[Federal Register Volume 65, Number 234 (Tuesday, December 5, 2000)]
[Proposed Rules]
[Pages 75881-75883]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-30949]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-275-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400 and 767 Series 
Airplanes Equipped With General Electric CF6-80C2 Series Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 747-400 and 
767 series airplanes. This proposal would require modification of the 
core cowl assemblies of the engines. This action is necessary to 
prevent failure of the core cowl latches during an engine fire, and 
consequent in-flight separation of an engine core cowl and its strut 
fire barrier from the airplane. This action is intended to address the 
identified unsafe condition.

DATES: Comments must be received by January 19, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-275-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
<a href="/cdn-cgi/l/email-protection#dce5f1bdb2b1f1b2acaeb1bfb3b1b1b9b2a89cbabdbdf2bbb3aa"><span class="__cf_email__" data-cfemail="1a23377b747737746a6877797577777f746e5a7c7b7b347d756c">[email protected]</span></a>. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-275-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 227-2686; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Submit comments using the following format:
    <bullet> Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
    <bullet> For each issue, state what specific change to the proposed 
AD is being requested.
    <bullet> Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this

[[Page 75882]]

proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-275-AD.'' The postcard will be date stamped 
and returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2000-NM-275-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA received a report indicating an in-flight engine fire 
occurred on a Model 747-400 series airplane powered by General Electric 
CF6-80C2 series engines. The fire was caused by a fuel leak in the 
Integrated Drive Generator fuel/oil heat exchanger and was ignited by 
fuel vapors coming in contact with the hot turbine case. The fire was 
located directly under the core cowls and caused significant damage to 
the cowls, which weakened the aluminum structure supporting the steel 
latches that hold the core cowls closed. Opening of the core cowls 
during an engine fire breaches the engine fire containment design 
features and could allow the engine fire to spread to the strut and 
wing. (Model 767 series airplanes powered by General Electric CF6-80C2 
series engines have a similar design.) Such conditions, if not 
corrected, could result in separation of an engine core cowl and its 
strut fire barrier from the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletins 747-71-
2285 (for Model 747-400 series airplanes) and 767-71-0088 (for Model 
767 series airplanes), both dated October 8, 1998, which describe 
procedures for modification of the left- and right-hand core cowl 
assemblies of the engines. The modification includes, but is not 
limited to, replacement of the aluminum forward and extension frames 
located between the forward hinge and the latch in each core cowl with 
inconel frames that provide fireproof reinforcement to the core cowl 
latches. The Boeing service bulletins reference ROHR Service Bulletin 
TBC/80C2-NAC-71-028, dated August 1, 1998, as an additional source of 
service information for accomplishment of the modification. 
Accomplishment of the actions specified in the service bulletins is 
intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require accomplishment of the actions specified in 
the service bulletins described previously, except as discussed below.

Difference Between Service Bulletins and This Proposed AD

    Operators should note that this proposed AD would require 
modification of the core cowl assemblies of the engines to be 
accomplished within 24 months after the effective date of this AD. The 
service bulletins recommend that this modification should be 
accomplished ``as soon as manpower and facilities are available.'' But 
in developing an appropriate compliance time for the proposed 
modification, the FAA considered not only the manufacturer's 
recommendation and the degree of urgency associated with addressing the 
subject unsafe condition, but also the average utilization of the 
affected fleet and the time necessary to perform the modification. The 
FAA has determined that 24 months represents an appropriate interval of 
time allowable wherein the modification can be accomplished during 
scheduled airplane maintenance and an ample number of required parts 
will be available for modification of the U.S. fleet within the 
proposed compliance period. The FAA also finds that such a compliance 
time will not adversely affect the safety of the affected airplanes.

Cost Impact

    There are approximately 563 airplanes of the affected design in the 
worldwide fleet.
    The FAA estimates that 14 Model 747-400 series airplanes of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 168 work hours (42 per engine) per airplane to accomplish 
the proposed modification, and that the average labor rate is $60 per 
work hour. Required parts would cost approximately $84,732 ($21,183 per 
engine) per airplane. Based on these figures, the cost impact of the 
modification proposed by this AD on U.S. operators is estimated to be 
$1,327,368, or $94,812 per airplane.
    The FAA estimates that 64 Model 767 series airplanes of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 84 work hours (42 per engine) per airplane to accomplish 
the proposed modification, and that the average labor rate is $60 per 
work hour. Required parts would cost approximately $42,366 ($21,183 per 
engine) per airplane. Based on these figures, the cost impact of the 
modification proposed by this AD on U.S. operators is estimated to be 
$3,033,984 or $47,406 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed requirements 
of this AD action, and that no operator would accomplish those actions 
in the future if this proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

Regulatory Impact

    The regulations proposed herein 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. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that 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) if promulgated, 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. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation

[[Page 75883]]

Administration proposes to amend part 39 of the Federal Aviation 
Regulations (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. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 2000-NM-275-AD.

    Applicability: Model 747-400 and 767 series airplanes equipped 
with General Electric CF6-80C2 series engines, certificated in any 
category; as listed in Boeing Service Bulletins 747-71-2285 or 767-
71-0088, both dated October 8, 1998.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance per paragraph (c) of this AD. The 
request should include an assessment of the effect of the 
modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent failure of the core cowl latches during an engine 
fire, and consequent in-flight separation of an engine core cowl and 
its strut fire barrier from the airplane, accomplish the following:

Modification

    (a) Within 24 months after the effective date of this AD: Modify 
the left- and right-hand core cowl assemblies of the engines per the 
Accomplishment Instructions of Boeing Service Bulletin 747-71-2285 
(for Model 747-400 series airplanes) or 767-71-0088 (for Model 767 
series airplanes), both dated October 8, 1998.

    Note 2: The Boeing service bulletins reference ROHR Service 
Bulletin TBC/80C2-NAC-71-028, dated August 1, 1998, as an additional 
source of service information for accomplishment of the 
modification.

Spares

    (b) As of 6 months after the effective date of this AD, no one 
may install an aluminum core cowl assembly, part number 224-2301-513 
(left-hand) or 224-2302-539 (right-hand), on any airplane.

Alternative Methods of Compliance

    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA. Operators shall submit their requests through an 
appropriate FAA Principal Operations Inspector or Principal 
Maintenance Inspector, as applicable, who may add comments and then 
send it to the Manager, Seattle ACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permit

    (d) Special flight permits may be issued per Secs. 21.197 and 
21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 
21.199) to operate the airplane to a location where the requirements 
of this AD can be accomplished.

    Issued in Renton, Washington, on November 29, 2000.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-30949 Filed 12-4-00; 8:45 am]
BILLING CODE 4910-13-U


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