Document ID: FAA-2019-0406-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: The Boeing Company Airplanes, 2019-NM-059-AD
Posted Date: 2019-06-21T04:00Z

[Federal Register Volume 84, Number 120 (Friday, June 21, 2019)]
[Proposed Rules]
[Pages 29105-29108]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-13057]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0406; Product Identifier 2019-NM-059-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: The FAA proposes to adopt a new airworthiness directive (AD) 
for all The Boeing Company Model MD-90-30 airplanes. This proposed AD 
was prompted by reports indicating that certain center wing stringers 
and skins have been identified to potentially be susceptible to 
cracking. This proposed AD would require repetitive eddy current, low 
frequency (ETLF) inspections of the left and right side fastener holes 
for any crack; repetitive eddy current, high frequency (ETHF) 
inspections of the lower skin for any crack; and repair if any crack is 
found. 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 5, 
2019.

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

[[Page 29106]]

http://www.regulations.gov by searching for and locating Docket No. 
FAA-2019-0406.

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-2019-
0406; 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 is listed above. 
Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: David Truong, Aerospace Engineer, 
Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5224; fax: 562-627-
5210; email: david.truong@faa.gov.

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 the ADDRESSES section. Include ``Docket No. FAA-2019-0406; 
Product Identifier 2019-NM-059-AD'' at the beginning of your comments. 
The FAA specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of this NPRM. The FAA will 
consider all comments received by the closing date and may amend this 
NPRM because of those comments.
    The FAA will post all comments, without change, to http://www.regulations.gov, including any personal information you provide. 
The FAA will also post a report summarizing each substantive verbal 
contact the agency receives about this NPRM.

Discussion

    The FAA has received reports indicating that the fastener holes 
common to stringers (S) S-11 through S-22, and around the external 
bracket angle at S-18 and S-19 have been identified to potentially be 
susceptible to cracking on the Model MD-90 airplanes. This 
determination is based on Model MD-80 airplane service experience. The 
Model MD-80 and Model MD-90 wings share the same basic design and have 
similar stresses.
    Operators of Model MD-80 airplanes have reported finding cracks in 
the center wing lower stringers, lower stringer end fittings, and lower 
forward and aft skins. The cracks in stringers occur at the inboard end 
where they are joined to the airplane centerline by end fittings. 
Cracks in the end fittings occur at the outboard end where they attach 
to stringers. The wing skin cracks occur underneath a cracked stringer. 
The cause of the cracks has been determined to be from fatigue. The 
Boeing Company has not received any reports of cracks on Model MD-90 
airplanes; however, the similarities with the Model MD-80 wings require 
agency action. If not addressed, cracking of the center wing stringers 
and skins could result in the inability of the structure to sustain 
limit loads, and adversely affect the structural integrity of the 
airplane.

Other Relevant Rulemaking

    The FAA issued AD 2016-07-28 (81 FR 21253, April 11, 2016) for all 
The Boeing Company Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 
(MD-83), and DC-9-87 (MD-87) airplanes, and Model MD-88 airplanes. That 
AD requires repetitive ETHF inspections for any cracking in the left 
and right side center wing lower skin, and corrective actions if 
necessary. That AD addresses cracks at S-15, S-16, or S-17, associated 
end fittings, and skins in the center wing fuel tank where the 
stringers meet the end fittings near Xcw=13 and Xcw=15. Such cracking 
could cause structural failure of the wings. Since that AD was issued, 
cracking has been found at fastener holes common to stringers S-11 
through S-22, and around the external bracket angle at S-18 and S-19. 
These areas were not addressed in AD 2016-07-28 or Boeing Alert Service 
Bulletin MD80-57A244, dated March 3, 2016, which is the service 
information operators are required to follow to complete the actions 
required by AD 2016-07-28. Boeing is developing new service information 
for Model MD-80 airplanes to address these additional areas where 
cracking was found. The FAA will consider further rulemaking to address 
the identified unsafe condition for Model MD-80 airplanes once this 
service information is approved.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Service Bulletin MD90-57A031, dated 
March 19, 2019. This service information describes procedures for 
repetitive ETLF inspections of the left and right side fastener holes 
for any crack, repetitive ETHF inspections of the lower skin for any 
crack, and repair if any crack is found.
    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

    The FAA is 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 require accomplishing the actions specified 
in the service information described previously. 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-2019-
0406.

Costs of Compliance

    The FAA estimates that this proposed AD affects 43 airplanes of 
U.S. registry. The FAA estimates the following costs to comply with 
this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                Cost on U.S.
           Action                  Labor cost         Parts cost      Cost per  product          operators
----------------------------------------------------------------------------------------------------------------
Inspection.................  30 work-hours x $85                $0  $2,550 per inspection  $109,650 per
                              per hour = $2,550                      cycle.                 inspection cycle.
                              per inspection cycle.
----------------------------------------------------------------------------------------------------------------

[[Page 29107]]

    The FAA has received no definitive data that would enable the 
agency to provide cost estimates for the on-condition actions 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.
    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.
    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 and associated appliances to the 
Director of the System Oversight Division.

Regulatory Findings

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would not 
have a substantial direct effect on the States, on the relationship 
between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) 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 Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13   [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

The Boeing Company: Docket No. FAA-2019-0406; Product Identifier 
2019-NM-059-AD.

(a) Comments Due Date

    The FAA must receive comments by August 5, 2019.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model MD-90-30 
airplanes, certificated in any category.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports indicating that certain center 
wing stringers and skins have been identified to potentially be 
susceptible to cracking. The FAA is issuing this AD to address 
cracking of the center wing stringers and skins, which could result 
in the inability of the structure to sustain limit loads, and 
adversely affect the structural integrity of the airplane.

(f) Compliance

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

(g) Required Actions

    Except as specified in paragraph (h) of this AD: At the 
applicable times specified in paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin MD90-57A031, dated March 19, 2019, do 
all applicable actions identified as ``RC'' (required for 
compliance) in, and in accordance with, the Accomplishment 
Instructions of Boeing Alert Service Bulletin MD90-57A031, dated 
March 19, 2019.

(h) Exceptions to Service Information Specifications

    (1) For purposes of determining compliance with the requirements 
of this AD: Where Boeing Alert Service Bulletin MD90-57A031, dated 
March 19, 2019, uses the phrase ``the original issue date of this 
service bulletin,'' this AD requires using ``the effective date of 
this AD.''
    (2) Where Boeing Alert Service Bulletin MD90-57A031, dated March 
19, 2019, specifies contacting Boeing for repair instructions and 
doing the repair: This AD requires doing the repair using a method 
approved in accordance with the procedures specified in paragraph 
(i) of this AD.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, 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 (j)(1) of this AD. Information 
may be emailed to 9-ANM-LAACO-AMOC-Requests@faa.gov.
    (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 Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, Los 
Angeles 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) 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 (i)(4)(i) and 
(i)(4)(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.

(j) Related Information

    (1) For more information about this AD, contact David Truong, 
Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5224; fax: 562-627-5210; email: david.truong@faa.gov.

[[Page 29108]]

    (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 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 June 4, 2019.
Michael Kaszycki,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2019-13057 Filed 6-20-19; 8:45 am]
 BILLING CODE 4910-13-P