[Federal Register Volume 74, Number 135 (Thursday, July 16, 2009)]
[Proposed Rules]
[Pages 34518-34520]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-16943]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-25001; Directorate Identifier 2006-NM-079-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, -900 and -900ER Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (NPRM); reopening of 
comment period.

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SUMMARY: We are revising an earlier proposed airworthiness directive 
(AD) for all Boeing Model 737-600, -700, -700C, -800, -900 and -900ER 
series airplanes. That supplemental NPRM would have required a one-time 
inspection to determine the part numbers of the aero/fire seals of the 
blocker doors on the thrust reverser torque boxes on the engines, and 
replacing affected aero/fire seals with new improved aero/fire seals. 
This action resulted from a report that the top 3 inches of the aero/
fire seals of the blocker doors on the thrust reverser torque boxes are 
not fireproof. This second supplemental NPRM revises the first 
supplemental NPRM by changing the compliance time for the replacement. 
We are proposing this second supplemental NPRM to prevent a fire in the 
fan compartment (a fire zone) from migrating through the seal to a 
flammable fluid in the thrust reverser actuator compartment (a 
flammable fluid leakage zone), which could result in an uncontrolled 
fire.

DATES: We must receive comments on this supplemental NPRM by August 10, 
2009.

[[Page 34519]]


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.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207; telephone 206-544-9990; fax 206-766-5682; 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 or 
425-227-1152.

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: 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: 

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-2006-
25001; Directorate Identifier 2006-NM-079-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

    We issued a notice of proposed rulemaking (NPRM) (the ``first 
supplemental NPRM'') to amend 14 CFR part 39 to include an 
airworthiness directive (AD) that would apply to all Boeing Model 737-
600, -700, -700C, -800, and -900 series airplanes. The first 
supplemental NPRM was published in the Federal Register on September 3, 
2008 (73 FR 51382). The first supplemental NPRM proposed to require a 
one-time inspection to determine the part numbers of the aero/fire 
seals of the blocker doors on the thrust reverser torque boxes on the 
engines, and replacing affected aero/fire seals with new improved aero/
fire seals.

Actions Since First Supplemental NPRM Was Issued

    Since we issued the first supplemental NPRM, we have determined 
that it is necessary to change the compliance time for the replacement 
action in paragraph (h) from ``within 60 months or 8,200 flight cycles 
after the effective date of this AD,'' to ``prior to further flight 
after doing the actions specified in paragraph (g) of this AD.'' Our 
intent in the first supplemental NPRM was to require replacement of an 
affected aero/fire seal before further flight after identification.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We considered the comment received on the first supplemental 
NPRM. Boeing supports the NPRM.

Additional Changes to Supplemental NPRM

    For clarification purposes, we have revised paragraph (h) of this 
second supplemental NPRM to change ``as having an affected P/N'' to 
``to have a non-fireproof seal.''
    We have also added new paragraph (d) in this supplemental NPRM to 
identify the Air Transport Association of America code.

FAA's Determination and Proposed Requirements of the Second 
Supplemental NPRM

    We are proposing this second supplemental NPRM because we evaluated 
all pertinent information and determined an unsafe condition exists and 
is likely to exist or develop on other products of the same type 
design. Certain changes described above expand the scope of the first 
supplemental NPRM. As a result, we have determined that it is necessary 
to reopen the comment period to provide additional opportunity for the 
public to comment on this second supplemental NPRM.

Costs of Compliance

    There are about 2,442 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                                         Cost per        U.S.-
                     Action                       Work hours    labor rate                 Parts                  airplane     registered    Fleet cost
                                                                 per hour                                                       airplanes
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Inspection for part number.....................            1           $80   None.............................          $80           803       $64,240
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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

[[Page 34520]]

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 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 this 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

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 adding the following new AD:

Boeing: Docket No. FAA-2006-25001; Directorate Identifier 2006-NM-
079-AD.

Comments Due Date

    (a) We must receive comments by August 10, 2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Boeing Model 737-600, -700, -700C, -
800, -900, and -900ER series airplanes, certificated in any 
category.

Subject

    (d) Air Transport Association (ATA) of America Code 78: Engine 
exhaust.

Unsafe Condition

    (e) This AD results from a report that the top 3 inches of the 
aero/fire seals of the blocker doors on the thrust reverser torque 
boxes are not fireproof. The Federal Aviation Administration is 
issuing this AD to prevent a fire in the fan compartment (a fire 
zone) from migrating through the seal to a flammable fluid in the 
thrust reverser actuator compartment (a flammable fluid leakage 
zone), which could result in an uncontrolled fire.

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.

Inspection To Determine Part Number (P/N)

    (g) Within 60 months or 8,200 flight cycles after the effective 
date of this AD, whichever occurs first: Perform a one-time detailed 
inspection to determine the color of the aero/fire seals of the 
blocker doors on the thrust reverser torque boxes on the engines. 
For any aero/fire seal having a completely grey color (which is the 
color of seals with P/N 315A2245-1 or 315A2245-2), with no red at 
the upper end of the seal, do the actions specified in paragraph (h) 
of this AD. For any aero/fire seal having a red color at the upper 
end of the seal (which indicates a different part number), no 
further action is required by this AD. A review of airplane 
maintenance records is acceptable in lieu of this inspection if the 
part number of the correct aero/fire seals (P/N 315A2245-7 or -8) 
can be conclusively determined to be installed from that review.

    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.''

Replace the Aero/Fire Seals

    (h) For any aero/fire seal identified during the inspection/
records check in paragraph (g) of this AD to have a non-fireproof 
seal: Prior to further flight after doing the actions specified in 
paragraph (g) of this AD, replace the aero/fire seals of the blocker 
doors on the thrust reverser torque boxes on the engines with new, 
improved aero/fire seals in accordance with the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 737-78-
1074, Revision 1, dated September 15, 2005.

Credit for Actions Done Using Previous Service Information

    (i) Replacements done before the effective date of this AD in 
accordance with the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-78-1074, dated April 7, 2005, are 
acceptable for compliance with the requirements of paragraph (h) of 
this AD.

Alternative Methods of Compliance (AMOCs)

    (j)(1) The Manager, Seattle Aircraft Certification Office, 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: 
Samuel Spitzer, Aerospace Engineer, Propulsion Branch, ANM-140S, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 
(425) 917-6510; fax (425) 917-6590. Or, e-mail information 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.

    Issued in Renton, Washington, on July 6, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-16943 Filed 7-15-09; 8:45 am]
BILLING CODE 4910-13-P