[Federal Register Volume 87, Number 17 (Wednesday, January 26, 2022)]
[Proposed Rules]
[Pages 3946-3949]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-01408]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-1169; Project Identifier AD-2021-01011-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 adopt a new airworthiness directive (AD) 
for certain The Boeing Company Model 737-800 series airplanes. This 
proposed AD was prompted by the determination that insufficient sealing 
may allow water to enter the lower lobe electronic equipment (EE) bay 
through the main deck floor structure at the rigid cargo barrier (RCB), 
which could cause damage to EE bay line replacement units (LRUs) in the 
E5 rack. This proposed AD would require detailed inspections for the 
presence and condition of sealant at certain locations and applicable 
on-condition actions. This proposed AD would also require replacing the 
moisture barrier tape at a certain location, replacing the weather seal 
at a certain location, and installing seat track fillers. 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 March 14, 
2022.

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 https://www.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

[[Page 3947]]

p.m., Monday through Friday, except Federal holidays.
    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; internet https://www.myboeingfleet.com. You may 
view this referenced 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 https://www.regulations.gov by searching for and locating Docket No. FAA-2021-
1169.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-1169; 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.

FOR FURTHER INFORMATION CONTACT: Courtney Tuck, Aerospace Engineer, 
Cabin Safety and Environmental Systems Section, FAA, Seattle ACO 
Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-
231-3986; email: [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-2021-1169; Project Identifier 
AD-2021-01011-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 
https://www.regulations.gov, including any personal information you 
provide. The agency will also post a report summarizing each 
substantive verbal contact received about this NPRM.

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 
Courtney Tuck, Aerospace Engineer, Cabin Safety and Environmental 
Systems Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3986; email: 
[email protected]. Any commentary that the FAA receives which is 
not specifically designated as CBI will be placed in the public docket 
for this rulemaking.

Background

    The FAA has received a report that an aircraft failed to depart 
when it was not possible to align the inertial reference units (IRUs) 
during a pre-flight check. Findings from a subsequent investigation by 
Boeing indicate there is insufficient sealing at the main deck floor 
structure and the bottom of the RCB, which allows water ingress into 
the lower lobe EE bay. Boeing indicated there may also be insufficient 
sealing in the following areas: Floor panel to floor panel, floor panel 
to seat track joints, and drain trough installation. The lower lobe EE 
bay houses the LRUs in the E5 rack, which house the air data inertial 
reference units (ADIRUs) and flight management computers (FMCs). The E5 
rack has a moisture shroud and a drip shield, but these provide 
inadequate protection to the LRUs for this amount of water ingression. 
Boeing reported that the source of water was found to be water or snow 
accumulated on cargo and pallets prior to loading, or through an open 
cargo door during inclement weather. A later report also indicated that 
the weather seal of the main deck cargo door may have an incorrect 
orientation, which may allow water to enter the main deck cargo 
compartment. These conditions, if not addressed, could result in water 
damage to the ADIRUs and FMCs during flight, leading to a complete loss 
of data to primary flight displays and electronic navigation functions, 
which could prevent continued safe flight and landing.

FAA's Determination

    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.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 737-53A1401 RB, 
dated April 27, 2021. This service information specifies procedures for 
detailed inspections of the forward main deck cargo compartment floor 
to RCB, floor panel joints, drain troughs, seat track splices, and, for 
some airplanes, the lower lobe E5 rack drain pan shroud for sealant 
condition and application, and applicable on-condition actions. This 
service information also specifies procedures for replacing the main 
deck cargo door weather seal, replacing the moisture barrier tape on 
the forward main deck cargo compartment floor, and installing seat 
track fillers in the EE bay. On-condition actions include repair, 
removing existing sealant, and applying new sealant. 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 ADDRESSES.

Proposed AD Requirements in This NPRM

    This proposed AD would require accomplishing the actions specified 
in the service information already described and 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 service information at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-1169.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 7 airplanes of U.S. registry. The FAA estimates the following 
costs to comply with this proposed AD:

[[Page 3948]]



                                                                     Estimated Costs
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               Action                         Labor cost                Parts cost               Cost per product             Cost on U.S. operators
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Inspect sealant....................  Up to 12 work-hours x $85    $0....................  Up to $1,020..................  Up to $7,140.
                                      per hour = Up to $1,020.
Remove/reinstall drain trough......  Up to 15 hours x $85 per     Negligible............  Up to $1,275..................  Up to $8,925.
                                      hour = Up to $1,275.
Replace weather seal...............  Up to 7 work-hours x $85     $9,680................  Up to $10,275.................  Up to $71,925.
                                      per hour = Up to $595.
Replace barrier tape...............  Up to 20 work-hours x $85    Negligible............  Up to $1,700..................  Up to $11,900.
                                      per hour = Up to $1,700.
Install seat track filler..........  Up to 2 work-hours x $85     Negligible............  Up to $170....................  Up to $1,190.
                                      per hour = Up to $170.
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    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
proposed inspection. The agency has no way of determining the number of 
aircraft that might need these replacements:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                Action                            Labor cost                   Parts cost             product
----------------------------------------------------------------------------------------------------------------
Install or replace sealant............  26 work-hours x $85 per hour =  Negligible..............          $2,210
                                         $2,210.
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition actions specified in this proposed AD.
    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some or all of the costs of 
this proposed AD may be covered under warranty, thereby reducing the 
cost impact on affected operators.

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 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 this 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 adding the following new airworthiness 
directive:

The Boeing Company: Docket No. FAA-2021-1169; Project Identifier AD-
2021-01011-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by March 14, 2022.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-800 series 
airplanes, certificated in any category, as identified in Boeing 
Alert Requirements Bulletin 737-53A1401 RB, dated April 27, 2021.

(d) Subject

    Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by the determination that insufficient 
sealing may allow water to enter the lower lobe electronic equipment 
(EE) bay through the main deck floor structure at the rigid cargo 
barrier, which could cause damage to EE bay line replacement units 
in the E5 rack. The FAA is issuing this AD to address water ingress 
in the lower lobe EE bay, which could result in water damage to the 
air data inertial reference units and flight management computers 
during flight, leading to a complete loss of data to primary flight 
displays and electronic navigation functions, which could prevent 
continued safe flight and landing.

(f) Compliance

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

(g) Required Actions

    Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 737-53A1401 RB, dated April 27, 2021, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-53A1401 RB, dated April 27, 2021.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service

[[Page 3949]]

Bulletin 737-53A1401, dated April 27, 2021, which is referred to in 
Boeing Alert Requirements Bulletin 737-53A1401 RB, dated April 27, 
2021.

(h) Exceptions to Service Information Specifications

    (1) Where the Compliance Time column of the tables in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 737-
53A1401 RB, dated April 27, 2021, uses the phrase ``the original 
issue date of Requirements Bulletin 737-53A1401 RB,'' this AD 
requires using ``the effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin 737-53A1401 RB, 
dated April 27, 2021, specifies contacting Boeing for repair 
instructions: This AD requires doing the repair using a method 
approved in accordance with the procedures specified in paragraph 
(i) of this AD.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle ACO 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 (j)(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 Organization Designation 
Authorization (ODA) that has been authorized by the Manager, Seattle 
ACO 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.

(j) Related Information

    (1) For more information about this AD, contact Courtney Tuck, 
Aerospace Engineer, Cabin Safety and Environmental Systems Section, 
FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; 
phone and fax: 206-231-3986; email: [email protected].
    (2) 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; internet https://www.myboeingfleet.com. You may view this referenced 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.

    Issued on December 22, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2022-01408 Filed 1-25-22; 8:45 am]
BILLING CODE 4910-13-P


