Airworthiness directives: Pratt & Whitney,

[Federal Register: July 14, 1998 (Volume 63, Number 134)]

[Rules and Regulations]

[Page 37765-37767]

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

[DOCID:fr14jy98-6]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-ANE-04; Amendment 39-10652; AD 97-25-10 R1]

RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

SUMMARY: This amendment revises an existing airworthiness directive (AD), applicable to certain Pratt & Whitney (PW) JT9D series turbofan engines, that currently requires initial and repetitive fluorescent penetrant inspections (FPI) for cracks in cooling air holes of first stage high pressure turbine (HPT) disks, and replacement of cracked disks with serviceable parts. In addition, the current AD requires initial and repetitive FPI for cracks in tie bolt holes of certain other affected second stage HPT disks installed in PW JT9D series turbofan engines. This amendment calls out the second stage HPT hub assembly by part number (P/N) in addition to the hub P/N for clarification of affected parts, and references a service bulletin that does not change any of the requirements in the AD, but better explains the inspection procedures that are referenced in the current AD. This amendment also increases the repetitive inspection interval of first stage HPT disks. This amendment is prompted by the need to clarify the inspection procedures and the parts affected by this AD and by a re- evaluation of the risk analysis, based on new data from service, to establish a new repetitive inspection interval for the first stage HPT disk. The actions specified by this AD are intended to prevent turbine disk failure due to cooling air hole or tie bolt hole cracking, which could result in an uncontained engine failure and damage to the aircraft.

DATES: Effective July 29, 1998.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of July 29, 1998.

Comments for inclusion in the Rules Docket must be received on or before September 14, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 97-ANE-04, 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.

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 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: 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: On November 28, 1997, the Federal Aviation Administration (FAA) issued AD 97-25-10, Amendment 39-10234 (62 FR 64514, December 8, 1997), applicable to certain Pratt & Whitney (PW) JT9D series turbofan engines, to require initial and repetitive fluorescent penetrant inspections (FPI) for cracks in cooling air holes of affected first stage high pressure turbine (HPT) disks, and, if necessary, replacement with serviceable parts. In addition, that airworthiness directive (AD) requires initial and repetitive FPI for cracks in tie bolt holes of all affected second stage HPT disks. Finally, that action requires reporting findings of cracked turbine disks. That action was prompted by reports of a cracked cooling air hole on one first stage HPT disk, and a cracked tie bolt hole on one second stage HPT disk. That condition, if not corrected, could result in turbine disk failure due to cooling air hole or tie bolt hole cracking, which could result in an uncontained engine failure and damage to the aircraft.

Since the issuance of that AD, the FAA received questions regarding clarifying the inspection procedures for second stage HPT disk tie bolt holes. In addition, one commenter requested that the 48 hour time requirement to notify the FAA that a cracked disk is found be changed to 10 working days. The commenter explained that 48 hours is not practical if a cracked disk is found over a holiday weekend. The FAA concurs, and has changed this revision to the final rule AD to include a 10 working day reporting requirement.

[[Page 37766]]

Also, based on new data and subsequent re-evaluation of the risk analysis since publication of the existing AD, the FAA has determined that the repetitive inspection interval for first stage HPT disks may be extended. This revision to the final rule AD includes the extended inspection interval.

The FAA has reviewed and approved the technical contents of PW Service Bulletin (SB) No. JT9D-7R4-72-536, Revision 2, dated April 30, 1998, that describes procedures for FPI for cracks in tie bolt holes of all affected second stage HPT disks.

Since an unsafe condition has been identified that is likely to exist or develop on other engines of this same type design, this AD revises AD 97-25-10 to call out the second stage HPT hub assembly by part number (P/N) in addition to the hub P/N for clarification of affected parts, and reference a SB that does not change any of the requirements in the AD, but better explains the inspection procedures that are referenced in the current AD. The actions are required to be accomplished in accordance with PW SB No. JT9D-7R4-72-536, Revision 2, dated April 30, 1998.

Since the issuance of that AD, the FAA received a request to increase the inspection interval for first stage HPT disks. The FAA has determined, by review of risk analysis, that extending the inspection interval provides an adequate margin of safety.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited

Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption Addresses. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD 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 97-NE-04.'' The postcard will be date stamped and returned to the commenter.

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.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a ``significant regulatory action'' under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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 removing Amendment 39-10234 (62 FR 64514, December 8, 1997) and by adding a new airworthiness directive, Amendment 39-10652, to read as follows:

   97-25-10 R1 Pratt & Whitney: Amendment 39-10652. Docket 97-ANE-04. Revises AD 97-25-10, Amendment 39-10234.

