[Federal Register Volume 83, Number 94 (Tuesday, May 15, 2018)]
[Proposed Rules]
[Pages 22422-22426]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-10299]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0412; Product Identifier 2017-NM-180-AD]
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: We propose to supersede Airworthiness Directive (AD) 2010-25-
06, which applies to certain The Boeing Company Model 737-200, -300, -
400, and -500 series airplanes. AD 2010-25-06 requires repetitive 
inspections for cracking of certain fuselage frames and stub beams, and 
corrective actions if necessary. AD 2010-25-06 also provides for an 
optional repair, which terminates the repetitive inspections. For 
airplanes on which a certain repair is done, AD 2010-25-06 also 
requires repetitive inspections for cracking of certain fuselage frames 
and stub beams,

[[Page 22423]]

and corrective actions if necessary. Since we issued AD 2010-25-06, 
additional cracking was found in areas not covered by the inspections. 
This proposed AD would retain the actions required by AD 2010-25-06 and 
would expand the inspection area. We are proposing this AD to address 
the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by June 29, 2018.

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 http://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 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 service information at the FAA, Transport Standards 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 on the internet at http://www.regulations.gov by searching 
for and locating Docket No. FAA-2018-0412.

Examining the AD Docket

    You may examine the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2018-
0412; 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, the regulatory evaluation, any comments received, and other 
information. The street address for Docket Operations (phone: 800-647-
5527) is in the ADDRESSES section. Comments will be available in the AD 
docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Galib Abumeri, Aerospace Engineer, 
Airframe Section, Los Angeles ACO Branch, FAA, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5324; fax: 562-627-
5210; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2018-0412; 
Product Identifier 2017-NM-180-AD'' at the beginning of your comments. 
We specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of this NPRM. We will consider all 
comments received by the closing date and may amend this NPRM because 
of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    We issued AD 2010-25-06, Amendment 39-16539 (75 FR 81409, December 
28, 2010) (``AD 2010-25-06''), for certain Model 737-200, -300, -400, 
and -500 series airplanes. AD 2010-25-06 requires repetitive 
inspections for cracking of certain fuselage frames and stub beams, and 
corrective actions if necessary. AD 2010-25-06 also provides for an 
optional repair, which terminates the repetitive inspections. For 
airplanes on which a certain repair is done, AD 2010-25-06 also 
requires repetitive inspections for cracking of certain fuselage frames 
and stub beams, and corrective actions if necessary. AD 2010-25-06 
resulted from reports of the detection of fatigue cracks at certain 
frame sections, in addition to stub beam cracking, caused by high 
flight cycle stresses from both pressurization and maneuver loads. We 
issued AD 2010-25-06 to detect and correct fatigue cracking of certain 
fuselage frames and stub beams and possible severed frames, which could 
result in reduced structural integrity of the frames. This reduced 
structural integrity can increase loading in the fuselage skin, which 
will accelerate skin crack growth and could result in rapid 
decompression of the fuselage.

