[Federal Register Volume 75, Number 184 (Thursday, September 23, 2010)]
[Proposed Rules]
[Pages 57882-57885]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-23841]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0855; Directorate Identifier 2010-NM-066-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model 737-300, -400, 
and -500 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 supersede an existing airworthiness 
directive (AD) that applies to all Model 737-300, -400, and -500 series 
airplanes. The existing AD currently requires repetitive inspections 
for discrepancies of the fuse pins of the inboard and outboard midspar 
fittings of the nacelle strut, and corrective actions if necessary. 
This proposed AD would add replacing the midspar fuse pins with new, 
improved fuse pins, which would terminate the repetitive inspections. 
This proposed AD results from a report of corrosion damage of the 
chrome runout on the head side found on all four midspar fuse pins of 
the nacelle strut. Additionally, a large portion of the chrome plate 
was missing from the corroded area of the shank. We are proposing this 
AD to prevent damage of the fuse pins of the inboard and outboard 
midspar fittings of the nacelle strut, which could result in reduced 
structural integrity of the fuse pins, and consequent loss of the strut 
and separation of the engine from the airplane.

DATES: We must receive comments on this proposed AD by November 8, 
2010.

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.

[[Page 57883]]

    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 [email protected]; 
Internet https://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.

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: Alan Pohl, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6450; 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-2010-0855; 
Directorate Identifier 2010-NM-066-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

    On September 29, 2008, we issued AD 2008-21-03, amendment 39-15687 
(73 FR 59493, October 9, 2008), for all Model 737-300, -400, and -500 
series airplanes. That AD requires repetitive inspections for 
discrepancies of the fuse pins of the inboard and outboard midspar 
fittings of the nacelle strut, and corrective actions if necessary. 
That AD resulted from a report of corrosion damage of the chrome runout 
on the head side found on all four midspar fuse pins of the nacelle 
strut. Additionally, a large portion of the chrome plate was missing 
from the corroded area of the shank. We issued that AD to detect and 
correct discrepancies of the fuse pins of the inboard and outboard 
midspar fittings of the nacelle strut, which could result in reduced 
structural integrity of the fuse pins, and consequent loss of the strut 
and separation of the engine from the airplane.

Actions Since Existing AD Was Issued

    In the preamble to the NPRM of AD 2008-21-03, the FAA specified 
that the actions required by that AD were considered ``interim action'' 
and that the manufacturer was developing a modification to address the 
unsafe condition. The FAA indicated that it may consider further 
rulemaking action once the modification was developed, approved, and 
available. The manufacturer now has developed such a modification, and 
the FAA has determined that further rulemaking action is indeed 
necessary; this proposed AD follows from that determination.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 737-54A1044, 
Revision 2, dated January 20, 2010. The repetitive detailed inspections 
and corrective actions are similar to those described in Boeing Special 
Attention Service Bulletin 737-54-1044, dated December 10, 2007 
(referenced in AD 2008-21-03 as the appropriate source of service 
information). Revision 2 of the service bulletin adds procedures for 
replacing the midspar fuse pins with new, improved fuse pins. 
Replacement with the new, improved fuse pin eliminates the need for 
repetitive detailed inspections.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to develop on other airplanes of the 
same type design. For this reason, we are proposing this AD, which 
would supersede AD 2008-21-03 and would retain the requirements of the 
existing AD. This proposed AD would also require replacing the midspar 
fuse pins with new, improved fuse pins, which would terminate the 
requirement for repetitive detailed inspections.

Change to Existing AD

    This proposed AD would retain all requirements of AD 2008-21-03. 
Since AD 2008-21-03 was issued, the AD format has been revised, and 
certain paragraphs have been rearranged. As a result, paragraph (f) of 
the existing AD has been re-identified as paragraph (g) in this NPRM.

Costs of Compliance

    There are about 1,961 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.

