Rule2022-19902
Airworthiness Directives; The Boeing Company Airplanes
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
September 15, 2022
Effective
October 20, 2022
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-8 airplanes. This AD was prompted by a report that, during production, a small number of fasteners in certain locations of the center fuel tank were cap sealed on top of a black stripe of ink with a clear overcoat. This clear overcoat is not an approved surface for sealing and can potentially compromise sealant adhesion. Compromised sealant adhesion can, over time, affect the lightning-protection properties of the airplane. This AD requires preparation of the affected surface areas to ensure that there is adequate sealant adhesion, and complete encapsulation of the discrepant fastener locations with the approved production sealant. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 87 Issue 178 (Thursday, September 15, 2022)</title>
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[Federal Register Volume 87, Number 178 (Thursday, September 15, 2022)]
[Rules and Regulations]
[Pages 56563-56566]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-19902]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-1168; Project Identifier AD-2021-00825-T;
Amendment 39-22138; AD 2022-16-09]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain The Boeing Company Model 737-8 airplanes. This AD was prompted
by a report that, during production, a small number of fasteners in
certain locations of the center fuel tank were cap sealed on top of a
black stripe of ink with a clear overcoat. This clear overcoat is not
an approved surface for sealing and can potentially compromise sealant
adhesion. Compromised sealant adhesion can, over time, affect the
lightning-protection properties of the airplane. This AD requires
preparation of the affected surface areas to ensure that there is
adequate sealant adhesion, and complete encapsulation of the discrepant
fastener locations with the approved production sealant. The FAA is
issuing this AD to address the unsafe condition on these products.
DATES: This AD is effective October 20, 2022.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of October 20,
2022.
ADDRESSES: For service information identified in this final rule,
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 <a href="http://www.myboeingfleet.com">www.myboeingfleet.com</a>. 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 <a href="http://www.regulations.gov">www.regulations.gov</a> by
searching for and locating Docket No. FAA-2021-1168.
Examining the AD Docket
You may examine the AD docket at <a href="http://www.regulations.gov">www.regulations.gov</a> by searching
for and locating Docket No. FAA-2021-1168; 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.
FOR FURTHER INFORMATION CONTACT: Chris Baker, Aerospace Engineer,
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des
Moines, WA 98198; phone and fax: 206-231-3552; email:
<a href="/cdn-cgi/l/email-protection#cdaea5bfa4beb9a2bda5a8bfe3bfe3afaca6a8bf8dabacace3aaa2bb"><span class="__cf_email__" data-cfemail="5f3c372d362c2b302f373a2d712d713d3e343a2d1f393e3e71383029">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Background
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to certain The Boeing
Company Model 737-8 airplanes. The NPRM published in the Federal
Register on February 23, 2022 (87 FR 10110). The NPRM was prompted by a
report that, during production, a small number of fasteners common to
upper wing panel stringers U-S1, U-S10, U-S12, U-S20, and U-S21 and
lower wing panel stringer L-S14 were cap sealed on top of a black
stripe of ink with a clear overcoat. The black stripe of ink and clear
overcoat were applied during airplane assembly to certain interior
areas of the center fuel tank to ensure proper alignment of components,
and this discrepancy was not identified by Boeing prior to the delivery
of certain airplanes. The purpose of cap sealing is to provide a
secondary layer of lightning protection to the metal-to-metal rivet
installation bond. The clear overcoat is not an approved surface for
sealing and can potentially compromise sealant adhesion.
Compromised sealant adhesion can, over time, affect the lightning
protection properties of the airplane. In the NPRM, the FAA proposed to
require preparation of the affected surface areas to ensure that there
is adequate sealant adhesion, and complete encapsulation of the
discrepant fastener locations with
[[Page 56564]]
the approved production sealant. This condition, if not addressed and
combined with a flammable center tank ullage and an independent failure
of the primary lightning protection feature, could result in ignition
of the fuel vapors and subsequent explosion in the event of a lightning
strike to that fastener.
Discussion of Final Airworthiness Directive
Comments
The FAA received comments from Air Line Pilots Association,
International (ALPA) and an anonymous commenter, who supported the NPRM
without change.
The FAA received additional comments from two commenters, Boeing
and Southwest Airlines (SWA). The following presents the additional
comments received on the NPRM and the FAA's response to each comment.
Request To Add Alternative Methods of Compliance to the Final Rule
SWA requested that the FAA provide an option to operators that
would allow removal of the current application of BMS5-45 sealant in
the affected areas and removal of the black stripe of ink in accordance
with certain operator procedures (or other acceptable procedures), then
allowing for refinishing and sealing of the affected area in accordance
with certain other operator instructions. SWA reasoned that these
additional methods would address the unsafe condition and would allow
airworthiness limitation (AWL) inspections and standard maintenance to
be accomplished as intended in the structural repair manual (SRM) and
maintenance planning document (MPD).
