The FAA proposed to amend 14 CFR part 39 with a proposed AD. The proposed AD applies to GE CF34-8C1/-8C5/-8C5B1/ -8E5/-8E5A1, and CF34-10E series turbofan engines with certain P/N and SN fuel metering units installed. We published the proposed AD in the Federal Register on September 7, 2007 (72 FR 51384). That action proposed to require a onetime test of the FMU for a miswired (reversed polarity) condition of the input wires to the overspeed solenoid.
Examinig the AD Docket
You may examine the AD docket on the Internet at http:// www.regulations.gov; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647-5527) is provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.
Comments
We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.
Request to Reference the Latest GE Service Bulletin Revisions
One commenter, GE, requests that we reference the latest GE service bulletin (SB) revisions, which are SB No. CF34-8C-AL S/B 73-0030, Revision 3, dated November 1, 2007, SB No. CF34-8E-AL S/B 73-0015, Revision 3, dated November 1, 2007, and SB No. CF34-10E S/B 72-0067, Revision 2, dated August 28, 2007.
We agree. We made that change in the AD.
Request to Modify the Discussion Paragraph
One commenter, Woodward Governor Company, requests that we modify the Discussion paragraph of the proposed AD by deleting the statement ``If the solenoid is miswired, the engine will fail to shut down as commanded''. The commenter interprets this statement as meaning that if the engine can be shut down normally, the AD is not required.
We partially agree. The statement is needed to explain that the AD is required by stating that shutdown failure is tied to overspeed in the unsafe condition statement in this AD. However, we deleted ``as commanded'' from the unsafe condition statements in the AD.
Request to Include 13 Additional FMU Serial Numbers
Woodward Governor Company requests that we include 13 additional FMU serial numbers, that were discovered to be affected since we issued the NPRM.
We agree. We changed the SN range of WYG94939 through WYGB4222 to WYG89156 through WYGB4222 in the AD and added the costs for them to the Cost section.
Request to Clarify Costs of Compliance
Woodward Governor Company requests that in the Costs of Compliance paragraph we clarify the statement ``We estimate that about 2 percent of the inspected solenoids are defective, and it will cost about $5,000 to replace each FMU'' to ``We estimate that about 2 percent of the inspected solenoids are defective, and it will cost about $5,000 to replace each FMU solenoid.''
We agree. We clarified the Cost statement in the AD.
Request to Extend the Compliance Time
One commenter, Mesa Airlines, requests that we extend the compliance time from 2,200 flight hours to 4,000 flight hours, due to potentially longer repair turn around times of failed FMUs from the manufacturer.
We do not agree. Our compliance interval includes anticipated repair turn-around times. We did not change the AD.
Removal of Reporting Requirement
We removed the reporting requirement from the AD, since we determined it was unnecesary.
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 1,055 engines installed on airplanes of U.S. registry. We also estimate that it will take about 0.25 work-hour per engine to perform the FMU inspections, and that the average labor rate is $80 per work-hour. We estimate that about 2 percent of the inspected solenoids are defective. Replacement solenoids will cost about $5,000 each. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $126,600. Our cost estimate is exclusive of possible warranty coverage.
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 flightof 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 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 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: