Airworthiness Directives; Pratt & Whitney JT8D Series Turbofan Engines

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 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 filed in 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 98-ANE-48-AD.'' 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. 98-ANE-48-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

On June 1, 1999, the Federal Aviation Administration (FAA) issued airworthiness directive (AD) 99-12-03, Amendment 39-11187 (64 FR 30379, June 8, 1999), to require revisions to the Time Limits Section (TLS) of the Pratt & Whitney (PW) JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR series Turbofan Engine Manuals to include required enhanced inspection of selected critical

life-limited parts at each piece-part exposure. That AD was prompted by a Federal Aviation Administration (FAA) study of in-service events involving uncontained failures of critical rotating engine parts that indicated the need for improved inspections. That condition, if not corrected, could result in critical life-limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane.

New Inspection Procedures

Since the issuance of that AD, PW has developed additional focused inspection procedures. This proposal would add first stage high pressure (HP) turbine disks and shafts that would require enhanced inspection at each piece-part exposure.

Proposed Actions

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 99-12-03 to add additional critical life-limited parts for enhanced inspection at each piece-part opportunity.

Economic Analysis

The FAA estimates that 5,821 engines installed on airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 8 work hours per engine to perform the enhanced inspection for the first stage HP turbine disks and shafts. The average labor rate is $60 per work hour. The cost impact of the added inspections per engine is approximately $480 per year, with the approximate total cost for the U.S. fleet of $2,794,080 per year.

Regulatory Impact

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:

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 39-11187 (64 FR 30379, June 8, 1999), and by adding a new airworthiness directive, to read as follows:

Pratt & Whitney: Docket No. 98-ANE-48-AD. Supersedes AD 99-12-03, Amendment 39-11187.

Applicability: Pratt & Whitney (PW) JT8D-1, -1A, -1B, -7, -7A, - 7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR series turbofan engines, installed on but not limited to Boeing 727 and 737 series, and McDonnell Douglas DC-9 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 (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 critical life-limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane, accomplish the following:

Inspections

(a) Within the next 30 days after the effective date of this AD, revise the Time Limits Section (TLS) of the JT8D-1, -1A, -1B, -7, - 7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR series Turbofan Engine Manuals, and for air carrier operations revise the approved continuous airworthiness maintenance program, by adding the following:

``Critical Life Limited Part Inspection

A. Inspection Requirements

(1) This section has the definitions for individual engine piece-parts and the inspection procedures which are necessary when these parts are removed from the engine. (2) It is necessary to do the inspection procedures of the piece-parts in Paragraph B when: (a) The part is removed from the engine and disassembled to the level specified in paragraph B and (b) The part has accumulated more than 100 cycles since the last piece part inspection, provided that the part is not damaged or related to the cause of its removal from the engine. (3) The inspections specified in this section do not replace or make unnecessary other recommended inspections for these parts or other parts.

B. Parts Requiring Inspection

Note: Piece part is defined as any of the listed parts with all the blades removed.

Engine Manual ------------------------------------------------------------------------ Description Section Inspection ------------------------------------------------------------------------ Hub (Disk), 1st Stage Compressor ------------------------------------------------------------------------ 491201............................. 72-33-31 -02, -03, -04 496501............................. 72-33-31 -02, -03, -04 504101............................. 72-33-31 -02, -03, -04 515201............................. 72-33-31 -02, -03, -04 594301............................. 72-33-31 -02, -03, -04 640501............................. 72-33-31 -02, -03, -04 640601............................. 72-33-31 -02, -03, -04 743301............................. 72-33-31 -02, -03, -04 749701............................. 72-33-31 -02, -03, -04 749801............................. 72-33-31 -02, -03, -04 750001............................. 72-33-31 -02, -03, -04 750101............................. 72-33-31 -02, -03, -04 778901............................. 72-33-31 -02, -03, -04 791401............................. 72-33-31 -02, -03, -04 791501............................. 72-33-31 -02, -03, -04 791601............................. 72-33-31 -02, -03, -04 791701............................. 72-33-31 -02, -03, -04 791801............................. 72-33-31 -02, -03, -04 806001............................. 72-33-31 -02, -03, -04 806101............................. 72-33-31 -02, -03, -04 817401............................. 72-33-31 -02, -03, -04 844401............................. 72-33-31 -02, -03, -04 845401............................. 72-33-31 -02, -03, -04 848001............................. 72-33-31 -02, -03, -04 848101............................. 72-33-31 -02, -03, -04 ------------------------------------------------------------------------ Disk, 2nd Stage Compressor ------------------------------------------------------------------------ 482502............................. 72-33-33 -02 502502............................. 72-33-33 -02 520602............................. 72-33-33 -02 570302............................. 72-33-33 -02 570402............................. 72-33-33 -02 678202............................. 72-33-33 -02 730202............................. 72-33-33 -02 730302............................. 72-33-33 -02

