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

[Federal Register Volume 66, Number 147 (Tuesday, July 31, 2001)]
[Rules and Regulations]
[Pages 39425-39429]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-18469]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-271-AD; Amendment 39-12349; AD 2001-15-15]
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.

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SUMMARY: This amendment supersedes 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

[[Page 39426]]

ultrasonic inspections, which, if accomplished, extend the repetitive 
interval for the required detailed visual inspections. This amendment 
requires 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 this 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 fracture of the lugs and separation of the engine from the 
airplane. This action is intended to address the identified unsafe 
condition.

DATES: Effective September 4, 2001.
    The incorporation by reference of Boeing Service Bulletin 747-
54A2200, Revision 1, dated February 15, 2001, as listed in the 
regulations, is approved by the Director of the Federal Register as of 
September 4, 2001.
    The incorporation by reference of Boeing Alert Service Bulletin 
747-54A2200, dated July 7, 2000, as listed in the regulations, was 
approved previously by the Director of the Federal Register as of 
September 18, 2000 (65 FR 53161, September 1, 2000).

ADDRESSES: 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 Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 2000-18-01, 
amendment 39-11886 (65 FR 53161, September 1, 2000), which is 
applicable to certain Boeing Model 747 series airplanes powered by 
Pratt & Whitney JT9D-7 series engines, was published in the Federal 
Register on March 21, 2001 (66 FR 15814). The action proposed 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 action also proposed to require ultrasonic inspections 
(which were provided as an option in the existing AD) and, for certain 
airplanes, rework of the bulkhead fitting of the rear engine mount.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Clarify Unsafe Condition

    One commenter requests that the FAA clarify the unsafe condition as 
stated in the SUMMARY and ``Discussion'' sections of the proposed AD. 
The commenter requests that the unsafe condition state that bushing 
migration, corrosion, or cracking of the lugs on the bulkhead fitting 
of the rear engine mount could result in fracture of the lugs, which 
could result in separation of the engine from the airplane.
    The FAA concurs with the commenter's request and has made this 
change in the SUMMARY section of this final rule. The ``Discussion'' 
section of the proposed AD is not restated in this final rule, so no 
change to that section is needed.

Revise Cost Impact

    One commenter requests that the FAA revise the cost impact 
information in the proposed AD to include the time needed for gaining 
access and closing up for the proposed ultrasonic inspection. The 
commenter notes that, due to the 9-month compliance time, it may be 
necessary for operators to do this inspection at a time other than a 
normal scheduled heavy maintenance visit.
    The FAA concurs with the commenter's request. We note that the cost 
analysis in AD rulemaking actions typically does not include incidental 
costs, such as the time required to gain access and close up, planning 
time, or time necessitated by other administrative actions. Because 
incidental costs may vary significantly from operator to operator, they 
are almost impossible to calculate. However, we acknowledge that it may 
or may not be possible to accomplish the ultrasonic inspection required 
by this AD during a normal scheduled maintenance visit due to the 
compliance times for the initial and repetitive inspections. Therefore, 
we have revised the cost impact information for the ultrasonic 
inspections in this final rule from 4 to 36 work hours to include the 
work hours necessary for gaining access and closing up.

Refer to Specific Part of Referenced Service Bulletin

    One commenter requests that the FAA revise paragraph (d) of the 
proposed AD to refer to Part 2 of Boeing Alert Service Bulletin 747-
54A2200, dated July 7, 2000; or Revision 1, dated February 15, 2001. 
The commenter does not state a reason for its request.
    The FAA infers that the commenter's request is to make paragraph 
(d) consistent with other paragraphs of the AD. The FAA concurs and has 
revised paragraph (d) of this final rule accordingly. Also, the same 
change has been made to paragraph (a) of this AD.

Give Credit for Inspections Accomplished Previously

    One commenter requests that the FAA revise paragraph (c) of the 
proposed AD to provide a third compliance time option for airplanes 
inspected per the ultrasonic method provided as an option in AD 2000-
18-01. The commenter states that operators who did the ultrasonic 
inspection per AD 2000-18-01 would be required to repeat this 
inspection within 9 months after the effective date of this AD. The 
commenter emphasizes that such a requirement would impose undue 
economic and scheduling burdens on affected operators.
    The FAA does not concur. Credit for inspections accomplished prior 
to the effective date of the AD is always provided in an AD by means of 
the statement at the beginning of the ``Compliance'' section of each 
AD: ``Required as indicated, unless accomplished previously.'' No 
change to the final rule is necessary in this regard.

