
[Federal Register Volume 81, Number 70 (Tuesday, April 12, 2016)]
[Proposed Rules]
[Pages 21497-21501]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-08349]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-5468; Directorate Identifier 2015-NM-021-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, and -900 series 
airplanes. This proposed AD was prompted by reports of paint 
deterioration on the surface of the main landing gear (MLG) and the 
early onset of corrosion in the trunnion bore of the MLG outer 
cylinder. This proposed AD would require identifying affected parts, 
repetitive external surface detailed inspection for damage of affected 
parts, and related investigative and corrective actions if necessary. 
For certain airplanes, this AD also would require a detailed inspection 
and bushing replacement of the trunnion bore, and related investigative 
and corrective action if necessary. We are proposing this AD to prevent 
stress corrosion cracking of the external surfaces of the MLG, which 
could result in a fracture of the MLG and consequent MLG collapse.

DATES: We must receive comments on this proposed AD by May 27, 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-

[[Page 21498]]

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: 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-2016-5468.

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-2016-
5468; 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: Alan Pohl, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-
6450; fax: 425-917-6590; email: alan.pohl@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-2016-5468; 
Directorate Identifier 2015-NM-021-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 from several operators of paint deterioration 
on the surface of the MLG and early onset of corrosion in the trunnion 
bore of the MLG outer cylinder. A maintenance repair and overhaul (MRO) 
facility observed forward trunnion bore corrosion on a right MLG while 
installing new bushings. Another MRO disclosed that between 2007 and 
2010, the primer used on the landing gear components did not comply 
with Boeing Material Specification (BMS) 10-79. Also, paint chip and 
trunnion bore analysis showed that unqualified primer was used; primer 
application was up to 5 times too thick while enamel was too thin; 
there was early deterioration of the fillet seal at the trunnion bore; 
and the trunnion bushing installation process, which may have damaged 
the finish on the bore, did not follow the standard overhaul practices 
manual. This condition, if not corrected, could result in a fracture of 
the MLG and consequent MLG collapse.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Special Attention Service Bulletin 737-32-1486, 
dated November 6, 2014, as revised by Boeing Special Attention Service 
Bulletin 737-32-1486, Revision 1, dated April 1, 2015. The service 
information describes procedures for identifying affected parts, 
repetitive external surface detailed inspection for damage of affected 
parts, and related investigative and corrective actions if necessary. 
For certain airplanes, this AD also would require a detailed inspection 
and bushing replacement of the trunnion bore, and related investigative 
and corrective action if necessary. The service information also 
describes procedures for certain airplanes that include a detailed 
inspection of the trunnion bore, 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 these same type 
designs.

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 ``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.
    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.

Differences Between This Proposed AD and the Service Information

    Boeing Special Attention Service Bulletin 737-32-1486, dated 
November 6, 2014, as revised by Boeing Special Attention Service 
Bulletin 737-32-1486, Revision 1, dated April 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.
    While the effectivity of Boeing Special Attention Service Bulletin 
737-32-1486, dated November 6, 2014, as revised by Boeing Special 
Attention Service Bulletin 737-32-1486, Revision 1, dated April 1, 
2015, is limited to those airplanes that are listed, the applicability 
of this AD affects all The Boeing Company Model 737-600, -700, -700C, -
800, and -900 series airplanes.

Clarification of Affected MLGs

    An MLG overhauled by SAFRAN Messier-Bugatti-Dowty outside of the 
Boeing Exchange program from June 1, 2009, to July 31, 2013, would also 
be affected by this proposed AD.

[[Page 21499]]

Costs of Compliance

    We estimate that this proposed AD affects 33 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                   Labor cost          Parts cost       Cost per  product       operators
----------------------------------------------------------------------------------------------------------------
External surface detailed         Up to 16 work-      $0................  $1,360 per          Up to $44,880 per
 Inspection.                       hours x $85 per                         inspection cycle.   inspection cycle.
                                   hour = $1,360 per
                                   inspection cycle.
Outer Cylinder assembly trunnion  70 work-hours x     Negligible........  $5,950............  $196,350.
 bore detailed inspection and      $85 per hour =
 bushing replacement (G1-2,        $5,950.
 configuration 1).
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary 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 
this replacement.