                                                                     Estimated Costs
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                                                                                                                        Number of
                                                            Average labor                                                 U.S.-
              Action                      Work hours        rate per hour          Parts           Cost per airplane    registered       Fleet cost
                                                                                                                        airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Repetitive detailed inspections     4....................             $85  None................  $340, per inspection          616  $209,440, per
 (required by AD 2008-21-03).                                                                     cycle.                             inspection cycle.
Midspar fuse pin replacement (new   1 per pin (up to 4                 85  $843 per pin........  Up to $3,712........          616  Up to $2,286,592.
 proposed action).                   pins per airplane).
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[[Page 57884]]

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, 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 removing amendment 39-15687 (73 FR 
59493, October 9, 2008) and adding the following new AD:

The Boeing Company: Docket No. FAA-2010-0855; Directorate Identifier 
2010-NM-066-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by November 
8, 2010.

Affected ADs

    (b) This AD supersedes AD 2008-21-03, Amendment 39-15687.

Applicability

    (c) This AD applies to all The Boeing Company Model 737-300, -
400, and -500 series airplanes, certificated in any category.

Subject

    (d) Air Transport Association (ATA) of America Code 54: 
Nacelles/Pylons.

Unsafe Condition

    (e) This AD results from a report of corrosion damage of the 
chrome runout on the head side found on all four midspar fuse pins 
of the nacelle strut. Additionally, a large portion of the chrome 
plate was missing from the corroded area of the shank. The Federal 
Aviation Administration is issuing this AD to prevent damage of the 
fuse pins of the inboard and outboard midspar fittings of the 
nacelle strut, which could result in reduced structural integrity of 
the fuse pins, and consequent loss of the strut and separation of 
the engine from the airplane.

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.

Restatement of Requirements of AD 2008-21-03

Repetitive Inspections/Corrective Actions, With Revised Service 
Information

    (g) At the applicable time specified in paragraph 1.E., 
``Compliance'' of Boeing Special Attention Service Bulletin 737-54-
1044, dated December 10, 2007; except, where the service bulletin 
specifies a compliance time after the date on the service bulletin, 
this AD requires compliance within the specified compliance time 
after November 13, 2008 (the effective date of AD 2008-21-03): Do a 
detailed inspection for discrepancies of the fuse pins of the 
inboard and outboard midspar fittings of the nacelle strut by doing 
all the actions, including all applicable corrective actions, in 
accordance with the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-54-1044, dated December 10, 2007; or 
Boeing Alert Service Bulletin 737-54A1044, Revision 2, dated January 
20, 2010. Do all applicable corrective actions before further 
flight. Repeat the inspection at the time specified in paragraph 
1.E. of Boeing Special Attention Service Bulletin 737-54-1044, dated 
December 10, 2007. Accomplishing the actions of paragraph (h) of 
this AD terminates the requirements of this paragraph.

New Requirements of This AD

Replacement

    (h) Within 120 months after the effective date of this AD, 
replace all midspar fuse pins having part number (P/N) 311A1092-2 
with a midspar fuse pin having P/N 311A1092-3, in accordance with 
the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-54A1044, Revision 2, dated January 20, 2010. Accomplishing the 
requirements of this paragraph terminates the requirements of 
paragraph (g) of this AD for that fuse pin.

Actions Accomplished According to Previous Revision of Service 
Information

    (i) Actions done before the effective date of this AD in 
accordance with Boeing Special Attention Service Bulletin 737-54-
1044, Revision 1, dated November 26, 2008, are acceptable for 
compliance with the corresponding requirements of this AD.

Alternative Methods of Compliance (AMOCs)

    (j)(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: Alan Pohl, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., 
Renton, Washington 98057-3356; telephone (425) 917-6450; fax (425) 
917-6590. Information may be e-mailed to: [email protected].
    (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 the 
Boeing Commercial Airplanes Organization Designation Authorization 
(ODA) that 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.
    (4) AMOCs approved in accordance with the requirements of AD 
2008-21-03 are acceptable for the corresponding requirements of this 
AD.


[[Page 57885]]


    Issued in Renton, Washington, on September 15, 2010.
Robert D. Breneman,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.

[FR Doc. 2010-23841 Filed 9-22-10; 8:45 am]
BILLING CODE 4910-13-P