[Federal Register Volume 69, Number 158 (Tuesday, August 17, 2004)]
[Proposed Rules]
[Pages 51017-51019]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-18744]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-18877; Directorate Identifier 2002-NM-340-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, -200C, and 
-300 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 737-100, -200, -200C, and -300 series 
airplanes. This proposed AD would require repetitive detailed 
inspections to detect discrepancies of the retaining pin lugs on the 
support fitting of the main landing gear (MLG) beam, and rework of the 
support fitting, or replacement of the fitting if necessary. This 
proposed AD is prompted by reports of discrepancies of the lugs. We are 
proposing this AD to prevent separation of the support beam of the MLG 
from the rear spar, which could cause cracking of the MLG support 
fitting and a consequent leak in the wing fuel tank or collapse of the 
MLG.

DATES: We must receive comments on this proposed AD by October 1, 2004.

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: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
     By fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    You can get the service information identified in this proposed AD 
from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 
98124-2207.
    You may examine the contents of this AD docket on the Internet at 
http://dms.dot.gov, or at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street, SW., Room PL-401, on 
the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT:
    Technical Information: Robert C. Hardwick, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6457; fax (425) 917-6590.
    Plain Language Information: Marcia Walters, [email protected].

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

    The FAA has implemented new procedures for maintaining AD dockets 
electronically. As of May 17, 2004, new AD actions are posted on DMS 
and assigned a docket number. We track each action and assign a 
corresponding directorate identifier. The DMS AD docket number is in 
the form ``Docket No. FAA-2004-99999.'' The Transport Airplane 
Directorate identifier is in the form ``Directorate Identifier 2004-NM-
999-AD.'' Each DMS AD docket also lists the directorate identifier 
(``Old Docket Number'') as a cross-reference for searching purposes.

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 under ADDRESSES. Include ``Docket No. FAA-2004-18877; 
Directorate Identifier 2002-NM-340-AD'' in the subject line 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 submitted 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.

[[Page 51018]]

Using the search function of that website, 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 can 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.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications that affect you. You can get more information about 
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the Docket

    You can examine the AD docket in person at the Docket Management 
Facility office between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Management Facility office 
(telephone (800) 647-5227) is on the plaza level of the Nassif Building 
at the DOT street address stated in the ADDRESSES section. Comments 
will be available in the AD docket shortly after the DMS receives them.

Discussion

    We have received a report indicating that broken or cracked 
retaining pin lugs have occurred on the support fitting of the main 
landing gear (MLG) beam, on certain Boeing Model 737-100 and -200 
series airplanes. There was also a report of an elongated bolt hole in 
the lug. There were no reports of the fuse pin migrating out of the 
fitting. Cracked lugs can result from excessive clamp-up of the lugs, 
excessive grease pressure during routine lubrication of the fuse pin, 
migration of the fuse pin, or a combination of those factors. Fracture 
of the lugs, if not corrected, could result in the loss of the 
retaining pin and migration of the fuse pin, and consequent leak in the 
wing fuel tank or collapse of the MLG.

Relevant Service Information

    We have reviewed Boeing Special Attention Service Bulletin 737-57-
1267, dated August 8, 2002. The service bulletin describes procedures 
for repetitive detailed inspections of the retaining pin lugs on the 
support fitting of the MLG beam for discrepancies, and rework of the 
support fitting if necessary. The rework includes performing a 
penetrant inspection of the fitting, and cutting off the support beam 
fitting lugs and installing a new fitting that replaces the removed 
lugs. Reworking the fitting would eliminate the need for the repetitive 
inspections.
    Boeing has also issued Service Bulletin 737-57-1216, Revision 2, 
dated May 6, 1999, which, among other things, describes procedures for 
replacing the support fitting of the MLG beam with a new fitting. For 
certain airplanes, the service bulletin describes procedures for 
installing a special bushing to prevent damage to the retainer bolt 
under certain circumstances. Replacing the support fitting would 
eliminate the need for the repetitive inspections.
    We have determined that accomplishment of the actions specified in 
the service bulletins will 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. Therefore, we are proposing this AD, which 
would require repetitive detailed inspections to detect discrepancies 
of the retaining pin lugs on the support fitting of the MLG beam, and 
rework of the support fitting, or replacement of the fitting if 
necessary. The proposed AD would require you to use the service 
information described previously to perform these actions, except as 
discussed under ``Differences Between the Proposed AD and the Service 
Bulletin.''
    Differences Between the Proposed AD and the Service Bulletin
    Boeing Service Bulletin 737-57-1216, Revision 2, specifies that you 
may contact the manufacturer for instructions on how to repair certain 
conditions, but this proposed AD would require you to repair those 
conditions in one of the following ways:
     Using a method that we approve; or
     Using data that meet the type certification basis of the 
airplane, and that have been approved by a Boeing Company Designated 
Engineering Representative who has been authorized by the FAA to make 
such findings.

