Document ID: FAA-2007-0267-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Boeing Model 747-400 and 747-400D Series Airplanes
Posted Date: 2007-12-04T05:00Z

[Federal Register: December 4, 2007 (Volume 72, Number 232)]
[Proposed Rules]               
[Page 68106-68107]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr04de07-21]                         

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Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

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[[Page 68106]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-0267; Directorate Identifier 2007-NM-245-AD]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 747-400 and 747-400D 
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 adopt a new airworthiness directive (AD) 
for certain Boeing Model 747-400 and 747-400D series airplanes. This 
proposed AD would require a general visual inspection of the power 
feeder wire bundle of the auxiliary power unit (APU) where it crosses 
the hydraulic system 4 return tube to determine if parts are installed 
to provide separation between the wire bundle and hydraulic tube. This 
proposed AD would also require related investigative and corrective 
actions if necessary. This proposed AD results from a report that the 
power feeder wire bundle of the APU was found touching the hydraulic 
system return tube during inspection of an airplane. We are proposing 
this AD to prevent insufficient clearance between the wire bundle and 
hydraulic tube that could lead to chafing of the wire bundle, which 
could cause arcing and a consequent hydraulic fluid fire in an area 
outside of the smoke detection and fire extinguishing zone; this 
condition could result in an uncontrolled fire on the airplane.

DATES: We must receive comments on this proposed AD by January 18, 
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 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: Georgios Roussos, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 917-6482; 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-2007-0267; 
Directorate Identifier 2007-NM-245-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 have received a report indicating that the power feeder wire 
bundle of the auxiliary power unit (APU) was found touching the 
hydraulic system return tube during inspection of an in-production 
Boeing Model 747-400 series airplane. Boeing subsequently surveyed 
several in-service airplanes and found that most of the airplanes had 
less than the allowable minimum clearance between the wire bundle and 
hydraulic tube. The wire bundle and hydraulic tube are installed in the 
aft bulk cargo compartment above the ceiling lining, in an area outside 
of the smoke detection and fire extinguishing zone. Insufficient 
clearance between the wire bundle and hydraulic tube could lead to 
chafing of the wire bundle, which could cause arcing and a consequent 
hydraulic fluid fire. This condition, if not corrected, could result in 
an uncontrolled fire on the airplane.

Relevant Service Information

    We have reviewed Boeing Special Attention Service Bulletin 747-24-
2257, Revision 1, dated August 2, 2007. The service bulletin describes 
procedures for doing a general visual inspection of the power feeder 
wire bundle of the APU where it crosses the hydraulic system 4 return 
tube to determine if parts are installed to provide separation between 
the wire bundle and hydraulic tube. The service bulletin also describes 
procedures for doing related investigative actions and corrective 
actions if necessary. The related investigative actions include the 
following actions:
     Measuring the clearance between the wire bundle and 
hydraulic tube to ensure that the clearance is a minimum of 0.5 inch, 
if the wire bundle is clamped directly above the hydraulic tube.
     Doing a general visual inspection for damage to the wire 
bundle where it crosses the hydraulic tube, if two loop clamps and a 
spacer are installed to provide separation, if a plastic tie strap and 
mount and loop clamp are installed to provide separation, or if no 
parts are installed to provide separation.
     Doing a general visual inspection for damage to the 
hydraulic tube where the wire bundle crosses the hydraulic

[[Page 68107]]

tube, if the wire bundle is found damaged. The corrective actions 
include the following actions:
     Adjusting the position of the wire bundle to maximize its 
separation from the hydraulic tube, if the clearance is less than 0.5 
inch.
     Removing any parts installed to provide separation between 
the wire bundle and hydraulic tube.
     Repairing the damaged wire bundle.
     Repairing the damaged hydraulic tube or replacing it with 
a new hydraulic tube.
     Installing a tetrafluoroethylene sleeve on the wire bundle 
and attaching the wire bundle and hydraulic tube with two loop clamps 
and a spacer.
    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 exist or develop on other airplanes 
of this same type design. For this reason, we are proposing this AD, 
which would require accomplishing the actions specified in the service 
information described previously.

Costs of Compliance

    There are about 462 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 61 airplanes of 
U.S. registry. The proposed inspection would take about 1 work hour per 
airplane, at an average labor rate of $80 per work hour. Based on these 
figures, the estimated cost of the proposed AD for U.S. operators is 
$4,880, or $80 per airplane.

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 
adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2007-0267; Directorate Identifier 2007-NM-
245-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by January 
18, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 747-400 and 747-400D series 
airplanes, certificated in any category; as identified in Boeing 
Special Attention Service Bulletin 747-24-2257, Revision 1, dated 
August 2, 2007.

Unsafe Condition

    (d) This AD results from a report that the power feeder wire 
bundle of the auxiliary power unit (APU) was found touching the 
hydraulic system return tube during inspection of an airplane. We 
are issuing this AD to prevent insufficient clearance between the 
wire bundle and hydraulic tube that could lead to chafing of the 
wire bundle, which could cause arcing and a consequent hydraulic 
fluid fire in an area outside of the smoke detection and fire 
extinguishing zone; this condition could result in an uncontrolled 
fire on the airplane.

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.

Inspection and Related Investigative and Corrective Actions

    (f) Within 24 months after the effective date of this AD, do a 
general visual inspection of the power feeder wire bundle of the APU 
where it crosses the hydraulic system 4 return tube to determine if 
parts are installed to provide separation between the wire bundle 
and hydraulic tube, and do all the related investigative and 
corrective actions as applicable, by accomplishing all of the 
actions specified in the Accomplishment Instructions of Boeing 
Special Attention Service Bulletin 747-24-2257, Revision 1, dated 
August 2, 2007. The related investigative and corrective actions 
must be accomplished before further flight after the inspection.

Credit for Actions Done According to Previous Issue of Service Bulletin

    (g) Actions done before the effective date of this AD in 
accordance with Boeing Special Attention Service Bulletin 747-24-
2257, dated May 18, 2006, are acceptable for compliance with the 
corresponding requirements of paragraph (f) of this AD.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle Aircraft Certification Office, 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 November 23, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-23460 Filed 12-3-07; 8:45 am]

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