[Federal Register Volume 62, Number 36 (Monday, February 24, 1997)]
[Proposed Rules]
[Pages 8198-8201]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-4370]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 97-ANE-08]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney JT8D-200 Series
Turbofan 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 Pratt & Whitney JT8D-200
series turbofan engines, that currently requires for front compressor
front hubs (fan hubs), cleaning; initial and repetitive eddy current
(ECI) and fluorescent penetrant inspections (FPI) of tierod and
counterweight holes for cracks; removal of bushings; the cleaning and
ECI and FPI of bushed holes for cracks; and, if necessary, replacement
with serviceable parts. In addition, the current AD requires reporting
the findings of cracked fan hubs. This action will not change the
current AD's inspection procedures, or the effectivity date that starts
the cycle count for the initial inspection schedules. This AD will,
however, add an additional inspection schedule that requires the
initial inspection of certain fan hubs with standard drilled holes and
coolant channel drilled (CCD) holes to occur earlier than the existing
AD requires. This proposal is prompted by additional investigation
since publication of the current AD that reveals that certain fan hubs
with standard drilled holes and CCD holes may be more susceptible to
cracking. This proposal also requires reporting the results of the
initial fan hub inspections. The actions specified by the proposed AD
are intended to prevent fan hub failure due to tierod, counterweight,
or bushed hole cracking, which could result in an uncontained engine
failure and damage to the aircraft.
DATES: Comments must be received by April 25, 1997.
ADDRESSES: Submit comments in triplicate to the Federal
Aviation Administration (FAA), New England Region, Office of the
Assistant Chief Counsel, Attention: Rules Docket No. 97-ANE-08, 12 New
England Executive Park, Burlington, MA 01803--5299. Comments may also
be sent via the Internet using the following address: ``engineprop@faa.dot.gov''. Comments sent via the Internet must contain
the docket number in the subject line. Comments may be inspected at
this location between 8:00 a.m. and 4:30 p.m., Monday through Friday,
except Federal holidays.
The service information referenced in the proposed rule may be
obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108;
telephone (860) 565-6600, fax (860) 565-4503. This information may be
examined at the FAA, New England Region, Office of the Assistant Chief
Counsel, 12 New England Executive Park, Burlington, MA.
FOR FURTHER INFORMATION CONTACT: Diane Cook, Aerospace Engineer, Engine
Certification Office, FAA, Engine and Propeller Directorate, 12 New
England Executive Park, Burlington, MA 01803-
[[Page 8199]]
5299; telephone (617) 238-7134, fax (617) 238-7199.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
they may desire. Communications should 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 notice may be changed in
light of the comments received.
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 notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 97-ANE-08.'' 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, New England Region, Office of the Assistant Chief Counsel,
Attention: Rules Docket No. 97-ANE-08, 12 New England Executive Park,
Burlington, MA 01803-5299.
Discussion
On January 13, 1997, the Federal Aviation Administration (FAA)
issued airworthiness directive AD 97-02-11, Amendment 39-9896 (62 FR
4902, February 3, 1997), applicable to Pratt & Whitney (PW) JT8D-200
series turbofan engines, to require cleaning, initial and repetitive
eddy current inspections (ECI) and fluorescent penetrant inspections
(FPI) for cracks of tierod and counterweight holes; removal of
bushings; the cleaning and initial and repetitive ECI and FPI of bushed
holes for cracks; and, if necessary, replacing with serviceable parts.
The compliance requirements allow selection of inspection schedules
depending on front compressor front hub (fan hub) Serial Numbers (S/Ns)
listed in PW Alert Service Bulletin (ASB) No. A6272, dated September
24, 1996, and includes an inspection schedule for those fan hubs whose
S/Ns are not listed in the ASB. In addition, the AD requires reporting
findings of cracked fan hubs. That action was prompted by a report of
an uncontained failure of a fan hub. That condition, if not corrected,
could result in fan hub failure due to tierod, counterweight, or bushed
hole cracking, which could result in an uncontained engine failure and
damage to the aircraft.
Since the issuance of that AD, the FAA has conducted additional
investigation of fan hub cracking and has determined it necessary to
include an additional inspection schedule for certain fan hubs with
standard drilled holes and coolant channel drilled (CCD) holes. The FAA
reviewed the manufacturing records of all fan hubs, a total of 253
which had notations related to the tierod or counterweight holes.
