed LPC OGV assembly has a life that could be substantially less than one shop visit interval. This AD requires initial and repetitive inspections of the LPC OGV outer mount ring assembly and, depending on the results of the inspections, replacement of the LPC OGV outer mount ring assembly, as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference (IBR). The FAA is issuing this AD to address the unsafe condition on these products.