
[Federal Register Volume 79, Number 138 (Friday, July 18, 2014)]
[Proposed Rules]
[Pages 41943-41945]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-16942]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2014-0450; Directorate Identifier 2013-NM-250-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 adopt a new airworthiness directive (AD) for all 
The Boeing Company Model MD-90-30 airplanes. This proposed AD was 
prompted by reports of cracks emanating from the aft-most barrel nut 
holes of the left and right upper rear spar caps of the horizontal 
stabilizer. This proposed AD would require repetitive high frequency 
eddy current (ETHF) inspections for cracks in the areas around the two 
aft-most barrel nut holes of the upper rear spar caps, and corrective 
action if necessary; and repetitive ETHF inspections for cracks in the 
areas around the two aft-most barrel nut holes of any repaired or 
replaced upper rear spar cap, and corrective actions if necessary. We 
are proposing this AD to detect and correct such cracks, which could 
propagate until the upper rear spar cap severs, and result in failure 
of the horizontal stabilizer upper center or aft skin panel and 
adversely affect the structural integrity of the airplane.

DATES: We must receive comments on this proposed AD by September 2, 
2014.

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 proposed AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
3855 Lakewood Boulevard, MC D800-0019, Long Beach, CA 90846-0001; 
telephone 206-544-5000, extension 2; fax 206-766-5683; Internet https://www.myboeingfleet.com. You may view this referenced service 
information at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue SW., Renton, WA. For information on the availability of this 
material at the FAA, call 425 227-1221.

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-2014-
0450; or in person at the Docket Management Facility between 9 a.m. and 
5 p.m., Monday through Friday, except Federal holidays. The AD docket 
contains this proposed AD, the regulatory evaluation, any comments 
received, and other information. The street address for the Docket 
Office (phone: 800-647-5527) is in the ADDRESSES section. Comments will 
be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: George Garrido, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-
627-5357;

[[Page 41944]]

fax: 562-627-5210; email: george.garrido@faa.gov.

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-2014-0450; 
Directorate Identifier 2013-NM-250-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD 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 have received reports of cracks emanating from the aft-most 
barrel nut holes of the left and right upper rear spar caps of the 
horizontal stabilizer. One airplane had accumulated 40,144 total flight 
hours and 32,253 total landing cycles, while another airplane had 
accumulated 58,296 total flight hours and 43,512 total landing cycles. 
Investigations have determined that the cracks were caused by fatigue. 
In both cases, the cracks originated inside of the barrel nut holes, 
and radiated vertically and in the aft direction from the barrel nut 
holes. This condition, if not corrected, could result in cracks in the 
horizontal stabilizer, which could propagate until it severs the upper 
rear spar cap, and result in failure of the horizontal stabilizer upper 
center or aft skin panel and adversely affect the structural integrity 
of the airplane.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin MD90-55A017, dated 
September 27, 2013. For information on the procedures and compliance 
times, see this service information at http://www.regulations.gov by 
searching for Docket No. FAA-2014-0450.

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 require accomplishing repetitive high 
frequency eddy current (ETHF) inspections for cracks of the areas 
around the aft-most barrel nut holes of the upper rear spar caps, and 
corrective actions if necessary; and repetitive ETHF inspections for 
cracks at the two aft-most barrel nut holes of the repaired or replaced 
upper rear spar cap, and corrective actions if necessary.
    The phrase ``corrective actions'' is used in this proposed AD. 
``Corrective actions'' are actions that correct or address any 
condition found. Corrective actions in an AD could include, for 
example, repairs.

Difference Between This Proposed AD and the Service Information

    Table 1 of paragraph 1.E., ``Compliance,'' of Boeing Alert Service 
Bulletin MD90-55A017, dated September 27, 2013, specifies post-repair 
inspections of the upper rear spar cap of the aft flange that has been 
splice-repaired, which may be used in support of compliance with 
Section 121.1109(c)(2) or 129.109(b)(2) of the Federal Aviation 
Regulations (14 CFR 121.1109(c)(2) or 14 CFR 129.109(b)(2)). However, 
this NPRM does not propose to require those post-repair inspections. 
This difference has been coordinated with Boeing.

Costs of Compliance

    We estimate that this proposed AD affects 52 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
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                                                                            Cost per
            Action                   Labor cost          Parts cost         product      Cost on U.S.  operators
----------------------------------------------------------------------------------------------------------------
Inspection...................  9 work-hours X $85     $1,410..........  $2,175 per       Up to $113,100 per
                                per hour = $765 per                      inspection       inspection cycle.
                                inspection cycle.                        cycle.
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    We estimate the following costs to do any necessary repairs and 
replacements that would be required based on the results of the 
proposed inspection. We have no way of determining the number of 
aircraft that might need these repairs and replacements:

                                               On-condition Costs
----------------------------------------------------------------------------------------------------------------
              Action                       Labor cost              Parts cost             Cost per product
----------------------------------------------------------------------------------------------------------------
Repair (per side)................  368 work[dash]hours X $85  Up to $90,129.......  Up to $121,409.
                                    per hour = $31,280.
Replacement......................  368 work[dash]hours X $85  $81,764.............  $113,044.
                                    per hour = $31,280.
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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.

