[Federal Register Volume 73, Number 197 (Thursday, October 9, 2008)]
[Rules and Regulations]
[Pages 59488-59491]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-23573]


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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; 
Amendment 39-15686; AD 2008-21-02]
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: Final rule.

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SUMMARY: The FAA is superseding an existing airworthiness directive 
(AD), which applies to certain Boeing Model 737-600, -700, and -800 
series airplanes. That 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 new AD adds airplanes to the applicability and requires 
installation of a new heat insulation blanket and new cover plate on 
the left and right side engine struts. This new AD does not retain the 
requirements of the existing AD but does terminate the requirements of 
the existing AD. 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 an uncontrollable fire and possible fuel tank 
explosion.

DATES: This AD becomes effective November 13, 2008.
    The Director of the Federal Register approved the incorporation by 
reference

[[Page 59489]]

of a certain publication listed in the AD as of November 13, 2008.

ADDRESSES: 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 AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (telephone 800-647-5527) is the Document Management 
Facility, U.S. Department of Transportation, Docket Operations, M-30, 
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Samuel Spitzer, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 
(425) 917-6510; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that supersedes AD 99-04-11, amendment 39-
11035 (64 FR 6791, February 11, 1999). The existing AD applies to 
certain Boeing Model 737-600, -700, and -800 series airplanes. That 
NPRM was published in the Federal Register on February 8, 2008 (73 FR 
7484). That NPRM proposed to add airplanes to the applicability of the 
existing AD and require installation of a new heat insulation blanket 
and new cover plate on the left and right side engine struts, which 
would terminate the requirements of the existing AD.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments that have been 
received on the NPRM.

Support for the NPRM

    Boeing concurs with the contents of the NPRM. AirTran Airways 
(AirTran) and Continental Airlines (CAL) agree with the rule.

Request To Delay AD Until Service Bulletin Is Revised

    CAL notes that Boeing has released Information Notice (IN) 737-54-
1045 IN 01, dated December 4, 2007. CAL notes that this IN states that 
Figures 2 and 4 of Boeing Special Attention Service Bulletin 737-54-
1045, dated July 25, 2007, do not correctly illustrate the proper 
configuration of the insulation blanket. (We cited Boeing Special 
Attention Service Bulletin 737-54-1045 in the NPRM as the appropriate 
source of service information.) Therefore, CAL requests that Boeing 
revise the service bulletin before we enact the AD.
    We disagree with waiting until Boeing revises its service bulletin 
before we issue the AD. We have determined that an unsafe condition 
exists and that the actions in this AD must be done to ensure continued 
safety. We do not consider that delaying this action until after the 
release of the manufacturer's planned service bulletin is warranted 
since sufficient instructions currently exist to do the required 
replacement within the compliance time. Paragraph (h) of this AD 
provides operators the opportunity to request an extension of the 
compliance time if data are presented to justify the extension. 
However, we agree that the information in IN 737-54-1045 IN 01, which 
relates to the configuration of the insulation blanket, is important. 
Therefore, we have revised paragraph (f) of this AD to include the 
relevant information from the IN.

Request To Identify Supplier Part Numbers (P/Ns)

    AirTran points out that P/N S315A213-57, as specified in paragraph 
(f) of the NPRM, is a specification number and that P/N 99A9257M is the 
supplier part number for the insulation blanket that is listed in the 
Boeing Model 737-700 Illustrated Parts Catalog. AirTran also points out 
a similar supplier part number exists for the insulation blankets that 
are prohibited from installation as specified in paragraph (g) of the 
NPRM. Therefore, AirTran requests that we identify both the Boeing 
specification number and the supplier part number in the AD.
    We disagree with the request to include supplier part numbers. The 
Boeing specification number (P/N) S315A213-57 is the high-level 
identifier for the part. This specification number is printed on each 
authorized vendor part that is made to Boeing specifications in 
accordance with the Boeing specification control document. Each 
authorized vendor can have a different part number. Therefore, using 
the specification P/N S315A213-57 should prevent any confusion. We have 
not changed the AD in this regard.

