
[Federal Register Volume 80, Number 229 (Monday, November 30, 2015)]
[Proposed Rules]
[Pages 74726-74729]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-30223]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-6541; Directorate Identifier 2015-NM-135-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 737-600, -700, -700C, -800, -900, and -900ER 
series airplanes. This proposed AD was prompted by reports of a 
manufacturing oversight, in which a supplier omitted the required 
protective finish on certain bushings installed in the rear spar upper 
chord on horizontal stabilizers, which could lead to galvanic corrosion 
and consequent cracking of the rear spar upper chord. This proposed AD 
would require an inspection or records check to determine if affected 
horizontal stabilizers are installed, related investigative actions, 
and for affected horizontal stabilizers, repetitive inspections for any 
crack of the horizontal stabilizer rear spar upper chord, and 
corrective action if necessary. We are proposing this AD to detect and 
correct cracking of the rear spar upper chord, which can result in the 
failure of the upper chord and consequent departure of the horizontal 
stabilizer from the airplane, which can lead to loss of continued safe 
flight and landing.

DATES: We must receive comments on this proposed AD by January 14, 
2016.

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, 
P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone: 206-544-
5000, extension 1; fax: 206-766-5680; 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. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2015-
6541.

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-2015-
6541; 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: Jason Deutschman, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-
6595; fax: 425-917-6590; email: jason.deutschman@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-2015-6541; 
Directorate Identifier 2015-NM-135-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 received reports of a manufacturing oversight, in which the 
required protective finish (zinc-nickel alloy plate or cadmium plate) 
was omitted on the 182A1508-4/-5/-6 bushings (in line with the terminal 
fitting holes) installed in the rear spar upper chord on horizontal 
stabilizers with certain serial numbers. This issue was discovered 
after production of the affected stabilizers.
    The 182A1508-4/-5/-6 bushings are made from aluminum-nickel-bronze. 
Installing these bushings, without the required protective finish, into 
the 2024-T3511 aluminum horizontal stabilizer rear spar upper chord can 
lead to galvanic corrosion between the dissimilar metals. Bushings with 
galvanic corrosion, if not corrected, can lead to cracking of the rear 
spar upper chord, which can result in the failure of the upper chord 
and consequent departure of the horizontal stabilizer from the 
airplane, which can lead to loss of continued safe flight and landing.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-55A1097, dated July 
1, 2015. The service information describes procedures for an inspection 
or records review to determine if affected horizontal stabilizers are 
installed,

[[Page 74727]]

related investigative actions, high frequency eddy current inspections 
for any crack of the horizontal stabilizer rear spar upper chord, and 
corrective action if necessary. 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 of this NPRM.

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 the actions specified 
in the service information described previously, except as discussed 
under ``Differences Between this Proposed AD and the Service 
Information.''
    The phrase ``related investigative actions'' is used in this 
proposed AD. ``Related investigative actions'' are follow-on actions 
that (1) are related to the primary action, and (2) further investigate 
the nature of any condition found. Related investigative actions in an 
AD could include, for example, inspections.
    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.

Differences Between This Proposed AD and the Service Information

    Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015, 
specifies to contact the manufacturer for instructions on how to repair 
certain conditions, but this proposed AD would require repairing those 
conditions in one of the following ways:
     In accordance with a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by the Boeing Commercial 
Airplanes Organization Designation Authorization (ODA) whom we have 
authorized to make those findings.

Explanation of ``RC'' Steps in Service Information

    The FAA worked in conjunction with industry, under the 
Airworthiness Directive Implementation Aviation Rulemaking Committee 
(ARC), to enhance the AD system. One enhancement was a new process for 
annotating which steps in the service information are required for 
compliance with an AD. Differentiating these steps from other tasks in 
the service information is expected to improve an owner's/operator's 
understanding of crucial AD requirements and help provide consistent 
judgment in AD compliance. The steps identified as Required for 
Compliance (RC) in any service information identified previously have a 
direct effect on detecting, preventing, resolving, or eliminating an 
identified unsafe condition.
    For service information that contains steps that are labeled as RC, 
the following provisions apply: (1) 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, and an AMOC is required for any 
deviations to RC steps, including substeps and identified figures; and 
(2) 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.

Costs of Compliance

    We estimate that this proposed AD affects 1,397 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Inspection or check...................  1 work-hour x $85 per                 $0             $85        $118,745
                                         hour = $85.
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    We estimate the following costs to do any necessary inspections 
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 inspections:

                                               On-Condition Costs
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                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Inspections...................................  4 work-hours x $85 per hour =                 $0            $340
                                                 $340.
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    According to the manufacturer, some of the costs of this proposed 
AD may be covered under warranty, thereby reducing the cost impact on 
affected individuals. We do not control warranty coverage for affected 
individuals. As a result, we have included all costs in our cost 
estimate.
    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition 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.

[[Page 74728]]

Regulatory Findings

    We 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) 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-2015-6541; Directorate Identifier 
2015-NM-135-AD.

