Proposed Rule2021-13930
Airworthiness Directives; The Boeing Company Airplanes
Primary source
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Published
June 30, 2021
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to supersede Airworthiness Directive (AD) 2005-05-18, which applies to certain The Boeing Company Model 737-600, -700, -700C, -800, and -900 series airplanes. AD 2005-05-18 requires repetitive inspections for cracking of the webs of the aft pressure bulkhead at a certain body station, and corrective action if necessary. Since the FAA issued AD 2005-05-18, cracking was found in that inspection area on airplanes not identified in the applicability of AD 2005-05-18. This proposed AD would retain the requirements of AD 2005- 05-18, revise the applicability to include additional airplanes, and add an inspection for existing repairs on the newly added airplanes. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 86 Issue 123 (Wednesday, June 30, 2021)</title>
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[Federal Register Volume 86, Number 123 (Wednesday, June 30, 2021)]
[Proposed Rules]
[Pages 34660-34662]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-13930]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0503; Project Identifier AD-2021-00163-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)
2005-05-18, which applies to certain The Boeing Company Model 737-600,
-700, -700C, -800, and -900 series airplanes. AD 2005-05-18 requires
repetitive inspections for cracking of the webs of the aft pressure
bulkhead at a certain body station, and corrective action if necessary.
Since the FAA issued AD 2005-05-18, cracking was found in that
inspection area on airplanes not identified in the applicability of AD
2005-05-18. This proposed AD would retain the requirements of AD 2005-
05-18, revise the applicability to include additional airplanes, and
add an inspection for existing repairs on the newly added airplanes.
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 August 16,
2021.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the instructions for submitting comments.
<bullet> Fax: 202-493-2251.
<bullet> 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.
<bullet> Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 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 <a href="https://www.myboeingfleet.com">https://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="https://www.regulations.gov">https://www.regulations.gov</a>
by searching for and locating Docket No. FAA-2021-0503.
Examining the AD Docket
You may examine the AD docket at <a href="https://www.regulations.gov">https://www.regulations.gov</a> by
searching for and locating Docket No. FAA-2021-0503; 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: Wayne Lockett, Aerospace Engineer,
Airframe Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des
Moines, WA 98198; phone and fax: 206-231-3524; email:
<a href="/cdn-cgi/l/email-protection#1b6c7a62757e35777478707e6f6f5b7d7a7a357c746d"><span class="__cf_email__" data-cfemail="592e3820373c7735363a323c2d2d193f3838773e362f">[email protected]</span></a>.
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-2021-0503; Project Identifier
AD-2021-00163-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
<a href="https://www.regulations.gov">https://www.regulations.gov</a>, 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 Wayne
Lockett, Aerospace Engineer, Airframe Section, FAA, Seattle ACO Branch,
2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-
3524; email: <a href="/cdn-cgi/l/email-protection#f08791899e95de9c9f939b958484b0969191de979f86"><span class="__cf_email__" data-cfemail="5423352d3a317a383b373f312020143235357a333b22">[email protected]</span></a>. 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 issued AD 2005-05-18, Amendment 39-14007 (70 FR 12410,
March 14, 2005) (AD 2005-05-18), for certain The Boeing Company Model
737-600, -700, -700C, -800, and -900 series airplanes. AD 2005-05-18
was prompted by a report of cracks found, during fatigue testing, at
several of the fastener rows in the web lap splices at the dome apex of
the aft pressure bulkhead. AD 2005-05-18 requires repetitive detailed,
low frequency eddy current (LFEC), and high frequency eddy current
(HFEC) inspections for cracking of the webs of the aft pressure
bulkhead at body station (BS) 1016, and corrective action if necessary.
The FAA issued AD 2005-05-18 to detect and correct fatigue cracks in
the webs of the aft pressure bulkhead, which could result in rapid
decompression of the airplane.
