[Federal Register Volume 73, Number 212 (Friday, October 31, 2008)]
[Proposed Rules]
[Pages 64894-64897]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-25990]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-1143; Directorate Identifier 2008-NM-136-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, and -900 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 certain Boeing Model 737-600, -700, -
700C, -800, and -900 series airplanes. The existing AD currently 
requires replacing brackets that hold the P5 panel to the airplane 
structure, the standby compass bracket assembly, the generator drive 
and standby power module, and the air conditioning module. The existing 
AD also currently requires, among other actions, inspecting for wire 
length and for damage of the connectors and the wire bundles, and doing 
applicable corrective actions if necessary. This proposed AD would 
require an additional operational test of the P5-14 panel. This 
proposed AD results from a report of an electrical burning smell in the 
flight compartment. We are proposing this AD to prevent wire bundles 
from contacting the overhead dripshield panel and modules in the P5 
overhead panel, which could result in electrical arcing and shorting of 
the electrical connector and consequent loss of several critical 
systems essential for safe flight; and to ensure proper operation of 
the passenger oxygen system. If an improperly functioning passenger 
oxygen system goes undetected, the passenger oxygen mask could fail to 
deploy and result in possible incapacitation of passengers during a 
depressurization event.

DATES: We must receive comments on this proposed AD by December 15, 
2008.

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 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

[[Page 64895]]

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: Binh Tran, Aerospace Engineer, Systems 
and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 
(425) 917-6485; 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-2008-1143; 
Directorate Identifier 2008-NM-136-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 May 8, 2006, we issued AD 2006-10-17, amendment 39-14601 (71 FR 
28766, May 18, 2006), for certain Boeing Model 737-600, -700, -700C, -
800, and -900 series airplanes. That AD requires replacing brackets 
that hold the P5 panel to the airplane structure, the standby compass 
bracket assembly, the generator drive and standby power module, and the 
air conditioning module. That AD also requires, among other actions, 
inspecting for wire length and for damage of the connectors and the 
wire bundles, and doing applicable corrective actions if necessary. 
That AD resulted from an electrical burning smell in the flight 
compartment. We issued that AD to prevent wire bundles from contacting 
the overhead dripshield panel and modules in the P5 overhead panel, 
which could result in electrical arcing and shorting of the electrical 
connector and consequent loss of several critical systems essential for 
safe flight.

Actions Since Existing AD Was Issued

    Since we issued AD 2006-10-17, a review of an operator's compliance 
document revealed that an operational test of only the crew oxygen 
pressure indication in the P5-14 panel had been done (the passenger 
oxygen system was not tested). The operator had done the operational 
test in accordance with Boeing Service Bulletin 737-24A1141, Revision 
2, dated December 1, 2005 (referred to as an appropriate source of 
service information for accomplishing certain actions required by AD 
2006-10-17). Paragraph 3.B., ``Work Instructions,'' paragraphs 92 and 
93, note (b), of the service bulletin refers to Chapter 35-12-00/501 of 
737-600/700/800/900 Airplane Maintenance Manual (AMM) as the 
appropriate source of service information for accomplishing the 
operational test on both the passenger oxygen system and crew oxygen 
pressure indication. However, Chapter 35-12-00/501 describes procedures 
for an operational test of only the crew oxygen pressure indication. 
Chapter 35-22-00/501 describes procedures for an operational test of 
the passenger oxygen system.
    If an operational test of the passenger oxygen system in the P5-14 
panel is not done, an improperly functioning passenger oxygen system 
could go undetected and result in the failure of the passenger oxygen 
mask to deploy and possible incapacitation of passengers during a 
depressurization event.

Relevant Service Information

    We have reviewed Boeing Service Bulletin 737-24A1141, Revision 3, 
dated February 20, 2008. The inspections, replacements, wiring changes, 
and corrective actions specified in Revision 3 of service bulletin are 
essentially identical to those specified in Revision 2 of the service 
bulletin. Revision 3 clarifies the Accomplishment Instructions, changes 
airplane operators (no additional airplanes have been added to the 
Effectivity of the service bulletin), and corrects typographical 
errors, including the incorrect AMM reference described previously. 
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 other airplanes of the 
same type design. For this reason, we are proposing this AD, which 
would supersede AD 2006-10-17 and would retain the requirements of the 
existing AD. This proposed AD would also require doing an additional 
operational test of the P5-14 panel and accomplishing the actions 
specified in the service information described previously.

Costs of Compliance

    There are about 740 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 333 airplanes of 
U.S. registry.
    For all airplanes, the required inspection, replacements, and 
wiring change that are required by AD 2006-10-17 and retained in this 
proposed AD take about 16 or 18 work hours per airplane (depending on 
airplane configuration), at an average labor rate of $80 per work hour. 
Required parts would cost about $10,231 or $11,139 per airplane 
(depending on the kit). Based on these figures, the estimated cost of 
the replacements and inspections required by this proposed AD for U.S. 
operators is between $3,833,163 and $4,188,807, or between $11,511 and 
$12,579 per airplane.
    For certain airplanes, the modification of the generator drive and 
standby power module assembly that is required by AD 2006-10-17 and 
retained in this proposed AD takes about 2 work hours per airplane, at 
an average labor rate of $80 per work hour. The airplane manufacturer 
states that it will supply required parts to operators at no cost. 
Based on these figures, the estimated cost of this modification 
proposed by this AD is $160 per airplane.
    For certain other airplanes, the modification of the air 
conditioning module assembly that is required by AD 2006-10-17 and 
retained in this proposed AD takes about 1 work hour per airplane, at 
an average labor rate of $80 per work hour. The airplane manufacturer 
states that it will supply required parts to operators at no cost. 
Based on these figures, the estimated cost of this modification 
proposed by this AD is $80 per airplane.
    For certain airplanes, the new proposed action would take about 21 
or 23 work hours per airplane depending on the airplane configuration, 
at an average labor rate of $80 per work hour. Based on these figures, 
the estimated cost of the new actions specified in this proposed AD for 
U.S. operators is $1,680 or $1,840 per airplane, depending on the 
airplane configuration.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue

