[Federal Register: August 16, 2004 (Volume 69, Number 157)]
[Proposed Rules]
[Page 50346-50349]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr16au04-28]
[[Page 50346]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-ANE-80-AD]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney JT8D-209, -217, -217A,
-217C, and -219 Series Turbofan Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to supersede an existing airworthiness
directive (AD) for Pratt & Whitney (PW) JT8D-209, -217, -217A, -217C,
and -219 series turbofan engines. That AD currently requires torque
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 proposed AD would require torque inspections
at shorter inspection intervals of the refurbished 3rd stage and 4th
stage LPT blades, but the same or longer inspection intervals of the
new 3rd stage and 4th stage LPT blades, for shroud notch wear and
replacement of the blade if wear limits are exceeded. This proposed AD
would also require replacing LPT-to-exhaust case bolts and nuts with
bolts and nuts made of Tinidur material. This proposed AD results from
reports of 194 blade fractures since 1991, with 37 of those blade
fractures resulting in LPT case separation, and three reports of
uncontained 3rd stage and 4th stage LPT blade failures with cowl
penetration. We are proposing this AD to prevent an uncontained blade
failure that could result in damage to the airplane.
DATES: We must receive any comments on this proposed AD by October 15,
2004.
ADDRESSES: Use one of the following addresses to submit comments on
this proposed AD:
By mail: Federal Aviation Administration (FAA), New
England Region, Office of the Regional Counsel, Attention: Rules Docket
No. 98-ANE-80-AD, 12 New England Executive Park, Burlington, MA 01803-
5299.
By fax: (781) 238-7055.
By e-mail: 9-ane-adcomment@faa.gov
You can get the service information identified in this proposed AD
from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone
(860) 565-8770, fax (860) 565-4503.
You may examine the AD docket at the FAA, New England Region,
Office of the Regional Counsel, 12 New England Executive Park,
Burlington, MA.
FOR FURTHER INFORMATION CONTACT: Keith Lardie, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (781)
238-7189, fax (781) 238-7199.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to submit any written relevant data, views, or
arguments regarding this proposal. Send your comments to an address
listed under ADDRESSES. Include ``ADDocket No. 98-ANE-80-AD'' in the
subject line of your comments. If you want us to acknowledge receipt of
your mailed comments, send us a self-addressed, stamped postcard with
the docket number written on it; we will date-stamp your postcard and
mail it back to you. We specifically invite comments on the overall
regulatory, economic, environmental, and energy aspects of the proposed
AD. If a person contacts us verbally, and that contact relates to a
substantive part of this proposed AD, we will summarize the contact and
place the summary in the docket. We will consider all comments received
by the closing date and may amend the proposed AD in light of those
comments.
We are reviewing the writing style we currently use in regulatory
documents. We are interested in your comments on whether the style of
this document is clear, and your suggestions to improve the clarity of
our communications that affect you. You may get more information about
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.Examining
the AD Docket
You may examine the AD Docket (including any comments and service
information), by appointment, between 8 a.m. and 4:30 p.m., Monday
through Friday, except Federal holidays. See ADDRESSES for the
location.
Discussion
On December 20, 1999, the FAA issued AD 99-27-01, Amendment 39-
11482 (64 FR 72916, December 29, 1999). That AD requires torque
inspection of the 3rd stage and 4th stage LPT blades for shroud notch
wear and replacement of the blade if wear limits are exceeded. That AD
was the result of a report of an uncontained blade failure. That
condition, if not corrected, could result in uncontained blade failure,
leading to damage to the airplane. Also, on October 21,1999, we issued
AD 99-22-14, Amendment 39-11392(64 FR 58328, October 29, 1999). That AD
requires replacingLPT-to-exhaust case bolts and nuts with improved
containment hardware. That AD was the result of reports of LPT flange
separation resulting from LPT blade failures. That condition, if not
corrected, could result in LPT flange separations resulting from LPT
blade failures.
