The FAA proposed to amend 14 CFR part 39 with a proposed AD. The proposed AD applies to RRD Tay 611-8, Tay 620- 15, Tay 650-15, and Tay 651-54 series turbofan engines, with certain low pressure (LP) compressor modules installed. We published the proposed AD in the Federal Register on June 27, 2006 (71 FR 36493). That action proposed to require a UI of LP compressor fan blades for cracks, within 30 days after the effective date of the AD on certain serial number (SN) Tay 650-15 engines. That action also proposed to require repetitive UIs of LP compressor fan blades on all engines. That action also proposed to require, for Tay 650-15 and Tay 651-54 engines, UIs of LP compressor fan blades whenever the blade set is removed from one engine and installed on a different engine.
Examining the AD Docket
You may examine the docket that contains the AD, any comments received, and any final disposition in person at the Docket Management Facility Docket Officesbetween 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the DMS receives them.
Comments
We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.
RRD Request To Change Compliance Paragraphs (h)(1) and (h)(2)
RRD requests that we change the compliance schedule for Tay 650-15 and Tay 651-54 engines in proposed AD paragraph (h)(1), from "at every shop visit for any reason or before reaching every 4,000 flight hours- since-last fan blade UI, whichever occurs first'' to "at every engine shop visit for any reason or before reaching every 10,000 flight hours- since-last fan blade UI, whichever occurs first.''
RRD also requests that we change the compliance schedule for Tay 620-15 engines in proposed AD paragraph (h)(2) from "before reaching every 8,000 flight hours but no later than every 10 years since-last- fan-blade UI, whichever occurs first'' to "before reaching every 10,000 flight hours for airline operation, and before reaching 8,000 flight hours but no later than every 10 years since-last-fan-blade UI, whichever occurs first, for non-airline operation.'' RRD bases these changes on their Engine Management Program.
We agree with the intent of the requested changes to proposed AD paragraph (h)(1). We changed that paragraph, and added subparagraphs to clarify the initial inspection requirements in the AD. Regarding paragraph (h)(2), we do not agree with having different inspection schedules for airline and non-airline operations. However, we changed paragraph (h)(2) to paragraph (h)(2)(iii), to read "before reaching every 10,000 flight hours but no later than every 10 years since-last- fan-blade UI, whichever occurs first''. We feel that this drawdown schedule will take care of both low- and high-utilization of Tay 620-15 engines.
Air Transport Association Request To Change Compliance Paragraph (h)(1)
Air Transport Association (ATA) requests that we change the compliance schedule in paragraph (h)(1) from "at every engine shop visit for any reason or before reaching every 4,000 flight hours-since- last fan blade UI, whichever occurs first'' to "at every engine shop visit for any reason or before reaching every 12 years or 15,000 flight hours-since-last fan blade UI, whichever occurs first''. ATA states that this schedule is described in the Engine Management Program for Tay 651-54 engines installed in the Boeing 727 airplanes. We do not agree. The intent of proposed AD paragraph (h)(1) is to UI Tay 650-15 and Tay 651-54 engines at all scheduled and unscheduled shop visits, using RRD SB No. TAY-72-1442, Revision 3, dated November 26, 2003. Also, the intent of the paragraph is to parallel the SB requirement of an initial UI within 3 months after the SB issue date. We did change paragraph (h) and added subparagraphs as described under the first comment above.
Request To Change Compliance Paragraph (h)(3)
One commenter requests that we change the Tay 611-8 compliance schedule in proposed AD paragraph (h)(3). The commenter requests that we call out an initial UI inspection to be done at the next engine mid- life or overhaul inspection after the effective date of this AD. The commenter also requests that we call out repetitive UI inspections to be done before reaching every 8,000 flight hours but no later than every 10 years since-last-fan blade UI, whichever occurs first. These changes would prevent many airplanes from being immediately grounded, upon issuance of the AD. We agree with the commenter's intent. We changed and added paragraphs (h) through (h)(2)(iii) to clarify the initial inspection requirements in the AD, and to incorporate the compliance schedule changes.
Request To Add LP Compressor Fan Blade Part Numbers
ATA requests that we include LP compressor fan blade part numbers in the AD. We agree and added the part numbers to the AD.
Incorrect Supplemental Type Certificate (STC) Number
In paragraph (c) of the proposed AD, STC number SA842SW is incorrect. That STC applies to a Cessna Model 414 airplane. We corrected the STC No. in paragraph (c) of this AD to SA8472SW, which applies to a Boeing 727 airplane.
Conclusion
We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
Costs of Compliance
We estimate that this AD will affect about 1,000 RRD Tay 611-8, Tay 620-15, Tay 650-15, and Tay 651-54 series turbofan engines installed on airplanes of U.S. registry. We also estimate that it will take about 4 work-hours per engine to perform an inspection, and that the average labor rate is $80 per work-hour. Required parts will cost about $95,000 per LP compressor fan disk and $140,000 per set of LP compressor fan blades. We estimate that 5 percent or 50 engines will require replacing the LP compressor fan disc and LP compressor fan blade set. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $11,750,000.
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, section 44701, "General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.
Regulatory Findings
We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will 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 this AD:
(1) Is not a "significant regulatory action'' under Executive Order 12866;
(2) Is not a "significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and
(3) Will not have asignificant 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 AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.
Sec. 39.13 [Amended]
2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive: