[Federal Register Volume 66, Number 55 (Wednesday, March 21, 2001)]
[Proposed Rules]
[Pages 15814-15817]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-6940]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-271-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Boeing Model 747 
series airplanes powered by Pratt & Whitney JT9D-7 series engines, that 
currently requires detailed visual inspections of the lugs on the 
bulkhead fitting of the rear engine mount, and corrective action, if 
necessary. The existing AD also specifies optional ultrasonic 
inspections, which, if accomplished, extend the repetitive interval for 
the required detailed visual inspections. This action would require 
accomplishment of the previously optional ultrasonic inspections and, 
for certain airplanes, rework of the bulkhead fitting of the rear 
engine mount. The actions specified by the proposed AD are intended 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: Comments must be received by May 7, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-271-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-271-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: 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:

Comments Invited

    Interested persons are invited to participate in the making of the

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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 2000-NM-271-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-271-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On August 25, 2000, the FAA issued AD 2000-18-01, amendment 39-
11886 (65 FR 53161, September 1, 2000), applicable to certain Boeing 
Model 747 series airplanes powered by Pratt & Whitney JT9D-7 series 
engines, to require inspection of the lugs on the bulkhead fitting of 
the rear engine mount, and corrective action, if necessary. That action 
was prompted by 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 requirements of that AD are intended 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.

Actions Since Issuance of Previous Rule

    In the preamble to AD 2000-18-01, the FAA indicated that the 
actions required by that AD were considered ``interim action'' and that 
further rulemaking action was being considered to require the 
repetitive ultrasonic inspections for cracking of the lugs on the 
bulkhead fitting of the rear engine mount, which were described in 
Boeing Alert Service Bulletin 747-54A2200, dated July 7, 2000 (which 
was referenced as the appropriate source of service information for the 
actions required by AD 2000-18-01). Those ultrasonic inspections were 
specified in AD 2000-18-01 as an option that, if accomplished, would 
extend the repetitive interval for the detailed visual and physical 
measurement inspections required by that AD. The FAA now has determined 
that further rulemaking action is indeed necessary, and this proposed 
AD follows from that determination.

Explanation of Relevant Service Information

    Since the issuance of AD 2000-18-01, the FAA has reviewed and 
approved Boeing Service Bulletin 747-54A2200, Revision 1, dated 
February 15, 2001. The procedures described in Revision 1 of the 
service bulletin for the inspections and interim rework are the same as 
those described in the original issue of the service bulletin. However, 
Part 5 of Revision 1 of the service bulletin includes new instructions 
for rework of the lugs on the bulkhead fitting of the rear engine 
mount. The rework procedures include a detailed visual inspection of 
the aft upper engine mount for damage; a Non-Destructive Testing 
inspection and repair of the aft upper engine mount, if necessary; and 
rework of the lugs, and installation of new bushings in the lug, on the 
bulkhead fitting of the rear engine mount. The service bulletin 
specifies that this rework is eventually necessary on any airplane on 
which bushing migration is found. This Part 5 rework is optional for 
airplanes on which no bushing migration, corrosion, or cracking is 
found; however, doing the rework per Part 5 of the service bulletin 
resets the compliance threshold for the repetitive detailed visual and 
ultrasonic inspections for cracking of the lugs on the bulkhead fitting 
of the rear engine mount. Accomplishment of the actions specified in 
Revision 1 of the service bulletin is intended to adequately address 
the identified unsafe condition.

Explanation of Change to Requirements of AD 2000-18-01

    The requirements of AD 2000-18-01 are restated in this new proposed 
rule. References to Revision 1 of the service bulletin have been added 
to provide an additional source of service information for 
accomplishment of these existing requirements.

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 supersede AD 2000-18-01 to continue to require 
detailed visual inspections of the lugs on the bulkhead fitting of the 
rear engine mount, and corrective action, if necessary. The proposed AD 
would also require accomplishment of the previously optional ultrasonic 
inspections and, for certain airplanes, rework of the bulkhead fitting 
of the rear engine mount. The actions would be required to be 
accomplished per the service bulletin described previously, except as 
discussed below.

Differences Between Service Bulletin and This Proposed AD

    Operators should note that, although the service bulletin specifies 
that the manufacturer may be contacted for certain repair instructions, 
this AD requires such repair to be done per a method approved by the 
FAA, or per 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.

Cost Impact

    There are approximately 200 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 47 airplanes of U.S. registry 
would be affected by this proposed AD.
    The detailed visual inspections that are currently required by AD 
2000-18-01 take approximately 8 work hours per airplane to accomplish, 
at an average labor rate of $60 per work hour. Based on these figures, 
the cost impact of the currently required actions on U.S. operators is 
estimated to be $22,560, or $480 per airplane, per inspection cycle.
    The new inspections that are proposed in this AD action would take 
approximately 4 work hours per airplane to accomplish, at an average

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labor rate of $60 per work hour. Based on these figures, the cost 
impact of the new proposed requirements of this AD on U.S. operators is 
estimated to be $11,280, or $240 per airplane, per inspection cycle.
    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 removing amendment 39-11886 (65 FR 
53161, September 1, 2000), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing: Docket 2000-NM-271-AD. Supersedes AD 2000-18-01, Amendment 
39-11886.

