Document ID: FAA-2007-29087-0011
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800 and -900 Series Airplanes
Posted Date: 2009-08-05T04:00Z

[Federal Register: August 5, 2009 (Volume 74, Number 149)]
[Proposed Rules]               
[Page 38988-38991]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr05au09-27]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-29087; Directorate Identifier 2007-NM-094-AD]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800 
and -900 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (NPRM); reopening of 
comment period.

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SUMMARY: We are revising an earlier proposed airworthiness directive 
(AD) for certain Boeing Model 737-600, -700, -700C, -800 and -900 
series airplanes. The original NPRM would have required repetitive 
lubrication of the left and right main landing gear (MLG) forward 
trunnion pins; and an inspection for discrepancies of the transition 
radius, lead-in chamfer, and cross bolt bore of the MLG forward 
trunnion pins, and repair or replacement if necessary. Doing the 
applicable inspections and repairs/replacements, or overhauling the 
trunnion pins as proposed in the original NPRM, would end the 
repetitive lubrication requirements of this proposed AD. The original 
NPRM resulted 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. This action revises the original NPRM by changing the 
inspection of the trunnion pins to allow inspection in-situ. If a 
certain repair is done, this action would require repetitive 
inspections for discrepancies of the transition radius. We are 
proposing this supplemental NPRM to prevent cracking of the forward 
trunnion pin, which could result in fracture of the pin and consequent 
collapse of the MLG.

DATES: We must receive comments on this supplemental NPRM by August 31, 
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 proposed 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:[sol][sol]www.myboeingfleet.com. You may review copies 
of the referenced service information at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information 
on the availability of this material at the FAA, call 425-227-1221 or 
425-227-1152.

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-2007-
29087; Directorate Identifier 2007-NM-094-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 issued a notice of proposed rulemaking (NPRM) (the ``original 
NPRM'') to amend 14 CFR part 39 to include an airworthiness directive 
(AD) that would apply to certain Boeing Model 737-600, -700, -700C, -
800 and -900 series airplanes. That original NPRM was published in the 
Federal Register on August 31, 2007 (72 FR 50292). That original NPRM 
proposed to require repetitive lubrication of the left and right main 
landing gear (MLG) forward trunnion pins; and an inspection for 
discrepancies of the transition radius, lead-in chamfer, and cross bolt 
bore of the MLG forward trunnion pins, and repair or replacement if 
necessary. The NPRM specified that the applicable inspections

[[Page 38989]]

and repairs/replacements, or overhauling the trunnion pins, ends the 
repetitive lubrication requirements of this AD.

Actions Since Original NPRM Was Issued

    We referred to Boeing Service Bulletin 737-32-1376, Revision 1, 
dated March 19, 2007, as the appropriate source of service information 
for accomplishing the actions proposed in the original NPRM. Since we 
issued the original NPRM, Boeing issued Service Bulletin 737-32-1376, 
Revision 2, dated August 6, 2008, to provide procedures for an in-situ 
detailed inspection for discrepancies of transition radius of the MLG 
forward trunnion pins, and for in-situ repair of the protective finish 
of the forward trunnion pin transition radius. Revision 2 of the 
service bulletin also provides procedures for inspecting the lead-in 
chamfer and the cross bolt bore with the MLG removed. Revision 2 of the 
service bulletin also includes new cost information. For airplanes on 
which the repair specified in Part 4 of Revision 2 of the service 
bulletin is done, the service bulletin provides procedures for 
repetitive inspections of the transition radius until the trunnion pin 
is overhauled or replaced.
    Boeing Service Bulletin 737-32-1376, Revision 2, dated August 6, 
2008, specifies that no more work is necessary on airplanes changed in 
accordance with Boeing Service Bulletin 737-32-1376, Revision 1, dated 
March 19, 2007.
    In Boeing Service Bulletin 737-32-1376, Revision 2, dated August 6, 
2008, the threshold has been changed to 120 months for doing the in-
situ detailed inspection of the lead-in chamfer and cross-bolt bore for 
any airplane on which a trunnion pin is not replaced.

