Airworthiness directives: Pratt & Whitney,

[Federal Register: September 2, 1998 (Volume 63, Number 170)]

[Proposed Rules]

[Page 46712-46714]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr02se98-30]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-ANE-57]

RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes the supersedure of an existing airworthiness directive (AD), applicable to Pratt & Whitney JT9D series turbofan engines, that currently requires installing an improved design turbine exhaust case (TEC) with a thicker containment wall,

[[Page 46713]]

modifying the existing TEC to incorporate a containment shield, or modifying the existing TEC to replace the ``P'' flange and case wall. This proposal is prompted by the need to add additional affected TEC assemblies eligible for modification, and to add an additional TEC modification compliance option. The actions specified by the proposed AD are intended to prevent release of uncontained debris from the TEC following an internal engine failure, which can result in damage to the aircraft.

DATES: Comments must be received by November 2, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 95-ANE-57, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: ``9-ad- engineprop@faa.dot.gov''. Comments sent via the Internet must contain the docket number in the subject line. 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, Publications Department, Supervisor Technical Publications Distribution, M/S 132-30, 400 Main St., East Hartford, CT 06108; telephone (860) 565-7700, fax (860) 565-4503. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Tara Goodman, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7130, fax (781) 238-7199.

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 filedin 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 95-ANE-57.'' 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 Regional Counsel, Attention: Rules Docket No. 95-ANE-57, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

On December 4, 1996, the Federal Aviation Administration (FAA) issued airworthiness directive (AD) 96-25-10, Amendment 39-9853 (61 FR 66892, December 19, 1996), applicable to Pratt & Whitney (PW) JT9D series turbofan engines, to require installing an improved design turbine exhaust case (TEC) with a thicker containment wall, modifying the existing TEC to incorporate a containment shield, or modifying the existing TEC to replace the ``P'' flange and case wall. That action was prompted by reports of 64 uncontained engine failures since 1972. That condition, if not corrected, could result in release of uncontained debris from the TEC following an internal engine failure, which can result in damage to the aircraft.

Since the issuance of that AD, PW has issued Service Bulletin (SB) No. 6157, Revision 2, dated January 28, 1998, that lists by part number additional affected TEC assemblies that are eligible for modification. This superseding AD references this revised SB. In addition, this proposed rule adds an additional TEC modification compliance option described in PW SB No. 6320, dated February 5, 1998.

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 supersede AD 96-25-10 to add additional affected TEC assemblies that are eligible for modification, and to add an additional TEC modification compliance option. The actions are required to be accomplished in accordance with the SBs described previously.

There are approximately 566 engines of the affected design in the worldwide fleet. The FAA estimates that 157 engines installed on aircraft of U.S. registry would be affected by this proposed AD, that it would take approximately zero additional work hours per engine to accomplish the proposed actions when done at complete disassembly/ assembly, and that the average labor rate is $60 per work hour. Required parts would cost approximately $6,705 per engine. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $1,052,685.

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:

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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 removing amendment 39-9853 (61 FR 66892, December 19, 1996) and by adding a new airworthiness directive to read as follows:

   Pratt & Whitney: Docket No. 95-ANE-57. Supersedes AD 96-25-10, Amendment 39-9853.

   Applicability: Pratt & Whitney (PW) JT9D-3, -7, -20, -59A, -70A, -7Q, and -7R4 series turbofan engines, installed on but not limited to Airbus A300 and A310 series; Boeing 747 and 767 series; and McDonnell Douglas DC-10 series aircraft.

   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 (c) 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 release of uncontained debris from the turbine exhaust case (TEC) following an internal engine failure, which can result in damage to the aircraft, accomplish the following:

   (a) At the next removal of the TEC from the low pressure turbine case ``P'' flange during a shop visit, but not later than 48 months after the effective date of this AD, accomplish the following:

   (1) For PW JT9D-3A, -7, -7A, -7AH, -7H, -7F, -7J, -20, and -20J series turbofan engines, accomplish any one of the following actions:

   (i) Install a thicker-walled TEC, with part numbers (P/N's) listed in PW service bulletin (SB) No. 6113, dated April 13, 1993, as applicable; or

   (ii) Install a modified TEC that incorporates a containment shield, with P/N's listed in PW SB No. 5907, dated March 27, 1990, as applicable; or

   (iii) Install a modified TEC that incorporates a replacement ``P'' flange and case wall, with P/N's listed in PW SB No. 6118, Revision 3, dated January 10, 1996, or

   (iv) Install a modified TEC that incorporates a replacement ``P'' flange and case wall, with Chromalloy Supplemental Type Certificate (STC) SE00047AT-D, dated October 15, 1996; or

   (v) Install a modified TEC that incorporates replacement or modified outer case detail in accordance with PW SB No. 6320, dated February 5, 1998.

