AD 2006-22-08

This AD becomes effective on December 1, 2006.

As of December 1, 2006, the Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulation.

To get the service information identified in this AD, contact Air Tractor, Inc., P.O. Box 485, Olney, Texas 76374; telephone: (940) 564-5616; facsimile: (940) 564-5612.

To view the AD docket, go to the Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-001 or on the Internet at http://dms.dot.gov. The docket number is FAA-2006-24228; Directorate Identifier 2006-CE-22-AD.

Andrew McAnaul, Aerospace Engineer, ASW-150 (c/o MIDO-43), 10100 Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: (210) 308-3365; facsimile: (210) 308-3370.

On April 26, 2006, we issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to all Air Tractor, Inc. Models AT-602, AT-802, and AT-802A airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on May 2, 2006 (71 FR 25793). The NPRM proposed to require you to repetitively inspect the engine mount for any cracks, repair or replace any cracked engine mount, and report any cracks found to the FAA.

We provided the public the opportunity to participate in developing this AD. The following presents the comment received on the proposal and FAA's response to the comment:

Ronald G. Bush suggests that proper flight testing of a correctly instrumented engine mount and structure, combined with analysis of the data collected, may provide for a more efficient solution to the cracking problem than the repetitive inspections currently provide. He notes that the cost of each inspection is estimated at $120, and a properly substantiated terminating action may prove less costly over time.

We partially agree that a properly executed flight test and analysis is a method to provide substantiating data that can be used to validate an alternate method for addressing the engine mount fatigue cracking. The FAA has not received any data at this time that proposes and substantiates a terminating action for the required inspections. If and when such information is received, we will consider mandating it through AD action.

We are not changing the AD as a result of this comment.

We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed except for minor editorial corrections. We have determined that these minor corrections:

• Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM.

We estimate that this AD affects 368 airplanes in the U.S. registry.

We estimate the following costs to do each required inspection:

We have no way of determining the number of airplanes that may need replacement of the engine mount. We estimate the following costs to do the replacement:

Any required “upon-condition” repairs would vary depending upon the damage found during each inspection. Based on this, we have no way of determining the potential repair costs for each airplane.

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 AD.

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 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.

We prepared a summary of the costs to comply with this AD (and other information as included in the Regulatory Evaluation) and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “Docket No. FAA-2006-24228; Directorate Identifier 2006-CE-22-AD” in your request.

Accordingly, under 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:

1. The authority citation for part 39 continues to read as follows:

2. FAA amends § 39.13 by adding a new AD to read as follows: