Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

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.

DATES:

The FAA must receive comments on this proposed AD by January 26, 2024.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments.

• Fax: 202–493–2251.

• Mail: U.S. Department of Transportation, Docket Operations, M–30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE, Washington, DC 20590.

• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA–2023–1993; 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.

Material Incorporated by Reference:

• For service information identified in this NPRM, 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 myboeingfleet.com.

• You may view this service information 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 regulations.gov by searching for and locating Docket No. FAA–2023–1993.

FOR FURTHER INFORMATION CONTACT:

Jeffrey W. Palmer, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562–627–5351; jeffrey.w.palmer@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under ADDRESSES . Include “Docket No. FAA–2023–1993; Project Identifier AD–2023–00129–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 the 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 regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this proposed AD.

Confidential Business Information

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 Jeffrey W. Palmer, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562–627–5351; jeffrey.w.palmer@faa.gov. Any commentary that the FAA receives that is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Background

The FAA issued AD 2020–03–20, Amendment 39–19844 (85 FR 8717, February 18, 2020) (AD 2020–03–20), for The Boeing Company Model MD–11 and MD–11F airplanes modified by supplemental type certificate (STC) ST01895WI; Model 717–200 airplanes modified by STC ST04416AT; all Model 737–8 and 737–9 airplanes; all Model 737–600, –700, –700C, –800, –900, and –900ER series airplanes; Model 747–400 and 747–400F series airplanes modified by STC ST01892WI; Model 757–200, –200PF, –200CB, and –300 series airplanes modified by STC ST04436AT; Model 767–200, –300, –300F, –400ER, and –2C series airplanes modified by STC ST04436AT or ST01883WI; and all Model 777–200, –200LR, –300, –300ER, and 777F series airplanes.

AD 2020–03–20 was prompted by reports of the loss of global positioning system (GPS) data or degraded GPS positional accuracy while using a certain MMR with certain Collins MMR software installed. When an airplane is within a specific geographic region, the software is failing to map the computed ionospheric pierce point to the correct hemisphere. As a result, AD 2020–03–20 requires airplanes with a certain MMR with certain software installed to revise the existing AFM to include a limitation to prohibit operations that require less than 0.3 RNP within the specified geographic area. The agency issued AD 2020–03–20 to address the loss of GPS data and degraded GPS positional accuracy, which, during a high-precision approach with this GPS error, could result in controlled flight into terrain.

Actions Since AD 2020–03–20 Was Issued

Since the FAA issued AD 2020–03–20, the FAA received reports from Boeing indicating there is an MMR software error that results in an MMR reset after a leap-second, which is occasionally applied to UTC. If the software calculation error occurs on all MMRs that are powered on at that time, there could be simultaneous loss of all MMR-based functions on all affected airplanes. If an affected airplane is in flight phase when this calculation error occurs, the loss of all MMR functions would result in increased flightcrew workload, as the flightcrew would reduce automation and switch to operating under visual flight rules, which requires contacting air traffic control (ATC) for direction and support. In the event of multiple airplanes simultaneously experiencing loss of MMR function in instrument meteorological conditions during landing or takeoff, this would result in increased ATC workload and consequent reduction in airplane spacing, which could result in a mid-air collision.

In addition, Boeing has developed new software that addresses both the unsafe condition identified in AD 2020–03–20 (software that fails to map the computed ionospheric pierce point to the correct hemisphere) and the additional unsafe condition identified in this proposed AD (software error that results in an MMR reset after a leap-second). Installing the new software would eliminate the need for the AFM revision required by AD 2020–03–20.

FAA's Determination

The FAA is issuing this NPRM after determining that the unsafe conditions described previously are likely to exist or develop on other products of the same type design.

Related Service Information Under 1 CFR Part 51

The FAA reviewed the following Boeing requirements bulletins:

• Boeing Alert Requirements Bulletin 737–34A3572 RB, dated October 15, 2020.
• Boeing Alert Requirements Bulletin 737–34A3573 RB, dated August 5, 2020.
• Boeing Alert Requirements Bulletin 777–34A0385 RB, Revision 1, dated March 8, 2021.

This service information specifies procedures for installation of MMR OPS part number (P/N) COL4C–0087–0003 (or later-approved software P/N) in MMR 1 and MMR 2, installation of MMR option selection software (OSS) P/N BCG27–U000–0730 or BCG48–U000–05W9, and software configuration checks. This service information also specifies taking concurrent actions, including replacement of MMRs, replacement of GPS antennas, and installation of additional software.

