[Federal Register Volume 64, Number 249 (Wednesday, December 29, 1999)]
[Rules and Regulations]
[Pages 72916-72918]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-33566]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-ANE-80-AD; Amendment 39-11482; AD 99-27-01]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney JT8D-209, -217, -217A,
-217C, and -219 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-209, -217, -217A, -217C, and -
219 series turbofan engines, that requires inspection of the 3rd stage
and 4th stage low pressure turbine (LPT) blades for shroud notch wear
and replacement of the blade if wear limits are exceeded. This
amendment is prompted by a report of an uncontained blade failure. The
actions specified by this AD are intended to prevent an uncontained
blade failure that could result in damage to the airplane.
DATES: Effective February 2, 2000.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of February 2, 2000.
ADDRESSES: The service information referenced in this AD may be
obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108;
telephone (860) 565-8770, fax (860) 565-4503. This information may be
examined at the Federal Aviation Administration (FAA), New England
Region, Office of the Regional 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: Christopher Spinney, Aerospace
Engineer, Engine Certification Office, FAA, Engine and Propeller
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299;
telephone (781) 238-7175, fax (781) 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-209, -
217, -217A, -217C, and -219 series turbofan engines was published in
the Federal Register on September 23, 1999 (64 FR 51484). That action
proposed to require inspection of the 3rd stage and 4th stage low
pressure turbine (LPT) blades for shroud notch wear and replacement of
the blade if wear limits are exceeded in accordance with PW Service
Bulletin (SB) No. 6224, Revision 2, dated August 27, 1998. That action
was prompted by a report of an uncontained blade failure. That
condition, if not corrected, could result in an uncontained blade
failure that could result in damage to the airplane.
Comments Received
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received from one commenter.
From Earlier to Later
One commenter wants to change the cyclic and hourly time limits
from whichever occurs first to whichever occurs later. The commenter
believes that the later of the cyclic or hourly limits provides an
adequate level of safety. The Federal Aviation Administration (FAA)
does not concur. The commenter does not provide the substantiating data
required to support such a claim. The FAA recognizes that many
operators manage their engine fleet safely with alternate inspection
techniques and intervals. The FAA is prepared to grant alternative
methods of compliance (AMOC) to those operators who submit a request
with data substantiating that an acceptable level of safety is
maintained using their program through the AMOC provisions of paragraph
(d) of this final rule.
SB Publication Date vs. Effective Date of This AD
The same commenter expresses confusion as to how to compute the
compliance intervals of this AD; specifically, if the effective date of
the AD should be used vs. the publication date of the SB for a
compliance baseline. The FAA concurs. For the purpose of this AD, all
baseline compliance times should be calculated based upon the effective
date of this AD. The FAA has added an explanatory paragraph (c) to this
final rule to clarify this issue.
Economic Impact Understated
The same commenter believes that the economic impact of the AD is
understated as based upon the numbers presented in the economic
analysis of the proposal. Specifically, the commenter believes that the
cost effect of hardware removals after failing an inspection should be
considered. The FAA concurs and has revised the
[[Page 72917]]
economic analysis to include an estimated cost of the hardware
replacement. The addition of the costs of blade replacement and
removals adds an additional $4, 720, 640 per year to the economic
impact of the AD.
Request for Terminating Action
Two commenters, including the manufacturer, request that the
installation of stronger LPT flange bolts be viewed as terminating
action for the inspections required by this AD. The commenters point to
a similar terminating action for an inspection requirement for JT8D-1
through -17AR engines, also intended to address a containment issue.
The FAA does not concur. While installation of improved LPT bolts will
provide some increase in containment capability, the improved bolts
alone are not equivalent to the required inspections for preventing an
uncontained blade failure in the JT8D-200 series engines. The
containment issue for the JT8D-1 through -17AR engines was addressed
through installation of improved bolts and a containment shield. At
present, there is no similar containment shield available for the JT8D-
200 series engines. In addition, the installation of improved LPT bolts
is already mandated by AD 99-22-14. The FAA has determined that for the
JT8D-200 series engines, an uncontained LPT blade failure must be
addressed through both the installation of improved LPT flange bolts
and the inspections required by this AD.
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 as 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.
Economic Analysis
There are approximately 2,631 engines of the affected design in the
worldwide fleet. The FAA estimates that 1,279 engines installed on
aircraft of US registry will be affected by this AD, that it will take
approximately 1 work hour per engine per year to accomplish the
required inspections, and that the average labor rate is $60 per work
hour. Based on these figures, the cost impact for the required
inspections is estimated to be $76,740 per year. It is estimated that
10% of the blade sets will fail the inspection per year and require
replacement. The average cost for a new blade set is $35,500. The new
blades take approximately 23 work hours to install and the average
labor rate is $60 per work hour. Based on these figures, the annual
replacement cost impact of the AD on US operators per year is
$4,720,640. Therefore the total annual cost impact of the AD on US
operators is 4,797,380.
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 (EO) 13132.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under EO 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:
99-27-01 Pratt & Whitney: Amendment 39-11482. Docket 98-ANE-80-AD.
Applicability: Pratt & Whitney (PW) JT8D-209, -217, -217A, -
217C, and -219 series turbofan engines, installed on, but not
limited to, McDonnell Douglas MD-80 series airplanes.
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 (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 an uncontained blade failure that could result in
damage to the airplane, accomplish the following:
Inspection
(a) For JT8D-209, -217, and -217A engines, perform the 3rd and
4th stage low pressure turbine (LPT) blade torque inspections in
accordance with the intervals and procedures described in PW Service
Bulletin (SB) No. 6224, Revision 2, dated August 27, 1998,
Accomplishment Instructions, Part 1, A(1) through B(3).
(b) For JT8D-217C and -219 engines, perform the 4th stage LPT
blade torque inspection in accordance with the intervals and
procedures described in PW SB No. 6224, Revision 2, dated August 27,
1998, Accomplishment Instructions, Part 2, C(1) through C(3).
Effective Date for Computing Compliance Intervals
(c) For the purpose of this AD, use the effective date of this
AD for computing compliance intervals whenever PW SB No. 6224,
Revision 2, dated August 27, 1998, refers to the publication date of
the SB.
Alternative Methods of Compliance
(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.
Operators shall submit their requests 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.
Ferry Flights
(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.
Incorporation by Reference
(f) The actions required by this AD shall be done in accordance
with Pratt & Whitney Service Bulletin No. 6224, Revision 2, dated
August 27, 1998. This incorporation by
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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) 565-8770, fax (860) 565-4503. Copies may be
inspected at the FAA, New England Region, Office of the Regional
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.
(g) This amendment becomes effective on February 2, 2000.
Issued in Burlington, Massachusetts, on December 20, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 99-33566 Filed 12-28-99; 8:45 am]
BILLING CODE 4910-13-U
