[Federal Register Volume 69, Number 157 (Monday, August 16, 2004)]
[Proposed Rules]
[Pages 50346-50349]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-18644]



[[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).

-----------------------------------------------------------------------

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: [email protected]
    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]
BILLING CODE 4910-13-P