83 FR 46380 - Airworthiness Directives; The Boeing Company Airplanes

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

Federal Register Volume 83, Issue 178 (September 13, 2018)

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD was prompted by reports of cracking in certain flanges, and the adjacent web, of the wing outboard flap track at certain positions, and a determination that new inspections of certain flap track flanges and webs forward of the rear spar attachment are necessary. This AD requires an inspection to determine the part number of the wing outboard flap track assembly; repetitive inspections of each affected wing outboard flap track for discrepancies, and applicable on-condition actions; and repetitive overhaul of each wing outboard flap track. We are issuing this AD to address the unsafe condition on these products.

[Federal Register Volume 83, Number 178 (Thursday, September 13, 2018)]
[Rules and Regulations]
[Pages 46380-46384]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2018-19185]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0112; Product Identifier 2017-NM-161-AD; Amendment 
39-19392; AD 2018-18-13]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for all The 
Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes. This AD was prompted by reports of cracking in certain 
flanges, and the adjacent web, of the wing outboard flap track at 
certain positions, and a determination that new inspections of certain 
flap track flanges and webs forward of the rear spar attachment are 
necessary. This AD requires an inspection to determine the part number 
of the wing outboard flap track assembly; repetitive inspections of 
each affected wing outboard flap track for discrepancies, and 
applicable on-condition actions; and repetitive overhaul of each wing 
outboard flap track. We are issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective October 18, 2018.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of October 18, 
2018.

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 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. It is also available on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2018-
0112.

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-
0112; 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, the regulatory evaluation, any comments received, and 
other information. The address for Docket Operations (phone: 800-647-
5527) is Docket Operations, 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: Payman Soltani, Aerospace Engineer, 
Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5313; fax: 562-627-
5210; email: [email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to all The Boeing Company 
Model

[[Page 46381]]

737-100, -200, -200C, -300, -400, and -500 series airplanes. The NPRM 
published in the Federal Register on February 21, 2018 (83 FR 7425). 
The NPRM was prompted by reports of cracking in certain flanges, and 
the adjacent web, of the wing outboard flap track at certain positions, 
and a determination that new inspections of certain flap track flanges 
and webs forward of the rear spar attachment are necessary. The NPRM 
proposed to require an inspection to determine the part number of the 
wing outboard flap track assembly; repetitive inspections of each 
affected wing outboard flap track for discrepancies, and applicable on-
condition actions; and repetitive overhaul of each wing outboard flap 
track.
    We are issuing this AD to detect and correct cracking of the wing 
outboard flap tracks. Cracking in the area between the forward and rear 
spar attachments of the wing outboard flap tracks could lead to the 
inability of a principal structural element to sustain required flight 
loads, and result in loss of the outboard trailing edge flap and 
consequent reduced controllability of the airplane.

Comments

    We gave the public the opportunity to participate in developing 
this final rule. The following presents the comments received on the 
NPRM and the FAA's response to each comment.

Request To Extend the Compliance Time

    All Nippon Airways (ANA) and Utair Aviation requested that 
paragraph (h) of the proposed AD be revised to extend the compliance 
time from 6 months to 18 months after the effective date of the final 
rule. The commenters are concerned that there are not enough spare flap 
track parts available. The commenters indicated that overhaul of the 
removed flap tracks takes significant time, and if the final rule is 
released without a sufficient number of spare flap tracks available, 
there could be a long-term aircraft on ground (AOG) situation if the 
proposed compliance times are used.
    Furthermore, Utair Aviation stated that a review of maintenance 
records on 38 airplanes for flap tracks at positions 1 and 8 did not 
find any records of inspections or overhaul, and it would not be able 
to replace the subject flap tracks within the compliance time specified 
in the proposed AD. Utair Aviation also noted that it took 60 days, 
including shipping, to replace the outboard flap tracks for similar 
requirements specified in AD 2013-09-02, Amendment 39-17443 (78 FR 
27010, May 9, 2013).
    We do not agree with the commenters' requests. The 6-month 
compliance time for inspection and overhaul is applicable only to flap 
tracks that have unknown maintenance records and flap tracks that were 
last overhauled several years ago. Airplanes with flap tracks that have 
known maintenance records generally have later compliance times, 
depending on how long it has been since the flap tracks were 
overhauled. The NPRM was issued to address findings of stress corrosion 
cracking in the flap tracks. Stress corrosion cracking is more likely 
to occur in flap tracks that have been in operation for a longer time. 
Flap tracks with unknown maintenance records and flap tracks that were 
last overhauled several years ago are more susceptible to the unsafe 
condition. The probability of the existence of stress corrosion 
cracking on flap tracks with unknown maintenance history is higher and 
warrants the shorter compliance time. We have verified that spare flap 
tracks are available on the parts surplus market; however, since we do 
not know how many flap tracks have unknown maintenance records, it is 
difficult to estimate how many spare flap tracks will be necessary to 
meet the demand. If there is a critical shortage of parts, operators 
may contact the FAA and request an adjustment to the compliance time 
using the procedures specified in paragraph (l) of this AD. We might 
approve a longer compliance time if additional data are presented that 
would justify an extension to the compliance time while still 
maintaining an adequate level of safety.
    We urge operators to seek out maintenance records for their flap 
tracks in order to justify use of the extended compliance times 
specified in Boeing Alert Requirements Bulletin 737-57A1338 RB, dated 
September 25, 2017. We cannot justify extending the compliance times 
for flap tracks without maintenance records to 18 months. We have not 
changed this AD in regard to this issue.