Actions Since We Issued AD 99-27-01 and AD 99-22-14
Since we issued AD 99-27-01, there have been two additional
uncontained engine failures. The fracture rate of 3rd stage and 4th
stage LPT blades remains unchanged, with about 12 to 18 fractures
occurring per year. PW has determined that torque inspections of the
3rd stage and 4th stage LPT blades for shroud notch wear must be
performed at shorter inspection intervals for refurbished blades, to
prevent LPT blade failures. Also, since we issued AD 99-22-14, PW
determined that the LPT-to-exhaust case bolts and nuts introduced by
that AD have a higher failure rate than the previous interim nut and
bolt configuration. We issued a Notice of Proposed Rulemaking (NPRM),
Docket No. 92-ANE-15-AD, on July 7, 2004, to supersede AD 99-22-14.
That NPRM proposes to no longer require replacing the LPT-to-exhaust
case bolts and nuts.
Relevant Service Information
We have reviewed and approved the technical contents of PW Alert
Service Bulletin (ASB) No. JT8D A6224, Revision 5, dated June 11, 2004,
that describes procedures for initial and repetitive torque inspections
of 3rd stage and 4th stage LPT blades for shroud notch wear at revised
inspection thresholds and intervals.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an
unsafe condition that is likely to exist or develop on other JT8D-209,
-217, -217A, -217C, and -219 series turbofan engines of this same type
design. We are proposing this AD, which would require initial and
repetitive torque inspections of the 3rd stage and 4th stage LPT blades
for shroud notch wear at the thresholds and intervals specified in the
compliance section, and replacement of LPT-to-exhaust case bolts part
number (P/N) ST1315-15 and nuts P/N 4023466 with bolts and nuts made of
Tinidur
[[Page 50347]]
material. The proposed AD would require that you do the torque
inspections using the service information described previously.
Interim Action
These actions are interim actions and we may take further
rulemaking actions in the future.
Costs of Compliance
There are about 2,345 PW JT8D-200 series turbofan engines of the
affected design in the worldwide fleet. We estimate that 1,143 engines
installed on airplanes of U.S. registry would be affected by this
proposed AD. We also estimate that it would take approximately 1 work
hour per engine to perform a proposed torque inspection, and 1 work
hour per engine to perform the proposed bolt and nut replacements. The
average labor rate is $65 per work hour. Required parts would cost
approximately $1,734 per engine. Based on these figures, we estimate
the total cost of the proposed AD to U.S. operators to perform one
torque inspection, and bolt and nut replacements to be $2,130,552.
Regulatory Findings
We have determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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.
For the reasons discussed above, I certify that the 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. Would not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.
We prepared a summary of the costs to comply with this proposal and
placed it in the AD Docket. You may get a copy of this summary by
sending a request to us at the address listed under ADDRESSES. Include
``AD Docket No. 98-ANE-80-AD'' in your request.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend 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. The FAA amends Sec. 39.13 by removing Amendment 39-11482 (64 FR
72916, December 29, 1999) and by adding a new airworthiness directive
to read as follows:
Pratt & Whitney: Docket No. 98-ANE-80-AD. Supersedes AD 99-27-01,
Amendment 39-11482.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive
comments on this airworthiness directive (AD) action by October 15,
2004.
Affected ADs
(b) This AD supersedes AD 99-27-01, Amendment 39-11482.
Applicability
(c) This AD applies to Pratt & Whitney (PW) JT8D-209, -217, -
217A, -217C, and -219 series turbofan engines. These engines are
installed on, but not limited to, Boeing 727 series and MD-80 series
airplanes.
Unsafe Condition
(d) This AD results from reports of 194 blade fractures since
1991, with 37 of those blade fractures resulting in LPT case
separation, and three reports of uncontained 3rd stage and 4th stage
LPT blade failures with cowl penetration. We are issuing this AD to
prevent an uncontained blade failure that could result in damage to
the airplane.