(a) Comments Due Date

    We must receive comments by January 14, 2016.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737-600, -700, -
700C, -800, -900, and 900ER series airplanes, certificated in any 
category.

(d) Subject

    Air Transport Association (ATA) of America Code 55, Stabilizers.

(e) Unsafe Condition

    This AD was prompted by reports of a manufacturing oversight, in 
which a supplier omitted the required protective finish on certain 
bushings installed in the rear spar upper chord on horizontal 
stabilizers, which could lead to galvanic corrosion and consequent 
cracking of the rear spar upper chord. We are issuing this AD to 
detect and correct cracking of the rear spar upper chord, which can 
result in the failure of the upper chord and consequent departure of 
the horizontal stabilizer from the airplane, which can lead to loss 
of continued safe flight and landing.

(f) Compliance

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

(g) Serial Number Check or Inspection To Determine If Certain 
Horizontal Stabilizers Are Installed, Related Investigative Actions, 
Repetitive Inspections for Cracks, and Corrective Action

    (1) Except as specified in paragraph (h)(1) of this AD, within 
the compliance time identified in paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015, do 
the actions specified in paragraph (g)(1)(i) or (g)(1)(ii) of this 
AD.
    (i) Do a records check to determine if an affected horizontal 
stabilizer is installed and if any horizontal stabilizer has been 
exchanged, and do all applicable related investigative actions, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-55A1097, dated July 1, 2015. Affected 
horizontal stabilizers are identified in the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-55A1097, dated 
July 1, 2015.
    (ii) Do an inspection of the horizontal stabilizer 
identification plate to determine if any affected horizontal 
stabilizer is installed, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-55A1097, dated 
July 1, 2015. Affected horizontal stabilizers are identified in the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
55A1097, dated July 1, 2015.
    (2) If, during any action required by paragraph (g)(1)(i) or 
(g)(1)(ii) of this AD, any affected horizontal stabilizer is found: 
Except as specified in paragraph (h)(1) of this AD, within the 
compliance time identified in paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015, do a 
high frequency eddy current (HFEC) inspection for any crack of the 
horizontal stabilizer rear spar upper chord and do all applicable 
corrective actions, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-55A1097, dated 
July 1, 2015, except as required by paragraph (h)(2) of this AD. 
Repeat the inspection thereafter at intervals identified in 
paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin 
737-55A1097, dated July 1, 2015.

(h) Exceptions to the Service Information Specifications

    (1) Where Boeing Alert Service Bulletin 737-55A1097, dated July 
1, 2015, 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.
    (2) If any cracking is found during any inspection required by 
this AD, and Boeing Alert Service Bulletin 737-55A1097, dated July 
1, 2015, specifies to contact Boeing for appropriate action: Before 
further flight, repair using a method approved in accordance with 
the procedures specified in paragraph (j) of this AD.

(i) Parts Installation Prohibition

    As of the effective date of this AD, no person may install a 
horizontal stabilizer on any airplane, except as specified in 
paragraphs (i)(1) and (i)(2) of this AD.
    (1) A horizontal stabilizer may be installed if the part is 
inspected in accordance with ``Part 2: Horizontal Stabilizer 
Identification Plate Inspection'' of the Accomplishments 
Instructions of Boeing Alert Service Bulletin 737-55A1097, dated 
July 1, 2015, and no affected serial number is found.
    (2) A horizontal stabilizer may be installed if the part is 
inspected in accordance with ``Part 2: Horizontal Stabilizer 
Identification Plate Inspection'' of the Accomplishments 
Instructions of Boeing Alert Service Bulletin 737-55A1097, dated 
July 1, 2015, and an affected serial number is found, provided the 
actions specified in paragraphs (i)(2)(i) and (i)(2)(ii) of this AD 
are done, as applicable.
    (i) An initial HFEC inspection specified in paragraph (g)(2) of 
this AD is done before further flight and thereafter repetitive HFEC 
inspections specified in paragraph (g)(2) of this AD are done within 
the compliance times specified in paragraph (g)(2) of this AD.
    (ii) All applicable corrective actions are done before further 
flight as required by paragraph (h)(2) of this AD.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle 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 (k) of this AD. 
Information may be emailed to: 9-ANM-Seattle-ACO-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 required by this AD if it is approved by the 
Boeing Commercial Airplanes Organization Designation Authorization 
(ODA) that has been authorized by the Manager, Seattle ACO, to make 
those findings. For a repair method to be approved, the repair must 
meet

[[Page 74729]]

the certification basis of the airplane, and the approval must 
specifically refer to this AD.
    (4) For service information that contains steps that are labeled 
as Required for Compliance (RC), the provisions of paragraphs 
(j)(4)(i) and (j)(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. 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 Jason 
Deutschman, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, 
Seattle ACO, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 
425-917-6595; fax: 425-917-6590; email: jason.deutschman@faa.gov.
    (2) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P. O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone: 206-
544-5000, extension 1; fax: 206-766-5680; 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 November 20, 2015.
Jeffrey E. Duven,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2015-30223 Filed 11-27-15; 8:45 am]
 BILLING CODE 4910-13-P