SWA explained that it is concerned that extending BMS5-45 sealant
0.6 inches beyond the current production application area could prevent
inspections performed in accordance with 737-7/8/8200/9/10
Airworthiness Limitations (AWL) D626A011-9-04 and MPD principal
structural element (PSE) 57-020-00. SWA went on to explain that
extending the BMS5-45 sealant up to 0.6 inches beyond the current
production application area to encapsulate the discrepant area
contradicts the sealant restoration procedures outlined in 737-8MAX SRM
51-80-01 which states, ``SEALANT MUST NOT EXTEND MORE THAN 0.125 INCH
(3.18mm) ON TO THE SURFACE OF THE PART FOR DAMAGE TOLERANCE INSPECTION
REASONS.'' SWA expressed concern that if an airplane requires repairs
or maintenance actions in the affected area, or requires AWL/MPD
required inspection 57-020-00, the BMS5-45 sealant will be stripped
and, if the affected area is restored in accordance with 737-8MAX SRM
51-80-01, could lead to an operator inadvertently undoing the actions
specified in Boeing Special Attention Requirements Bulletin 737-57-1352
RB, dated February 1, 2021.
The FAA agrees that the service bulletin instructions could
conflict with future actions required by the 737-7/8/8200/9/10
Airworthiness Limitations (AWL) D626A011-9-04, in that the added
sealant might impede the operator's ability to inspect the structure.
The FAA also agrees that operators could use the existing sealant
restoration procedures to remove the current application of BMS5-45
sealant in the discrepant areas, remove the black stripe of ink in
accordance with acceptable surface preparation procedures, and reseal
the fasteners in accordance with standard sealing procedures of
fasteners penetrating the fuel tank. The FAA has added an optional
method of removing the existing sealant and black stripe of ink prior
to reapplying a fastener seal in paragraph (h) of this AD and
redesignated subsequent paragraphs.
Request for Additional Detail to the Unsafe Condition Statement
Boeing requested that the unsafe condition statement found in the
Background section of the preamble and paragraph (e) of the proposed AD
include more detail of the conditions and failures required for a fuel
tank ignition to occur. Boeing stated that in the proposed AD, the
unsafe condition statement lists only compromised sealant adhesion as
the condition needed for an ignition of fuel tank vapors in the event
of a lightning strike. Boeing pointed out that ignition of fuel tank
vapor requires an independent failure of the primary ignition
prevention feature, a failed cap seal, a lightning attachment to the
particular fastener, and that the fuel tank is flammable.
Boeing requested that the FAA change the fifth sentence in the
Background section of the proposed AD to state, ``This condition, if
not addressed and combined with a flammable center tank ullage and an
independent failure of the primary lightning protection feature, could
result in ignition of the fuel vapors and subsequent explosion in the
event of a lightning strike to that fastener.'' Boeing requested
similar changes to the second sentence of paragraph (e) of the proposed
AD.
The FAA agrees with the request for the reasons provided. Boeing
provided a more detailed description of the potential failure sequence.
The FAA has revised the Background section of this final rule and the
second sentence of paragraph (e) of this AD accordingly.
Conclusion
The FAA reviewed the relevant data, considered any comments
received, and determined that air safety requires adopting this AD as
proposed. Except for minor editorial changes, and any other changes
described previously, this AD is adopted as proposed in the NPRM. None
of the changes will increase the economic burden on any operator.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Boeing Special Attention Requirements Bulletin
737-57-1352 RB, dated February 1, 2021. This service information
specifies procedures for preparing the surface and completely
encapsulating the black stripe of ink, the clear overcoat, and the
existing sealant with the approved production (BMS5-45) sealant at
upper stringer U-S1, U-S10, U-S12, U-S20, and U-S21, and lower stringer
L-S14. The affected areas are all located on the portion of the
stringers just outboard of the center wing box. 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.
Costs of Compliance
The FAA estimates that this AD affects 11 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Apply Sealant....................... 106 work-hours x $85 $500 $9,510 $104,610
per hour = $9,010.
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[[Page 56565]]
Estimated Costs for Optional Actions
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Cost per
Action Labor cost Parts cost product
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Remove Sealant and Black Stripe of Ink, and 118 work-hours x $85 per hour = $500 $10,030
Reapply Fastener Seal. $10,030.
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The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, some or all of the costs of
this 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
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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
The Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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:
2022-16-09 The Boeing Company: Amendment 39-22138; Docket No. FAA-
2021-1168; Project Identifier AD-2021-00825-T.