Compliance
(e) You are responsible for having the actions required by this
AD performed within the compliance times specified unless the
actions have already been done.
Initial Torque Inspection for JT8D-209, -217, and -217A Engines
(f) For JT8D-209, -217, and -217A engines, perform the initial
torque inspection of 3rd and 4th stage LPT blades for shroud notch
wear. Use the procedures described in Accomplishment Instructions,
Part 1, Paragraphs 1. through 3. of PW Alert Service Bulletin (ASB)
No. A6224, Revision 5, dated June 11, 2004, at the applicable
threshold in the following Table 1:
Table 1.--Initial Torque Inspection Threshold for JT8D-209, -217, and -
217A Engines
------------------------------------------------------------------------
Hours time-in- Inspection
Blade type service (TIS) threshold
------------------------------------------------------------------------
(1) New pre-Service Bulletin Any number........ Within 6,000 hours
(SB) No. 5867 (small notch) 3rd TIS.
stage turbine blades.
(2) Refurbished pre-SB No. 5867 (i) Fewer than Within 4,000 hours
(small notch) 3rd stage turbine 3,000. TIS.
blades.
(ii) 3,000 or more Within 6,000 hours
TIS, or within
1,000 hours TIS
after the
effective date of
this AD,
whichever occurs
first.
(3) New post-SB No. 5867 (large Any number........ Within 10,000
notch) 3rd stage turbine blades. hours TIS.
(4) Refurbished post-SB No. 5867 (i) Fewer than Within 7,000 hours
(large notch) 3rd stage turbine 6,000. TIS.
blades.
(ii) 6,000 or more Within 8,000 hours
TIS, or within
1,000 hours TIS
after the
effective date of
this AD,
whichever occurs
first.
(5) New pre-SB No. 6029 (small Any number........ Within 6,000 hours
notch) 4th stage turbine blades. TIS.
(6) Refurbished pre-SB No. 6029 (i) Fewer than Within 4,000 hours
(small notch) 4th stage turbine 3,000. TIS.
blades.
(ii) 3,000 or more Within 6,000 hours
TIS, or within
1,000 hours TIS
after the
effective date of
this AD,
whichever occurs
first.
(7) New post-SB No. 6029 or new Any number........ Within 10,000
post-SB No. 6308 (large notch) hours TIS.
4th stage turbine blades.
[[Page 50348]]
(8) Refurbished post-SB No. 6029 (i) Fewer than Within 7,000 hours
or refurbished post-SB No. 6308 6,000. TIS.
(large notch) 4th stage turbine
blades.
(ii) 6,000 or more Within 8,000 hours
TIS, or within
1,000 hours TIS
after the
effective date of
this AD,
whichever occurs
first.
------------------------------------------------------------------------
Repetitive Torque Inspections for JT8D-209, -217, and -217A Engines
(g) For JT8D-209, -217, and -217A engines, perform repetitive
torque inspections of 3rd and 4th stage LPT blades for shroud notch
wear. Use the procedures described in Accomplishment Instructions,
Part 1, Paragraph 1. of PW ASB No. A6224, Revision 5, dated June 11,
2004, at the applicable intervals in the following Table 2 and Table
3:
Table 2.--3rd Stage Repetitive Torque Inspection Intervals for JT8D-209,
-217, and -217A Engines
------------------------------------------------------------------------
Inspection torque readings Number of readings Disposition
------------------------------------------------------------------------
Greater than or equal to 15 LB- All............... Repeat torque
IN (1.695 N.m). inspection within
1,000 hours TIS
since last
inspection.
Less than or equal to 15 LB-IN One or more....... Repeat torque
(1.695 N.m) but greater than or inspection within
equal to 10 LB-IN (1.130 N.m). 500 hours TIS
since last
inspection.