Actions Since AD 2005-05-18 Was Issued
Since the FAA issued AD 2005-05-18, cracking has been found at apex
webs on airplanes outside the applicability of AD 2005-05-18, which
includes line numbers 1 through 1166 inclusive. Line numbers 1167
through 1755 inclusive, which are included in this proposed AD, use a
revised fastener pattern in the 0.032-inch webs that was intended to
correct the cracking addressed by AD 2005-05-18. During the assembly
process on line numbers 1167 through 1755, the fasteners in the apex
dome region are subjected to
[[Page 34661]]
fuselage pressurization fatigue cycles and clamp-up stresses. Cracks in
the inspection area of AD 2005-05-18 have now been found on airplanes
within the range of line numbers 1167 through 1755 inclusive. At one
location, the crack was linked from the first to the second fastener
row. This cracking was identified during an inspection for cracking of
the web lap splice of the aft pressure bulkhead, as required by AD
2017-10-22, Amendment 39-18896 (82 FR 23507, May 23, 2017) (AD 2017-10-
22). The inspections and intervals specified in AD 2017-10-22 are not
adequate to address the specific fatigue cracking occurring in the web
apex area that is the subject of this NPRM.
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 Service Bulletin 737-53A1251,
Revision 2, dated January 20, 2021. This service information specifies
procedures for a general visual inspection for existing repairs,
repetitive detailed and HFEC inspections for cracks around the web
fasteners, repetitive LFEC inspection for cracks around the hidden web
lap splice fastener locations, and repair of cracks. 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
Although this proposed AD does not explicitly restate the
requirements of AD 2005-05-18, this proposed AD would retain all of the
requirements of AD 2005-05-18. Those requirements are referenced in the
service information identified previously, which, in turn, is
referenced in paragraph (g) of this proposed AD. This proposed AD would
revise the applicability to include additional airplanes, and add an
inspection for existing repairs on those airplanes. This proposed AD
would also require accomplishment of the actions identified as ``RC''
(required for compliance) in the Accomplishment Instructions of Boeing
Alert Service Bulletin 737-53A1251, Revision 2, dated January 20, 2021,
described previously, 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 <a href="https://www.regulations.gov">https://www.regulations.gov</a> by searching for and
locating Docket No. FAA-2021-0503.
Differences Between This Proposed AD and the Service Information
For Group 1 airplanes, the Accomplishment Instructions of Boeing
Alert Service Bulletin 737-53A1251 Revision 2, dated January 20, 2021,
do not include any ``RC'' (required for compliance) steps. The RC
tagging was inadvertently removed from Boeing Alert Service Bulletin
737-53A1251 Revision 2, dated January 20, 2021. For Group 1 airplanes,
this proposed AD would therefore require treating Step 3.B.2. of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1251 Revision 2, dated January 20, 2021, as an RC step.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 744 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:
Estimated Costs
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Cost on U.S.
Action Labor cost Parts cost Cost per product operators
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Detailed, HFEC, and LFEC Up to 10 work-hours x $0 Up to $850 per Up to $632,400 per
inspections. $85 per hour = Up to inspection cycle. inspection cycle.
$850 per inspection
cycle.
General visual inspection (194 1 work-hour x $85 per 0 $85............... $16,490.
airplanes). hour = $85.
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The FAA estimates the following costs to do any necessary repairs
that would be required based on the results of the proposed
inspections. The FAA has no way of determining the number of aircraft
that might need these repairs:
On-Condition Costs
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Action Labor cost Parts cost Cost per product
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Repair.................... Up to 30 * work-hours Up to $30,000 *............... Up to $32,550 *
x $85 per hour = Up
to $2,550.
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* Repair costs will vary depending on size of the repair required.
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
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(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) 2005-05-18, Amendment 39-14007
(70 FR 12410, March 14, 2005), and
0
b. Adding the following new AD:
The Boeing Company: Docket No. FAA-2021-0503; Project Identifier AD-
2021-00163-T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) action by August 16, 2021.
(b) Affected ADs
This AD replaces AD 2005-05-18, Amendment 39-14007 (70 FR 12410,
March 14, 2005) (AD 2005-05-18).
(c) Applicability
This AD applies to The Boeing Company Model 737-600, -700, -
700C, -800, and -900 series airplanes, certificated in any category;
as identified in Boeing Alert Service Bulletin 737-53A1251 Revision
2, dated January 20, 2021.
(d) Subject
Air Transport Association (ATA) of America Code 53, Fuselage.
(e) Unsafe Condition
This AD was prompted by a report of cracks found at several of
the fastener rows in the web lap splices at the dome apex of the aft
pressure bulkhead, and the determination that airplanes not affected
by AD 2005-05-18 are subject to this unsafe condition. The FAA is
issuing this AD to address fatigue cracks in the webs of the aft
pressure bulkhead, which could result in rapid decompression of the
airplane.