Request To Omit Inspection 1 in the Service Information

    Utair Aviation stated that it is inadvisable to require operators 
to do the inspections included in ``INSPECTION 1,'' as defined in 
Boeing Alert Requirements Bulletin 737-57A1338 RB, dated September 25, 
2017. The commenter noted that ``ACTION 1'' in Table 1 and Table 2 of 
paragraph 3, ``Compliance,'' of Boeing Alert Requirements Bulletin 737-
57A1338 RB, dated September 25, 2017, states that operators need to do 
INSPECTION 1. The commenter suggested that ``ACTION 2,'' overhaul of 
each affected flap track, would already include all of the inspections 
included in INSPECTION 1.
    We infer that the commenter is requesting that the proposed 
requirement to do the inspections included in INSPECTION 1 of the 
specified service bulletin be removed from the proposed AD. We do not 
agree with the commenter's request. ACTION 1 and ACTION 2 have 
different purposes. The inspections included in ACTION 1 are intended 
to detect specific existing damage on the flap track, including cracks, 
nicks, corrosion, galling, broken pieces, and stop drills. The 
intention of ACTION 2, overhaul of each affected flap track, is a 
visual examination for defects. The intent of this visual examination 
during overhaul is to identify additional discrepancies, such as 
excessive wear or degraded surface finish, that might not be noted 
during INSPECTION 1. It is important to detect these additional 
discrepancies since they can be early indicators of stress corrosion 
cracking. Since the inspections to detect specific existing damage on 
the flap track are not included in the overhaul instructions, it is 
necessary to require both ACTION 1 and ACTION 2 in this AD. We have not 
changed this AD in regard to this issue.

Request for Alternative To Overhaul

    ANA requested that an alternative to overhaul of the flap tracks be 
provided that does not involve removing the flap tracks from the wing. 
The commenter suggested that an on-wing inspection could be used 
instead of the overhaul. The commenter is concerned that there is not a 
sufficient supply of spare flap track parts.
    We do not agree with the commenter's request. There is no on-wing 
inspection method available that can detect the additional 
discrepancies that overhaul of the flap tracks is designed to address. 
The concern regarding availability of spare flap track parts was 
addressed in the response to an earlier comment. We have not changed 
this AD in regard to this issue.

Request To Revise Parts Installation Limitation Paragraph

    Boeing requested that the Parts Installation Limitation Paragraph, 
paragraph (k) in the proposed AD, be revised to allow flap tracks to be 
installed and inspected at the time of installation. Boeing noted that 
paragraph (k) states ``. . . no person may install a flap track unless 
the flap track is inspected prior to installation.'' Boeing pointed out 
that there are several

[[Page 46382]]

inspections that pertain to the track-to-wing joint, which cannot be 
accomplished until after the flap track is installed.
    We agree with the commenter's request for the reasons provided by 
the commenter. We have revised paragraph (k) of this AD to state ``As 
of the effective date of this AD, no person may install, on any 
airplane, a wing outboard flap track having a part number listed in 
paragraph 1.B. of Boeing Alert Requirements Bulletin 737-57A1338 RB, 
dated September 25, 2017, unless the inspections . . . are accomplished 
prior to or concurrently with the part's installation on the 
airplane.''

