Airworthiness Directives; The Boeing Company Airplanes

DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2024-2713; Project Identifier AD-2024-00328-T]</DEPDOC> <RIN>RIN 2120-AA64</RIN> <SUBJECT>Airworthiness Directives; The Boeing Company Airplanes</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Federal Aviation Administration (FAA), DOT. <HD SOURCE="HED">ACTION:</HD> Notice of proposed rulemaking (NPRM). <SUM> <HD SOURCE="HED">SUMMARY:</HD> The FAA proposes to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 777-200, -200LR, -300, -300ER, and 777F series airplanes. This proposed AD was prompted by a report indicating that an airplane experienced a glideslope (G/S) beam anomaly during an instrument landing system (ILS) approach, which resulted in a higher-than-expected descent rate during the final segment of an ILS approach. The flightcrew might follow misleading flight director (F/D) guidance after disconnecting the autopilot, without reference to the other available information and flight deck indications. This proposed AD would require installing new autopilot flight director computer (AFDC) operational program software (OPS) and doing a software configuration check. The FAA is proposing this AD to address the unsafe condition on these products. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> The FAA must receive comments on this proposed AD by February 25, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods: • <E T="03">Federal eRulemaking Portal:</E> Go to <E T="03">regulations.gov.</E> Follow the instructions for submitting comments. • <E T="03">Fax:</E> 202-493-2251. • <E T="03">Mail:</E> U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. • <E T="03">Hand Delivery:</E> Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. <E T="03">AD Docket:</E> You may examine the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2024-2713; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this NPRM, any comments received, and other information. The street address for Docket Operations is listed above. <E T="03">Material Incorporated by Reference:</E> • For Boeing material identified in this proposed AD, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone 562-797-1717; website <E T="03">myboeingfleet.com.</E> • You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. It is also available at <E T="03">regulations.gov</E> under Docket No. FAA-2024-2713. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Michael Closson, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3973; email: <E T="03">Michael.P.Closson@faa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">Comments Invited</HD> The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the <E T="02">ADDRESSES</E> section. Include “Docket No. FAA-2024-2713; Project Identifier AD-2024-00328-T” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this proposal because of those comments. Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to <E T="03">regulations.gov,</E> including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM. <HD SOURCE="HD1">Confidential Business Information</HD> CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this NPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI should be sent to Michael Closson, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3973; email: <E T="03">Michael.P.Closson@faa.gov.</E> Any commentary that the FAA receives that is not specifically designated as CBI will be placed in the public docket for this rulemaking. <HD SOURCE="HD1">Background</HD> The FAA has received a report indicating that a Model 787-8 airplane captured an anomalous G/S beam during an ILS approach, which resulted in a higher-than-expected descent rate during the final segment of an ILS approach due to persistent inertial coasting, which can result in misleading flight director guidance. When the autopilot was disconnected, the F/D continued to command a flight path away from the G/S without warning, which the flightcrew appeared to follow. Both GLIDESLOPE and TOO LOW TERRAIN alerts annunciated while the airplane continued to descend. Ultimately, the flightcrew was able to recover the airplane and conducted a Go-Around procedure. No injuries to passengers or crew, or damage to the airframe, was reported. It has been determined that Model 777 airplanes can experience the same anomaly. G/S beam anomalies that occur in a discrete G/S capture window can result in reversion to inertial paths in which the auto-flight vertical guidance diverges from the G/S beam at higher-than-expected descent rates. The flightcrew may follow the misleading F/D guidance after disconnecting the A/P, without reference to the other available information and flight deck indications. This condition, if not addressed, could result in a late touchdown, a runway excursion, or controlled flight into terrain. <HD SOURCE="HD1">Related Rulemaking</HD> The FAA may consider issuing additional rulemaking to address the identified unsafe condition on additional Boeing airplane models with the same G/S issue. <HD SOURCE="HD1">FAA's Determination</HD> The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> The FAA reviewed Boeing Alert Requirements Bulletin 777-22A0046 RB, dated October 25, 2022. This material specifies procedures for installing new AFDC OPS, doing a software configuration check, and making sure that the correct software part number is installed in the correct location. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the <E T="02">ADDRESSES</E> section. <HD SOURCE="HD1">Proposed AD Requirements in This NPRM</HD> This proposed AD would require accomplishing the actions specified in the material already described, except for any differences identified as exceptions in the regulatory text of this proposed AD. For information on the procedures and compliance times, see this material at <E T="03">regulations.gov</E> under Docket No. FAA-2024-2713. <HD SOURCE="HD1">Costs of Compliance</HD> The FAA estimates that this AD, if adopted as proposed, would affect 266 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD: <GPOTABLE COLS="5" OPTS="L2,nj,i1" CDEF="s50,r50,10,12,12"> <TTITLE>Estimated Costs</TTITLE> <CHED H="1">Action</CHED> <CHED H="1">Labor cost</CHED> <CHED H="1">Parts cost</CHED> Cost on U.S. operators </CHED> <ROW> <ENT I="01">Software installation and configuration check</ENT> <ENT>2 work-hours × $85 per hour = $170</ENT> <ENT>$13</ENT> <ENT>$183</ENT> <ENT>$48,678</ENT> </ROW> </GPOTABLE> <HD SOURCE="HD1">Authority for This Rulemaking</HD> Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority. The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. <HD SOURCE="HD1">Regulatory Findings</HD> The FAA determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 17k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━