                           On-Condition Costs
------------------------------------------------------------------------
                                                             Cost per
             Action                    Labor cost            product
------------------------------------------------------------------------
Outer cylinder assembly          28 work-hours x $85             $2,380
 replacement (if required as a    per hour = $2,380.
 result of the outer cylinder
 trunnion bore detailed
 inspection).
------------------------------------------------------------------------

    We have received no definitive data that would enable us to provide 
cost estimates for certain on-condition actions (MLG external surface 
repair, MLG component replacement, outer cylinder repair, and MLG 
replacement) specified in this proposed AD.
    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.
    The previous info is based on known airplanes. However, the MLG may 
have been overhauled outside of the Boeing Exchange Program as 
specified in the Clarification of Affected MLGs section of 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.

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-2016-5468; Directorate Identifier 
2015-NM-021-AD.

(a) Comments Due Date

    We must receive comments by May 27, 2016.

(b) Affected ADs

    None.

(c) Applicability

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

(d) Subject

    Air Transport Association (ATA) of America Code 32, Landing 
Gear.

(e) Unsafe Condition

    This AD was prompted by reports of paint deterioration on the 
surface of the main

[[Page 21500]]

landing gear (MLG) and early onset of corrosion in the trunnion bore 
of the MLG outer cylinder. We are issuing this AD to prevent stress 
corrosion cracking of the external surfaces of the MLG, which could 
result in a fracture of the MLG and consequent MLG collapse.

(f) Compliance

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

(g) Inspection for Affected Part/Serial Numbers

    At the applicable time specified in table 1 of paragraph 1.E., 
``Compliance,'' of Boeing Special Attention Service Bulletin 737-32-
1486, dated November 6, 2014, as revised by Boeing Special Attention 
Service Bulletin 737-32-1486, Revision 1, dated April 1, 2015, 
except as required by paragraph (k)(1) of this AD: Do the actions 
specified in paragraphs (g)(1) and (g)(2) of this AD in order to 
identify affected parts.
    (1) Inspect the MLG to determine if it has any component 
installation or side strut assembly having a part number and serial 
number listed in Appendix D of Boeing Special Attention Service 
Bulletin 737-32-1486, dated November 6, 2014, as revised by Boeing 
Special Attention Service Bulletin 737-32-1486, Revision 1, dated 
April 1, 2015; except that the ``Variable Number'' column of 
Appendix D is to be disregarded in determining affected part and 
serial numbers. A MLG that has any MLG component installation or 
side strut assembly having a part number and serial number listed in 
Appendix D of Boeing Special Attention Service Bulletin 737-32-1486, 
dated November 6, 2014, as revised by Boeing Special Attention 
Service Bulletin 737-32-1486, Revision 1, dated April 1, 2015, is an 
affected part. A review of airplane maintenance records is 
acceptable in lieu of this inspection if the part number and serial 
number of the MLG component installation and side strut assembly can 
be conclusively identified from that review.
    (2) Do a records review to determine if the MLG has been 
overhauled by SAFRAN Messier-Bugatti-Dowty outside of the Boeing 
Exchange program from June 1, 2009 to July 31, 2013. If the MLG has 
been overhauled by SAFRAN Messier-Bugatti-Dowty outside of the 
Boeing Exchange program from June 1, 2009 to July 31, 2013, that MLG 
is an affected part. If the records review cannot conclusively 
determine that an overhauled MLG was overhauled by an MRO other than 
SAFRAN Messier-Bugatti-Dowty, or if the records review cannot 
conclusively determine that an MLG overhauled by SAFRAN Messier-
Bugatti-Dowty was part of the Boeing Exchange program from June 1, 
2009 to July 31, 2013; that MLG is an affected part.

(h) Requirements for Affected Parts

    If any affected part is identified during the inspection or 
records review required by paragraph (g) of this AD: At the 
applicable time specified in table 3 of paragraph 1.E., 
``Compliance,'' of Boeing Special Attention Service Bulletin 737-32-
1486, dated November 6, 2014, as revised by Boeing Special Attention 
Service Bulletin 737-32-1486, Revision 1, dated April 1, 2015, 
except as required by paragraph (k)(1) of this AD: Do detailed 
inspections of the external surfaces of the MLG, and do all 
applicable related investigative and corrective actions, in 
accordance with Parts 1, 3, and 4 of the Accomplishment Instructions 
of Boeing Special Attention Service Bulletin 737-32-1486, dated 
November 6, 2014, as revised by Boeing Special Attention Service 
Bulletin 737-32-1486, Revision 1, dated April 1, 2015, except as 
required by paragraph (k)(2) of this AD. Repeat the inspections 
thereafter at the applicable time specified in table 3 of paragraph 
1.E., ``Compliance,'' of Boeing Special Attention Service Bulletin 
737-32-1486, dated November 6, 2014, as revised by Boeing Special 
Attention Service Bulletin 737-32-1486, Revision 1, dated April 1, 
2015. All applicable related investigative and corrective actions 
must be done before further flight.