(a) Effective Date
This airworthiness directive (AD) is effective October 20, 2022.
(b) Affected ADs
None.
(c) Applicability
This AD applies to The Boeing Company Model 737-8 airplanes,
certificated in any category, as identified in Boeing Special
Attention Requirements Bulletin 737-57-1352 RB, dated February 1,
2021.
(d) Subject
Air Transport Association (ATA) of America Code 57, Wings.
(e) Unsafe Condition
This AD was prompted by a report that, during production, a
small number of fasteners in certain locations of the center fuel
tank were cap sealed on top of a black stripe of ink with a clear
overcoat. This clear overcoat is not an approved surface for sealing
and can potentially compromise sealant adhesion. Compromised sealant
adhesion can, over time, affect the lightning protection properties
of the airplane. The FAA is issuing this AD to address compromised
sealant adhesion within the center fuel tank, which, if combined
with a flammable center tank ullage and an independent failure of
the primary lightning protection feature, could result in ignition
of fuel vapors and subsequent explosion of the fuel tank in the
event of a lightning strike to that fastener.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
Within 10 years after the date of issuance of the original
airworthiness certificate or the original export certificate of
airworthiness, do all applicable actions identified in, and in
accordance with, the Accomplishment Instructions of Boeing Special
Attention Requirements Bulletin 737-57-1352 RB, dated February 1,
2021, except as specified by paragraph (h) of this AD.
Note 1 to paragraph (g): Guidance for accomplishing the actions
required by this AD can be found in Boeing Special Attention Service
Bulletin 737-57-1352, dated February 1, 2021, which is referred to
in Boeing Special Attention Requirements Bulletin 737-57-1352 RB,
dated February 1, 2021.
(h) Optional Method To Remove Previously Applied Sealant and Black
Stripe of Ink, and Reapply Fastener Seal
As an option to the sealant application required by paragraph
(g) of this AD, it is acceptable to remove the existing sealant and
the black stripe of ink prior to reapplying a fastener seal. Remove
existing sealant and black stripe of ink as follows:
(1) Remove existing sealant to expose the black stripe of ink.
(2) Remove existing black stripe of ink using aluminum oxide
cloth or paper, 150 to 220 grit.
Note 2 to paragraph (h)(2): Take caution not to abrade through
the existing oven cured BMS10-20 coating under the black stripe of
ink. The BMS10-20 was previously applied during production.
(3) Touch up exposed aluminum with Alodine 600 (Type I, II, or
III) or Bonderite M-CR 600 Aero (Type I, II, or III).
(4) Apply fastener seal (cap seal) with BMS5-45.
(5) Apply BMS10-20 Type II fuel tank coating to any exposed
alodine/bonderite surfaces not covered by the fastener seal; it is
acceptable to extend BMS10-20 Type II coating over fastener seal.
(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: <a href="/cdn-cgi/l/email-protection#94adb9d5dad9c7f1f5e0e0f8f1b9d5d7dbb9d5d9dbd7b9c6f1e5e1f1e7e0e7d4f2f5f5baf3fbe2"><span class="__cf_email__" data-cfemail="d8e1f59996958bbdb9acacb4bdf5999b97f59995979bf58abda9adbdabacab98beb9b9f6bfb7ae">[email protected]</span></a>.
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the responsible Flight Standards Office.
[[Page 56566]]
(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 Chris Baker,
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch,
2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-
3552; email: <a href="/cdn-cgi/l/email-protection#7f1c170d160c0b100f171a0d510d511d1e141a0d3f191e1e51181009"><span class="__cf_email__" data-cfemail="284b405a415b5c4758404d5a065a064a49434d5a684e4949064f475e">[email protected]</span></a>.
(2) Service information identified in this AD that is not
incorporated by reference is available at the addresses specified in
paragraphs (k)(3) and (4) of this AD.
(k) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference (IBR) 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 Special Attention Requirements Bulletin 737-57-1352
RB, dated February 1, 2021.
(ii) [Reserved]
(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; internet <a href="http://www.myboeingfleet.com">www.myboeingfleet.com</a>.
(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 service information that is incorporated
by reference at the National Archives and Records Administration
(NARA). For information on the availability of this material at
NARA, <a href="/cdn-cgi/l/email-protection#5c3a2e7235322f2c393f283533321c323d2e3d723b332a"><span class="__cf_email__" data-cfemail="fa9c88d49394898a9f998e939594ba949b889bd49d958c">[email protected]</span></a>, or go to: <a href="http://www.archives.gov/federal-register/cfr/ibr-locations.html">www.archives.gov/federal-register/cfr/ibr-locations.html</a>.
Issued on July 29, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2022-19902 Filed 9-14-22; 8:45 am]
BILLING CODE 4910-13-P
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