Airworthiness Directives; Boeing Model 747 Series Airplanes Powered By Pratt & Whitney JT9D-7 Series Engines

[Federal Register Volume 65, Number 171 (Friday, September 1, 2000)]
[Rules and Regulations]
[Pages 53161-53163]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-22284]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-270-AD; Amendment 39-11886; AD 2000-18-01]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes 
Powered By Pratt & Whitney 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 series airplanes powered by 
Pratt & Whitney JT9D-7 series engines. This action requires inspection 
of the lugs on the bulkhead fitting of the rear engine mount, and 
corrective action, if necessary. This action is necessary to detect and 
correct bushing migration, corrosion, or cracking of the lugs on the 
bulkhead fitting of the rear engine mount, which could result in 
separation of the engine from the airplane. This action is intended to 
address the identified unsafe condition.

DATES: Effective September 18, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 18, 2000.
    Comments for inclusion in the Rules Docket must be received on or 
before October 31, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-270-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. 2000-NM-270-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 L. 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 a report of cracking of 
the inboard lug on the bulkhead fitting of the rear engine mount on the 
number 3 engine pylon on a Boeing Model 747-200B series airplane 
powered by Pratt & Whitney JT9D-7Q series engines. The affected 
airplane had accumulated 13,941 flight cycles and 73,356 flight hours. 
The lug was cracked completely

[[Page 53162]]

through the cross-section. The cracking is thought to be due to 
corrosion and fatigue. This condition, if not corrected, could result 
in separation of the engine from the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-54A2200, dated July 7, 2000. Among other actions, the service 
bulletin describes procedures for repetitive detailed visual 
inspections for bushing migration, corrosion, or cracking; and a 
physical measurement inspection for bushing migration; of the lugs on 
the bulkhead fitting of the rear engine mount. If light corrosion or 
any bushing migration is found, the corrective action includes interim 
rework to remove corrosion and restore the finish of the fitting. If 
cracking or moderate-to-heavy corrosion is found, the service bulletin 
specifies to contact Boeing for rework instructions. The service 
bulletin also describes procedures for repetitive ultrasonic 
inspections for cracking of the lugs on the bulkhead fitting of the 
rear engine mount, which, if accomplished, extend the repetitive 
inspection interval for the detailed visual inspections.

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 bushing migration, corrosion, or 
cracking of the lugs on the bulkhead fitting of the rear engine mount, 
which could result in separation of the engine from the airplane. This 
AD requires accomplishment of the actions 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 repetitive ultrasonic inspections for 
cracking of the lugs on the bulkhead fitting of the rear engine mount, 
which are described in the service bulletin. Accomplishment of these 
ultrasonic inspections would extend the repetitive interval for the 
detailed visual and physical measurement inspections required by this 
AD. The FAA is also considering requiring the rework specified in Part 
5 of the service bulletin for airplanes other than those required to do 
the Part 5 rework in accordance with this AD. However, the planned 
compliance time for these actions is sufficiently long so that notice 
and opportunity for prior public comment will be practicable.

Differences Between Service Bulletin and This AD

    As described previously, the service bulletin recommends 
accomplishment of the ultrasonic inspections for cracking of the lugs 
on the bulkhead fitting of the rear engine mount within 9 months after 
accomplishment of the initial detailed visual inspection. This AD does 
not require these ultrasonic inspections. However, paragraph (c) of 
this AD provides the repetitive ultrasonic inspections as an option 
that extends the repetitive interval for the detailed visual and 
physical measurement inspections required by paragraph (a) of this AD.
    Operators should note that, although the service bulletin specifies 
that the manufacturer may be contacted for certain rework instructions, 
this AD requires such rework to be done 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-270-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.

[[Page 53163]]

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:

2000-18-01 Boeing: Amendment 39-11886. Docket 2000-NM-270-AD.

    Applicability: Model 747 series airplanes powered by Pratt & 
Whitney JT9D-7 series engines, as listed in Boeing Alert Service 
Bulletin 747-54A2200, dated July 7, 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 detect and correct bushing migration, corrosion, or cracking 
of the lugs on the bulkhead fitting of the rear engine mount, 
accomplish the following:

Repetitive Detailed Visual Inspections

    (a) At the later of the times in paragraphs (a)(1) and (a)(2) of 
this AD, perform a detailed visual inspection for bushing migration, 
corrosion, or cracking; and a physical measurement inspection using 
feeler gages for bushing migration; of the lugs on the bulkhead 
fitting of the rear engine mount, in accordance with Boeing Alert 
Service Bulletin 747-54A2200, dated July 7, 2000. Thereafter, repeat 
the inspection at intervals not to exceed 90 days, except as 
provided by paragraph (c) of this AD.
    (1) Prior to the accumulation of 10,000 total flight cycles, or 
within 15 years since the date of manufacture of the airplane, 
whichever occurs first.
    (2) Within 90 days after the effective date of this AD.

    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.''

Corrective Actions

    (b) During any inspection accomplished in accordance with 
paragraph (a) or (c) of this AD, if bushing migration, corrosion, or 
cracking is detected, accomplish paragraph (b)(1) or (b)(2) of this 
AD, as applicable.
    (1) If light corrosion or bushing migration is found: Prior to 
further flight, do interim rework in accordance with Part 4 of the 
service bulletin; EXCEPT where the service bulletin specifies to 
contact Boeing, 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 (DER) 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.

    Note 3: The ultrasonic inspection described in Part 3 of Boeing 
Alert Service Bulletin 747-54A2200, dated July 7, 2000, and the 
rework described in Part 5 are not required by paragraph (b)(1) of 
this AD. However, the repetitive detailed visual inspections 
required by paragraph (a) of this AD continue to be required.

    (2) If moderate to severe corrosion or any cracking is found: 
Prior to further flight, rework in accordance with a method approved 
by the Manager, Seattle ACO; or in accordance with 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 by the 
Manager, Seattle ACO, as required by this paragraph, the approval 
letter must specifically reference this AD.

Optional Ultrasonic Inspection

    (c) Accomplishment of the repetitive ultrasonic inspections 
specified in Part 3 of Boeing Alert Service Bulletin 747-54A2200, 
dated July 7, 2000, at intervals not to exceed 1,400 flight cycles 
or 18 months, whichever occurs first; extends the interval for the 
repetitive detailed visual and physical measurement inspections 
required by paragraph (a) of this AD to the interval stated in 
paragraph (c)(1) or (c)(2) of this AD, as applicable.
    (1) If no bushing migration is found, the repetitive interval is 
not to exceed 1,400 flight cycles or 18 months, whichever occurs 
first.
    (2) If any bushing migration is found, the repetitive interval 
is not to exceed 180 days.

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 4: 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

    (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.

Incorporation by Reference

    (f) Except as provided by paragraphs (b)(1) and (b)(2) of this 
AD, the actions shall be done in accordance with Boeing Alert 
Service Bulletin 747-54A2200, dated July 7, 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

    (g) This amendment becomes effective on September 18, 2000.

    Issued in Renton, Washington, on August 25, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-22284 Filed 8-31-00; 8:45 am]
BILLING CODE 4910-13-U

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