[Federal Register Volume 67, Number 169 (Friday, August 30, 2002)]
[Proposed Rules]
[Pages 55739-55742]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-22130]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-17-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes 
Powered by General Electric (GE) 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

[[Page 55740]]

directive (AD) that is applicable to certain Boeing Model 747 series 
airplanes powered by GE CF6-80C2 series engines. This proposal would 
require repetitive inspections and torque checks to find discrepancies 
of the fasteners that attach the diagonal brace fittings of the lower 
spar to the inboard engine struts, and modification of the fasteners if 
discrepancies are found. This proposal also would require eventual 
modification of all the fasteners, which would end the repetitive 
inspections and checks. This action is necessary to find and fix 
discrepant fasteners of the diagonal brace fittings, which could result 
in reduced structural integrity of the diagonal brace-to-strut 
attachment, and possible separation of the strut and engine from the 
airplane. This action is intended to address the identified unsafe 
condition.

DATES: Comments must be received by October 15, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-17-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: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2001-NM-17-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:
    Technical Information: Tamara Anderson, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2771; fax (425) 227-1181.
    Other Information: Sandi Carli, Airworthiness Directive Technical 
Editor/Writer; telephone (425) 687-4243, fax (425) 687-4248. Questions 
or comments may also be sent via the Internet using the following 
address: [email protected]. Questions or comments sent via the 
Internet as attached electronic files must be formatted in Microsoft.

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:
     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.
     For each issue, state what specific change to the proposed 
AD is being requested.
     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 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 2001-NM-17-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. 2001-NM-17-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that, during installation 
of the modification required by AD 95-13-06 (described below), loose 
and fractured fasteners of the diagonal brace fitting were found on 
certain Boeing Model 747 series airplanes powered by GE CF6-80C2 series 
engines. The cause of the fastener discrepancies was determined to be 
fatigue. The diagonal brace fitting of the lower spar is located at the 
lower aft end of the strut and provides the structural attachment of 
the strut to the diagonal brace. The fasteners attach the fitting to 
the inboard strut. Cracking of the fitting or surrounding structure due 
to loose and/or fractured fasteners could lead to the loss of the 
diagonal brace-to-strut attachment and possible loss of the strut and 
engine from the airplane.

Other Relevant Rulemaking

    On June 16, 1995, we issued AD 95-13-06, amendment 39-9286 (60 FR 
33338, June 28, 1995). That AD applies to certain Boeing Model 747 
series airplanes equipped with General Electric CF6-80C2 series engines 
or Pratt & Whitney Model PW4000 series engines. That AD requires 
modification of the nacelle strut and wing structure, inspections and 
checks to detect discrepancies, and correction of discrepancies.

Explanation of Relevant Service Information

    We have reviewed and approved Boeing Alert Service Bulletin 747-
54A2207, dated November 16, 2000, which describes procedures for 
repetitive inspections and rotational checks (torque checks) to find 
discrepancies of the fasteners that attach the diagonal brace fittings 
of the lower spar to the inboard engine struts, and modification of the 
fasteners if discrepancies (loose, fractured, missing fastener heads) 
are found. Doing the modification eliminates the need for the 
repetitive inspections and checks. The modification includes doing a 
high frequency eddy current inspection (HFEC) of the fastener holes 
where discrepant fasteners are found and other indicated fastener 
holes, oversizing the holes, and installing new fasteners. The service 
bulletin specifies to contact Boeing if cracking is found during the 
HFEC inspection. Accomplishment of the actions specified in the service 
bulletin 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 bulletin

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described previously, except as discussed below.

Differences Between the Service Bulletin and This Proposed AD

    The service bulletin does not provide a compliance time for 
accomplishing the modification, but the proposed AD would require that 
the modification be accomplished within 72 months after the effective 
date of this AD. In developing an appropriate compliance time for this 
proposed AD, we considered not only the manufacturer's recommendation, 
but also the degree of urgency associated with addressing the unsafe 
condition, the average utilization of the affected fleet, and the time 
necessary to perform the modification. In light of all of these 
factors, we find a 72-month compliance time for completing the required 
modification to be warranted, in that it represents an appropriate 
interval of time allowable for affected airplanes to continue to 
operate without compromising safety.
    Although the service bulletin specifies that the manufacturer may 
be contacted for disposition of certain repairs, this proposed AD would 
require such repairs to be accomplished per a method approved by us, or 
per data meeting the type certification basis of the airplane approved 
by a Boeing Company Designated Engineering Representative who we have 
authorized to make such findings.