Actions Since AD 2010-25-06 Was Issued

    Since we issued AD 2010-25-06, additional cracking was found in 
areas not covered by the inspections. During an inspection of the body 
station (BS) 616 stub beam upper chord, an operator identified 
additional cracking at buttock line (BL) 64. We determined that eddy 
current inspections of the upper chord at BL 64 and BL 65 must be done 
to maintain structural integrity. In addition, during inspections of 
the longitudinal floor beam web at the BS 639 stub beams operators 
found cracking in the floor beam web. It was determined that the 
inspections required by AD 2010-25-06 were inadequate, and eddy current 
inspections of the BL 45.5 floor beam web at the BS 639 stub beam 
interface must be done to address this cracking.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-53A1254, Revision 3, 
dated November 13, 2017. The service information describes procedures 
for detailed and eddy current inspections of the fuselage frame and 
over wing stub beam at BS 616, BS 639, and BS 597 or BS 601, and BL 
45.5 floor beam web at the BS 639 stub beam attachment, and relative 
investigative and corrective actions. 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.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This proposed AD would retain all requirements of AD 2010-25-06. 
This proposed AD does not explicitly restate the requirements of AD 
2010-25-06. Those requirements are referenced in the service 
information identified previously, which, in turn, is referenced in 
this proposed AD, except for any differences identified as exceptions 
in the regulatory text of this proposed AD. This proposed AD would add 
new repetitive inspections for cracking of certain other fuselage 
frames and stub beams. For information on the procedures and compliance 
times, see this service information at http://www.regulations.gov by 
searching for and locating Docket No. FAA-2018-0412.
    Boeing Alert Service Bulletin 737-53A1254, Revision 3, dated 
November 13, 2017, provides two economic inspections to find cracking 
prior to frame damage, which could require extensive repairs. These 
inspections are recommended but are not mandated in this proposed AD.

[[Page 22424]]

    The phrase ``corrective actions'' is used in this proposed AD. 
Corrective actions correct or address any condition found. Corrective 
actions in an AD could include, for example, repairs.

Costs of Compliance

    We estimate that this proposed AD affects 67 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

                                      Estimated Costs for Required Actions
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                                                                                                 Cost on U.S.
             Action                    Labor cost         Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Inspections.....................  Up to 67                         $0   Up to $5,695 per     Up to $381,565 per
                                   work[dash]hours x                     inspection cycle.    inspection cycle.
                                   $85 per hour =
                                   $5,695.
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    We estimate the following costs to do certain necessary repairs/
replacements that would be required based on the results of the 
proposed inspections. We have no way of determining the number of 
aircraft that might need these repairs/replacements:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
               Action **                       Labor cost            Parts cost           Cost per product
----------------------------------------------------------------------------------------------------------------
Repairs/replacements..................  Up to 76 work[dash]hours               *   Up to $6,460.
                                         x $85 per hour = $6,460.
----------------------------------------------------------------------------------------------------------------
* All required parts are supplied by the operator. This cost is minimal, and we have no way to determine what an
  operator would pay for these parts.
** We have received no definitive data that would enable us to provide cost estimates for certain other repairs
  specified in 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.
    We are 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.
    This proposed AD is issued in accordance with authority delegated 
by the Executive Director, Aircraft Certification Service, as 
authorized by FAA Order 8000.51C. In accordance with that order, 
issuance of ADs is normally a function of the Compliance and 
Airworthiness Division, but during this transition period, the 
Executive Director has delegated the authority to issue ADs applicable 
to transport category airplanes to the Director of the System Oversight 
Division.

Regulatory Findings

    We have 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) Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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 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 removing Airworthiness Directive (AD) 
2010-25-06, Amendment 39-16539 (75 FR 81409, December 28, 2010), and 
adding the following new AD:

The Boeing Company: Docket No. FAA-2018-0412; Product Identifier 
2017-NM-180-AD.

(a) Comments Due Date

    The FAA must receive comments on this AD action by June 29, 
2018.

(b) Affected ADs

    This AD replaces AD 2010-25-06, Amendment 39-16539 (75 FR 81409, 
December 28, 2010) (``AD 2010-25-06'').

(c) Applicability

    This AD applies to The Boeing Company Model 737-200, -300, -400, 
and -500 series airplanes, certificated in any category, as 
identified in Boeing Alert Service Bulletin 737-53A1254, Revision 3, 
dated November 13, 2017.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by the detection of fatigue cracks at 
certain frame sections, in addition to stub beam cracking, caused by 
high flight cycle stresses from both pressurization and maneuver 
loads and additional cracking found in areas not covered by the 
inspections in AD 2010-25-06. We are issuing this AD to address 
fatigue cracking of certain fuselage frames and stub beams and 
possible severed frames, which could result in reduced structural 
integrity of the frames. This reduced structural integrity can 
increase loading in the fuselage skin, which will accelerate skin 
crack growth and

[[Page 22425]]

could result in rapid decompression of the fuselage.

