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1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. 2. The FAA amends § 39.13 by adding the following new airworthiness directive: 2026-13-14 The Boeing Company: Amendment 39-23397; Docket No. FAA-2026-7205; Project Identifier AD-2026-00549-T. (a) Effective Date This airworthiness directive (AD) is effective July 1, 2026. (b) Affected ADs None. (c) Applicability This AD applies to all The Boeing Company Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -400D, and -400F series airplanes, certificated in any category. (d) Subject Air Transport Association (ATA) of America Code 34, Navigation. (e) Unsafe Condition This AD was prompted by the determination that radio altimeters cannot be relied upon to perform their intended function if they experience interference from wireless broadband operations in the 3.7-3.98 GHz frequency band (5G Lower C-Band) when operating in Canadian airspace, and the determination that during takeoff, approach, landings, and go-arounds, as a result of this interference, certain airplane systems may not properly function, resulting in increased flightcrew workload while on approach with the flight director, autothrottle, or autopilot engaged. The FAA is issuing this AD to address 5G Lower C-Band interference that could result in increased flightcrew workload and could lead to reduced ability of the flightcrew to maintain safe flight and landing of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Definitions (1) For purposes of this AD, a "radio altimeter tolerant airplane" is one for which the radio altimeter, as installed, demonstrates the tolerances specified in paragraphs (g)(1)(i) and (ii) of this AD, using a method approved by the FAA. No actions are required by this AD for radio altimeter tolerant airplanes. (i) Tolerance to radio altimeter interference, for the fundamental emissions (3.7-3.98 GHz), at or above the power spectral density (PSD) curve threshold specified in figure 1 to paragraph (g)(1)(i) of this AD. ER30JN26.003 (ii) Tolerance to radio altimeter interference, for the spurious emissions (4.2-4.4 GHz), at or above the PSD curve threshold specified in figure 2 to paragraph (g)(1)(ii) of this AD. ER30JN26.004 (2) For purposes of this AD, a "non-radio altimeter tolerant airplane" is one for which the radio altimeter, as installed, does not demonstrate the tolerances specified in paragraphs (g)(1)(i) and (ii) of this AD. (h) Airplane Flight Manual (AFM) Revision For non-radio altimeter tolerant airplanes: Before further flight in Canadian airspace, do the actions specified in paragraphs (h)(1) and (2) of this AD. (1) Revise the Limitations Section of the existing AFM to include the information specified in figure 3 to paragraph (h)(1) of this AD. This may be done by inserting a copy of figure 3 to paragraph (h)(1) of this AD into the existing AFM. ER30JN26.005 (2) Revise the Operating Procedures Section of the existing AFM to include the information specified in figure 4 to paragraph (h)(2) of this AD. This may be done by inserting a copy of figure 4 to paragraph (h)(2) of this AD into the existing AFM. An AFM with an Operating Procedures Section that complies with paragraph (h)(2) of AD 2023-12-14, Amendment 39-22472 (88 FR 40003, June 21, 2023) is acceptable for compliance with the requirements of this paragraph of this AD. ER30JN26.006 (i) Terminating Action for AFM Revision (1) Modifying the airplane from a non-radio altimeter tolerant airplane to a radio altimeter tolerant airplane terminates the limitations in paragraph (h)(1) of this AD and the operating procedures in paragraph (h)(2) of this AD for that airplane. (2) After modifying the airplane to a radio altimeter tolerant airplane, the limitations in paragraph (h)(1) of this AD and the operating procedures in paragraph (h)(2) of this AD may be removed from the AFM. (j) Alternative Methods of Compliance (AMOCs) (1) The Manager, AIR-520, Continued Operational Safety Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or responsible Flight Standards Office, as appropriate. If sending information directly to the manager of AIR-520, Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (k) of this AD and email to: AMOC@faa.gov. (2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office. (3) The following AMOCs approved previously for AD 2023-12-14, Amendment 39-22472 (88 FR 40003, June 21, 2023) are approved as AMOCs for paragraph (g)(1) of this AD: FAA AMOC letters 720-23-00133, 720-23-00137, 720-23-00138, and 720-23-00169. (k) Additional Information For more information about this AD, contact Ken Fairhurst, Continued Operational Safety Technical Advisor, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 817-222-5390; email: operationalsafety@faa.gov. (l) Material Incorporated by Reference None. Issued on June 25, 2026. Brian Knaup, Acting Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service. [FR Doc. 2026-13207 Filed 6-26-26; 4:15 pm]BILLING CODE 4910-13-P