Regulatory Findings

    We determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This

[[Page 41945]]

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) 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 adding the following new airworthiness 
directive (AD):

The Boeing Company: Docket No. FAA-2014-0450; Directorate Identifier 
2013 NM-250-AD.

(a) Comments Due Date

    We must receive comments by September 2, 2014.

(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 Stabilizers, 55.

(e) Unsafe Condition

    This AD was prompted by reports of cracks emanating from the 
aft-most barrel nut holes of the left and right upper rear spar caps 
of the horizontal stabilizer. We are issuing this AD to detect and 
correct cracks in the horizontal stabilizer, which could propagate 
until the upper rear spar cap severs, and result in failure of the 
horizontal stabilizer upper center or aft skin panel and adversely 
affect the structural integrity of the airplane.

(f) Compliance

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

(g) Inspection

    At the applicable compliance time specified in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin MD90-55A017, dated 
September 27, 2013, except as provided by paragraph (i) of this AD: 
Do a high frequency eddy current inspection (ETHF) for cracks in the 
areas around the two aft-most barrel nut holes of the upper rear 
spar cap; and do all applicable corrective actions; in accordance 
with the Accomplishment Instructions of Boeing Alert Service 
Bulletin MD90-55A017, dated September 27, 2013. Thereafter, repeat 
the ETHF inspection at the applicable time specified in paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin MD90-55A017, 
dated September 27, 2013. Do all corrective actions before further 
flight.

(h) Post-Repair/Replacement Actions

    For airplanes on which a splice repair or replacement was done 
as specified in Boeing Alert Service Bulletin MD90-55A017: At the 
applicable compliance time specified in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin MD90-55A017, dated 
September 27, 2013, do an ETHF inspection for cracks at the two aft-
most barrel nut holes of any repaired or replaced upper rear spar 
cap, in accordance with the Accomplishment Instructions of Boeing 
Alert Service Bulletin MD90-55A017, dated September 27, 2013. 
Thereafter, repeat the ETHF inspection at the applicable time 
specified in paragraph 1.E., ``Compliance,'' of Boeing Alert Service 
Bulletin MD90-55A017, dated September 27, 2013. If any cracking is 
found, before further flight, do the repair or replacement, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-55A017, dated September 27, 2013.

(i) Post-Repair Inspections

    The post-repair inspections of the upper rear spar cap of the 
aft flange that has been splice-repaired specified in Table 1 of 
paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin 
MD90-55A017, dated September 27, 2013, are not required by this AD.

    Note 1 to paragraph (h) of this AD: The damage tolerance 
inspections (post-repair inspections of the upper rear spar cap aft 
flange) specified in Table 1 of paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, 
may be used in support of compliance with Section 121.1109(c)(2) or 
129.109(b)(2) of the Federal Aviation Regulations (14 CFR 
121.1109(c)(2) or 14 CFR 129.109(b)(2)). The corresponding actions 
specified in the Accomplishment Instructions of Boeing Alert Service 
Bulletin MD90-55A017, dated September 27, 2013, are not required by 
this AD.

(j) Exception to the Service Information

    Where Boeing Alert Service Bulletin MD90-55A017, dated September 
27, 2013, specifies a compliance time ``after the original issue 
date of this service bulletin,'' this AD requires compliance within 
the specified compliance time after the effective date of this AD.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles Aircraft Certification Office 
(ACO), 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 ACO, send it to the 
attention of the person identified in paragraph (l)(1) of this AD.
    (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 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, to 
make those findings. For a repair method to be approved, the repair 
must meet the certification basis of the airplane, and 14 CFR 
25.571, Amendment 45, and the approval must specifically refer to 
this AD.

(l) Related Information

    (1) For more information about this AD, contact George Garrido, 
Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles 
Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, 
CA 90712-4137; phone: 562-627-5357; fax: 562-627-5210; email: 
george.garrido@faa.gov.
    (2) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
3855 Lakewood Boulevard, MC D800 0019, Long Beach, CA 90846-0001; 
telephone 206-544-5000, extension 2; fax 206-766-5683; Internet 
https://www.myboeingfleet.com. You may view this referenced service 
information at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue SW., Renton, WA. For information on the availability of this 
material at the FAA, call 425-227-1221.

    Issued in Renton, Washington, on July 11, 2014.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2014-16942 Filed 7-17-14; 8:45 am]
BILLING CODE 4910-13-P


