Document ID: FAA-2009-0411-0002
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Boeing 737-600, -700, -700C, and -800 Series Airplanes
Posted Date: 2009-05-05T04:00Z

[Federal Register Volume 74, Number 85 (Tuesday, May 5, 2009)]
[Proposed Rules]
[Pages 20661-20663]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-10303]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0411; Directorate Identifier 2008-NM-190-AD]
RIN 2120-AA64

Airworthiness Directives; Boeing 737-600, -700, -700C, and -800 
Series 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 certain Boeing Model 737-600, -700, -700C, and -800 series 
airplanes. This proposed AD would require repetitive lubrications of 
the right and left main landing gear (MLG) forward trunnion pins. This 
proposed AD also would require an inspection for discrepancies of the 
transition radius of the MLG forward trunnion pins, and corrective 
actions if necessary. For certain airplanes, this proposed AD would 
also require repetitive detailed inspections for discrepancies 
(including finish damage, corrosion, pitting, and base metal scratches) 
of the transition radius of the left and right MLG trunnion pins, and 
corrective action if necessary. Replacing or overhauling the trunnion 
pins would terminate the actions required by this AD. This proposed AD 
results from a report that the protective finishes on the forward 
trunnion pins for the left and right MLG might have been damaged during 
final assembly. We are proposing this AD to prevent stress corrosion 
cracking of the forward trunnion pins, which could result in fracture 
of the pins and consequent collapse of the MLG.

DATES: We must receive comments on this proposed AD by June 19, 2009.

ADDRESSES: You may send comments 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: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this AD, contact Boeing 
Commercial Airplanes, Attention: Data & Services Management, P. O. Box 
3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, 
extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; Internet  
https://www.myboeingfleet.com.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; 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 (telephone 800-647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Nancy Marsh, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6440; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2009-0411; 
Directorate Identifier 2008-NM-190-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 a report indicating that the protective finishes 
on the main landing gear (MLG) forward trunnion pins might have been 
damaged during final assembly of certain Boeing Model 737-600, -700, -
700C, and -800 series airplanes. The protective coating could be 
damaged at one location because the pins were not handled correctly. 
The MLG forward trunnion pins may have been delivered to operators with 
compromised corrosion protection in one critical area: The transition 
radius between the chrome-plated outer diameter and the spherical ball 
bearing surface. Damage to the protective finish puts the base metal of 
the trunnion pins at risk from corrosion pitting. This condition, if 
not corrected, could lead to stress corrosion cracking of the forward 
trunnion pins, which could result in fracture of the pins and 
consequent collapse of the MLG.

Relevant Service Information

    We have reviewed Boeing Special Attention Service Bulletin 737-32-
1402, dated August 6, 2008. The service bulletin describes procedures 
for repetitive lubrication of the MLG forward trunnion pins. The 
service bulletin states that accomplishing the inspections and 
applicable repairs/replacements described below, or overhauling the 
trunnion pins, eliminates the need for the repetitive lubrication. The 
service bulletin also describes procedures for a detailed inspection 
for discrepancies (including finish damage, corrosion, pitting, and 
base metal scratches) of the transition radius of the left and right 
MLG trunnion pins, and applicable corrective actions. The corrective 
actions include repairing the finish if finish damage is found without 
corrosion, pitting, or base metal scratches, and replacing the trunnion 
pins. For airplanes on which the finish repair is done, the service 
bulletin describes procedures for repeating the detailed inspections 
for discrepancies of the MLG trunnion pins and doing applicable 
corrective actions. Replacement or overhaul of the trunnion pins 
eliminates need for the actions specified in the service bulletin.

[[Page 20662]]

    The service bulletin also specifies that the corrective actions 
should be done before further flight. For airplanes on which the finish 
repair is done, the service bulletin specifies doing the detailed 
inspection within 24 months after doing the repair and thereafter at 
intervals not to exceed 24 months.

FAA's Determination and Requirements of This Proposed AD

    We are proposing this AD because we evaluated all relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design. 
This proposed AD would require accomplishing the actions specified in 
the service information described previously, except as discussed under 
``Differences Between the Proposed AD and Service Bulletin.''

Differences Between the Proposed AD and Service Bulletin

    Although Boeing Special Attention Service Bulletin 737-32-1402, 
dated August 6, 2008, specifies to send inspection reports to the 
manufacturer, this proposed AD would not require that action.