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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 39-14601 (71 FR 28766, May 18, 2006) and adding the 
following new airworthiness directive (AD):

Boeing: Docket No. FAA-2008-1143; Directorate Identifier 2008-NM-
136-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by December 
15, 2008.

Affected ADs

    (b) This AD supersedes AD 2006-10-17.

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 Service Bulletin 737-24A1141, Revision 3, dated 
February 20, 2008.

Unsafe Condition

    (d) This AD results from a report of an electrical burning smell 
in the flight compartment. We are issuing this AD to prevent wire 
bundles from contacting the overhead dripshield panel and modules in 
the P5 overhead panel, which could result in electrical arcing and 
shorting of the electrical connector and consequent loss of several 
critical systems essential for safe flight; and to ensure proper 
operation of the passenger oxygen system. If an improperly 
functioning passenger oxygen system goes undetected, the passenger 
oxygen mask could fail to deploy and result in possible 
incapacitation of passengers during a depressurization event.

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.

Requirements of AD 2006-10-17

Inspection/Replacements/Wiring Changes/Corrective Actions

    (f) Within 36 months after June 22, 2006 (the effective date of 
AD 2006-10-17), do the actions in paragraphs (f)(1) through (f)(5) 
of this AD by accomplishing all the applicable actions specified in 
the Accomplishment Instructions of Boeing Service Bulletin 737-
24A1141, Revision 2, dated December 1, 2005, except as provided by 
paragraph (i) of this AD. Any applicable corrective actions must be 
done before further flight.
    (1) Replace the five brackets that hold the P5 panel to the 
airplane structure with new brackets;
    (2) Do a general visual inspection for wire length and damage of 
the connectors and the wire bundles, and applicable corrective 
actions;
    (3) Make wiring changes;
    (4) Replace the standby compass bracket assembly with a new 
assembly; and
    (5) Replace the stud assemblies with new assemblies.

    Note 1: For the purposes of this AD, a general visual inspection 
is: ``A visual examination of an interior or exterior area, 
installation, or assembly to detect obvious damage, failure, or 
irregularity. This level of inspection is made from within touching 
distance unless otherwise specified. A mirror may be necessary to 
ensure visual access to all surfaces in the inspection area. This 
level of inspection is made under normally available lighting 
conditions such as daylight, hangar lighting, flashlight, or 
droplight and may require removal or opening of access panels or 
doors. Stands, ladders, or platforms may be required to gain 
proximity to the area being checked.''

    (g) Actions done before June 22, 2006, in accordance with Boeing 
Alert Service Bulletin 737-24A1141, Revision 1, dated December 23, 
2004, are acceptable for compliance with the requirements of 
paragraph (f) of this AD.

Concurrent Requirements

    (h) Before or concurrently with the requirements of paragraph 
(f) of this AD, do the applicable action specified in Table 1 of 
this AD.

                    Table 1--Concurrent Requirements
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   For airplanes identified in Boeing
      Component Service Bulletin--                   Action--
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(1) 233A3205-24-01, dated July 26, 2001  Modify the generator drive and
                                          standby power module assembly
                                          in accordance with the
                                          Accomplishment Instructions of
                                          the Service Bulletin.
(2) 69-37319-21-02, Revision 1, dated    Modify the air conditioning
 August 30, 2001.                         module assembly in accordance
                                          with the Accomplishment
                                          Instructions of the Service
                                          Bulletin.
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New Actions Required by This AD

New Service Bulletin Revision

    (i) As of the effective date of this AD, use only the 
Accomplishment Instructions of Boeing Service Bulletin 737-24A1141, 
Revision 3, dated February 20, 2008, to do all the applicable 
actions required by paragraph (f) of this AD.

Additional Operational Test

    (j) For airplanes on which the actions required by paragraph (f) 
of this AD have been done in accordance with Boeing Service Bulletin 
737-24A1141, Revision 2, dated December 1, 2005, before the 
effective date of this AD: Within 12 months after the effective date 
of this AD, do an operational test of the P5-14 panel in accordance 
with paragraphs 3.B.92. and 3.B.93., as applicable, of the 
Accomplishment Instructions of Boeing Service Bulletin 737-24A1141, 
Revision 3, dated February 20, 2008.

Alternative Methods of Compliance (AMOCs)

    (k)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, ATTN: Binh Tran, Aerospace Engineer, Systems and Equipment 
Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 
Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6485; 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.
    (3) AMOCs approved previously in accordance with AD 2006-10-17 
are approved as AMOCs for the corresponding provisions of this AD.

    Issued in Renton, Washington, on October 20, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-25990 Filed 10-30-08; 8:45 am]
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