A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding (AD) 99-08-14, Amendment 39-11120 (64 FR 17949, dated April 13, 1999) that is applicable to Pratt & Whitney (PW) PW2000 series turbofan engines was published in the Federal Register on October 8, 1999 (64 FR 54799).That action proposed revisions to the engine manufacturers time limits section (TLS) to include enhanced inspection of selected critical life-limited parts at each piece-part exposure. That action proposed to add additional critical life-limited parts for enhanced inspection.
Comments Received
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.
Part numbers in the AD
One comment states that the use of part numbers (P/N's) in the AD places undue burden on operators who must keep track of the Engine Manual changes to ensure consistency with P/N's, and creates a potential need for revisions to the AD as additional P/N's are introduced into service.
The FAA agrees. The final rule has been revised to eliminate specific P/N's and to use the term "ALL" in the P/N column.
Extend the Comment Period
One comment states that the proposed additional inspections have not been published in the Engine Manual, and that the comment period should be extended to allow for publication and evaluation by the operators.
The FAA does not agree. The FAA believes that the nature and scope of the added inspections will not be significantly different from existing inspections. In addition, the effective date of this AD has been extended to 90 days after publication to allow time for the specific procedures to be published. The extra time until the AD becomes effective should also allow the manufacturer to issue a manual revision. Operators may submit comments to the docket file on the specific procedures, once they are published, and the FAA will consider extending the effective date further or additional rulemaking, as necessary. The FAA does not believe, however, that this final rule need be delayed pending the publication of the inspection procedures, or the initial compliance time extended to accommodate the manufacturer's manual revision cycle.
Discussion Section Changed From Original Proposed Rule
One comment states that the summary and discussion sections of the proposed rule did not include the same guidelines concerning required enhanced inspections, as the summary and discussion sections published in the proposed rule for current AD 99-08-14. The commenter therefore asks that the discussion from the notice of proposed rule making, that preceded the current AD, be included in this final rule.
The FAA does not agree. The inspection program established by the current AD has not been changed. The proposed rule adds more parts to the list that must be inspected, but does not change how air carriers must manage the inspection program. Future AD's may be issued to introduce additional intervention strategies in order to further reduce uncontained engine failures. These strategies may include AD's to add new parts to the list of parts to be inspected. The inspection program established by the current AD will remain unchanged unless specifically changed in a future proposal.
Incorrect Manual Reference
Two comments state that Engine Manual 72-52-02, Inspection/Check-02 is only a dimensional inspection to the HPT 1st stage disk. The required fluorescent-penetrant inspection (FPI) reference for all HPT 1st stage disks and HPT 2nd stage hubs should be Engine Manual 72-52-00, Inspection/Check-02.
The FAA agrees. The final rule has been revised to reference the correct Engine Manual task and subtasks for HPT 1st stage disks and HPT 2nd stage hubs.
Clarification of FPI Procedures
One comment requests clarification for FPI procedures for parts repaired byplasma spray, as to whether the plasma spray should be removed before inspection.
Upon investigation, the FAA has concluded that the manufacturer's engine manual has no plasma spray procedures for HPT disks at the critical locations to be fluorescent-penetrant-inspected. The engine manual does allow a plasma spray repair for the buildup of the HPT snap diameter. This plasma spray coating is not required to be removed to accomplish the FPI procedure.
Conclusion
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.
Economic Analysis
No comments were received on the economic analysis contained in the proposed rule. The FAA has determined that the annual cost of complying with this AD does not create a significant economic impact on small entities.
Regulatory Impact
This 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 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) 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 actionand 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, 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 by removing Amendment 39-11120, (64 FR 17949, April 13, 1999), and by adding the following new airworthiness directive: