AD 2000-23-25

[Federal Register Volume 65, Number 229 (Tuesday, November 28, 2000)]
[Rules and Regulations]
[Pages 70781-70783]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-29603]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-353-AD; Amendment 39-11998; AD 2000-23-25]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, 747-200, 747-300, 
747SP, and 747SR Series Airplanes Powered by Pratt & Whitney JT9D-3 and 
JT9D-7 Series Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 747-100, 747-200, 747-300, 747SP, 
and 747SR series airplanes powered by Pratt & Whitney JT9D-3 or JT9D-7 
series engines. This action requires inspections of the vertical chords 
of the aft torque bulkhead of the outboard nacelle struts, and 
corrective action, if necessary. This action also provides optional 
terminating action for the inspections. This action is necessary to 
detect and correct cracking of the vertical chords adjacent to the 
lower spar fitting, which could result in separation of the diagonal 
brace load path. Continued operation with a separated diagonal brace 
load path increases loads on the upper link, midspar fitting, and dual 
side links, which could result in separation of the strut and engine 
from the airplane. This action is intended to address the identified 
unsafe condition.

DATES: Effective December 13, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 13, 2000.
    Comments for inclusion in the Rules Docket must be received on or 
before January 29, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-353-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 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: 
9-anm-

[[Page 70782]]

<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="5b323a29383436363e352f1b3d3a3a753c342d">[email&#160;protected]</a>. Comments sent via fax or the Internet must contain 
``Docket No. 2000-NM-353-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 this AD 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; or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: 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.

SUPPLEMENTARY INFORMATION: The FAA has received numerous reports of 
fatigue cracking of the vertical chords of the aft torque bulkhead of 
the outboard nacelle struts on certain Boeing Model 747-100, 747-200, 
747-300, 747SR, and 747SP series airplanes powered by Pratt & Whitney 
JT9D-3 or JT9D-7 series engines. The cracks have been found adjacent to 
the lower spar fitting. Such cracking of the vertical chords adjacent 
to the lower spar fitting could result in separation of the diagonal 
brace load path. Continued operation with a separated diagonal brace 
load path, if not corrected, increases loads on the upper link, midspar 
fitting, and dual side links, which could result in separation of the 
strut and engine from the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-54A2201, dated September 28, 2000, which describes procedures for 
repetitive detailed visual, ultrasonic, and surface eddy current 
inspections to detect cracking of the vertical chords of the aft torque 
bulkhead of the outboard nacelle struts. The service bulletin also 
describes procedures for a modification that involves installation of 
doublers on the vertical chords, which constitutes terminating action 
for the repetitive inspections.
    The service bulletin provides for deferment of the initial 
inspections if Boeing Service Letter 747-SL-54-055, dated April 24, 
1998, has been accomplished. That service letter recommends 
accomplishment of detailed visual and high frequency eddy current 
inspections of the chords of the aft torque bulkhead during 
modification of the nacelle strut. The FAA finds that, if the 
inspections recommended in Boeing Service Letter 747-SL-54-055 were 
accomplished during the modification of the nacelle strut and wing in 
accordance with AD 95-10-16, amendment 39-9233 (60 FR 27008, May 22, 
1995), the initial inspections required by this AD may be deferred 
until 3,000 flight cycles after accomplishment of Boeing Service Letter 
747-SL-54-055.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design, this AD is 
being issued to detect and correct cracking of the vertical chords 
adjacent to the lower spar fitting, which could result in separation of 
the diagonal brace load path. This AD requires accomplishment of the 
inspections specified in the service bulletin described previously, 
except as discussed below.

Interim Action

    This is considered to be interim action. The FAA is currently 
considering requiring the modification specified in the service 
bulletin, which will constitute terminating action for the repetitive 
inspections required by this AD action. However, the planned compliance 
time for the installation of the modification is sufficiently long so 
that notice and opportunity for prior public comment will be 
practicable.