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that accomplishing the installation 
of winglets using Supplemental Type Certificate (STC) ST01219SE does 
not affect compliance with the actions proposed in the NPRM.
    We concur with the commenter. We have redesignated paragraph (c) of 
the proposed AD as paragraph (c)(1) of this AD and added paragraph 
(c)(2) to this AD to state that installation of STC ST01219SE does not 
affect the ability to accomplish the actions required by this AD. 
Therefore, for airplanes on which STC ST01219SE is installed, a 
``change in product'' alternative method of compliance (AMOC) approval 
request is not necessary to comply with the requirements of 14 CFR 
39.17.

Additional Change to This AD

    The proposed AD included Note 1 to paragraph (h), which stated that 
guidance for accomplishing the proposed actions could be found in 
Boeing Alert Service Bulletin 737-57A1338, dated September 25, 2017, 
which is referred to in Boeing Alert Requirements Bulletin 737-57A1338 
RB, dated September 25, 2017. Since the proposed AD was published, 
Boeing has issued Boeing Information Notice 737-57A1338 IN 01, dated 
October 16, 2017; Boeing Information Notice 737-57A1338 IN 02, dated 
March 16, 2018; and Boeing Information Notice 737-57A1338 IN 03, dated 
March 20, 2018. These information notices provide additional guidance 
material related to Boeing Alert Service Bulletin 737-57A1338, dated 
September 25, 2017, including clarification of compliance times for 
spares (not AD compliance times), inspection figures, and the 
relationship between flap track part numbers and airplanes groups. We 
have revised Note 1 to paragraph (h) in this AD to include these 
information notices.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
this final rule with the changes described previously and minor 
editorial changes. We have determined that these minor changes:
     Are consistent with the intent that was proposed in the 
NPRM for addressing the unsafe condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this final 
rule.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Requirements Bulletin 737-57A1338 RB, 
dated September 25, 2017. This service information describes procedures 
for repetitive inspections and repetitive overhaul of the wing outboard 
flap tracks, and applicable on-condition actions including repair and 
replacement of the wing outboard flap tracks. 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.

Costs of Compliance

    We estimate that this AD affects 160 airplanes of U.S. registry. We 
estimate the following costs to comply with this AD:

                                                          Estimated Costs for Required Actions
--------------------------------------------------------------------------------------------------------------------------------------------------------
               Action                      Labor cost          Parts cost             Cost per product                   Cost on U.S. operators
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection (positions 1 and 8;       78 work-hours x $85                 $0  $6,630 per cycle.................  $1,060,800 per cycle.
 Group 2 and Group 3, configuration   per hour = $6,630 per
 1).                                  cycle.
Inspection (positions 1 and 8;       89 work-hours x $85                  0  7,565 per cycle..................  1,210,400 per cycle.
 Group 3, configuration 2).           per hour = $7,565 per
                                      cycle.
Inspection (positions 2 and 7;       83 work-hours x $85                  0  7,055 per cycle..................  1,128,800 per cycle.
 Group 2 and Group 3, configuration   per hour = $7,055 per
 1).                                  cycle.
Inspection (positions 2 and 7;       86 work-hours x $85                  0  7,310 per cycle..................  1,169,600 per cycle.
 Group 3, configuration 2).           per hour = $7,310 per
                                      cycle.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We have received no definitive data that will enable us to provide 
cost estimates for the actions for Group 1 airplanes, the repetitive 
overhaul, or the on-condition actions specified in this 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 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 and 
associated appliances to

[[Page 46383]]

the Director of the System Oversight Division.

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) Is not a ``significant rule'' under 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.

Adoption of 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 (AD):

2018-18-13 The Boeing Company: Amendment 39-19392; Docket No. FAA-
2018-0112; Product Identifier 2017-NM-161-AD.

 (a) Effective Date

    This AD is effective October 18, 2018.

 (b) Affected ADs

    This AD affects AD 2013-09-02, Amendment 39-17443 (78 FR 27010, 
May 9, 2013) (``AD 2013-09-02'').