Costs of Compliance

    This proposed AD would affect about 1,670 airplanes worldwide and 
668 airplanes of U.S. registry. The proposed actions would take about 2 
work hours per airplane, at an average labor rate of $65 per work hour. 
Based on these figures, the estimated cost of the proposed AD for U.S. 
operators is $86,840, or $130 per airplane.
    The rework, if accomplished, would take approximately 24 work hours 
per airplane to accomplish at an average labor rate of $65 per work 
hour. Required parts would cost approximately $1,006 per airplane. 
Based on these figures, the cost impact of the rework provided by this 
AD is estimated to be $2,566 per airplane.
    The replacement of the support fitting of the MLG beam, if 
accomplished, would take approximately 128 work hours per airplane to 
accomplish at an average labor rate of $65 per work hour. Required 
parts would cost approximately between $4,540 and $5,271 per airplane. 
Based on these figures, the cost impact of the replacement provided by 
this AD is estimated to be between $12,860 and $13,591 per airplane.
    The replacement of the support fitting and installation of a 
special bushing of the MLG beam (for Group 9 and Group 10 airplanes), 
if accomplished, would take approximately 144 work hours per airplane 
to accomplish at an average labor rate of $65 per work hour. Required 
parts would cost approximately $5,081 per airplane. Based on these 
figures, the cost impact of this action is estimated to be $14,441 per 
airplane.

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. 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.

[[Page 51019]]

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 
airworthiness directive (AD):

Boeing: Docket No. FAA-2004-18877; Directorate Identifier 2002-NM-
340-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by October 1, 2004.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 737-100, -200, -200C, and -
300 series airplanes, certificated in any category; line numbers 1 
through 1670 inclusive.

Unsafe Condition

    (d) This AD was prompted by reports of discrepancies of the lugs 
on the support fitting of the main landing gear (MLG) beam. We are 
issuing this AD to prevent separation of the support beam of the MLG 
from the rear spar, which could cause cracking of the MLG support 
fitting and a consequent leak in the wing fuel tank or 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.

Inspection

    (f) Prior to the accumulation of 15,000 total flight cycles, or 
within 3,000 flight cycles after the effective date of this AD, 
whichever occurs later: Perform a detailed inspection to detect 
cracking of the retaining pin lugs of the support fitting of the MLG 
beam, or elongation of a bolt hole in a lug, per the Accomplishment 
Instructions, Part I: Inspection, of Boeing Special Attention 
Service Bulletin 737-57-1267, dated August 8, 2002. If no cracked 
lug or elongated bolt hole is found, repeat the inspection at 
intervals not to exceed 12,000 flight cycles, until the actions 
specified in paragraph (h) of this AD are accomplished.

    Note 1: For the purposes of this AD, a detailed inspection is 
``an intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirrors magnifying lenses, etc. may be necessary. Surface cleaning 
and elaborate procedures may be required.''

Corrective Action

    (g) If any cracked lug or elongated bolt hole is found during 
any inspection required by paragraph (f) of this AD, before further 
flight, do paragraph (g)(1) or (g)(2) of this AD.
    (1) Rework the fitting per the Accomplishment Instructions, Part 
II: Rework, of Boeing Special Attention Service Bulletin 737-57-
1267, dated August 8, 2002.
    (2) Replace the fitting per the Accomplishment Instructions, 
Part III--Fitting Replacement, of Boeing Service Bulletin 737-57-
1216, Revision 2, dated May 6, 1999.

Optional Terminating Action

    (h) Reworking or replacing the fitting per paragraph (g)(1) or 
(g)(2) of this AD constitutes terminating action for the inspections 
required by paragraph (f) of this AD.

Repair

    (i) If any cracking is found during any inspection required by 
this AD, and the bulletin specifies to contact Boeing for 
appropriate action: Before further flight, repair per a method 
approved by the Manager, Seattle Aircraft Certification Office 
(ACO), FAA; or per data meeting the type certification basis of the 
airplane approved by a Boeing Company Designated Engineering 
Representative (DER) who has been authorized by the Manager, Seattle 
ACO, to make such findings. For a repair method to be approved, the 
approval must specifically reference this AD.

Parts Installation

    (j) As of the effective date of this AD: With the exception of a 
new lug, all lugs must be inspected or reworked, as applicable, in 
accordance with this AD before being installed on any airplane.

Alternative Methods of Compliance (AMOCs)

    (k)(1) The Manager, Seattle 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) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by a 
Boeing Company DER who has been authorized by the Manager, Seattle 
ACO, to make such findings.

    Issued in Renton, Washington, on August 9, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-18744 Filed 8-16-04; 8:45 am]
BILLING CODE 4910-13-P