[Federal Register Volume 67, Number 41 (Friday, March 1, 2002)]
[Rules and Regulations]
[Pages 9396-9399]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-4888]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-363-AD; Amendment 39-12669; AD 2002-05-01]
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 supersedes an existing airworthiness directive 
(AD), applicable to certain Boeing Model 747-100, 747-200, 747-300, 
747SP, and 747SR series airplanes powered by Pratt

[[Page 9397]]

& Whitney JT9D-3 or JT9D-7 series engines. That AD currently requires 
inspections of the vertical chords of the aft torque bulkhead of the 
outboard nacelle struts, corrective action, if necessary, and a 
modification of the vertical chords, which ends the inspections. This 
amendment will reduce the compliance time and repetitive intervals for 
the currently required inspections. These actions are necessary to 
prevent 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. These actions are intended to address the identified 
unsafe condition.

DATES: Effective March 18, 2002.
    The incorporation by reference of Boeing Alert Service Bulletin 
747-54A2201, dated September 28, 2000, as listed in the regulations, 
was approved previously by the Director of the Federal Register as of 
December 13, 2000 (65 FR 70781, November 28, 2000).
    Comments for inclusion in the Rules Docket must be received on or 
before April 30, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-363-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: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2001-NM-363-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: On June 14, 2001, the FAA issued AD 2001-12-
23, amendment 39-12279 (66 FR 33459, June 22, 2001), 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, 
to require inspections of the vertical chords of the aft torque 
bulkhead of the outboard nacelle struts, corrective action, if 
necessary, and a modification of the vertical chords, which ends the 
inspections. That action was prompted by numerous reports of fatigue 
cracking of the vertical chords of the aft torque bulkhead of the 
outboard nacelle struts. The actions required by that AD are intended 
to prevent 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.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the FAA has received new reports of 
cracking in the vertical chords of the aft torque bulkhead. One report 
describes a crack on an airplane that had accumulated 9,479 total 
flight cycles. Paragraph (a) of the existing AD has a compliance 
threshold of 14,000 total flight cycles.
    Another report describes a crack that was found on an airplane that 
had accumulated only 1,590 flight cycles since an inspection per Boeing 
Service Letter 747-54-055, dated April 24, 1998. Paragraph (b) of AD 
2001-12-23 allows deferral of the initial inspections in paragraph (a) 
of that AD for 3,000 flight cycles after accomplishment of Boeing 
Service Letter 747-54-055.
    Based on these new reports, the FAA has determined that the 
existing compliance threshold and repetitive intervals for the 
inspections required by the existing AD may not be adequate to ensure 
that cracking is detected in a timely manner.

Explanation of Requirements of Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of this same type design, this AD 
supersedes AD 2001-12-23 to continue to require inspections of the 
vertical chords of the aft torque bulkhead of the outboard nacelle 
struts, corrective action, if necessary, and a modification of the 
vertical chords, which ends the inspections. This AD will reduce the 
compliance threshold and repetitive intervals for the currently 
required inspections. The actions are required to be accomplished in 
accordance with Boeing Alert Service Bulletin 747-54A2201, dated 
September 28, 2000 (which is referenced in AD 2001-12-23 as the 
appropriate source of service information for certain actions therein), 
except as discussed below.

Differences Between Service Bulletin and This AD

    Operators should note that the compliance thresholds and repetitive 
intervals for the inspections required by this AD are lower than the 
compliance thresholds and repetitive intervals specified in the service 
bulletin. As described previously, the FAA has determined that the 
compliance thresholds and repetitive intervals specified in the service 
bulletin may not be adequate to ensure timely detection of cracking.
    Operators also 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

[[Page 9398]]

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:
     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 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 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 2001-NM-363-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.
    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 removing amendment 39-12279 (66 FR 
33459, June 22, 2001), and by adding a new airworthiness directive 
(AD), amendment 39-12669, to read as follows:

2002-05-01 Boeing: Amendment 39-12669. Docket 2001-NM-363-AD. 
Supersedes AD 2001-12-23, Amendment 39-12279.

    Applicability: Model 747-100, 747-200, 747-300, 747SP, and 747SR 
series airplanes powered by Pratt & Whitney JT9D-3 or JT9D-7 series 
engines; as 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 (h)(1) 
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 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:

Restatement of Requirements of AD 2001-12-23:

Inspections

    (a) Except as provided by paragraphs (b), (e), and (f) of this 
AD, prior to the accumulation of 14,000 total flight cycles, or 
within 90 days after December 13, 2000 (the effective date of AD 
2000-23-25, amendment 39-11998), 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) or (e) 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) or (f) of this AD is accomplished.

    Note 2: For the purposes of this AD, a detailed visual 
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.''

Optional Compliance Time

    (b) For airplanes on which the inspections required by paragraph 
(a) HAVE been accomplished prior to the effective date of this AD: 
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 or 
modification 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.