Notations are made in the manufacturing records if an event occurred
during manufacture of the hole such as a tool break, which can result
in work hardened material, which is more susceptible to cracking. Of
the 253 fan hubs with such notations, 113 were manufactured with a CCD
and the remaining 140 were manufactured with a standard drill. Although
CCD fan hubs are more prone to a work hardened layer, a standard drill,
under certain circumstances, may also cause a work hardened layer and
subsequent cracking.
The FAA has reviewed and approved the technical contents of PW ASB
No. A6272, dated September 24, 1996, that describes procedures for
cleaning and ECI and FPI of tierod and counterweight holes for cracks;
removal of bushings; and the cleaning, FPI, and ECI of bushed holes for
cracks. Even though the ASB contains three of the S/Ns of the fan hubs
that were removed from service in accordance with AD 96-15-06, the
manufacturer has informed the FAA that these fan hubs have been
destroyed during the investigation to confirm the failure mode.
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 97-02-11 to include an additional
inspection schedule for certain fan hubs with standard drilled holes
and CCD holes without changing inspection procedures, the existing
inspection schedules, or the current effectivity date of March 5, 1997.
There are approximately 2,624 engines of the affected design in the
worldwide fleet. The FAA estimates that 1,279 engines installed on
aircraft of U.S. registry would be affected by this proposed AD, that
it would take 20 work hours per engine for 360 engines to disassemble,
remove, inspect, and reassemble engines, and 4 work hours per engine
for 919 engines to inspect at piece-part exposure, and that the average
labor rate is $60 per work hour. Based on these figures, the total cost
impact of the proposed AD on U.S. operators is estimated to be
$862,560.
The regulations proposed herein would not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
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 USC 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-9896 (62 FR
4902, February 3, 1997) and by adding
[[Page 8200]]
a new airworthiness directive to read as follows:
Pratt & Whitney: Docket No. 97-ANE-08. Supersedes AD 97-02-11,
Amendment 39-9896.
Applicability: Pratt & Whitney JT8D-209, -217, -217C, and -219
series turbofan engines with front compressor front hub (fan hub),
Part Number (P/N) 5000501-01, installed. These engines are installed
on but not limited to McDonnell Douglas MD-80 series aircraft.
Note 1: This airworthiness directive (AD) applies to each engine
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 engines 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 (c) 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 fan hub failure due to tierod, counterweight, or
bushed hole cracking, which could result in an uncontained engine
failure and damage to the aircraft, accomplish the following:
(a) Inspect fan hubs for cracks in accordance with the
Accomplishment Instructions, Paragraph A, Part 1, and, if
applicable, Paragraph B, of PW ASB No. A6272, dated September 24,
1996, as follows:
(1) For fan hubs identified by Serial Numbers (S/Ns) in Table 2
of this AD, after the fan hub has accumulated more than 4,000 cycles
since new (CSN), as follows:
(i) Initially inspect within 790 cycles in service after March
5, 1997 (the effective date of AD 97-02-11), or 4,790 CSN, whichever
occurs later.
(ii) Thereafter, reinspect after accumulating 2,500 CIS since
last inspection, but not to exceed 10,000 CIS since last inspection.
(2) For fan hubs identified by S/Ns in Appendix A of PW ASB No.
A6272, dated September 24, 1996, after the fan hub has accumulated
more than 4,000 CSN, as follows:
(i) Select an initial inspection interval from Table 1 of this
AD, and inspect accordingly.
Table 1
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Initial inspection Reinspection
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1. Within 1,050 cycles in service (CIS) After accumulating 2,500
after the effective date of AD 97-02- CIS since last
11, March 5, 1997, or prior to inspection, but not to
accumulating 5,050 CSN, whichever exceed 6,000 CIS since
occurs later; last inspection.
or
2. Within 990 CIS after the effective After accumulating 2,500
date of AD 97-02-11, March 5, 1997, or CIS since last
prior to accumulating 4,990 CSN, inspection, but not to
whichever occurs later; exceed 8,000 CIS since
last inspection.
or
3. Within 965 CIS after the effective After accumulating 2,500
date of AD 97-02-11, March 5, 1997, or CIS since last
prior to accumulating 4,965 CSN, inspection, but not to
whichever occurs later. exceed 10,000 CIS since
last inspection.
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Table 2
[Hubs with traveler notations]
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Non CCD Non CCD Non CCD Non CCD
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M67663 M67802 P66880 S25545
M67671 M67812 P66885 S25558
M67675 M67826 R32732 S25564
M67681 M67829 R32733 S25598
M67685 M67830 R32735 S25618
M67686 M67831 R32740 S25621
M67687 M67832 R32741 S25637
M67697 M67834 R32810 S25640
M67700 M67843 R32849 T50693
M67706 M67849 R32850 T50752
M67710 M67858 S25222 T50785
M67712 M67866 S25464 T50791
M67713 M67868 S25481 T50792
M67714 M67869 S25483 T50819
M67715 M67872 S25484 T50823
M67716 M67888 S25486 T50827
M67717 N71771 S25488 T50874
M67722 N71804 S25489 T50875
M67723 N71806 S25490 T51058
M67725 N71810 S25491 T51104
M67726 N71811 S25492 R33186
M67730 N71875 S25494 S25528
M67731 N71876 S25495
M67746 N71921 S25497
M67751 N71965 S25498
M67753 N72062 S25499
M67764 N72126 S25500
M67765 N72152 S25501
M67784 N72162 S25502
M67791 N72207 S25505
M67792 N72216 S25506
M67793 N72219 S25507
M67794 N72242 S25508
M67795 P66693 S25509
M67796 P66695 S25514
M67797 P66696 S25529
M67798 P66698 S25532
M67799 P66699 S25541
M67800 P66737 S25543
M67801 P66753 S25544
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CCD Hub CCD Hub CCD Hub
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P66747 R33099 S25292
P66756 R33107 S25299
P66800 R33113 S25301
P66814 R33124 S25302
P66819 R33131 S25308
P66831 R33132 S25312
R32767 R33133 S25316
R32787 R33136 S25323
R32792 R33152 S25334
R32795 R33157 S25335
R32796 R33163 S25337
R32800 R33165 S25344
R32807 R33168 S25369
R32856 R33171 S25377
R32860 R33173 S25378
R32870 R33180 S25381
R32883 R33181 S25394
R32905 R33189 S25399
R32926 R33194 S25402
R32930 R33198 S25406
R32952 R33201 S25411
R32964 R33202 S25413
R32966 R33207 S25414
R32971 S25193 S25415
R32976 S25195 S25418
R32981 S25207 S25419
R32990 S25208 S25421
R32994 S25221 S25422
R33000 S25229 S25430
R33004 S25238 S25437
R33040 S25246 S25439
R33055 S25248 S25449
R33059 S25250
R33077 S25256
R33080 S25262
R33082 S25268
R33086 S25278
R33087 S25287
R33089 S25288
R33090
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(ii) Thereafter, reinspect at intervals that correspond to the
selected inspection interval.
(3) If a fan hub is identified in both Table 2 of this AD and
Appendix A of PW ASB No. A6272, dated September 24, 1996, inspect in
accordance with paragraph (a)(1) of this AD.
(4) For fan hubs with S/Ns not listed in Table 2 of this AD or
in Appendix A of PW ASB No. A6272, dated September 24, 1996, after
the fan hub has accumulated more than 4,000 CSN, inspect the next
time the fan hub is in the shop at piece-part level, but not to
exceed 10,000 CIS after March 5, 1997.
(5) Prior to further flight, remove from service fan hubs found
cracked or that exceed the bushed hole acceptance criteria described
[[Page 8201]]
in PW ASB No. A6272, dated September 24, 1996.
(b) Report the number of completed inspections on a monthly
basis and report findings of cracked fan hubs in accordance with
Accomplishment Instructions, Paragraph F, of Attachment 1 to PW ASB
No. A6272, dated September 24, 1996, within 48 hours after
inspection to Robert Guyotte, Manager, Engine Certification Branch,
Engine Certification Office, FAA, Engine and Propeller Directorate,
12 New England Executive Park, Burlington, MA 01803-5299; telephone
(617) 238-7142, fax (617) 238-7199; Internet:
Robert.Guyotte@faa.dot.gov. Reporting requirements have been
approved by the Office of Management and Budget and assigned OMB
control number 2120-0056.
(c) 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, Engine Certification Office. The
request should be forwarded through an appropriate FAA Principal
Maintenance Inspector, who may add comments and then send it to the
Manager, Engine Certification Office.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this airworthiness directive,
if any, may be obtained from the Engine Certification Office.
(d) 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 aircraft to a location where
the inspection requirements of this AD can be accomplished.
Issued in Burlington, Massachusetts, on February 14, 1997.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 97-4370 Filed 2-21-97; 8:45 am]
BILLING CODE 4910-13-P