These documents are distinct since they apply to different airplane models and configurations. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

Proposed AD Requirements in This NPRM

This proposed AD would retain all requirements of AD 2020–03–20. This proposed AD would also require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between this Proposed AD and the Service Information.” For information on the procedures and compliance times, see this service information at regulations.gov by searching for and locating Docket No. FAA–2023–1993. For airplanes for which the service information is not applicable, this proposed AD would require installing MMR OPS P/N COL4C–0087–0003 (or later-approved software version) and conducting a software configuration check, both of which must be done in accordance with a method approved by the Manager, AIR–520, Continued Operational Safety Branch, FAA.

Differences Between This Proposed AD and the Service Information

Where the service information specifies installing MMR OSS P/N BCG27–U000–0730 or BCG48–U000–05W9, this proposed AD would not require that action. Those MMR OSS part numbers are not used to calculate position nor time functions; therefore, the installation of those MMR OSS part numbers is not required for addressing the unsafe condition.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 409 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:

Authority for This Rulemaking

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.

Regulatory Findings

The FAA has determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 the proposed regulation:

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

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

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

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

The Proposed Amendment

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

PART 39—AIRWORTHINESS DIRECTIVES

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:

a. Removing Airworthiness Directive (AD) 2020–03–20, Amendment 39–19844 ( 85 FR 8717, February 18, 2020), and

b. Adding the following new AD:

The Boeing Company: Docket No. FAA–2023–1993; Project Identifier AD–2023–00129–T.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by January 26, 2024.

(b) Affected ADs

This AD replaces AD 2020–03–20, Amendment 39–19844 (85 FR 8717, February 18, 2020) (AD 2020–03–20).

(c) Applicability

This AD applies to The Boeing Company airplanes, certificated in any category, as identified in paragraphs (c)(1) through (9) of this AD.

(1) Model MD–11 and MD–11F airplanes modified by supplemental type certificate (STC) ST01895WI.

(2) Model 717–200 airplanes modified by STC ST04416AT.

(3) All Model 737–8 and 737–9 airplanes.

(4) All Model 737–600, –700, –700C, –800, –900, and –900ER series airplanes.

(5) Model 747–400 and 747–400F series airplanes modified by STC ST01892WI.

(6) Model 757–200, –200PF, –200CB, and –300 series airplanes modified by STC ST04436AT.

(7) Model 767–200, –300, –300F, –400ER, and –2C series airplanes modified by STC ST04436AT or ST01883WI.

(8) All Model 777–200, –200LR, –300, and –300ER series airplanes.

(9) All Model 777F series airplanes.

(d) Subject

Air Transport Association (ATA) of America Code 34, Navigation.

(e) Unsafe Condition

This AD was prompted by reports of the loss of global positioning system (GPS) data or degraded GPS positional accuracy and additional reports of an error in calculating Coordinated Universal Time (UTC) while using a certain multi-mode receiver (MMR) with certain software installed. The FAA is issuing this AD to address loss of GPS data and degraded GPS positional accuracy, which, during a high-precision approach with this GPS error, could result in controlled flight into terrain, and to address UTC calculation errors that could result in simultaneous MMR resets on multiple airplanes, increased air traffic control workload, and consequent reduction in airplane separation and potential for mid-air collision.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Retained Airplane Flight Manual (AFM) Revision, With No Changes

This paragraph restates the requirements of paragraph (g) of AD 2020–03–20, with no changes. For airplanes equipped with Collins GLU–2100 MMR, part number (P/N) 822–2532–100, having any applicable GLU–2100 operational software (OPS) identified in figure 1 to paragraph (g) of this AD installed: At the applicable time specified in paragraphs (g)(1) and (2) of this AD, revise the limitations or certificate limitations section, as applicable, of the existing AFM to include the information specified in figure 2 to paragraph (g) of this AD and revise the procedures or normal procedures section, as applicable, of the existing AFM to include the information specified in figure 3 to paragraph (g) of this AD. This may be done by inserting a copy of figures 2 and 3 to paragraph (g) of this AD into the existing AFM.

(1) For Model 737–8 and 737–9 airplanes: Before further flight.

(2) For all airplanes except Model 737–8 and 737–9 airplanes: Within 7 days after February 18, 2020 (the effective date of AD 2020–03–20).

Figure 1 to Paragraph (g)—Affected OPS Software

Figure 2 to Paragraph (g)—AFM—Limitations or Certificate Limitations

Figure 2 to Paragraph (g)—AFM—Limitations or Certificate Limitations Continued

Figure 3 to Paragraph (g)—AFM—Procedures or Normal Procedures

(h) Software Installation for Certain Airplanes

For airplanes identified in paragraphs (h)(1) through (7) of this AD: Within 12 months after the effective date of this AD, install MMR OPS P/N COL4C–0087–0003, or later-approved software version, and do a software configuration check to confirm that P/N COL4C–0087–0003 or later-approved software version is installed. Both the installation and the check must be done in accordance with a method approved by the Manager, AIR–520, Continued Operational Safety Branch, FAA. Later-approved software versions are those Boeing software versions that are approved as a replacement for MMR OPS P/N COL4C–0087–0003 and are approved as part of the type design by the FAA or by The Boeing Company Organization Designation Authorization (ODA).