730402............................. 72-33-33 -02 740502............................. 72-33-33 -02 745702............................. 72-33-33 -02 745902............................. 72-33-33 -02 746002............................. 72-33-33 -02 746802............................. 72-33-33 -02 760402............................. 72-33-33 -02 760502............................. 72-33-33 -02 807502............................. 72-33-33 -02 500240201.......................... 72-33-33 -02 790832 (Disk assembly)............. 72-33-33 -02 ------------------------------------------------------------------------ Turbine Disk, First Stage With Integral Shaft ------------------------------------------------------------------------ 481135............................. 72-52-04 -03 494211............................. 72-52-04 -03 500701............................. 72-52-04 -03 516101............................. 72-52-04 -03 529115............................. 72-52-04 -03 538901............................. 72-52-04 -03 544501............................. 72-52-04 -03 544601............................. 72-52-04 -03 544701............................. 72-52-04 -03 553201............................. 72-52-04 -03 558401............................. 72-52-04 -03 565101............................. 72-52-04 -03 565201............................. 72-52-04 -03 565301............................. 72-52-04 -03 578201............................. 72-52-04 -03 579001............................. 72-52-04 -03 ------------------------------------------------------------------------ HP Turbine Disk, First Stage, Separable ------------------------------------------------------------------------ 587501............................. 72-52-02 -03 5006101-01......................... 72-52-02 -03 578001............................. 72-52-02 -03 5005201-01......................... 72-52-02 -03 696801............................. 72-52-02 -03 742501............................. 72-52-02 -03 752401............................. 72-52-02 -03 767601............................. 72-52-02 -03 792801............................. 72-52-02 -03 856501............................. 72-52-02 -03 832201............................. 72-52-02 -03 855701............................. 72-52-02 -03 856401............................. 72-52-02 -03 5003601-01......................... 72-52-02 -03 5003601-021........................ 72-52-02 -03 5004301-01......................... 72-52-02 -03'' ------------------------------------------------------------------------

(b) Except as provided in paragraph (c) of this AD, and notwithstanding contrary provisions in section 43.16 of the Federal Aviation Regulations (14 CFR 43.16), these mandatory inspections shall be performed only in accordance with the TLS of the PW JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR series Turbofan Engine Manuals.

Alternative Methods of Compliance

(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 Engine Certification Office (ECO). Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector (PMI), who may add comments and then send it to the ECO.

Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO.

Ferry Flights

(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 airplane to a location where the requirements of this AD can be accomplished.

Continuous Airworthiness Maintenance Program

(e) FAA-certificated air carriers that have an approved continuous airworthiness maintenance program in accordance with the record keeping requirement of Sec. 121.369(c) of the Federal Aviation Regulations (14 CFR 121.369(c)) of this chapter must maintain records of the mandatory inspections that result from revising the TLS of the PW JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR series Turbofan Engine Manuals, and the air carrier's continuous airworthiness program. Alternately, certificated air carriers may establish an approved system of record retention that provides a method for preservation and retrieval of the maintenance records that include the inspections resulting from this AD, and include the policy and procedures for implementing this alternate method in the air carrier's maintenance manual required by Sec. 121.369(c) of the Federal Aviation Regulations (14 CFR 121.369(c)); however, the alternate system must be accepted by the appropriate PMI and require the maintenance records be maintained either indefinitely or until the work is repeated. Records of the piece-part inspections are not required under Sec. 121.380(a)(2)(vi) of the Federal Aviation Regulations (14 CFR 121.380(a)(2)(vi)). All other operators must maintain the records of mandatory inspections required by the applicable regulations governing their operations.

Note 3: The requirements of this AD have been met when the engine manual changes are made and air carriers have modified their continuous airworthiness maintenance plans to reflect the requirements in the PW JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR series Turbofan Engine Manuals.

Issued in Burlington, Massachusetts, on September 30, 1999. David A. Downey, Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service. [FR Doc. 99-26213 Filed 10-6-99; 8:45 am] BILLING CODE 4910-13-P