Remove Inspections From Paragraph (f)

    One commenter requests that the FAA revise paragraph (f) to remove 
the requirement to perform detailed visual and non-destructive test 
inspections for damage of the upper engine mount during accomplishment 
of the rework of the lugs on the bulkhead fitting of the rear engine 
mount. The commenter states that these inspections should be necessary 
only if there is insufficient clearance between the migrated end of the 
outer lug plain bushing and the adjacent lug of the aft upper engine 
mount.
    The FAA does not concur. We infer that the commenter assumes that 
there will be no damage to the upper engine mount if sufficient 
clearance is maintained between the migrated end of the outer lug plain 
bushing and the adjacent lug of the aft upper engine mount. However, we 
have determined that the bushing may migrate in either

[[Page 39427]]

direction. For example, the bushing may have migrated to a position of 
no positive clearance and caused damage, but then subsequently may have 
migrated inward to a position where there is sufficient clearance. 
Thus, we find it necessary to require the inspections during the rework 
according to the service bulletin. No change to the final rule is 
necessary in this regard.

Reference Alternative Method of Compliance for AD 2000-18-01

    One commenter requests that the FAA revise the proposed AD to 
reference a specific alternative method of compliance (AMOC) that was 
approved previously for AD 2000-18-01. The commenter states that the 
AMOC addresses conditions of no positive clearance, which may be found 
during the rework according to Part 4 of the service bulletin.
    The FAA does not concur with the request. Paragraph (h)(2) of the 
proposed AD allows the use of previously approved AMOCs for AD 2000-18-
01 for compliance with corresponding actions in the proposed AD. 
Listing references for specific AMOCs would unnecessarily complicate 
this final rule. No change to the final rule is necessary in this 
regard.

Make Specific Tooling Optional

    One commenter requests that the FAA revise the proposed AD to make 
the use of specific tooling identified in the service bulletin optional 
for compliance with the proposed AD. The commenter refers to a specific 
boring fixture called out in the service bulletin, and states that use 
of this specific tooling should be optional. The commenter states that 
other tooling capable of producing the desired dimensions and finishes 
specified in the service bulletin should be acceptable for compliance. 
The commenter notes that inspection requirements and dimensional checks 
contained in the service bulletin are sufficient to ensure that lugs 
are properly reworked and free of damage.
    The FAA does not concur with the commenter's request. We find that 
the tooling used to bore the lugs may affect the unsafe condition 
addressed by this AD and, therefore, it is inappropriate not to specify 
the tooling to be used. However, operators may request approval of an 
AMOC under paragraph (h)(1) of this AD if they can show that tooling 
other than that identified in the service bulletin will provide an 
acceptable level of safety. No change to the final rule is necessary in 
this regard.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 200 Model 747 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 47 
airplanes of U.S. registry will be affected by this 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 required by this AD will take approximately 36 
work hours per airplane to accomplish (including time for gaining 
access and closing up), at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the new requirements of this 
AD on U.S. operators is estimated to be $101,520, or $2,160 per 
airplane, per inspection cycle.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the requirements of this 
AD action, and that no operator would accomplish those actions in the 
future if this 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. However, for the new inspections required by 
this AD, the time for gaining access and closing up has been included 
in the figures above because it may not be possible for operators to 
accomplish these inspections during normal scheduled maintenance due to 
the compliance times associated with these inspections.

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.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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 39-11886 (65 FR 
53161, September 1, 2000), and by adding a new airworthiness directive 
(AD), amendment 39-12349, to read as follows:

2001-15-15  Boeing: Amendment 39-12349. 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

[[Page 39428]]

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 Part 2 of 
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.

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 Part 2 of 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 
Secs. 21.197 and 21.199 of the

[[Page 39429]]

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 paragraphs (b) and (g) of this AD, the 
actions shall be done in accordance with Boeing Alert Service 
Bulletin 747-54A2200, dated July 7, 2000; or Boeing Service Bulletin 
747-54A2200, Revision 1, dated February 15, 2001; as applicable.
    (1) The incorporation by reference of Boeing Service Bulletin 
747-54A2200, Revision 1, dated February 15, 2001, is approved by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) 
and 1 CFR part 51.
    (2) The incorporation by reference of Boeing Alert Service 
Bulletin 747-54A2200, dated July 7, 2000, was approved previously by 
the Director of the Federal Register as of September 18, 2000 (65 FR 
53161, September 1, 2000).
    (3) Copies of these service bulletins 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 September 4, 2001.

    Issued in Renton, Washington, on July 19, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-18469 Filed 7-30-01; 8:45 am]
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