01-18760. Airworthiness Directives; Pratt & Whitney JT8D Series Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), that is applicable to Pratt & Whitney (PW) JT8D series turbofan engines. This amendment requires removing certain 2nd stage compressor disks, specified by part number (P/N) and serial number (SN), from service. This amendment is prompted by a report from PW of a number of JT8D engine 2nd stage compressor disks that were delivered to the field with potential machining damage to the tie rod, counterweight, and pin holes. The actions specified by this AD are intended to prevent rupture of the 2nd stage compressor disk caused by machining damage, which could result in an uncontained engine failure and damage to the airplane.

DATES:

Effective date September 4, 2001. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of September 4, 2001.

ADDRESSES:

The service information referenced in this AD may be obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone [phone], fax [phone]. This information may be examined at the Federal Aviation Administration (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:

Robert McCabe, 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:

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that is applicable to Pratt & Whitney JT8D series turbofan engines was published in the Federal Register on December 12, 2000 (65 FR 77530). That action proposed to require removing certain 2nd stage compressor disks, specified by P/N and SN, from service in accordance with PW JT8D Alert Service Bulletin (ASB) JT8D A6336, Revision 1, dated June 29, 1999, that lists the SN's of certain 2nd stage compressor disks, P/N 745902, P/N 790832, and P/N 807502, and describes procedures replacing the disk if it is listed by SN in the ASB.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Limit AD Applicability

Two commenters request that the AD be limited to only those later or upper engine models specified by the JT8D Illustrated Parts Catalog, P/N 481675, referenced in the P&W Alert Service Bulletin (ASB) A6336, Revision 1, dated June 29, 1999. The affected 2nd stage compressor disk P/N's 745902, 790832 and 807502 are applicable only to engine models JT8D -9, -9A, -11, -15, -15A, -17A, -17R and -17AR. The FAA agrees and will limit applicability of the amendment to these specific engine models.

Cost Impact Statement

The manufacturer requests that the Cost Impact Statement reflect that PW has provided a support program for the disk replacement, and that the program is identified in the PW ASB A6336, Revision 1, dated June 29, 1999. The FAA agrees. The cost statement reflects the costs of compliance with the AD without considering any original equipment manufacturer (OEM) industry support program. The cost statement also states that the OEM may offset some of those costs.

Two commenters agree with the AD as written.

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact

There are approximately 110 engines of the affected design in the worldwide fleet. The FAA estimates that 60 engines, installed on airplanes of U.S. registry, would be affected by this proposed AD, that it would take approximately 48 work hours per engine to accomplish the proposed actions, and that the average labor rate is $60 per work hour. The prorated average cost of the unusable life of a 2nd stage disk is $30,000. Based on these figures, the FAA estimates the total cost impact of the proposed AD on U.S. operators to be $1,972,800. The manufacturer has informed the FAA that it may pay the cost of the disk, which may lower the cost to operators.

Regulatory Impact

This final 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 final rule.

For the reasons discussed above, I certify that this action (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 final evaluation has been prepared for this action and it 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
• 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.

§ 39.13

[Amended]

2. Section 39.13 is amended adding a new airworthiness directive to read as follows:

2001-15-18 Pratt & Whitney: Amendment 39-12353. Docket 98-ANE-71-AD.

Applicability

This airworthiness directive (AD) is applicable to Pratt & Whitney (PW) JT8D-9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR series turbofan engines with 2nd stage compressor disks, part number (P/N) 745902, P/N 790832, and P/N 807502, installed. These engines are installed on, but not limited to, Boeing 727 series airplanes, Boeing 737-100 and -200 series airplanes and McDonnell Douglas DC-9 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 (b) 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 a rupture of the 2nd stage compressor disk caused by machining damage, which could result in an uncontained engine failure and damage to the airplane, accomplish the following:

Removal of Disk

(a) Remove from service 2nd stage compressor disks, P/N 745902, P/N 790832, and P/N 807502, identified by serial number (SN) in the Accomplishment Instructions of PW JT8D Alert Service Bulletin (ASB) JT8D A6336, Revision 1, dated June 29, 1999, prior to accumulating 2,000 cycles since new.

Alternative Methods of Compliance

(b) 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 shall submit their requests 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

(c) 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 aircraft to a location where the requirements of this AD can be accomplished.

Documents That Have Been Incorporated By Reference

(d) The disks identified by SN's must be removed in accordance with Pratt & Whitney ASB JT8D A6336, Revision 1, dated June 29, 1999. 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 of the ASB may be obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone [phone], fax [phone]. 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.

(e) This amendment becomes effective on September 4, 2001.

Issued in Burlington, Massachusetts on July 20, 2001.

Francis A. Favara,

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