    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 (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 detect and correct bushing migration, corrosion, or cracking 
of the lugs on the bulkhead fitting of the rear engine mount, 
accomplish the following:

Restatement of Requirements of AD 2000-18-01:

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, or Revision 1, 
dated February 15, 2001. Thereafter, repeat the inspection at 
intervals not to exceed 90 days, until the inspections required by 
paragraphs (c) and (d) of this AD have been accomplished.
    (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 September 18, 2000 (the effective date 
of AD 2000-18-01, amendment 39-11886).

    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), (c), or (d) 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 
Boeing Alert Service Bulletin 747-54A2200, dated July 7, 2000, or 
Revision 1, dated February 15, 2001; 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.
    (2) If moderate to severe corrosion or any cracking is found: 
Prior to further flight, rework the lugs on the bulkhead fitting of 
the rear engine mount in accordance with Part 5 of Boeing Service 
Bulletin 747-54A2200, Revision 1, dated February 15, 2001, except as 
provided by paragraph (g) of this AD; or 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. Such rework 
resets the compliance threshold for the inspections per paragraphs 
(c) and (d) of this AD to 15 years or 10,000 flight cycles since 
rework, whichever is earlier.

New Requirements of This AD

Ultrasonic Inspection--Initial and Repetitive Inspections

    (c) At the later of the times in paragraphs (c)(1) and (c)(2) of 
this AD, except as provided by paragraph (f) of this AD, perform an 
ultrasonic inspection to detect corrosion or cracking of the lugs on 
the bulkhead fitting of the rear engine mount, per Part 3 of Boeing 
Alert Service Bulletin 747-54A2200, dated July 7, 2000, or Revision 
1, dated February 15, 2001. Thereafter, repeat the ultrasonic 
inspection described in this paragraph at intervals not to exceed 
1,400 flight cycles or 18 months, whichever occurs first.
    (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 9 months after the effective date of this AD.

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Repetitive Detailed Visual and Physical Measurement Inspections

    (d) After initial accomplishment of the inspections required by 
paragraph (c) of this AD, perform repetitive detailed visual 
inspections for bushing migration, corrosion, or cracking; and 
physical measurement inspections using feeler gages for bushing 
migration; of the lugs on the bulkhead fitting of the rear engine 
mount; per Boeing Alert Service Bulletin 747-54A2200, dated July 7, 
2000, or Revision 1, dated February 15, 2001. Perform the 
inspections at the interval stated in paragraph (d)(1) or (d)(2) of 
this AD, except as provided by paragraph (f) of this AD. 
Accomplishment of repetitive inspections per this paragraph 
constitutes terminating action for the inspections required by 
paragraph (a) of this AD.
    (1) If no bushing migration is found during any inspection per 
this AD, the repetitive interval is not to exceed 1,400 flight 
cycles or 18 months, whichever occurs first.
    (2) If any bushing migration is found during any inspection per 
this AD, the repetitive interval is not to exceed 180 days, until 
paragraph (e) of this AD has been done.

On-Condition Rework

    (e) If any bushing migration is found during any inspection per 
this AD, within 30 months after finding the migrated bushing, or 
within 18 months after the effective date of this AD, whichever 
occurs later, do rework of the lugs on the bulkhead fitting of the 
rear engine mount (including a detailed visual inspection of the aft 
upper engine mount for damage; a Non-Destructive Testing inspection 
and repair of the aft upper engine mount, as applicable; and rework 
of the lugs, and installation of new bushings in the lug, on the 
bulkhead fitting of the rear engine mount) per Part 5 of Boeing 
Alert Service Bulletin 747-54A2200, Revision 1, dated February 15, 
2001. Such rework resets the compliance threshold for the 
inspections per paragraphs (c) and (d) of this AD to 15 years or 
10,000 flight cycles since rework, whichever is earlier.

Optional Rework

    (f) Rework of the lugs on the bulkhead fitting of the rear 
engine mount (including a detailed visual inspection of the aft 
upper engine mount for damage; a Non-Destructive Testing inspection 
and repair of the aft upper engine mount, as applicable; and rework 
of the lugs, and installation of new bushings in the lug, on the 
bulkhead fitting of the rear engine mount) per Part 5 of Boeing 
Alert Service Bulletin 747-54A2200, Revision 1, dated February 15, 
2001, resets the compliance threshold for the inspections per 
paragraphs (c) and (d) of this AD to 15 years or 10,000 flight 
cycles since rework, whichever is earlier.

Exception to Repair Requirement

    (g) Where Boeing Alert Service Bulletin 747-54A2200, dated July 
7, 2000, or Revision 1, dated February 15, 2001, says to contact 
Boeing for repair instructions: 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 by the 
Manager, Seattle ACO, as required by this paragraph, the approval 
letter must specifically reference this AD.

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 2000-18-01, Amendment 39-11886, are approved as 
alternative methods of compliance for corresponding actions in this 
AD.

    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 Permits

    (i) 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 March 14, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-6940 Filed 3-20-01; 8:45 am]
BILLING CODE 4910-13-P