Clarification of Service Bulletin

    In paragraph 1.E., ``Compliance'' of Boeing Service Bulletin 737-
32-1376, Revision 2, dated August 6, 2008, note (d) of Table 1 and note 
(a) of Table 2 state that repair of the trunnion pin in accordance with 
the Boeing 737 Component Maintenance Manual (CMM) 57-15-01 meets ``all 
compliance requirements of this service bulletin for that pin only.'' 
However, operators should note that an overhaul of the entire pin 
rather than a local repair is necessary to comply with the requirements 
of this proposed AD.

Explanation of Additional Paragraph in the Supplemental NPRM

    We have added a new paragraph (d) to this supplemental NPRM to 
provide the Air Transport Association (ATA) of America code. This code 
is added to make this supplemental NPRM parallel with other new AD 
actions. We have reidentified subsequent paragraphs accordingly.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We considered the comments received.

Agreement with Lubrication Task

    Air Transport Association (ATA), on behalf of its member American 
Airlines (AA), agrees with the lubrication task required every 30 days.

Requests to Reduce Burden on Operators

    We received several comments regarding the burden on operators 
imposed by the actions proposed in the original NPRM. These commenters 
note the difficulty and expense of accomplishing certain inspections, 
and request we reduce that burden as follows:
     Southwest Airlines and Continental Airlines request that 
we clarify the original NPRM to note that the inspections of the 
transition radius do not require removing the MLG. Southwest also 
requests that we revise the compliance time from 96 months to 120 
months for some inspections of the trunnion pin, and that we postpone 
the issuance of the final rule pending development of a new inspection 
procedure. Continental states that the complexity of the inspections 
will affect the operation of the airline by removing multiple airplanes 
from service.
     ATA, on behalf of AA, states that the cost impact is 
grossly underestimated, and that the costs to AA alone will be over 
$1.7 million, including out-of-service revenue costs.
    We agree that requiring operators to remove the MLG in order to do 
the actions proposed in the original NPRM could impose an undue burden. 
The proposed requirement to remove the MLG could severely affect the 
airlines by forcing multiple airplanes to be out of service at the same 
time. As a result of the comments we received, we held a multi-operator 
meeting. Boeing, the FAA, and several operators attended the meeting. 
Operators provided Boeing with new inspection data from airplanes that 
had already been inspected. Boeing evaluated the data and, in 
cooperation with the airlines, developed an alternative inspection 
procedure that does not require removal of the MLG. That alternative 
procedure is specified in Boeing Service Bulletin 737-32-1376, Revision 
2, dated August 6, 2008, described above. We have included that 
alternative procedure in this supplemental NPRM. In addition, we have 
revised paragraph (h) of the original NPRM (paragraph (i) of this 
supplemental NPRM) from 96 months to 120 months in this supplemental 
NPRM, as recommended in Boeing Service Bulletin 737-32-1376, Revision 
1, dated March 19, 2007.

Request to Remove Certain Inspections

    Continental Airlines requests that we delete paragraph (h) of the 
original NPRM (paragraph (i) of this supplemental NPRM). Paragraph (h) 
of the original NPRM specifies doing a detailed inspection for 
discrepancies of the lead-in chamfer and cross-bolt bore, and repairing 
or replacing the trunnion pin if any discrepancy is found. The 
commenter believes there is no propensity for stress corrosion to exist 
in certain areas of the trunnion pin.
    We partially agree with the commenter. We agree that the 
inspections specified in Boeing Service Bulletin 737-32-1376, Revision 
1, dated March 19, 2007, can be modified. However, we do not agree that 
the inspections can be deleted entirely. Additional information 
provided to Boeing during the multi-operator meeting discussed 
previously resulted in revised inspections that are included in Boeing 
Service Bulletin 737-32-1376, Revision 2, dated August 6, 2008. The 
revised inspections are included in paragraph (i) of this supplemental 
NPRM.

Request to Revise Compliance Time for Certain Airplanes

    Boeing requests that the AD specify a separate compliance time for 
Boeing Model 737-BBJ, C40A, and C40B airplanes. Boeing notes that these 
airplanes might not enter service immediately upon delivery and, 
therefore, their exposure to the effects of the environment is reduced.
    We disagree with the request to specify a separate compliance time 
for these airplanes. The circumstances surrounding when these airplanes 
enter service are variable; therefore, defining a consistent compliance 
time for all of these airplanes is not possible. However, under the 
provisions of paragraph (l) of this supplemental NPRM, we will consider 
requests for adjustments to the compliance time if data are submitted 
to substantiate that such an adjustment would provide an acceptable 
level of safety. We have not changed the AD in this regard.