(i) Additional Actions for Groups 1 and 2, Configuration 1

    For airplanes that are identified as Groups 1 and 2, 
Configuration 1, in Boeing Special Attention Service Bulletin 737-
32-1486, dated November 6, 2014, as revised by Boeing Special 
Attention Service Bulletin 737-32-1486, Revision 1, dated April 1, 
2015, and that have an affected part identified during the 
inspection or records review required by paragraph (g) of this AD: 
At the applicable time specified in table 4 of Paragraph 1.E, 
``Compliance,'' of Boeing Special Attention Service Bulletin 737-32-
1486, dated November 6, 2014, as revised by Boeing Special Attention 
Service Bulletin 737-32-1486, Revision 1, dated April 1, 2015, 
except as required by paragraph (k)(1) of this AD, do a detailed 
inspection and bushing replacement of the MLG trunnion bore, and do 
all applicable related investigative and corrective actions, in 
accordance with Parts 2, 5, and 6 of the Accomplishment Instructions 
of Boeing Special Attention Service Bulletin 737-32-1486, dated 
November 6, 2014, as revised by Boeing Special Attention Service 
Bulletin 737-32-1486, Revision 1, dated April 1, 2015, except as 
required by paragraph (k)(2) of this AD.

(j) Terminating Action

    (1) MLG replacement in accordance with Part 8 of the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-32-1486, dated November 6, 2014, as revised by Boeing 
Special Attention Service Bulletin 737-32-1486, Revision 1, dated 
April 1, 2015, terminates the requirements of paragraphs (g), (h), 
and (i) of this AD for that MLG only.
    (2) MLG component replacement in accordance with Part 4 of the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-32-1486, dated November 6, 2014, as revised by Boeing 
Special Attention Service Bulletin 737-32-1486, Revision 1, dated 
April 1, 2015, terminates the requirements of paragraph (h) of this 
AD for that component only.
    (3) MLG outer cylinder replacement in accordance with Part 7 of 
the Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-32-1486, dated November 6, 2014, as revised by Boeing 
Special Attention Service Bulletin 737-32-1486, Revision 1, dated 
April 1, 2015, terminates the requirements of paragraph (i) of this 
AD for that component only.

(k) Exceptions to Service Information Specifications

    (1) Where paragraph 1.E., ``Compliance,'' of Boeing Special 
Attention Service Bulletin 737-32-1486, dated November 6, 2014, as 
revised by Boeing Special Attention Service Bulletin 737-32-1486, 
Revision 1, dated April 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) Although Boeing Special Attention Service Bulletin 737-32-
1486, dated November 6, 2014, as revised by Boeing Special Attention 
Service Bulletin 737-32-1486, Revision 1, dated April 1, 2015, 
specifies to contact Boeing for repair instructions, and specifies 
that action as ``RC'' (Required for Compliance), this AD requires 
repair before further flight using a method approved in accordance 
with the procedures specified in paragraph (m) of this AD.

(l) Parts Installation Prohibition

    As of the effective date of this AD, no person may install the 
following on any airplane identified in paragraph (c) of this AD, 
unless the MLG has been overhauled using a method approved in 
accordance with the procedures specified in paragraph (m) of this 
AD:
    (1) An MLG having a part number and serial number identified in 
Appendix D to Boeing Special Attention Service Bulletin 737-32-1486, 
dated November 6, 2014, as revised by Boeing Special Attention 
Service Bulletin 737-32-1486, Revision 1, dated April 1, 2015.
    (2) An MLG that was overhauled from June 1, 2009, to July 31, 
2013, by SAFRAN Messier-Bugatti-Dowty.

(m) 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 (n)(1) 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, modification, or alteration required by this AD 
if it is approved by the Boeing

[[Page 21501]]

Commercial Airplanes Organization Designation Authorization (ODA) 
that has been authorized by the Manager, Seattle ACO, 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 required by paragraph (k)(2) of this AD: For 
service information that contains steps that are labeled as RC, the 
provisions of paragraphs (m)(4)(i) and (m)(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.

(n) Related Information

    (1) For more information about this AD, contact Alan Pohl, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO, 
1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6450; 
fax: 425-917-6590; email: alan.pohl@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. For information on the availability of this 
material at the FAA, 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 March 31, 2016.
Victor Wicklund,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-08349 Filed 4-11-16; 8:45 am]
 BILLING CODE 4910-13-P


