03-6997. 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-209, -217, -217A, -217C, and -219 series turbofan engines. This proposal would require removal and replacement of protective coating of the 7th and 9th through 12th stage high pressure compressor (HPC) disks and the 8th stage HPC hub, initial and repetitive inspections for corrosion pits and cracks, and removal from service as required. This proposal is prompted by reports from operators of cracks observed in JT8D engine steel HPC disks. The actions specified by the proposed AD are intended to prevent fracture of the 7th and 9th through 12th stage HPC disks and 8th stage HPC hub, resulting in uncontained engine failure and damage to the airplane.

DATES:

Comments must be received by May 27, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2002-NE-41-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may be inspected at this location, by appointment, between 8 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: [e-mail]. 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 [phone]; fax [phone]. 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 [phone]; fax [phone].

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 2002-NE-41-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. 2002-NE-41-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The FAA has received reports of cracks observed in steel HPC disks on PW JT8D-209, -217, -217A, -217C, and -219 series turbofan engines. Investigation has revealed that four of these disks cracked as the result of corrosion pits originating in the disk dovetail slots and one disk cracked as the result of corrosion pits in the tierod hole area.

Manufacturer's Service Information

The FAA has reviewed and approved the technical contents of PW alert service bulletin (ASB) A6435, Revision 1, dated March 7, 2003, that describes procedures for initial and repetitive inspections to detect corrosion and cracks in 7th and 9th through 12th stage HPC disks and 8th stage HPC hubs, and removal from service of those HPC disks and hubs corroded beyond serviceable limits or cracked.

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 Pratt & Whitney JT8D-200 series turbofan engines of the same type design, the proposed AD would require removal and replacement of protective coating of the 7th and 9th through 12th stage high pressure compressor (HPC) disks and the 8th stage HPC hub, initial and repetitive inspections for corrosion pits and cracks, and removal from service as required. The actions would be required to be done in accordance with the alert service bulletin described previously.

Economic Analysis

There are approximately 2,200 JT8D-200 series turbofan engines of the affected design in the worldwide fleet. The FAA estimates that 1,470 engines installed on airplanes of U.S. registry would be affected by this proposed AD. The FAA also estimates that it would take approximately 96 work hours per engine to perform the proposed actions, and that the average labor rate is $60 per work hour. The FAA estimates that 60% of the inspected disks will require replacement at a prorated cost $29,090 per engine. Based on these figures, the total cost of the proposed AD to U.S. operators is estimated to be $51,229,500.

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.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

Pratt & Whitney: Docket No. 2002-NE-41-AD.

 

Applicability: This airworthiness directive (AD) is applicable to Pratt & Whitney (PW) JT8D-209, -217, -217A, -217C, and -219 series turbofan engines. These engines are installed on, but not limited to McDonnell Douglas MD-80 and series airplanes.

Note 1:

This 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: Compliance with this AD is required as indicated, unless already done.

To prevent fracture of the 7th and 9th through 12th stage high pressure compressor (HPC) disks and 8th stage HPC hub, resulting in uncontained engine failure and damage to the airplane, do the following:

(a) Perform initial and repetitive inspections of 7th and 9th through 12th stage HPC disks and 8th stage HPC hubs for corrosion pits and cracks after stripping the protective coating in accordance with the intervals specified in the compliance section and procedures specified in the accomplishment instructions of PW alert service bulletin (ASB) A6435, Revision 1, dated March 7, 2003.

(b) Before further flight, replace 7th and 9th through 12th stage HPC disks and 8th stage HPC hubs found with corrosion pits or cracks beyond serviceable limits as defined by PW ASB A6435, Revision 1, dated March 7, 2003.

(c) For the purposes of this AD, use the effective date of this AD for computing compliance intervals whenever PW ASB A6435, Revision 1, dated March 7, 2003, refers to the release date of the ASB.

Alternative Methods of Compliance

(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 (ECO). Operators must submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, 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.

Special Flight Permits

(e) Special flight permits may be issued in accordance with §§ 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 done.

Issued in Burlington, Massachusetts, on March 18, 2003.

Robert G. Mann,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.