[[Page 38990]]

FAA's Determination and Proposed Requirements of the Supplemental NPRM

    We are proposing this supplemental NPRM because we evaluated all 
pertinent information and determined an unsafe condition exists and is 
likely to exist or develop on other products of the same type design. 
The changed inspections described above expand the scope of the 
original NPRM. As a result, we have determined that it is necessary to 
reopen the comment period to provide additional opportunity for the 
public to comment on this supplemental NPRM.

Costs of Compliance

    There are about 890 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD. The average labor rate 
is $80 per work hour.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                           Number of U.S.-
              Action                  Work hours      Cost per airplane      registered          Fleet cost
                                                                              airplanes
----------------------------------------------------------------------------------------------------------------
Repetitive lubrication............               2  $160 per lubrication              300  $48,000 per
                                                     cycle.                                 lubrication cycle.
Inspections (in situ).............               2  $160.................             300  $48,000.
----------------------------------------------------------------------------------------------------------------

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-2007-29087; Directorate Identifier 2007-NM-
094-AD.

Comments Due Date

    (a) We must receive comments by August 31, 2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 737-600, -700, -700C, -800 
and -900 series airplanes, certificated in any category, as 
identified in Boeing Service Bulletin 737-32-1376, Revision 2, 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 that the protective finishes 
on the forward trunnion pins for the left and right main landing 
gear (MLG) might have been damaged during final assembly. We are 
issuing this AD to prevent cracking of the forward trunnion pin, 
which could result in fracture of the pin and consequent collapse of 
the MLG.

Compliance

    (f) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Lubrication or Overhaul

    (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 Service Bulletin 737-
32-1376, Revision 2, dated August 6, 2008. Repeat the lubrication at 
intervals not to exceed 30 days until all applicable requirements of 
paragraphs (h) and (i) of this AD have been accomplished. 
Overhauling the trunnion pin in accordance with the Accomplishment 
Instructions of Boeing Service Bulletin 737-32-1376, Revision 2, 
dated August 6, 2008, ends the repetitive lubrication requirements 
of this paragraph for that pin.

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: Do a detailed inspection 
for discrepancies (corrosion, finish damage, surface deformation, or 
scratches) of the transition radius of the left and right MLG 
trunnion pins; and if any discrepancy is found, repair or replace 
the trunnion pin before further flight. Do all actions in accordance 
with the Accomplishment Instructions of Boeing Service Bulletin 737-
32-1376, Revision 2, dated August 6, 2008. If the repair specified 
in Part 4 of the service bulletin is done, within 24 months after 
doing the repair, do the detailed inspection of the transition 
radius, and do the inspection thereafter at intervals not to exceed 
24 months until the trunnion pin is overhauled or replaced in 
accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 737-32-1376, Revision 2, dated August 6, 2008.
    (i) For airplanes on which the trunnion pin has not been 
replaced or overhauled: Within 120 months after the date of issuance 
of the original airworthiness certificate or date of

[[Page 38991]]

issuance of the original export certificate of airworthiness, or 
within 6 months after the effective date of this AD, whichever 
occurs later, do a detailed inspection for discrepancies of the 
lead-in chamfer and cross-bolt bore; and if any discrepancy is 
found, repair or replace the trunnion pin before further flight. Do 
all actions in accordance with the Accomplishment Instructions of 
Boeing Service Bulletin 737-32-1376, Revision 2, dated August 6, 
2008.

No Report Required

    (j) Although Boeing Service Bulletin 737-32-1376, Revision 2, 
dated August 6, 2008, specifies to send inspection reports to the 
manufacturer, this AD does not include that requirement.

Credit for Actions Done Using Previous Issue of Service Information

    (k) Actions done before the effective date of this AD in 
accordance with Boeing Service Bulletin 737-32-1376, dated May 12, 
2005; or Revision 1, dated March 19, 2007; are acceptable for 
compliance with the corresponding actions of this AD.

Alternative Methods of Compliance (AMOCs)

    (l)(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 Aircraft Certification Office, 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 July 24, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-18642 Filed 8-4-09; 8:45 am]

BILLING CODE 4910-13-P