[Federal Register Volume 70, Number 51 (Thursday, March 17, 2005)]
[Proposed Rules]
[Pages 12986-12988]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-5289]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-20629; Directorate Identifier 2004-NM-266-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 767-300 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 767-300 series airplanes. This proposed AD 
would require replacing the frequency converters used to supply power 
for medical outlets with modified frequency converters, and related 
actions. This proposed AD is prompted by a report indicating that a 
hard short circuit condition between the output of certain frequency 
converters and their downstream circuit breakers will produce a 
continuous output current that could cause the undersized output wiring 
to overheat when the frequency converters fail to shut off. We are 
proposing this AD to prevent overheating of the output wiring of the 
frequency converters, which could result in the failure of a wire 
bundle and consequent adverse effects on other systems sharing the 
affected wire bundle.

DATES: We must receive comments on this proposed AD by May 2, 2005.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, 
Washington, DC 20590.
     By fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, 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.
    You can examine the contents of this AD docket on the Internet at 
http://dms.dot.gov, or in person at the Docket Management Facility, 
U.S. Department of Transportation, 400 Seventh Street, SW., room PL-
401, on the plaza level of the Nassif Building, Washington, DC. This 
docket number is FAA-2005-20629; the directorate identifier for this 
docket is 2004-NM-266-AD.

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 98055-4056; telephone 
(425) 917-6485; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2005-20629; 
Directorate Identifier 2004-NM-266-AD'' in the subject line of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments submitted by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You can review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
can visit http://dms.dot.gov.

Examining the Docket

    You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the DMS receives them.

Discussion

    We have received a report indicating that analysis by the airplane 
manufacturer has shown that a hard short circuit condition between the 
output of certain frequency converters and their downstream, load 
circuit breakers will produce a continuous output current of 170--200 
percent of nominal, on certain Boeing Model 747-200F and -400 series 
airplanes; Model 767-300 and -400ER series airplanes; and Model 777 
series airplanes. The continuous current could cause the undersized 
output wiring to exceed its wire temperature rating of 150 degrees 
Celsius and consequently overheat when the frequency converters fail to 
shut off in response to a short circuit or overload. Overheating of the 
output wiring, if not corrected, could result in the failure of a wire 
bundle and consequent adverse effects on other systems sharing the 
affected wire bundle.

Other Related Rulemaking

    On September 1, 2004, we proposed to amend 14 CFR part 39 with an 
AD for certain Boeing Model 747-200F and -400 series airplanes; Model 
767-400ER series airplanes; and Model 777 series airplanes. That 
action, published in the Federal Register on September 13, 2004 (69 FR 
55120), proposed to require replacing the frequency converter(s) used 
to supply electrical power for utility outlets (for the galley, medical 
equipment, or personal computers) with modified frequency converter(s). 
That action also proposed to require any specified action and related 
concurrent actions, as necessary. That proposed AD was prompted by a 
report that a hard short condition between the frequency

[[Page 12987]]

converter's output and its downstream circuit breakers will produce a 
continuous circuit that could cause the undersized output wiring to 
overheat. The actions required by that proposed AD are intended to 
prevent the overheating of the frequency converter's undersized output 
wiring, which could lead to the failure of a wire bundle, and 
consequent adverse effects on other systems sharing the affected wire 
bundle.
    Since issuance of that proposed AD, we have determined that the 
same unsafe condition addressed in that proposed AD also exists on 
certain Model 767-300 series airplanes. We have been advised that 54 
Model 767-300 series airplanes were delivered with outlet installations 
using frequency converters affected by that proposed AD. Therefore, 
these additional airplanes are also subject to the same unsafe 
condition addressed in that proposed AD.