(f) Compliance

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

(g) Repetitive Inspections of Body Stations 616 and 639 Frames and Stub 
Beams and Corrective Actions

    At the applicable time specified table 1 of paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1254, 
Revision 3, dated November 13, 2017: Do a detailed or high frequency 
eddy current (HFEC) inspection for cracking of the body station (BS) 
616 and 639 frames and stub beams and do all applicable related 
investigative and corrective actions, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1254, Revision 3, dated November 13, 2017, except as required by 
paragraph (m)(1) of this AD. Do all applicable related investigative 
and corrective actions before further flight. Thereafter, repeat the 
inspection at the applicable time specified in table 1 of paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1254, 
Revision 3, dated November 13, 2017.

(h) Repetitive Post-Repair Inspections of Body Stations 616 and 639 
Frames and Integral Stub Beams and Corrective Actions

    At the applicable time specified table 2 of paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1254, 
Revision 3, dated November 13, 2017: Do the inspections required by 
paragraphs (h)(1) and (h)(2) of this AD; or the inspection required 
by paragraph (h)(3) of this AD; as applicable, in accordance with 
the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-53A1254, Revision 3, dated November 13, 2017, except as required 
by paragraph (m)(1) of this AD. Do all applicable related 
investigative and corrective actions before further flight. 
Thereafter, repeat the inspection at the applicable time specified 
in table 2 of paragraph 1.E., ``Compliance,'' of Boeing Alert 
Service Bulletin 737-53A1254, Revision 3, dated November 13, 2017.
    (1) Do a low frequency eddy current (LFEC) inspection of the 
web, and an HFEC inspection of the inner and outer chord common to 
the upper end fastener rows of the web splice doubler for cracking.
    (2) Do the inspection specified in paragraph (h)(2)(i) or 
(h)(2)(ii) of this AD.
    (i) Do a detailed inspection of the replacement frame section 
for cracking.
    (ii) Do an HFEC and LFEC inspection of the replacement frame 
section for cracking.
    (3) Do a detailed or HFEC inspection of the replacement stub 
beam for cracking.

(i) Repetitive Inspections of Buttock Line 45.5 Longitudinal Floor Beam 
Web at Body Station 639 Stub Beam Attachment and Corrective Actions

    For Group 1 and Group 2 airplanes as identified in Boeing Alert 
Service Bulletin 737-53A1254, Revision 3, dated November 13, 2017, 
at the time specified table 3 or table 4, as applicable, of 
paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin 
737-53A1254, Revision 3, dated November 13, 2017, except as required 
by paragraph (m)(2) of this AD: Do the inspections required by 
paragraph (i)(1) and (i)(2) of this AD and all applicable corrective 
actions, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1254, Revision 3, dated 
November 13, 2017, except as required by paragraph (m)(1) of this 
AD. Do all applicable corrective actions before further flight. 
Thereafter, repeat the inspections at the time specified in table 3 
or table 4, as applicable, of paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin 737-53A1254, Revision 3, dated 
November 13, 2017.
    (1) Do an open-hole HFEC inspection for cracking of the buttock 
line (BL) 45.5 longitudinal floor beam web at each fastener hole 
common to the stub beam attachment angle.
    (2) Do an HFEC surface inspection for cracking of the BL 45.5 
longitudinal floor beam web around the fastener head/tail at each 
fastener location common to the backup strap.