Explanation of Terminology

    Although Boeing Special Attention Service Bulletin 737-32-1402, 
dated August 6, 2008, refers to ``stress cracking,'' this proposed AD 
refers to ``stress corrosion cracking.''

Costs of Compliance

    We estimate that this proposed AD would affect 100 airplanes of 
U.S. registry. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

                                                                 Table--Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                 Number of
                                                          Average                                                  U.S.-
                  Action                    Work hours   labor rate     Parts           Cost per product         registered           Fleet cost
                                                          per hour                                               airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Repetitive lubrication...................            1          $80           $0  $80.........................          100  $8,000.
Inspections..............................            8           80            0  $640 per inspection cycle...          100  $64,000 per inspection
                                                                                                                              cycle.
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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 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), 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

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

    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]

    2. The FAA amends Sec.  39.13 by adding the following new AD:

Boeing: Docket No. FAA-2009-0411; Directorate Identifier 2008-NM-
190-AD.

Comments Due Date

    (a) We must receive comments by June 19, 2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 737-600, -700, -700C, and -
800 series airplanes, certificated in any category; as identified in 
Boeing Special Attention Service Bulletin 737-32-1402, dated August 
6, 2008.

Subject

    (d) Air Transport Association (ATA) of America Code 32: Landing 
gear.

Unsafe Condition

    (e) This AD results from a report indicating that the protective 
finishes on the main landing gear (MLG) forward trunnion pins might 
have been damaged during final assembly. We are issuing this AD to 
prevent stress corrosion cracking of the forward trunnion pins, 
which could result in fracture of the pins and consequent collapse 
of the MLG.

Compliance

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

Lubrication

    (g) Within 30 days after the effective date of this AD: 
Lubricate the left and right MLG forward trunnion pins in accordance 
with the Accomplishment Instructions of Boeing Special Attention 
Service Bulletin 737-32-1402, dated August 6, 2008. Repeat the 
lubrication at intervals not to exceed 30 days until all applicable 
requirements of paragraph (h) of this AD have been accomplished.

Inspection and Corrective Actions

    (h) Within 60 months after the date of issuance of the original 
airworthiness certificate or date of issuance of the original export 
certificate of airworthiness, or within 6 months after the effective 
date of this AD, whichever occurs later: Except as provided

[[Page 20663]]

by paragraph (i) of this AD, do a detailed inspection for 
discrepancies (including finish damage, corrosion, pitting, and base 
metal scratches) of the transition radius of the left and right MLG 
trunnion pins, in accordance with the Accomplishment Instructions of 
Boeing Special Attention Service Bulletin 737-32-1402, dated August 
6, 2008. At the times specified in paragraph 1.E., ``Compliance,'' 
of the service bulletin, do all applicable repetitive inspections 
and corrective actions, in accordance with the service bulletin. 
Accomplishing the detailed inspections (initial and repetitive) and 
all applicable corrective actions specified in this paragraph 
terminates the repetitive lubrication requirements of paragraph (g) 
of this AD.

No Report Required

    (i) Although Boeing Special Attention Service Bulletin 737-32-
1402, dated August 6, 2008, specifies to send inspection reports to 
the manufacturer, this AD does not include that requirement.

Optional Terminating Action

    (j) Overhauling or replacing a trunnion pin in accordance with 
the Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-32-1402, dated August 6, 2008, ends the repetitive 
lubrication requirements of paragraph (g) of this AD, and the 
actions required by paragraph (h) of this AD, for that pin. 
Replacement or overhaul of the left and right MLG trunnion pins in 
accordance with Boeing Special Attention Service Bulletin 737-32-
1402, dated August 6, 2008, terminates the requirements of this AD.

Alternative Methods of Compliance (AMOCs)

    (k)(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. Send information to 
ATTN: Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, 
FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 917-6440; fax (425) 917-6590. Or, e-mail 
information to 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your principal maintenance inspector (PMI) or 
principal avionics inspector (PAI), as appropriate, or lacking a 
principal inspector, your local Flight Standards District Office. 
The AMOC approval letter must specifically reference this AD.
    (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 an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, Seattle ACO, to make those findings. For a repair 
method to be approved, the repair must meet the certification basis 
of the airplane and the approval must specifically refer to this AD.

    Issued in Renton, Washington, on April 27, 2009.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-10303 Filed 5-4-09; 8:45 am]
BILLING CODE 4910-13-P