Request To Extend Compliance Time

    Air Transport Association (ATA), on behalf of its member American 
Airlines (AA), is concerned with the proposed 60-month compliance 
period. The commenters note that the industry standard maintenance 
interval for the affected Boeing Model 737 airplanes is 72 months. 
Therefore, a 60-month compliance period would unnecessarily increase 
out-of-service time and related costs. The commenters propose a 72-
month compliance time, which would align more economically with 
industry standard maintenance review board (MRB) task intervals.
    We do not agree with the request to extend the compliance time. In 
developing an appropriate compliance time for this action, we 
considered the urgency associated with the subject unsafe condition, 
the availability of required parts, and the fact that the modification 
takes 4 work hours. According to the manufacturer, an ample number of 
required parts will be available to do the installation on the U.S. 
fleet within the proposed compliance time. In consideration of these 
items, we have determined that a 60-month compliance time will ensure 
an acceptable level of safety. However, according to the provisions of 
paragraph (h) of this AD, we may approve requests to adjust the 
compliance time if the request includes data that prove that the new 
compliance time would provide an acceptable level of safety. We have 
not changed the AD in this regard.

Request To Allow Additional Time for Parts Installation

    CAL notes that paragraph (g) of the NPRM states that operators may 
not install a heat insulation blanket, P/N S315A213-42 or -47, on any 
airplane after the effective date of the AD. CAL requests that 
operators be given an additional 60 days after the effective date of 
the AD to ensure ``illegal'' parts are purged from the inventory and 
Boeing is able to supply spare parts.
    We contacted CAL to obtain additional technical information in 
respect to this comment. CAL indicated that they initially had concerns 
over parts availability and long lead times to obtain P/N S315A213-57 
heat insulation blankets. CAL stated that after checking with Boeing, 
parts availability and lead times are adequate and their comment is no 
longer relevant. We have not changed the AD in this regard.

Conclusion

    We have carefully reviewed the available data, including the 
comments

[[Page 59490]]

that have been received, and determined that air safety and the public 
interest require adopting the AD with the change described previously. 
We have determined that this change will neither increase the economic 
burden on any operator nor increase the scope of the AD.

Costs of Compliance

    There are about 2,148 airplanes of the affected design in the 
worldwide fleet. This AD affects about 740 airplanes of U.S. registry. 
The following table provides the estimated costs for U.S. operators to 
comply with this AD. The average labor rate is $80 per work hour.

                                                 Estimated Costs
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                                                        Work                        Cost per
                       Action                          hours        Parts           airplane        Fleet cost
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Installation (new 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 AD will not have federalism 
implications under Executive Order 13132. This AD will 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 this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866;
    (2) Is not a ``significant rule'' under 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 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.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
removing amendment 39-11035 (64 FR 6791, February 11, 1999) and by 
adding the following new airworthiness directive (AD):

2008-21-02 Boeing: Amendment 39-15686. Docket No. FAA-2008-0147; 
Directorate Identifier 2007-NM-294-AD.

Effective Date

    (a) This AD becomes effective November 13, 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, part number (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, except 
Figure 2 and Figure 4 of the service bulletin should show four holes 
on the aft edge of the heat insulation blanket instead of two. 
Operators should also note that on installation of the heat 
insulation blanket, the two inner holes on the aft edge of the heat 
insulation blanket are not used or filled.

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, ATTN: Samuel Spitzer, Aerospace Engineer, Propulsion Branch, 
ANM-140S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; telephone (425) 917-6510; fax (425) 917-6590; 
has the authority to approve AMOCs for this AD, if requested using 
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.

Material Incorporated by Reference

    (i) You must use Boeing Special Attention Service Bulletin 737-
54-1045, dated July 25, 2007, to perform the actions that are 
required by this AD, unless the AD specifies otherwise. The Director 
of the Federal Register approved the incorporation by reference of 
this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for a copy of this service information. You 
may review copies at the FAA, Transport Airplane Directorate, 1601 
Lind Avenue,

[[Page 59491]]

SW., Renton, Washington; or at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Renton, Washington, on September 29, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-23573 Filed 10-8-08; 8:45 am]
BILLING CODE 4910-13-P