Difference Between Service Bulletin and This AD

    Operators should note that, although the service bulletin specifies 
that the manufacturer may be contacted for disposition of certain 
repair conditions, this AD requires the repair of those conditions to 
be accomplished in accordance with a method approved by the FAA, or in 
accordance with data meeting the type certification basis of the 
airplane approved by a Boeing Company Designated Engineering 
Representative who has been authorized by the FAA to make such 
findings.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    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 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 rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-353-AD.'' The postcard will be date stamped 
and returned to the commenter.

Regulatory Impact

    The regulations adopted herein will 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 final rule does not have federalism 
implications under Executive Order 13132.

[[Page 70783]]

    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

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

2000-23-25  Boeing: Amendment 39-11998. Docket 2000-NM-353-AD.

    Applicability: Model 747-100, 747-200, 747-300, 747SP, and 747SR 
series airplanes powered by Pratt & Whitney JT9D-3 or JT9D-7 series 
engines; listed in Boeing Alert Service Bulletin 747-54A2201, dated 
September 28, 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 (e) 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 detect and correct cracking of the vertical chords adjacent 
to the lower spar fitting, which could result in separation of the 
diagonal brace load path and lead to separation of the strut and 
engine from the airplane, accomplish the following:

Inspections

    (a) Except as provided by paragraph (b) of this AD, prior to the 
accumulation of 14,000 total flight cycles, or within 90 days after 
the effective date of this AD, whichever occurs later: Accomplish 
paragraphs (a)(1) and (a)(2) of this AD.
    (1) Perform a detailed visual inspection to detect cracking of 
the vertical chords of the aft torque bulkhead of the outboard 
nacelle struts, in accordance with Part 2 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-54A2201, dated 
September 28, 2000. Thereafter, repeat this inspection at intervals 
not to exceed 600 flight cycles until paragraph (d) of this AD is 
accomplished.
    (2) Perform surface eddy current and ultrasonic inspections to 
detect cracking of the vertical chords of the aft torque bulkhead of 
the outboard nacelle struts, in accordance with Part 3 of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
54A2201, dated September 28, 2000. Thereafter, repeat these 
inspections at intervals not to exceed 1,200 flight cycles until 
paragraph (d) of this AD is accomplished.

Optional Compliance Time

    (b) If Boeing Service Letter 747-54-055, dated April 24, 1998, 
was accomplished on the airplane during the modification of the 
nacelle strut in accordance with AD 95-10-16, amendment 39-9233: 
Accomplishment of the initial inspection in paragraph (a) of this AD 
may be deferred until 3,000 flight cycles after accomplishment of 
the service letter.

Repair

    (c) If any cracking is detected during any inspection required 
by this AD: Prior to further flight, repair in accordance with a 
method approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA; or in accordance with data meeting the type 
certification basis of the airplane approved by a Boeing Company 
Designated Engineering Representative who has been authorized by the 
Manager, Seattle ACO, to make such findings. For a repair method to 
be approved by the Manager, Seattle ACO, as required by this 
paragraph, the approval letter must specifically reference this AD.

Optional Terminating Action

    (d) Accomplishment of the modification specified in Part 4 of 
Boeing Alert Service Bulletin 747-54A2201, dated September 28, 2000, 
constitutes terminating action for the repetitive inspections 
required by paragraph (a) of this AD.

Alternative Methods of Compliance

    (e) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (f) 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.

Incorporation by Reference

    (g) Except as provided by paragraph (c) of this AD, the actions 
shall be done in accordance with Boeing Alert Service Bulletin 747-
54A2201, dated September 28, 2000. This incorporation by reference 
was approved by the Director of the Federal Register in accordance 
with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from 
Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 
98124-2207. Copies may be inspected at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the 
Office of the Federal Register, 800 North Capitol Street, NW., suite 
700, Washington, DC.

Effective Date

    (h) This amendment becomes effective on December 13, 2000.

    Issued in Renton, Washington, on November 14, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-29603 Filed 11-27-00; 8:45 am]
BILLING CODE 4910-13-U