[Federal Register Volume 73, Number 27 (Friday, February 8, 2008)]
[Proposed Rules]
[Pages 7484-7485]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-2351]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0147; Directorate Identifier 2007-NM-294-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, and -900 Series Airplanes, Equipped with CFM56-7 Engines

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 certain Boeing Model 737-600, -700, and 
-800 series airplanes. The existing AD currently requires repetitive 
inspections to detect damage of the aft strut insulation blanket, and 
eventual replacement of the insulation blankets with new, improved 
blankets. This proposed AD would add airplanes to the applicability and 
require installation of a new heat insulation blanket and new cover 
plate on the left and right side engine struts. This proposed AD would 
not retain the requirements of the existing AD and would terminate the 
requirements of the existing AD. This proposed AD results from reports 
of damaged heat insulation blankets on the engine struts. We are 
proposing this AD to prevent exposure of the lower surface of the strut 
to extreme high temperatures, consequent creation of a source of fuel 
ignition, and increased risk of an uncontrollable fire and possible 
fuel tank explosion.

DATES: We must receive comments on this proposed AD by March 24, 2008.

ADDRESSES: You may send comments by any of the following methods:
    <bullet> Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
    <bullet> Fax: 202-493-2251.
    <bullet> 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.
    <bullet> 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, P.O. Box 3707, Seattle, Washington 98124-2207.

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: Kathrine Rask, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6505; 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-2008-0147; 
Directorate Identifier 2007-NM-294-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 February 4, 1999, we issued AD 99-04-11, amendment 39-11035 (64 
FR 6791, February 11, 1999), for certain Boeing Model 737-600, -700, 
and -800 series airplanes. That AD requires repetitive inspections to 
detect damage of the aft strut insulation blanket. That AD also 
requires eventual replacement of the insulation blankets with new, 
improved blankets, which constitutes terminating action for the 
requirements of that AD. That AD resulted from reports of damaged aft 
strut insulation blankets. We issued that AD to prevent such damage, 
which could result in exposure of the lower surface of the strut to 
extreme high temperatures, consequent creation of a source of fuel 
ignition, and increased risk of an uncontrollable fire and possible 
fuel tank explosion.

Actions Since Existing AD Was Issued

    Since we issued AD 99-04-11, we have received reports of failures 
of the insulation blankets that were installed in accordance with the 
requirements of that AD. A failed heat insulation blanket might go 
undetected in that area.

Relevant Service Information

    We have reviewed Boeing Special Attention Service Bulletin 737-54-
1045, dated July 25, 2007. The service bulletin describes procedures 
for installing a new heat insulation blanket, P/N S315A213-57, and a 
new cover plate on the left and right side engine struts. 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 develop on

[[Page 7485]]

other airplanes of the same type design. For this reason, we are 
proposing this AD, which would supersede AD 99-04-11 and require 
accomplishing the actions specified in the service bulletin described 
previously. This proposed AD would also add Model 737-700C and -900 
series airplanes to the applicability.

Costs of Compliance

    There are about 2,148 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 740 airplanes of 
U.S. registry. 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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                                                                                    Cost per
                   Action                        Work hours         Parts           airplane        Fleet cost
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Installation (new proposed action)..........               4           $4,730           $5,050       $3,737,000
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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:

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 
removing amendment 39-11035 (64 FR 6791, February 11, 1999) and adding 
the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2008-0147; Directorate Identifier 2007-NM-
294-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by March 24, 
2008.

Affected ADs

    (b) This AD supersedes AD 99-04-11.

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 Special Attention Service Bulletin 737-54-1045, 
dated July 25, 2007.

Unsafe Condition

    (d) This AD results from reports of damaged heat insulation 
blankets on the engine struts. We are issuing this AD to prevent 
exposure of the lower surface of the strut to extreme high 
temperatures, consequent creation of a source of fuel ignition, and 
increased risk of uncontrollable fire and possible fuel tank 
explosion.

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.

Installation

    (f) Within 60 months after the effective date of this AD, 
install a new heat insulation blanket, P/N S315A213-57, and a new 
cover plate on the left and right side engine struts in accordance 
with the Accomplishment Instructions of Boeing Special Attention 
Service Bulletin 737-54-1045, dated July 25, 2007.

Parts Installation

    (g) As of the effective date of this AD, no person may install a 
heat insulation blanket, P/N S315A213-42 or -47, on any airplane.

Alternative Methods of Compliance (AMOCs)

    (h)(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.

    Issued in Renton, Washington, on January 31, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E8-2351 Filed 2-7-08; 8:45 am]
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