
[Federal Register Volume 88, Number 237 (Tuesday, December 12, 2023)]
[Proposed Rules]
[Pages 86073-86080]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-24306]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-1993; Project Identifier AD-2023-00129-T]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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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; [email protected].

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; [email protected]. 
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.

[[Page 86074]]

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:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                              Cost per          Cost on U.S.
              Action                      Labor cost         Parts cost        product           operators
----------------------------------------------------------------------------------------------------------------
AFM revision (retained action from  1 work-hour x $85 per              $0             $85  $34,765.
 AD 2020[dash]03[dash]20).           hour = $85.
Software installation and check     2 work-hours x $85                265             435  $177,915.
 (new proposed action).              per hour = $170.
Concurrent actions................  5 work-hours x $85 =              795           1,220  Up to $498,980.*
                                     $425.
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* Not all airplanes would be required to do the concurrent actions. However, the FAA does not have an estimate
  of how many airplanes are in a configuration that would require concurrent actions.

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

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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

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by:
0
a. Removing Airworthiness Directive (AD) 2020-03-20, Amendment 39-19844 
(85 FR 8717, February 18, 2020), and
0
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).
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Figure 1 to Paragraph (g)--Affected OPS Software
[GRAPHIC] [TIFF OMITTED] TP12DE23.003


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Figure 2 to Paragraph (g)--AFM--Limitations or Certificate Limitations
[GRAPHIC] [TIFF OMITTED] TP12DE23.004


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Figure 2 to Paragraph (g)--AFM--Limitations or Certificate Limitations 
Continued
[GRAPHIC] [TIFF OMITTED] TP12DE23.005


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Figure 3 to Paragraph (g)--AFM--Procedures or Normal Procedures
[GRAPHIC] [TIFF OMITTED] TP12DE23.006

BILLING CODE 4910-13-C

(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: [email protected].
    (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; [email protected].

[[Page 86080]]

    (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 [email protected].

    Issued on October 4, 2023.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-24306 Filed 12-11-23; 8:45 am]
BILLING CODE 4910-13-P