   Applicability: Pratt & Whitney (PW) JT9D-59A, -70A, -7Q, -7Q3, - 7R4D, -7R4D1, -7R4E, and -7R4E1 (AI-500) series turbofan engines, installed on but not limited to Airbus Industrie A300 and A310, Boeing 747 and 767, 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 (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 turbine disk failure due to cooling hole or tie bolt hole cracking, which could result in an uncontained engine failure and damage to the aircraft, accomplish the following:

   (a) For first stage high pressure turbine (HPT) disks, part numbers (P/Ns) 768001, 792701, 812901, 819801, 840501, 840401, 840701, 840601, and 840301, installed in PW JT9D-59A, -70A, -7Q, and -7Q3 engines, accomplish the following:

   (1) Disks that have not been fluorescent penetrant inspected or eddy current inspected since introduction into service, perform an initial fluorescent penetrant inspection (FPI) for cracks in all 40 cooling air holes in accordance with PW Turbojet Engine Standard Practices Manual, P/N 585005, Chapter/Section 70-33, Special Process Operation Procedure (SPOP) 84, as follows:

   (i) Disks with 3,500 cycles since new (CSN) or more on the effective date of this AD, inspect prior to accumulating 5,000 CSN, or within 1,500 cycles in service (CIS) after the effective date of this AD, whichever occurs later.

   [[Page 37767]]

   (ii) Disks with less than 3,500 CSN on the effective date of this AD, inspect prior to accumulating 5,000 CSN.

   (2) Disks that have been reoperated in accordance with PW Service Bulletin (SB) No. 5815, Revision 2, dated July 31, 1992, or prior revisions, that have not been fluorescent penetrant inspected or eddy current inspected since reoperation, perform an initial FPI for cracks in all 40 cooling air holes in Chapter/Section 70-33, SPOP 84, as follows:

   (i) Disks with 3,500 CIS or more since reoperation on the effective date of this AD, inspect prior to accumulating 5,000 CIS since reoperation, or within 1,500 CIS after the effective date of this AD, whichever occurs later.

   (ii) Disks with less than 3,500 CIS since reoperation on the effective date of this AD, inspect prior to accumulating 5,000 CIS since reoperation.

   (3) Disks that have been fluorescent penetrant inspected, or eddy current inspected, since introduction into service or since reoperation, in accordance with PW SB No. 5744, Revision 3, dated March 31, 1993, or prior revisions, or PW JT9D-7Q, -7Q3 Engine Manual, P/N 777210, 72-51-00, Inspection -03, or PW JT9D-59A, -70A Engine Manual, P/N 754459, 72-51-00, Heavy Maintenance Check -03, perform an FPI for cracks in all 40 cooling air holes, prior to accumulating 5,000 CIS since last FPI or ECI, or within 250 CIS after the effective date of this AD, whichever occurs later, in accordance with PW Turbojet Engine Standard Practices Manual, P/N 585005, Chapter/Section 70-33, SPOP 84.

   (4) Thereafter, perform FPI for cracks in all 40 cooling air holes at intervals not to exceed 5,000 CIS since last FPI, in accordance with PW Turbojet Engine Standard Practices Manual, P/N 585005, Chapter/Section 70-33, SPOP 84.

   (5) Prior to further flight, remove from service cracked disks, and replace with serviceable parts.

   (b) For second stage HPT disks, P/N 5001802-01, or hub assembly, P/N 808242, installed in PW JT9D-7R4D, -7R4D1, -7R4E, and -7R4E1 (AI-500) engines, accomplish the following:

   (1) Disks that have not been fluorescent penetrant inspected since introduction into service, perform an initial FPI for cracks in all 30 tie bolt holes in accordance with PW SB No. JT9D-7R4-72- 536, Revision 2, dated April 30, 1998, as follows:

   (i) Disks with 6,000 CSN or more on the effective date of this AD, inspect within 2,000 CIS after the effective date of this AD.

   (ii) Disks with less than 6,000 CSN on the effective date of this AD, inspect prior to accumulating 8,000 CSN.

   (2) Disks that have been fluorescent penetrant inspected since introduction into service, perform an FPI for cracks in all 30 tie bolt holes, prior to accumulating 8,000 CIS since last FPI, or within 250 CIS after the effective date of this AD, whichever occurs later, in accordance with PW SB No. JT9D-7R4-72-536, Revision 2, dated April 30, 1998.

   (3) Thereafter, perform FPI for cracks in all 30 tie bolt holes at intervals not to exceed 8,000 CIS since last FPI, in accordance with PW SB No. JT9D-7R4-72-536, Revision 2, dated April 30, 1998.

   (4) Prior to further flight, remove from service cracked disks, and replace with serviceable parts.

   (c) Report findings of cracked turbine disks within 10 working days after inspection to 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, Internet: ``Tara.Goodman@faa.dot.gov''. Reporting requirements have been approved by the Office of Management and Budget and assigned OMB control number 2120-0056.

   (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 method of compliance with this AD, if any, may be obtained from the Engine Certification Office.

   (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.

   (f) The inspections shall be done in accordance with the following PW SB:

   Document Number

   Pages

   Revision

   Date

   JT9D-7R4-72-536.....................

   1 2...................... April 30, 1998.

   2 Original............... February 28, 1997.

   3, 4 2...................... April 30, 1998.

   5, 6 Original............... February 28, 1997.

   7 2...................... April 30, 1998.

   8-10 1...................... October 13, 1997.

   Total pages: 10.

   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 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 July 29, 1998.

   Issued in Burlington, Massachusetts, on July 6, 1998. Jay J. Pardee, Manager, Engine and Propeller Directorate, Aircraft Certification Service.

   [FR Doc. 98-18649Filed7-10-98; 9:33 am]

   BILLING CODE 4910-13-P