[Federal Register Volume 62, Number 22 (Monday, February 3, 1997)]
[Rules and Regulations]
[Pages 4902-4904]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1703]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-ANE-33; Amendment 39-9896; AD 97-02-11]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney JT8D-200 Series
Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to Pratt & Whitney (PW) JT8D-200 series turbofan engines,
that 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,
this AD requires reporting the findings of cracked fan hubs. This
amendment is prompted by a report of an uncontained failure of a fan
hub. The actions specified by this 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: Effective March 5, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 5, 1997.
ADDRESSES: The service information referenced in this AD 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 Federal Aviation Administration (FAA), New England
Region, Office of the Assistant Chief Counsel, 12 New England Executive
Park, Burlington, MA; or at the Office of the Federal Register, 800
North Capitol Street, NW., Suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Diane Cook, Aerospace Engineer, Engine
Certification Office, FAA, Engine and Propeller Directorate, 12 New
England Executive Park, Burlington, MA 01803-5299; telephone (617) 238-
7134, fax (617) 238-7199.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to Pratt & Whitney (PW) JT8D-200
series turbofan engines was published in the Federal Register on
October 4, 1996 (61 FR 51847). That action proposed to require
cleaning, initial and repetitive eddy current inspections (ECI) and
fluorescent penetrant inspections (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 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 proposed AD requires reporting the
number of initial inspections and the findings of cracked fan hubs.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter states that the Notice of Proposed Rulemaking (NPRM)
as written was confusing and subject to interpretation, and offered a
number of editorial suggestions. The FAA reviewed the suggestions and
concurs in part with the changes.
The commenter states that the applicability should be expressed to
the lowest practical level by including the phrase ``front compressor
front hub (fan hub)'' and its corresponding part number in the
applicability statement. The FAA concurs. The applicability section in
this final has been revised to read ``* * * engines with front
compressor front hub (fan hub) Part Number 5000501-01 installed''.
The commenter states that a stronger statement regarding the
initial inspections for fan hubs with less than 4,000 cycles since new
(CSN) was
[[Page 4903]]
needed. The commenter suggests adding the intent of the first note on
page 8 of PW ASB No. A6272, dated September 24, 1996, which requires
inspection after the fan hub has accumulated more than 4,000 cycles in
service. This change would eliminate the need for paragraph (a) of the
proposed rule. The FAA concurs. The structure of the compliance section
in this final rule has been modified to include the initial 4,000 CSN
inspection requirement in the beginning of each of two compliance
paragraphs. Paragraph (a) of this final rule will cover coolant channel
drilled (CCD) fan hubs identified by S/N in the SB, and paragraph (b)
for inspection of all other affected fan hubs. For each population of
hubs, the initial inspection must not be completed until the fan hub
has accumulated more than 4,000 CSN.
The commenter states that paragraph (c) of the NPRM is vague and
should specify what is to be reported. The FAA concurs and has added
the requirement of reporting in accordance with Accomplishment
Instructions, Paragraph F, of Attachment 1 to PW ASB No. A6272, dated
September 24, 1996, to this final rule.
The commenter states that paragraph (a) and Table 1 of the NPRM do
not clearly indicate that the operator is to choose one of the three
options in Table 1 and stick with the corresponding reinspection
interval. The commenter suggests adding ``or'' after options 1 and 2 in
Table 1 and adding a note to require that the operator follow the
initial and repetitive requirements of the option chosen. The FAA
concurs in part. The ``or'' has been added as suggested. The original
proposal contained such a requirement in proposed paragraph (b)(1)(i),
which has been carried over into new paragraph (a)(2). Operators must
follow the repetitive inspection interval corresponding to the selected
initial inspection time.
The commenter states that the time limit for reporting in paragraph
(c) of the NPRM is unreasonable because its administrative personnel do
not work on weekends and during holiday periods. The commenter
recommends a 10 day limit for reporting. The FAA does not concur. A 48
hour period should be adequate and is a standard reporting requirement
time limit in ADs. The AD does not require that only administrative
personnel submit the report to the FAA.
