Airworthiness Directives; Pratt & Whitney JT8D-200 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 JT8D-200 series turbofan engines. That AD currently requires installation of high pressure turbine (HPT) containment hardware on JT8D-217C and -219 engines. That AD also currently requires replacing LPT-to-exhaust case bolts and nuts with improved containment hardware on JT8D-209, -217, -217A, -217C, and -219 engines. This proposed AD would require installation of improved HPT containment hardware on JT8D-209, -217, -217A, -217C, and -219 engines. This proposed AD results from four reports of uncontained HPT failures of JT8D-200 series engines, since AD 99-22-14 was issued. We are proposing this AD to prevent uncontained HPT events resulting from HPT shaft fractures.

DATES:

We must receive any comments on this proposed AD by September 13, 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. 92-ANE-15-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
• By fax: (781) 238-7055.
• By e-mail: 9-ane-adcomment@faa.gov.

You may get the service information identified in this proposed AD from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-7700; fax (860) 565-1605.

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 “AD Docket No. 92-ANE-15-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 October 21, 1999, the FAA issued AD 99-22-14, Amendment 39-11392 (64 FR 58328, October 29, 1999). That AD requires installation of HPT containment hardware on JT8D-217C and -219 engines. That AD also requires replacing LPT-to-exhaust case bolts and nuts with improved containment hardware on JT8D-209, -217, -217A, -217C, and -219 engines. That AD was the result of reports of uncontained HPT events resulting from HPT shaft fractures and LPT flange separations resulting from LPT blade failures. That condition, if not corrected, could result in uncontained HPT events resulting from HPT shaft fractures and LPT flange separations resulting from LPT blade failures.

Actions After AD 99-22-14 was Issued

After AD 99-22-14 was issued, we received four reports of uncontained HPT shaft fractures on JT8D-200 series engines. During one of these failures on a JT8D-217A engine, parts escaped forward of the old configuration HPT containment shield. This event demonstrates that the old configuration HPT containment shield is insufficient for preventing uncontained engine failures. AD 99-22-14 did not require JT8D-209, -217, and -217A engines to install the improved HPT containment shields.

Also, after that AD was issued, PW determined that the LPT-to-exhaust case bolts and nuts introduced by AD 99-22-14 have a higher failure rate than the previous bolt and nut configuration. We are preparing a separate proposed AD to address the replacement of that hardware, as recommended in a recently issued PW SB. This proposal no longer requires the replacement of LPT-to-exhaust case bolts and nuts with the bolts and nuts required by AD 99-22-14.

Also, after that AD was issued, we discovered that the requirements from superseded AD 93-23-10, Amendment 39-8746, to install HPT containment shields on JT8D-209, -217, and -217A engines, were inadvertently omitted from AD 99-22-14.

Relevant Service Information

We have reviewed and approved the technical contents of Pratt & Whitney Alert Service Bulletin (ASB) No. A6346, Revision 3, dated May 21, 2004, which describes the installation of improved HPT containment hardware on JT8D-209, -217, -217A, -217C, and -219 engines.

Differences Between This Proposed AD and the Manufacturer's Service Information

Although Pratt & Whitney ASB No. A6346, Revision 3, dated May 21, 2004, has an installation termination date of December 31, 2004, for all the affected engine models, this proposed AD would require the installation on JT8D-209, -217, and -217A engines no later than December 31, 2007.

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 products of this same type design. Therefore, we are proposing this AD, which would require the installation of improved HPT containment hardware at the following:

• For JT8D-209, -217, and -217A engines, at the next engine shop visit after the effective date of this proposed AD, but no later than December 31, 2007; and
• For JT8D-217C and -219 engines, at the next engine shop visit after the effective date of this AD, but no later than December 31, 2004.

The proposed AD would require that you do these actions using the service information described previously.

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 are installed on airplanes of U.S. registry, and that 280 engines would be affected by this proposed AD. We estimate that 80% of the -217C and -219 engines already have the improved HPT containment hardware installed. We also estimate that no additional labor costs will be incurred when these parts are installed during engine shop visit. Required parts would cost about $19,991 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $5,597,480.

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. 92-ANE-15-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.