 (c) Applicability

    (1) This AD applies to all The Boeing Company Model 737-100, -
200, -200C, -300, -400, and -500 series airplanes, certificated in 
any category.
    (2) Installation of Supplemental Type Certificate (STC) 
ST01219SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/
rgstc.nsf/0/ebd1cec7b301293e86257cb30045557a/$FILE/ST01219SE.pdf) 
does not affect the ability to accomplish the actions required by 
this AD. Therefore, for airplanes on which STC ST01219SE is 
installed, a ``change in product'' alternative method of compliance 
(AMOC) approval request is not necessary to comply with the 
requirements of 14 CFR 39.17.

 (d) Subject

    Air Transport Association (ATA) of America Code 57, Wings.

(e) Unsafe Condition

    This AD was prompted by reports of cracking in certain flanges, 
and the adjacent web, of the wing outboard flap track at certain 
positions, and a determination that new inspections of certain flap 
track flanges and webs forward of the rear spar attachment are 
necessary. We are issuing this AD to detect and correct cracking of 
the wing outboard flap tracks. Cracking in the area between the 
forward and rear spar attachments of the wing outboard flap tracks 
could lead to the inability of a principal structural element to 
sustain required flight loads, and result in loss of the outboard 
trailing edge flap and consequent reduced controllability of the 
airplane.

(f) Compliance

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

(g) Required Actions for Group 1 Airplanes

    For airplanes identified as Group 1 in Boeing Alert Requirements 
Bulletin 737-57A1338 RB, dated September 25, 2017: Within 120 days 
after the effective date of this AD, do actions to correct the 
unsafe condition using a method approved in accordance with the 
procedures specified in paragraph (l) of this AD.

(h) Required Actions

    For airplanes not specified in paragraph (g) of this AD: Except 
as required by paragraph (i) of this AD, at the applicable times 
specified in the ``Compliance'' paragraph of Boeing Alert 
Requirements Bulletin 737-57A1338 RB, dated September 25, 2017, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-57A1338 RB, dated September 25, 2017.

    Note 1 to paragraph (h) of this AD: Guidance for accomplishing 
the actions required by this AD can be found in Boeing Alert Service 
Bulletin 737-57A1338, dated September 25, 2017, which is referred to 
in Boeing Alert Requirements Bulletin 737-57A1338 RB, dated 
September 25, 2017. Additional guidance can be found in Boeing 
Information Notice 737-57A1338 IN 01, dated October 16, 2017; Boeing 
Information Notice 737-57A1338 IN 02, dated March 16, 2018; and 
Boeing Information Notice 737-57A1338 IN 03, dated March 20, 2018.

(i) Exceptions to Service Information Specifications

    For purposes of determining compliance with the requirements of 
this AD: Where Boeing Alert Requirements Bulletin 737-57A1338 RB, 
dated September 25, 2017, uses the phrase ``the original issue date 
of Requirements Bulletin 737-57A1338 RB,'' this AD requires using 
``the effective date of this AD.''

(j) Terminating Action for Requirements of AD 2013-09-02

    Accomplishment of the requirements specified in paragraph (h) of 
this AD terminates all requirements of AD 2013-09-02.

(k) Parts Installation Limitation

    As of the effective date of this AD, no person may install, on 
any airplane, a wing outboard flap track having a part number listed 
in paragraph 1.B. of Boeing Alert Requirements Bulletin 737-57A1338 
RB, dated September 25, 2017, unless the inspections and corrective 
actions specified in the Accomplishment Instructions of Boeing Alert 
Requirements Bulletin 737-57A1338 RB, dated September 25, 2017, are 
accomplished prior to or concurrently with the part's installation 
on the airplane.

(l) 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 (m)(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.

(m) Related Information

    (1) For more information about this AD, contact Payman Soltani, 
Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 
3960 Paramount Boulevard, Lakewood, CA 90712 4137; phone: 562-627-
5313; fax: 562-627-5210; email: [email protected].
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (n)(3) and (n)(4) of this AD.

(n) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this

[[Page 46384]]

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 737-57A1338 RB, dated 
September 25, 2017.
    (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 https://www.myboeingfleet.com.
    (4) 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.
    (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, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Des Moines, Washington, on August 24, 2018.
James Cashdollar,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2018-19185 Filed 9-12-18; 8:45 am]
 BILLING CODE 4910-13-P