Relevant Service Information

    We have reviewed Boeing Service Bulletin 767-25-0334, Revision 1, 
dated June 19, 2002. The service bulletin describes procedures for 
replacing the frequency converters used to supply power for medical 
outlets with modified frequency converters, and related actions. 
Replacement includes removing and sending the frequency converters to 
the vendor (Avionic Instruments, Inc.) for rework, and installing the 
reworked frequency converters. The other related actions include the 
following:
     Collaring and labeling the circuit breaker(s) of the 
frequency converter input as ``INOP'' and removing the label(s) after 
installation of the modified frequency converters;
     Capping and stowing the wire bundles of the frequency 
converters and reinstalling/connecting the wire bundles after 
installation of the modified frequency converters;
     Installing a ``DEACTIVATED'' label on the frequency 
converter outlets and removing the labels after installation of the 
modified frequency converters;
     Contacting the vendor for coordination of the rework; and
     Doing a functional test of the replaced frequency 
converters.
    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. Therefore, we are proposing this AD, which 
would require accomplishing the actions specified in the service 
information described previously.
    We have considered a number of factors in determining whether to 
issue a separate proposed AD or a supplemental notice of proposed 
rulemaking (NPRM) to the ``related'' NPRM (69 FR 55120, September 13, 
2004). Although the 54 additional airplanes included in the 
applicability of this proposed AD were inadvertently omitted from the 
``related'' NPRM, issuing a supplemental NPRM would require reopening 
the comment period of the ``related'' NPRM. However, to delay that 
action would be inappropriate, since we have determined that an unsafe 
condition exists and that modifications need to be made to ensure 
continued safety. We also have considered the entire fleet size that 
would be affected by issuing a supplemental NPRM and the fact that no 
new work would be required for airplanes affected by the ``related'' 
NPRM. In light of this, we have determined that a less burdensome 
approach is to propose a separate AD applicable only to the additional 
airplanes. This proposed AD would not reopen the comment period of the 
``related'' NPRM; airplanes listed in the applicability of the 
``related'' NPRM would be required to comply with the requirements of 
that proposed AD. This proposed AD is a separate AD action that is 
applicable only to certain Boeing Model 767-300 series airplanes, 
certificated in any category.

Costs of Compliance

    There are about 55 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 54 airplanes of 
U.S. registry. The proposed actions would take about 1 work hour per 
frequency converter, at an average labor rate of $65 per work hour. 
There are about 2 frequency converters per airplane. Based on these 
figures, the estimated cost of the proposed AD for U.S. operators is 
$7,020, or $130 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. 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 FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

Boeing: Docket No. FAA-2005-20629; Directorate Identifier 2004-NM-
266-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by May 2, 2005.

[[Page 12988]]

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to certain Boeing Model 767-300 series 
airplanes, certificated in any category; as listed in Boeing Service 
Bulletin 767-25-0334, Revision 1, dated June 19, 2002.

Unsafe Condition

    (d) This AD was prompted by a report indicating that a hard 
short circuit condition between the output of certain frequency 
converters and their downstream circuit breakers will produce a 
continuous output current that could cause the undersized output 
wiring to overheat when the frequency converters fail to shut off. 
We are issuing this AD to prevent overheating of the output wiring 
of the frequency converters, which could result in the failure of a 
wire bundle and consequent adverse effects on other systems sharing 
the affected wire bundle.

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.

Replace Frequency Converters

    (f) Within 18 months after the effective date of this AD, 
replace the frequency converters used to supply power for medical 
outlets with modified frequency converters, and do any related 
actions, by doing all of the actions specified in the Accomplishment 
Instructions of Boeing Service Bulletin 767-25-0334, Revision 1, 
dated June 19, 2002.

Credit for Previous Service Bulletin

    (g) Actions done before the effective date of this AD in 
accordance with Boeing Service Bulletin 767-25-0334, dated November 
7, 2002, are acceptable for compliance with the requirements of 
paragraph (f) of this AD.

Alternative Methods of Compliance (AMOCs)

    (h) 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.

    Issued in Renton, Washington, on March 8, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-5289 Filed 3-16-05; 8:45 am]
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