SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send us any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES . Include “Docket No. FAA-2005-21864; Directorate Identifier-2005-NE-29-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of the Docket Management System (DMS) Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78) or you may visit http://dms.dot.gov.

Examining the AD Docket

You may examine the docket that contains the proposal, any comments received and, any final disposition in person at the Docket Management Facility Docket Offices between 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 Docket Management Facility receives them.

Discussion

On September 16, 2002, we issued AD 2002-19-03, Amendment 39-12883 (67 FR 59139) applicable to Textron Lycoming LTIO-540 and TIO-540 series engines, rated at 300 HP or higher. That AD requires replacing certain crankshafts manufactured using a hammer-forged process with crankshafts manufactured using a press-forged process. AD 2002-19-03 resulted from reports of 18 crankshaft failures in LTIO-540 and TIO-540 engines, rated at 300 HP or higher. Our investigation into the cause of the crankshaft failures found that the failures result from subsurface metallurgical flaws. Lack of crankshaft process control caused the subsurface metallurgical flaws. While this proposed AD would affect different crankshafts than those affected by AD 2002-19-03, the crankshafts have the same possible unsafe condition. This proposed AD results from 12 reports of crankshaft failures on engines rated at 300 HP or lower. This proposed AD would require replacing certain crankshafts installed in engines manufactured new or rebuilt, overhauled, or that had a crankshaft replaced after March 1, 1999. This condition, if not corrected, could result in crankshaft failure, which could result in total engine power loss, in-flight engine failure, and possible loss of the aircraft.

Relevant Service Information

We have reviewed and approved the technical contents of Lycoming Mandatory Service Bulletin (MSB) No. 566, dated July 11, 2005, that describes procedures for replacing crankshafts listed by serial number in that MSB.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. We are proposing this AD, which would require replacing certain crankshafts within 50 hours time-in-service or 6 months after the effective date of the proposed AD, whichever is earlier. The proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

We estimate that this proposed AD would affect 1,128 engines installed on aircraft of U.S. registry. We estimate that it would take the following work hours to perform the inspection:

We also estimate that it would take about 33 work hours to replace the crankshaft. We estimate the average labor rate is $65 per work hour and that required parts for each engine would cost about $16,218. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $18,594,724. Lycoming Engines informed us that they intend to supply the new parts at no charge, which would substantially reduce the estimated cost of this proposed AD.

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 proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify that the 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. Would 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 regulatory evaluation of the estimated costs to comply with this proposed AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

The Proposed Amendment

Under the authority delegated to me by the Administrator, the Federal ( printed page 42284) Aviation Administration proposes to amend 14 CFR part 39 as follows: