AD 2023-12-05

This AD is effective June 21, 2023.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA–2023–0670; 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 final rule, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M–30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE, Washington, DC 20590.

Brett Portwood, Continued Operational Safety Technical Advisor, COS Program Management Section, Operational Safety Branch, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712–4137; phone: 817–222–5390; email: operationalsafety@faa.gov.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2022–03–05, Amendment 39–21922 (87 FR 4150, January 27, 2022) (AD 2022–03–05). AD 2022–03–05 applied to all The Boeing Company (Boeing) Model 747–8F and 747–8 series airplanes and Model 777 airplanes equipped with a radio altimeter. The NPRM published in the Federal Register on May 3, 2023 (88 FR 27799). The NPRM was prompted by a determination that radio altimeters cannot be relied upon to perform their intended function if they experience interference from wireless broadband operations in the 5G C-Band, and a determination that this interference may affect other airplane systems using radio altimeter data, including the pitch control laws, including those that provide tail strike protection, regardless of the approach type or weather.

In the NPRM, the FAA proposed to retain the AFM revisions required by AD 2022–03–05 until June 30, 2023. On or before June 30, 2023, the FAA proposed to require replacing those AFM revisions with limitations prohibiting dispatching or releasing to airports, and approaches or landings on runways, in the contiguous U.S. airspace for non-radio altimeter tolerant airplanes. For radio altimeter tolerant airplanes, the FAA proposed to allow the prohibited operations at 5G C-Band mitigated airports (5G CMAs) as identified in an FAA Domestic Notice. The FAA proposed this AD to address missing or erroneous radio altimeter data, which, in combination with multiple flight deck effects, could lead to loss of continued safe flight and landing.

The FAA provided the public with an opportunity to comment on the proposed AD and received comments from five commenters. The following presents the comments received on the NPRM and the FAA's response to each comment.

Boeing and the Air Line Pilots Association, International (ALPA), supported the NPRM without change.

The supportive comments from ALPA included additional viewpoints without a suggestion specific to the AD or a request the FAA can act on. These comments are outside the scope of this AD.

Comment summary: All Nippon Airways (All Nippon) requested the FAA revise the proposed AD to allow AMOCs approved for AD 2023–10–02, Amendment 39–22438 (88 FR 34065, May 26, 2023) (AD 2023–10–02) as AMOCs for this AD.

FAA response: The FAA does not agree. An airplane that is a radio altimeter tolerant airplane for purposes of AD 2023–10–02 will also be a radio altimeter tolerant airplane for purposes of this AD. However, because the hazards mitigated by AD 2023–10–02 are separate and distinct from the hazards mitigated by this AD, the FAA has determined that AMOCs approved for compliance with AD 2023–10–02 may not always be appropriate to address the unsafe condition specified in this AD. For this reason, operators with an approved AMOC for AD 2023–10–02 will need to request approval of it as an AMOC for compliance with this AD.

Comment summary: American Airlines expressed concern regarding the compliance time for the proposed actions and requested the FAA revise the AD to provide a minimum of 30 days from the effective date of the AD.

FAA response: The FAA understands the commenter's concern and made every effort to publish this AD as soon as possible. After refraining from operating at their FCC-authorized levels for a year and a half, wireless companies are now able to operate at higher levels, yet still not at the levels authorized. Specifically, wireless companies expect to operate their networks in urban areas with minimal restrictions due to the completion of retrofits. Additionally, the FAA anticipates 19 additional telecommunication companies will begin transmitting in the C-Band after June 30, 2023. Although the FAA continues to work with the companies that intend to transmit in the 3.7–3.98–GHz band near 5G CMAs, the FAA has no agreement with those companies to provide the FAA with tower locations and other information necessary to support the current NOTAM/AMOC process. Therefore, the FAA will not be able to extend the June 30, 2023, date.

Comment summary: All Nippon requested the FAA clarify how to determine whether a radio altimeter (for example, LRA–900 P/N 822–0334–004) corresponds to a radio altimeter tolerant airplane or non-radio altimeter tolerant airplane. An individual requested the FAA revise the AD to add the list of the part numbers for compliant radio altimeters ( e.g., Collins LRA–900+ and THALES ERT–530R).

FAA response: The FAA does not maintain a list of tolerant radio altimeters because the determination of a radio altimeter tolerant airplane must consider the installation details, which vary from airplane to airplane. The FAA has developed a policy statement that provides a means of compliance with this AD for all transport and commuter category airplanes and rotorcraft equipped with a radio altimeter. The FAA requested public comments on this proposed policy on May 8, 2023 (88 FR 29554). The proposed policy describes an acceptable framework and method for demonstrating that an airplane or rotorcraft is radio altimeter tolerant. The policy discusses compliance methods that should be applied to programs for type certificates, amended type certificates, STCs, and amended STCs. The proposed policy addresses how to assess 5G C-Band tolerance. Although most data submitted to demonstrate compliance in accordance with the FAA policy statement will be proposed by design approval holders, any person/entity can propose a method to demonstrate compliance.

Comment summary: All Nippon and an individual requested the FAA clarify why the proposed AD would prohibit radio altimeter tolerant airplanes from landing at non-5G CMAs after July 2023. All Nippon stated that there are many non-5G CMAs that are unaffected by 5G C-Band interference and operations should not be restricted at such airports.

FAA response: The FAA disagrees. Boeing has not submitted any substantiating data that demonstrates the hazards addressed by this AD are adequately mitigated for radio altimeter tolerant airplanes at non-5G CMAs.

The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. This AD is adopted as proposed in the NPRM.

The FAA considers this AD to be an interim action. Once the Technical Standard Order (TSO) standard for radio altimeters is established, which will follow the existing international technical consensus on the establishment of the minimum operational performance standards (MOPS), the FAA anticipates that the MOPS will be incorporated into the TSO. Once a new radio altimeter TSO is developed, approved, and available, the FAA might consider additional rulemaking.

Section 553(d) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq.) requires publication of a rule not less than 30 days before its effective date. However, section 553(d) authorizes agencies to make rules effective in less than 30 days when the agency finds “good cause.” Radio altimeters cannot be relied upon to perform their intended function if they experience interference from wireless broadband operations in the 5G C-Band. This interference may affect other airplane systems using radio altimeter data, including the pitch control laws, including those that provide tail strike protection, regardless of the approach type or weather, which, in combination with multiple flight deck effects, could lead to loss of continued safe flight and landing. To address this unsafe condition, the actions required by this AD must be accomplished before the compliance date of June 30, 2023. The FAA based this date on the changes to the 5G C-Band environment beginning on July 1, 2023. These changes include increased wireless broadband deployment and transmissions closer to the parameters authorized by the FCC. The earlier operators learn of the requirements in this AD, the earlier they can take action to ensure compliance. An effective date less than 30 days would ensure the AD is codified earlier, thereby increasing awareness of its requirements. Therefore, the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment immediately effective.

The cost information below describes the costs to change the AFM. Although this AD largely maintains the AFM limitations currently required by AD 2022–03–05, the FAA acknowledges that this AD may also impose costs on some aircraft operators from having to change their conduct to comply with the amended AFM. However, the FAA lacks the data necessary to quantify the costs associated with aircraft operators changing their conduct.

The FAA estimates that this AD affects 347 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:

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.

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Will not affect intrastate aviation in Alaska, and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by:

a. Removing Airworthiness Directive (AD) 2022–03–05, Amendment 39–21922 (87 FR 4150, January 27, 2022), and

b. Adding the following new AD: