[Federal Register Volume 61, Number 194 (Friday, October 4, 1996)]
[Proposed Rules]
[Pages 51847-51849]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-25596]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-ANE-33]
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 adoption of a new airworthiness
directive (AD) that is applicable to Pratt & Whitney JT8D-200 series
turbofan engines. This proposal would require, 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, this proposal would require
reporting findings of cracked fan hubs. This proposal is prompted by a
report of an uncontained failure of a fan hub. 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 November 4, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Assistant Chief
Counsel, Attention: Rules Docket No. 96-ANE-33, 12 New England
Executive Park, Burlington, MA 01803-5299. 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: Robert E. 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.
[[Page 51848]]
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 96-ANE-33.'' 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. 96-ANE-33, 12 New England Executive Park,
Burlington, MA 01803-5299.
Discussion
The Federal Aviation Administration (FAA) received a report of an
uncontained failure of a front compressor front hub (fan hub), Part
Number 5000501-01, installed on a Pratt & Whitney (PW) JT8D-200 series
turbofan engine. The investigation revealed a localized work hardened
layer found in the tierod hole of the fan hub from which a crack
initiated and propagated to failure in low cycle fatigue. The FAA has
determined that the work hardened layer was the result of a coolant
channel drill using a single plunge drilling procedure during
manufacture. This condition, if not corrected, could result in fan hub
failure due to tierod or counterweight hole cracking, which could
result in an uncontained engine failure and damage to the aircraft.
The FAA has reviewed and approved the technical contents of PW
Alert Service Bulletin (ASB) No. A6272, dated September 24, 1996, that
describes procedures for cleaning and eddy current (ECI) and
fluorescent penetrant (FPI) inspection 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
serial numbers (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 require cleaning, initial and repetitive ECI and FPI
for cracks of tierod and counterweight holes; removing bushings;
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 fan
hub S/Ns listed in the ASB, and includes an inspection schedule for
those fan hubs whose S/Ns are not listed in the ASB. In addition, this
AD would require reporting findings of cracked fan hubs. The actions
would be required to be accomplished in accordance with the ASB
described previously.
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 approximately 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. 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 adding the following new
airworthiness directive:
Pratt & Whitney: Docket No. 96-ANE-33.
Applicability: Pratt & Whitney (PW) JT8D-209, -217, -217C, and -
219 series turbofan engines, installed on but not limited to
McDonnell Douglas MD-80 series aircraft.
Note: 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 (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 prevent front compressor front hub (fan hub), Part Number
5000501-01, failure due to tierod, counterweight, or bushed hole
cracking, which could result in an
[[Page 51849]]
uncontained engine failure and damage to the aircraft, accomplish
the following:
(a) Fan hubs with fewer than 4,000 cycles since new (CSN) on the
effective date of this AD need not be inspected until accumulating
4,000 CSN. After the effective date of this AD, upon accumulating
4,000 CSN, perform the requirements of paragraph (b) of this AD.
(b) For fan hubs with 4,000 CSN, accomplish the following:
(1) For fan hubs identified by serial numbers (S/Ns) in Appendix
A of PW Alert Service Bulletin (ASB) No. A6272, dated September 24,
1996, inspect for cracks in accordance with the initial inspection
intervals of Table 1 of this AD, in accordance with the
Accomplishment Instructions, Paragraph A, Part 1, and, if
applicable, Paragraph B, of PW ASB No. A6272, dated September 24,
1996.
(i) Fan hubs that have been initially inspected in accordance
with paragraph (b)(1) of this AD must be reinspected in accordance
with the reinspection requirements of the schedule selected for
initial inspection.
(ii) Reinspect for cracks in accordance with the reinspection
intervals of Table 1 of this AD in accordance with the
Accomplishment Instructions, Paragraph A, Part 1, and, if
applicable, Paragraph B, of PW ASB No. A6272, dated September 24,
1996.
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 CIS
after the effective date of this AD, or since last inspection, but
prior to accumulating 5,050 CSN, not to exceed 6,000 CIS
whichever occurs later. since last inspection.
2. Within 990 CIS after the effective date After accumulating 2,500 CIS
of this AD, or prior to accumulating since last inspection, but
4,990 CSN, whichever occurs later. not to exceed 8,000 CIS
since last inspection.
3. Within 965 CIS after the effective date After accumulating 2,500 CIS
of this AD, or prior to accumulating since last inspection, but
4,965 CSN, whichever occurs later. not to exceed 10,000 CIS
since last inspection.
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(2) For fan hubs with S/Ns not listed in Appendix A of PW ASB
No. A6272, dated September 24, 1996, inspect at the next time the
fan hub is in the shop at piece-part level, but not to exceed 10,000
CIS after effective date of this AD in accordance with the
Accomplishment Instructions, Paragraph A, Part 2, and, if
applicable, Paragraph B, of PW ASB No. A6272, dated September 24,
1996.
(3) Remove from service fan hubs found cracked or exceed the
bushed hole acceptance criteria in accordance with PW ASB No. A6272,
dated September 24, 1996, and replace with serviceable parts.
(c) Report findings of cracked fan hubs 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.
(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, 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: Information concerning the existence of approved
alternative methods of compliance with this airworthiness directive,
if any, may be obtained from the Engine Certification Office.
(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 aircraft to a location where
the requirements of this AD can be accomplished.
Issued in Burlington, Massachusetts, on September 27, 1996.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 96-25596 Filed 10-3-96; 8:45 am]
BILLING CODE 4910-13-U