   (2) For PW JT9D-7Q and -7Q3 series turbofan engines, accomplish any one of the following actions:

   (i) Install a thicker-walled TEC, with P/N's listed in PW SB No. 5977, dated December 14, 1990; or

   (ii) Install a modified TEC that incorporates a containment shield, with P/N's listed in PW SB No. 5907, dated March 27, 1990, as applicable; or

   (iii) Install a modified TEC that incorporates a replacement ``P'' flange and case wall, with P/N's listed in PW SB No. 6157, Revision 2, dated January 28, 1998; or

   (iv) Install a modified TEC that incorporates a replacement ``P'' flange and case wall, with Chromalloy STC SE00047AT-D, dated October 15, 1996; or

   (v) Install a modified TEC that incorporates replacement or modified outer case detail in accordance with PW SB No. 6320, dated February 5, 1998.

   (3) For PW JT9D-59A and -70A series turbofan engines, accomplish one of the following actions:

   (i) Install a thicker-walled TEC, with P/N's listed in PW SB No. 6243, dated February 1, 1996; or

   (ii) Install a modified TEC that incorporates a containment shield, with P/N's listed in PW SB No. 5907, dated March 27, 1990, as applicable;

   (iii) Install a modified TEC that incorporates a replacement ``P'' flange and case wall, with P/N's listed in PW SB No. 6157, Revision 2, dated January 28, 1998; or

   (iv) Install a modified TEC that incorporates a replacement ``P'' flange and case wall, with Chromalloy STC SE00047AT-D, dated October 15, 1996; or

   (v) Install a modified TEC that incorporates replacement or modified outer case detail in accordance with PW SB No. 6320, dated February 5, 1998.

   (4) For PW JT9D-7R4D (BG-700 series) turbofan engines, accomplish one of the following actions:

   (i) Install a thicker-walled TEC, with P/N's listed in PW SB No. JT9D-7R4-72-479, Revision 1, dated November 12, 1993; or

   (ii) Install a modified TEC that incorporates a containment shield, with P/N's listed in PW SB No. JT9D-7R4-72-407, Revision 1, dated August 16, 1990, as applicable; or

   (iii) Install a modified TEC that incorporates a replacement ``P'' flange and case wall, with Chromalloy STC SE00047AT-D, dated October 15, 1996.

   (5) For PW JT9D-7R4D (BG-800 series), -7R4D (BG-900 series), - 7R4D1 (AI-500 series), -7R4E (BG-800 series), -7R4E (BG-900 series), -7R4E1 (AI-500 series), -7R4E1 (AI-600 series), -7R4E4 (BG-900 series), -7R4G2 (BG-300 series), and -7R4H1 (AI-600 series) turbofan engines, accomplish any one of the following actions:

   (i) Install a thicker-walled TEC, with P/N's listed in PW SB No. JT9D-7R4-72-534, dated October 18, 1996; or

   (ii) Install a modified TEC that incorporates a containment shield, with P/N's listed in PW SB No. JT9D-7R4-72-466, Revision 2, dated May 10, 1996; or

   (iii) Install a modified TEC that incorporates a replacement ``P'' flange and case wall, with P/N's listed in PW SB No. JT9D-7R4- 72-534, dated October 18, 1996; or

   (iv) Install a modified TEC that incorporates a replacement ``P'' flange and case wall, with Chromalloy STC SE00054AT-D, dated October 19, 1994.

   (6) For PW JT9D-7R4D (BG-800 series), -7R4D (BG-900 series), - 7R4D1 (AI-500 series), -7R4E (BG-800 series), -7R4E (BG-900 series), -7R4E1 (AI-500 series), -7R4E1 (AI-600 series), -7R4E4 (BG-900 series), -7R4G2 (BG-300 series), and -7R4H1 (AI-600 series) turbofan engines, with TECs that have been modified to incorporate a replacement ``P'' flange and case wall, in accordance with PW SB No. JT9D-7R4-72-513, Revision 3, dated November 13, 1996, or previous revisions, perform heat treatment of the TECs in accordance with the Accomplishment Instructions of PW SB No. JT9D-7R4-72-534, dated October 18, 1996.

   (b) For the purpose of this AD, a shop visit is defined as induction of an engine into the shop for scheduled maintenance.

   (c) 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 forward 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.

   (d) 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 August 26, 1998. Jay J. Pardee, Manager, Engine and Propeller Directorate, Aircraft Certification Service.

   [FR Doc. 98-23617Filed9-1-98; 8:45 am]

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