(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 paragraph 1.E., ``Compliance,'' of
Boeing Alert Service Bulletin 737-53A1251 Revision 2, dated January
20, 2021, do all applicable actions identified as ``RC'' (required
for compliance) in, and in accordance with, the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1251 Revision
2, dated January 20, 2021. For Group 1 airplanes, as defined in
Boeing Alert Service Bulletin 737-53A1251 Revision 2, dated January
20, 2021: Step 3.B.2. of the Accomplishment Instructions of Boeing
Alert Service Bulletin 737-53A1251 Revision 2, dated January 20,
2021, is an RC step, and the provisions of paragraphs (j)(5)(i) and
(ii) of this AD apply.
(h) Exceptions to Service Information Specifications
(1) Where Boeing Alert Service Bulletin 737-53A1251 Revision 2,
dated January 20, 2021, uses the phrase ``the Revision 1 date of
this service bulletin,'' this AD requires using ``the effective date
of this AD.''
(2) Where Boeing Alert Service Bulletin 737-53A1251, Revision 2,
dated January 20, 2021, specifies contacting Boeing for repair
instructions or for alternative inspections: This AD requires doing
the repair, or doing the alternative inspections and applicable on-
condition actions using a method approved in accordance with the
procedures specified in paragraph (j) of this AD.
(i) Credit for Previous Actions
(1) For airplanes having line numbers 1 through 1166 inclusive:
This paragraph provides credit for the corresponding actions of
Boeing Alert Service Bulletin 737-53A1251 Revision 2, dated January
20, 2021, that are required by paragraph (g) of this AD, if those
actions were performed before the effective date of this AD using
Boeing Service Bulletin 737-53-1251, dated June 3, 2004, which was
incorporated by reference in AD 2005-05-18.
(2) This paragraph provides credit for the corresponding actions
of Boeing Alert Service Bulletin 737-53A1251 Revision 2, dated
January 20, 2021, that are required by paragraph (g) of this AD, if
those actions were performed before the effective date of this AD
using Boeing Alert Service Bulletin 737-53-1251, Revision 1, dated
September 22, 2020, which is not incorporated by reference in this
AD.
(j) 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 Related Information. Information may be emailed to: <a href="/cdn-cgi/l/email-protection#50697d111e1d7d03353124243c357d11131f7d111d1f137d0235212535232423103631317e373f26"><span class="__cf_email__" data-cfemail="576e7a16191a7a04323623233b327a1614187a161a18147a05322622322423241731363679303821">[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.
(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.
(4) AMOCs approved for AD 2005-05-18 are approved as AMOCs for
the corresponding provisions of Boeing Alert Service Bulletin 737-
53A1251 Revision 2, dated January 20, 2021, that are required by
paragraph (g) of this AD.
(5) Except as specified by paragraph (h) of this AD: For service
information that contains steps that are labeled as Required for
Compliance (RC), the provisions of paragraphs (j)(5)(i) and (ii) of
this AD apply.
(i) The steps labeled as RC, including substeps under an RC step
and any figures identified in an RC step, must be done to comply
with the AD. If a step or substep is labeled ``RC Exempt,'' then the
RC requirement is removed from that step or substep. An AMOC is
required for any deviations to RC steps, including substeps and
identified figures.
(ii) Steps not labeled as RC may be deviated from using accepted
methods in accordance with the operator's maintenance or inspection
program without obtaining approval of an AMOC, provided the RC
steps, including substeps and identified figures, can still be done
as specified, and the airplane can be put back in an airworthy
condition.
(k) Related Information
(1) For more information about this AD, contact Wayne Lockett,
Aerospace Engineer, Airframe Section, FAA, Seattle ACO Branch, 2200
South 216th St., Des Moines, WA 98198; phone and fax: 206-231-3524;
email: <a href="/cdn-cgi/l/email-protection#5e293f27303b7032313d353b2a2a1e383f3f70393128"><span class="__cf_email__" data-cfemail="215640584f440f4d4e424a445555614740400f464e57">[email protected]</span></a>.
(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 <a href="https://www.myboeingfleet.com">https://www.myboeingfleet.com</a>. 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 June 11, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification
Service.
[FR Doc. 2021-13930 Filed 6-29-21; 8:45 am]
BILLING CODE 4910-13-P
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