[Federal Register: August 31, 2007 (Volume 72, Number 169)]
[Proposed Rules]
[Page 50292-50294]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr31au07-23]
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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), Department of
Transportation (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, -800 and -900 series
airplanes. This proposed AD would require repetitive lubrication of the
left and right main landing gear (MLG) forward trunnion pins. This
proposed AD would also require an inspection for discrepancies of the
transition radius of the MLG forward trunnion pins, and repair or
replacement if necessary. This proposed AD would also require a one-
time inspection for discrepancies of the lead-in chamfer and cross-bolt
bore, and repair or replacement if necessary. Doing the applicable
inspections and repairs/replacements, or overhauling the trunnion pins
ends the repetitive lubrication requirements of this proposed 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
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 proposed AD by October 15,
2007.
ADDRESSES: Use one of the following addresses to submit comments on
this proposed AD.
DOT Docket Web site: Go to http://dms.dot.gov and follow
the instructions for sending your comments electronically.
Government-wide rulemaking Web site: Go to http://
www.regulations.gov and follow the instructions for sending your
comments electronically.
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.
Fax: (202) 493-2251.
Hand Delivery: Room W12-140 on the ground floor of the
West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle,
Washington 98124-2207, for the service information identified in this
proposed AD.
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 submit any relevant written data, views, or
arguments regarding this proposed AD. Send your comments to an address
listed in the ADDRESSES section. Include the docket number ``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 the proposed AD. We will
consider all comments received by the closing date and may amend the
proposed AD in light of those comments.
We will post all comments we receive, without change, to http://
dms.dot.gov, including any personal information you provide. We will
also post a report summarizing each substantive verbal contact with FAA
personnel concerning this proposed AD. Using the search function of
that Web site, anyone can find and read the comments in any of our
dockets, including the name of the individual who sent the comment (or
signed the comment on behalf of an association, business, labor union,
etc.). You may review DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78), or you
may visit http://dms.dot.gov.
Examining the Docket
You may examine the AD docket on the Internet at http://
dms.dot.gov, or in person at the Docket Operations office between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The
Docket Operations office (telephone (800) 647-5527) is located on the
ground floor of the West Building at the street address stated in the
ADDRESSES section. Comments will be available in the AD docket shortly
after the Docket Management System receives them.
[[Page 50293]]
Discussion
We have received a report indicating that the protective finishes
on the forward trunnion pins for the main landing gear (MLG) might have
been damaged during final assembly of Boeing Model 737-600, -700, -
700C, -800 and -900 series airplanes. The protective coating could be
damaged at two locations because of the use of an unauthorized process,
and damaged at one location because the pin was not handled correctly.
Therefore, it is possible that these trunnion pins have been delivered
to operators with compromised corrosion protection in these critical
areas:
The cross-bolt bore and outer diameter surface.
The lead-in chamfer and outer diameter surface.
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
pin at risk from corrosion pitting. This condition, if not corrected,
could lead to cracking of the forward trunnion pin, which could result
in fracture of the pin and consequent collapse of the MLG.
Relevant Service Information
We have reviewed Boeing Service Bulletin 737-32-1376, Revision 1,
dated March 19, 2007. 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
in accordance with Boeing 737 Component Maintenance Manual 57-15-01,
eliminates the need for the repetitive lubrication.
The service bulletin also describes procedures for an inspection
for discrepancies (corrosion, finish damage, surface deformation, or
scratches) of the transition radius. If any discrepancy is found, the
service bulletin specifies repairing or replacing the trunnion pin, as
applicable, depending on the type of discrepancy found. The repair
includes blending and restoring the protective finish. If the trunnion
pin is not replaced, the service bulletin specifies an additional
inspection for discrepancies of the lead-in chamfer and the cross-bolt
bore. If any discrepancy is found, the service bulletin specifies
repairing or replacing the trunnion pin, as applicable, depending on
the type of discrepancy found.
Accomplishing the actions specified in the service information is
intended to adequately address the unsafe condition.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an
unsafe condition that is likely to exist or develop on other airplanes
of this same type design. For this reason, we are proposing this AD,
which would require accomplishing the actions specified in the service
information described previously, except as discussed under
``Difference Between the Proposed AD and the Service Bulletin.''
Difference Between the Proposed AD and the Service Bulletin
Although Boeing Service Bulletin 737-32-1376, Revision 1, dated
March 19, 2007, specifies to send inspection reports to the
manufacturer, this proposed AD would not require that action.
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
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Number of
Work U.S.-
Action hours Parts Cost per airplane registered Fleet cost
airplanes
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Repetitive lubrication........... 1 $0 $80, per lubrication 300 $24,000, per
cycle. lubrication cycle.
Inspections...................... 4 0 320................. 300 $96,000.
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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 have 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 that the 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.
We prepared a regulatory evaluation of the estimated costs to
comply with this proposed AD and placed it in the AD docket. See the
ADDRESSES section for a location to examine the regulatory evaluation.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, 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:
[[Page 50294]]
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 Federal Aviation Administration (FAA) amends Sec. 39.13 by
adding the following new airworthiness directive (AD):
Boeing: Docket No. FAA-2007-29087; Directorate Identifier 2007-NM-
094-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by October
15, 2007.
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 1, dated
March 19, 2007.
Unsafe Condition
(d) 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
(e) 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
(f) 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 1, dated March 19, 2007. Repeat the lubrication at
intervals not to exceed 30 days until all applicable requirements of
paragraphs (g) and (h) of this AD have been accomplished.
Overhauling the trunnion pin as given in the Accomplishment
Instructions of Boeing Service Bulletin 737-32-1376, Revision 1,
ends the repetitive lubrication requirements of this paragraph for
that pin.
Inspection and Corrective Actions
(g) Within 60 months after the date of issuance of the original
standard airworthiness certificate or date of issuance of the
original standard 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 pin; 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 1, dated March 19,
2007.
(h) For any airplane on which a trunnion pin is not replaced in
accordance with paragraph (g) of this AD, within 96 months after the
date of issuance of the original standard airworthiness certificate
or date of issuance of the original standard export certificate of
airworthiness, or within 12 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 1,
dated March 19, 2007.
No Report Required
(i) Although Boeing Service Bulletin 737-32-1376, Revision 1,
dated March 19, 2007, 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
(j) Actions done before the effective date of this AD in
accordance with Boeing Service Bulletin 737-32-1376, dated May 12,
2005, are acceptable for compliance with the corresponding actions
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 in
accordance with the procedures found in 14 CFR 39.19.
(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 appropriate principal inspector (PI) in the FAA
Flight Standards District Office (FSDO), or lacking a PI, your local
FSDO.
(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 August 17, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-17285 Filed 8-30-07; 8:45 am]
BILLING CODE 4910-13-P