[[Page 9399]]

Modification (Terminating Action)

    (d) Within 4 years after July 27, 2001 (the effective date of AD 
2001-12-23), do the modification of the vertical chords of the aft 
torque bulkhead of the outboard nacelle struts according to Part 4 
of Boeing Alert Service Bulletin 747-54A2201, dated September 28, 
2000. After this modification, stop the repetitive inspections 
required by paragraph (a), (e), or (f) of this AD, as applicable.

New Requirements of this AD

Detailed Visual Inspections: New Compliance Times

    Note 3: The inspection in paragraph (e) of this AD is identical 
to that in paragraph (a)(1) of this AD. However, the compliance 
threshold (for airplanes not inspected prior to the effective date 
of this AD) and the repetitive intervals for this inspection are 
reduced in paragraph (e) of this AD.

    (e) 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. Do the initial inspection per this paragraph at 
the applicable time specified in paragraph (e)(1) or (e)(2) of this 
AD, and thereafter, repeat this inspection at intervals not to 
exceed 300 flight cycles until paragraph (d) of this AD is 
accomplished. Accomplishment of this paragraph constitutes 
terminating action for inspections in accordance with paragraph 
(a)(1) of this AD.
    (1) For airplanes that have NOT been inspected per paragraph (a) 
of this AD prior to the effective date of this AD: Except as 
provided by paragraph (g) of this AD, inspect at the earlier of the 
times specified in paragraphs (e)(1)(i) and (e)(1)(ii) of this AD.
    (i) Prior to the accumulation of 14,000 total flight cycles.
    (ii) Prior to the accumulation of 7,000 total flight cycles or 
within 90 days after the effective date of this AD, whichever comes 
later.
    (2) For airplanes that HAVE been inspected per paragraph (a) of 
this AD prior to the effective date of this AD: Inspect at the 
earlier of the times specified in paragraphs (e)(2)(i) and 
(e)(2)(ii) of this AD.
    (i) Within 600 flight cycles since the most recent inspection 
per paragraph (a)(1) of this AD.
    (ii) Within 300 flight cycles since the most recent inspection 
per paragraph (a)(1) of this AD, or within 90 days after the 
effective date of this AD, whichever occurs later.

Eddy Current and Ultrasonic Inspections: New Compliance Times

    Note 4: The inspection in paragraph (f) of this AD is identical 
to that in paragraph (a)(2) of this AD. However, the compliance 
threshold (for airplanes not inspected prior to the effective date 
of this AD) and the repetitive intervals for this inspection are 
reduced in paragraph (f) of this AD.

    (f) 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. Do the initial inspection per 
this paragraph at the applicable time specified in paragraph (f)(1) 
or (f)(2) of this AD, and thereafter, repeat this inspection at 
intervals not to exceed 600 flight cycles until paragraph (d) of 
this AD is accomplished. Accomplishment of this paragraph 
constitutes terminating action for inspections in accordance with 
paragraph (a)(2) of this AD.
    (1) For airplanes that have NOT been inspected per paragraph (a) 
of this AD prior to the effective date of this AD: Except as 
provided by paragraph (g) of this AD, inspect at the earlier of the 
times specified in paragraphs (f)(1)(i) and (f)(1)(ii) of this AD.
    (i) Prior to the accumulation of 14,000 total flight cycles.
    (ii) Prior to the accumulation of 7,000 total flight cycles or 
within 90 days after the effective date of this AD, whichever comes 
later.
    (2) For airplanes that HAVE been inspected per paragraph (a) of 
this AD prior to the effective date of this AD: Inspect at the 
earlier of the times specified in paragraph (f)(2)(i) and (f)(2)(ii) 
of this AD.
    (i) Within 1,200 flight cycles since the most recent inspection 
per paragraph (a)(2) of this AD.
    (ii) Within 600 flight cycles since the most recent inspection 
per paragraph (a)(2) of this AD, or within 90 days after the 
effective date of this AD, whichever occurs later.

Optional Compliance Time (Airplanes Not Inspected Previously)

    (g) For airplanes that have NOT been inspected per paragraph (a) 
of this AD as of the effective date of this AD: 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 
inspections in paragraph (a) of this AD may be deferred until the 
earlier of the times specified in paragraphs (g)(1) and (g)(2) of 
this AD.
    (1) Within 3,000 flight cycles after accomplishment of the 
service letter.
    (2) Within 1,200 flight cycles after accomplishment of the 
service letter, or 90 days after the effective date of this AD, 
whichever occurs later.

Alternative Methods of Compliance

    (h)(1) 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.
    (2) Alternative methods of compliance, approved previously in 
accordance with AD 2001-12-23, amendment 39-12279, are approved as 
alternative methods of compliance with paragraphs (a), (b), (c), and 
(d) of this AD.

    Note 5: 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

    (i) Special flight permits may be issued in accordance with 
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.

Incorporation by Reference

    (j) 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. The incorporation by reference of 
that document was approved previously by the Director of the Federal 
Register as of December 13, 2000 (65 FR 70781, November 28, 2000). 
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

    (k) This amendment becomes effective on March 18, 2002.


    Issued in Renton, Washington, on February 25, 2002.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-4888 Filed 2-28-02; 8:45 am]
BILLING CODE 4910-13-U