(1) Model MD–11 and MD–11F airplanes modified by STC ST01895WI.

(2) Model 717–200 airplanes modified by STC ST04416AT.

(3) Model 737–600, –700, –700C, –800, and –900 series airplanes.

(4) Model 747–400 and 747–400F series airplanes modified by STC ST01892WI.

(5) Model 757–200, –200PF, –200CB, and –300 series airplanes modified by STC ST04436AT.

(6) Model 767–200, –300, –300F, –400ER, and –2C series airplanes modified by STC ST04436AT or ST01883WI.

(7) Model 777–200, –200LR, and –300 series airplanes.

(i) Software Installation for Certain Other Airplanes

For Model 737–8 and –9 airplanes, Model 737–900ER series airplanes, and Model 777–300ER and 777F series airplanes: Within 12 months after the effective date of this AD, except as specified in paragraph (j) of this AD, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of the applicable requirements bulletin identified in paragraphs (i)(1) through (3) of this AD.

(1) For Model 737–8 and –9 airplanes: Boeing Alert Requirements Bulletin 737–34A3572 RB, dated October 15, 2020.

Note 1 to paragraph (i)(1): Guidance for accomplishing the actions required by paragraph (i)(1) of this AD can be found in Boeing Alert Service Bulletin 737–34A3572, dated October 15, 2020, which is referred to in Boeing Alert Requirements Bulletin 737–34A3572 RB, dated October 15, 2020.

(2) For Model 737–900ER series airplanes: Boeing Alert Requirements Bulletin 737–34A3573 RB, dated August 5, 2020.

Note 2 to paragraph (i)(2): Guidance for accomplishing the actions required by paragraph (i)(2) of this AD can be found in Boeing Alert Service Bulletin 737–34A3573, dated August 5, 2020, which is referred to in Boeing Alert Requirements Bulletin 737–34A3573 RB, dated August 5, 2020.

(3) For Model 777–300ER and 777F series airplanes: Boeing Alert Requirements Bulletin 777–34A0385 RB, Revision 1, dated March 8, 2021.

Note 3 to paragraph (i)(3): Guidance for accomplishing the actions required by paragraph (i)(3) of this AD can be found in Boeing Alert Service Bulletin 777–34A0385, Revision 1, dated March 8, 2021, which is referred to in Boeing Alert Requirements Bulletin 777–34A0385 RB, Revision 1, dated March 8, 2021.

(j) Exceptions to Service Information Specifications

Where the requirements bulletins identified in paragraphs (i)(1) through (3) of this AD specify installing MMR option selection software (OSS) P/N BCG27–U000–0730 or BCG48–U000–05W9 and doing the associated software configuration check, this AD does not require those actions.

(k) Terminating Action

After accomplishing the actions required by paragraph (h) or (i) of this AD, as applicable, you may remove the AFM revision required by paragraph (g) of this AD.

(l) Credit for Previous Actions

This paragraph provides credit for the actions required by paragraph (i)(3) of this AD, if the actions were performed before the effective date of this AD using Boeing Alert Requirements Bulletin 777–34A0385 RB, dated August 7, 2020.

(m) 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 the certification office, send it to the attention of the person identified in paragraph (n)(1) of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@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) An AMOC that provides an acceptable level of safety may be used for any repair, modification, or alteration required by this AD if it is approved by The Boeing Company ODA that has been authorized by the Manager, AIR–520, Continued Operational Safety Branch, FAA, to make those findings. To be approved, the repair method, modification deviation, or alteration deviation must meet the certification basis of the airplane, and the approval must specifically refer to this AD.

(n) Related Information

(1) For more information about this AD, contact Jeffrey W. Palmer, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562–627–5351; jeffrey.w.palmer@faa.gov.

(2) Service information identified in this AD that is not incorporated by reference is available at the addresses specified in paragraphs (o)(3) and (4) of this AD.

(o) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise.

(i) Boeing Alert Requirements Bulletin 737–34A3572 RB, dated October 15, 2020.

(ii) Boeing Alert Requirements Bulletin 737–34A3573 RB, dated August 5, 2020.

(iii) Boeing Alert Requirements Bulletin 777–34A0385 RB, Revision 1, dated March 8, 2021.

(3) For service information identified in this 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 myboeingfleet.com.

(4) You may view this service information 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.

(5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email fr.inspection@nara.gov.