Less than or equal to 10 LB-IN One to three...... Repeat torque
(1.130 N.m) but greater than or inspection within
equal to 5 LB-IN (0.565 N.m). 125 hours TIS
since last
inspection.
Less than or equal to 10 LB-IN Four or more...... Remove engine from
(1.130 N.m) but greater than or service within 20
equal to 5 LB-IN (0.565 N.m). hours TIS since
last inspection.
Less than 5 LB-IN (0.565 N.m)... One or more....... Remove engine from
service within 20
hours TIS since
last inspection.
------------------------------------------------------------------------
Table 3.--4th Stage Repetitive Torque Inspection Intervals for JT8D-209,
-217, and -217A Engines
------------------------------------------------------------------------
Inspection torque readings Number of readings Disposition
------------------------------------------------------------------------
Greater than or equal to 15 LB- All............... Repeat torque
IN (1.695 N.m). inspection within
1,000 hours TIS
since last
inspection.
Less than or equal to 15 LB-IN One or more....... Repeat torque
(1.695 N.m) but greater than or inspection within
equal to 10 LB-IN (1.130 N.m). 500 hours TIS
since last
inspection.
Less than or equal to 10 LB-IN One to six........ Repeat torque
(1.130 N.m) but greater than or inspection within
equal to 5 LB-IN (0.565 N.m). 125 hours TIS
since last
inspection.
Less than or equal to 10 LB-IN Seven or more..... Remove engine from
(1.130 N.m) but greater than or service within 20
equal to 5 LB-IN (0.565 N.m). hours TIS since
last inspection.
Less than 5 LB-IN (0.565 N.m)... One or more....... Remove engine from
service within 20
hours TIS since
last inspection.
------------------------------------------------------------------------
(h) Subsequent repeat inspection intervals must not exceed the
previous inspection interval.
JT8D-209, -217, and -217A Engines Removed From Service
(i) JT8D-209, -217, and -217A engines removed from service may
be returned to service after a detailed inspection and repair or
replacement for all blades that exceed Engine Manual limits is done,
using procedures described in Accomplishment Instructions, Part 1,
Paragraph 4, of PW ASB No. A6224, Revision 5, dated June 11, 2004.
Information on repairing or replacing turbine blades can also be
found in JT8D-200 Engine Manual, Part No. 773128.
Initial Inspection for JT8D-217C and -219 Engines
(j) For JT8D-217C and -219 engines, perform the initial torque
inspection of 4th stage LPT blades for shroud notch wear. Use the
procedures described in Accomplishment Instructions, Part 2,
Paragraphs 1. through 3. of PW ASB No. A6224, Revision 5, dated June
11, 2004, at the applicable threshold in the following Table 4:
Table 4.--Initial Torque Inspection Threshold for JT8D-217C and -219
Engines
------------------------------------------------------------------------
Inspection
Blade type TIS threshold
------------------------------------------------------------------------
(1) New pre-SB No. 6090 (small Any number........ Within 5,000 hours
notch) 4th stage turbine blades. TIS.
[[Page 50349]]
(2) Refurbished pre-SB No. 6090 (i) Fewer than Within 4,000 hours
(small notch) 4th stage turbine 3,000.. TIS.
blades.
(ii) 3,000 or more Within 5,000 hours
TIS, or within
1,000 hours TIS
after the
effective date of
this AD,
whichever occurs
first.
(3) New post-SB No. 6090, new Any number........ Within 10,000
post-SB No. 6402, or new post- hours TIS.
SB No. 6412 (large notch) 4th
stage turbine blades.
(4) Refurbished ``As-Cast'' post- Any number........ Within 7,000 hours
SB No. 6090, post-SB No. 6402, TIS.
or post-SB No. 6412 (large
notch) 4th stage turbine blades.
(5) Refurbished ``Modified'' (i) Fewer than Within 4,000 hours
post-SB No. 6090, post-SB No. 3,000. TIS.
6402, or post-SB No. 6412
(large notch) 4th stage turbine
blades.