(j) Repetitive Post-Repair Inspections of Buttock Line 45.5 
Longitudinal Floor Beam Web at Body Station 639 and Corrective Actions

    For Group 2 airplanes as identified in Boeing Alert Service 
Bulletin 737-53A1254, Revision 3, dated November 13, 2017, at the 
applicable time specified table 5 of paragraph 1.E., ``Compliance,'' 
of Boeing Alert Service Bulletin 737-53A1254, Revision 3, dated 
November 13, 2017, except as required by paragraph (m)(2) of this 
AD: Do the inspections required by paragraphs (j)(1) and (j)(2) of 
this AD and all applicable corrective actions, in accordance with 
the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-53A1254, Revision 3, dated November 13, 2017, except as required 
by paragraph (m)(1) of this AD. Do all applicable corrective actions 
before further flight. Thereafter, repeat the inspections at the 
applicable time specified in table 5 of paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1254, 
Revision 3, dated November 13, 2017.
    (1) Do an open-hole HFEC inspection for cracking of the BL 45.5 
longitudinal floor beam web filler at each fastener hole common to 
the stub beam attachment angle.
    (2) Do an HFEC surface inspection for cracking of the BL 45.5 
longitudinal floor beam web filler around the fastener head/tail at 
each fastener location common to the backup strap.

(k) Repetitive Inspections for Cracking of BS 616 Machined Stub Beam 
Upper Chord and Corrective Actions

    For Group 2 and Group 3 airplanes as identified in Boeing Alert 
Service Bulletin 737-53A1254, Revision 3, dated November 13, 2017, 
at the applicable time specified in table 9 of paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1254, 
Revision 3, dated November 13, 2017, except as required by paragraph 
(m)(2) of this AD; do detailed and medium frequency eddy current 
subsurface inspections for cracking of the BS 616 machined stub beam 
upper chord, and all applicable corrective actions, except as 
required by paragraph (m)(1) of this AD. Do all applicable 
corrective actions before further flight. Thereafter, repeat the 
inspections at the applicable time specified in table 9 of paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1254, 
Revision 3, dated November 13, 2017.

(l) Credit for Previous Actions

    (1) This paragraph provides credit for actions 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-
53A1254, Revision 1, dated July 9, 2009; or Boeing Alert Service 
Bulletin 737-53A1254, Revision 2, dated February 22, 2012.
    (2) This paragraph provides credit for actions required by 
paragraph (h) of this AD, if those actions were performed before the 
effective date of this AD, using Boeing Alert Service Bulletin 737-
53A1254, Revision 2, dated February 22, 2012.

(m) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Service Bulletin 737-53A1254, Revision 3, 
dated November 13, 2017, specifies to contact Boeing for repair 
instructions: Before further flight, do the repair using a method 
approved in accordance with the procedures specified in paragraph 
(n) of this AD.
    (2) Where Paragraph 1.E., ``Compliance,'' of Boeing Alert 
Service Bulletin 737-53A1254, Revision 3, dated November 13, 2017, 
specifies a compliance time ``after the Revision 3 date of this 
service bulletin,'' this AD requires compliance within the specified 
compliance time after the effective date of this AD.

(n) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles 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 local Flight Standards 
District 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 (o)(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 local flight standards district office/certificate holding 
district 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 Commercial Airplanes Organization 
Designation Authorization (ODA) that has been authorized by the 
Manager, Los Angeles ACO Branch, 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.

[[Page 22426]]

    (4) AMOCs approved previously for AD 2010-25-06 are approved as 
AMOCs for the corresponding provisions of Boeing Alert Service 
Bulletin 737-53A1254, Revision 3, dated November 13, 2017, that are 
required by paragraphs (g) and (h) of this AD.

(o) Related Information

    (1) For information about this AD, contact Galib Abumeri, 
Aerospace Engineer, Airframe Section, Los Angeles ACO Branch, FAA, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5324; fax: 562-627-5210; 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, Transport Standards Branch, 2200 South 216th 
St., Des Moines, WA. For information on the availability of this 
material at the FAA, call 206-231-3195.


    Issued in Des Moines, Washington, on May 8, 2018.
Jeffrey E. Duven,
Director, System Oversight Division, Aircraft Certification Service.
[FR Doc. 2018-10299 Filed 5-14-18; 8:45 am]
 BILLING CODE 4910-13-P