Cost Impact

    There are approximately 237 airplanes of the affected design in the 
worldwide fleet. We estimate that 14 airplanes of U.S. registry would 
be affected by this proposed AD.
    It would take approximately 5 work hours per airplane to accomplish 
the proposed inspection and torque check at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of this 
proposed action on U.S. operators is estimated to be $4,200, or $300 
per airplane, per inspection/check cycle.
    It would take approximately 76 work hours per airplane to 
accomplish the proposed terminating action at an average labor rate of 
$60 per work hour. Required parts would cost approximately $4,268 per 
airplane. Based on these figures, the cost impact of this proposed 
action on U.S. operators is estimated to be $123,592, or $8,828 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 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 2001-NM-17-AD.

    Applicability: Model 747-200B, -300, -400, -400D, and -400F 
series airplanes powered by GE CF6-80C2 series engines, as listed in 
Boeing Alert Service Bulletin 747-54A2207, dated November 16, 2000, 
certificated in any category.

    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 in accordance with paragraph (d) 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 find and fix discrepant fasteners of the diagonal brace 
fittings, which could result in reduced structural integrity of the 
diagonal brace-to-strut attachment, and possible separation of the 
strut and engine from the airplane, accomplish the following:

Repetitive Inspections and Torque Checks/Corrective Action

    (a) Do a detailed inspection and torque check to find 
discrepancies of the fasteners (e.g., loose, fractured, or missing 
fastener heads) that attach the diagonal brace fittings of the lower 
spar to the inboard engine struts, at the applicable time specified 
in paragraph (a)(1) or (a)(2) of this AD, per Boeing Alert Service 
Bulletin 747-54A2207, dated November 16, 2000. Repeat the inspection 
and check after that every 8,000 flight hours or 24 months, 
whichever is first.

    Note 2: For the purposes of this AD, a detailed inspection is 
defined as: ``An intensive visual examination of a specific 
structural area, system, installation, or assembly to detect damage, 
failure, or irregularity. Available lighting is normally 
supplemented with a direct source of good lighting at intensity 
deemed appropriate by the inspector. Inspection aids such as mirror, 
magnifying lenses, etc., may be used. Surface cleaning and elaborate 
access procedures may be required.''

    (1) For airplanes that have not been modified as required by AD 
95-13-06, amendment 39-9286 (all Group 2 airplanes): Before the 
accumulation of 6,000 total flight cycles or within 24 months after 
the effective date of this AD, whichever is later.
    (2) For airplanes that have been modified as required by AD 95-
13-06 (all Group 1 airplanes): Before the accumulation of 6,000 
total flight cycles after doing the modification or within 24 months 
after the effective date of this AD, whichever is later.
    (b) If no discrepancy is found during any inspection/check 
required by paragraph (a) of this AD, repeat the inspection/check at 
the time specified in paragraph (a) of this AD until the terminating 
action specified in paragraph (c) of this AD is done. If any 
discrepancy is found, do the applicable actions specified in 
paragraph (b)(1) or (b)(2) of this AD.
    (1) If any discrepancy is found in the area that connects the 
diagonal brace fitting to the

[[Page 55742]]

aft bulkhead, before further flight, repair per a method approved by 
the Manager, Seattle Aircraft Certification Office (ACO), FAA; or 
per data meeting the type certification basis of the airplane 
approved by a Boeing Company Designated Engineering Representative 
(DER) who has been authorized by the Manager, Seattle ACO, to make 
such findings. For a repair method to be approved, as required by 
this paragraph, the approval must specifically reference this AD.
    (2) If any discrepancy is found in any area other than that 
specified in paragraph (b)(1) of this AD, before further flight, do 
the terminating action specified in paragraph (c) of this AD.

Terminating Action

    (c) Except as provided by paragraph (b)(2) of this AD, within 72 
months after the effective date of this AD: Do the modification 
(including doing a high frequency eddy current (HFEC) inspection, 
oversizing the fastener holes, and installing new fasteners) as 
specified in and per Figure 3 of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 747-54A2207, dated November 16, 2000. 
If any cracking is found during the HFEC inspection and the service 
bulletin specifies contacting Boeing for repair procedures, before 
further flight, repair per a method approved by the Manager, Seattle 
ACO; or per data meeting the type certification basis of the 
airplane approved by a Boeing Company DER who has been authorized by 
the Manager, Seattle ACO, to make such findings. For a repair method 
to be approved, as required by this paragraph, the approval must 
specifically reference this AD. Accomplishment of the actions 
specified in this paragraph ends the repetitive inspections and 
checks.

Alternative Methods of Compliance

    (d) 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 ACO. Operators shall submit 
their requests through an appropriate FAA Principal Maintenance 
Inspector, 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

    (e) Special flight permits may be issued in accordance with 
sections 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 August 20, 2002.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-22130 Filed 8-29-02; 8:45 am]
BILLING CODE 4910-13-P