Airworthiness Directives; Pratt & Whitney JT8D-200 Series Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to Pratt & Whitney (PW) JT8D-200 series turbofan engines. This proposal would require initial and repetitive visual inspections, fluorescent magnetic particle inspections (FMPI), and fretting wear inspections of high pressure compressor (HPC) front hubs that have operated with PWA-110 coating in the interface between the hub and the stage 8-9 spacer. This proposal is prompted by the discovery of cracked tierod holes found during routine engine overhauls. The actions specified by the proposed AD are intended to prevent a rupture of the HPC front hub that could result in an uncontained engine failure and damage to the airplane.

DATES:

Comments must be received by October 21, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2001-NE-30-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may be inspected at this location, by appointment, between 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. Comments may also be sent via the Internet using the following address: “9-ane-adcomment@faa.gov”. Comments sent via the Internet must contain the docket number in the subject line.

The service information referenced in the proposed rule 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, by appointment, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT:

Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7175, 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 action 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 action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NE-30-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRM's

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. 2001-NE-30-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The FAA has received reports of eighteen cracked PW JT8D-200 series HPC front hubs with PWA-110 coating in the interface between the hub and the stage 8-9 spacer. The cracks were discovered at engine overhauls after the engines had accumulated as few as 9,900 cycles-in-service. The cracks initiated at the site of fretting wear between the interface of the stage 8-9 spacer and the HPC front hub. The results of metallurgical examination indicate that the cracks had begun to propagate due to low-cycle fatigue (LCF). Eventually these cracks could propagate to a critical crack length, causing a rupture of the HPC front hub, which could result in an uncontained engine failure and damage to the airplane. The FAA has reviewed the statistical evaluation of the crack data and has determined that HPC front hubs should be inspected using the intervals and procedures outlined in PW Alert Service Bulletin (ASB) JT8D A6430, dated September 5, 2002. This condition, if not corrected, could result in an uncontained engine failure and damage to the airplane.

Manufacturer's Service Information

The FAA has reviewed and approved the technical contents of PW Alert Service Bulletin (ASB) JT8D A6430, dated September 5, 2002, that describes procedures for visual, FMPI, and fretting inspections of HPC front hubs and replacement of the hubs, if necessary.

FAA's Determination of an Unsafe Condition and Proposed Actions

Since an unsafe condition has been identified that is likely to exist or develop on other PW JT8D-200 series turbofan engines, this proposal would require initial and repetitive visual inspections, FMPI's, and fretting wear inspections of HPC front hubs that have operated with PWA-110 coating in the interface between the hub and the stage 8-9 spacer. The actions would be required to be done in accordance with the service bulletin described previously.

Economic Analysis

There are approximately 2,648 PW JT8D-200 series turbofan engines of the affected design in the worldwide fleet. The FAA estimates that 2,352 engines installed on airplanes of U.S. registry would be affected by this proposed AD. The FAA also estimates that it would take approximately 6 work hours per engine to perform the proposed inspection, and that the average labor rate is $60 per work hour. Based on these figures, the total cost of the initial inspection to U.S. operators is estimated to be $846,720.

Regulatory Analysis

This proposed rule does not have federalism implications, as defined in Executive Order 13132, because it 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. Accordingly, the FAA has not consulted with state authorities prior to publication of this proposed rule.

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.