(ii) 3,000 or more Within 7,000 hours
TIS, or within
1,000 hours TIS
after the
effective date of
this AD,
whichever occurs
first.
------------------------------------------------------------------------
Repetitive Torque Inspections for JT8D-217C and -219 Engines
(k) For JT8D-217C and -219 engines, perform repetitive torque
inspections of 4th stage LPT blades for shroud notch wear. Use the
procedures described in Accomplishment Instructions, Part 2,
Paragraph 1. of PW ASB No. A6224, Revision 5, dated June 11, 2004,
at the applicable intervals in the following Table 5:
Table 5.--Repetitive Torque Inspection Intervals for JT8D-217C and -219
Engines
------------------------------------------------------------------------
Inspection torque readings Number of readings Disposition
------------------------------------------------------------------------
Greater than or equal to 15 LB- All............... Repeat torque
IN (1.695 N.m). inspection within
1,000 hours TIS
since last
inspection.
Less than or equal to 15 LB-IN One or more....... Repeat torque
(1.695 N.m) but greater than or inspection within
equal to 10 LB-IN (1.130 N.m). 500 hours TIS
since last
inspection.
Less than or equal to 10 LB-IN One to six........ Repeat torque
(1.130 N.m) but greater than or inspection within
equal to 5 LB-IN (0.565 N.m). 125 hours TIS
since last
inspection.
Less than or equal to 10 LB-IN Seven or more..... Remove engine from
(1.130 N.m) but greater than or service within 20
equal to 5 LB-IN (0.565 N.m). hours TIS since
last inspection.
Less than 5 LB-IN (0.565 N.m)... One or more....... Remove engine from
service within 20
hours TIS since
last inspection.
------------------------------------------------------------------------
(l) Subsequent repeat inspection intervals must not exceed the
previous inspection interval.
JT8D-217C and -219 Engines Removed From Service
(m) JT8D-217C and -219 engines removed from service may be
returned to service after a detailed inspection and repair or
replacement for all blades that exceed Engine Manual limits is done,
using procedures described in Accomplishment Instructions, Part 2,
Paragraph 4, of PW ASB No. A6224, Revision 5, dated June 11, 2004.
Information on repairing or replacing turbine blades can also be
found in JT8D-200 Engine Manual, Part No. 773128.
Other Criteria for All Engine Models Listed in This AD
(n) Whenever a refurbished or used blade is intermixed with new
blades in a rotor, use the lowest initial inspection threshold that
is applicable.
(o) The initial torque inspection or the repetitive inspection
intervals should not be reset unless the blades are refurbished.
(p) Whenever a used (service run) blade is reinstalled in a
rotor, the previous used time should be subtracted from the initial
torque inspection threshold.
LPT-to-Exhaust Case Bolts and Nuts Replacement
(q) At next accessibility to the LPT-to-exhaust case bolts, part
number (P/N) ST1315-15, and nuts, P/N 4023466, replace bolts and
nuts with bolts and nuts made of Tinidur material. Information on
replacing the bolts and nuts can be found in PW Service Bulletin No.
6455, dated January 15, 2004.
Definitions
(r) For the purpose of this AD, refurbishment is defined as
restoration of either the shrouds or blade retwist or both, per the
JT8D-200 Engine Manual, Part No. 773128.
(s) For the purpose of this AD, ``As-Cast'' refers to blades
that were machined from new castings and ``Modified'' refers to
blades that were derived from the pre-SB No. 6090 configuration.
Alternative Methods of Compliance
(t) The Manager, Engine Certification Office, has the authority
to approve alternative methods of compliance for this AD if
requested using the procedures found in 14 CFR 39.19.
Material Incorporated by Reference
(u) None.
Related Information
(v) None.
Issued in Burlington, Massachusetts, on August 9, 2004.
Ann Mollica,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 04-18644 Filed 8-13-04; 8:45 am]
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