Two commenters, including the National Transportation Safety Board,
state that they agree with the NPRM's proposed initial and repetitive
inspection program on the population of hubs that were produced using
the CCD procedure, based on the investigation that indicates that these
hubs may have a higher risk of abusive machining damage. However, since
the commenters do not agree that CCD hubs are the only suspect fan
hubs, the commenters do not agree with the proposed inspection program
for the remaining hub population. The NPRM proposed to inspect the
remaining population (those hubs not CCD) when the hub assembly is
stripped to the piece part level. The commenters are concerned that
this proposal may allow hubs to be initially inspected as late as
10,000 cycles in service (CIS) after the effective date of this AD. The
commenters believe that these hubs are of nearly equal concern as the
fan hubs produced by CCD and the proposed interval is too long to
detect all potential cracks before they may be expected to propagate to
failure. The commenters propose that inspection/reinspection occur at
the next shop visit for all of those hubs that have between 10,000 and
15,000 CIS since new regardless of the type of drill used during
manufacture.
The FAA does not concur at this time. The FAA's analysis of this
problem indicates that hubs manufactured using coolant-channel drills
are more susceptible to work hardened areas in the tierod and
counterweight holes that could serve as a crack origin. The FAA
concludes, therefore, that it is logical to treat these two distinct
populations of compressor hubs differently in terms of when operators
must perform the required inspections. Requiring all hubs to be
inspected according to the CCD schedule is not supported by the
available data. The investigation, however, continues and should any
additional data become available, the FAA may initiate further
rulemaking as required.
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 described
previously. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
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 will be affected by this AD, that it will
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, and that
the average labor rate is $60 per work hour. Based on these figures,
the total cost impact of the AD on U.S. operators is estimated to be
$862,560.
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
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 adding the following new
airworthiness directive:
97-02-11 Pratt & Whitney: Amendment 39-9896. Docket 96-ANE-33.
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.
[[Page 4904]]
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 (e) 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) 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) For fan hubs identified by serial numbers (S/Ns) in Appendix
A of PW Alert Service Bulletin (ASB) No. A6272, dated September 24,
1996, after the fan hub has accumulated more than 4,000 cycles in
service since new (CSN), accomplish the following:
(1) Select an initial inspection interval from Table 1 of this
AD and inspect 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.
(2) Reinspect at the interval in Table 1 of this AD that
corresponds to the selected initial inspection interval, and 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.
OR
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.
OR
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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(b) For fan hubs with S/Ns not listed in Appendix A of PW ASB
No. A6272, dated September 24, 1996, after the fan hub has
accumulated more than 4,000 CSN, 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.
(c) Remove from service fan hubs found cracked or fan hubs that
exceed the bushed hole acceptance criteria in accordance with PW ASB
No. A6272, dated September 24, 1996, and replace with serviceable
parts.
(d) 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.G[email protected]. Reporting requirements have been
approved by the Office of Management and Budget and assigned OMB
control number 2120-0056.
(e) 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.
(f) 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.
(g) The actions required by this AD shall be done in accordance
with the following PW ASB:
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Document No. Pages Revision Date
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A6272.......................... 1-21 Original September 24,
1996.
NDIP-892....................... 1-30 A September 15,
1996.
Attachment I................... AI-1- .................
AI-4 A September 15,
1996.
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Total pages: 55.
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 Pratt & Whitney, 400 Main St.,
East Hartford, CT 06108; telephone (860) 565-6600, fax (860) 565-
4503. Copies may be inspected at the FAA, New England Region, Office
of the Assistant Chief Counsel, 12 New England Executive Park,
Burlington, MA; or at the Office of the Federal Register, 800 North
Capitol Street NW., Suite 700, Washington, DC.
(h) This amendment becomes effective on March 5, 1997.
Issued in Burlington, Massachusetts, on January 13, 1997.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 97-1703 Filed 1-31-97; 8:45 am]
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