Discussion
On March 8, 2007, 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 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 March 15, 2007 (72 FR 12131). The NPRM proposed to retain the actions of AD 2006-22-08 while requiring the initial inspection at 1,300 hours TIS.
Comments
We provided the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and FAA's response to each comment:
Comment Issue No. 1: Installation of a Welded Gusset Is Terminating Action for the Proposed Inspections
Leland Snow, President of Air Tractor, Inc., believes that Snow Engineering Co. Report Number 1727, Revision A, dated April 12, 2007 (referred to after this as Report 1727), justifies terminating action for the proposed inspections. Mr. Snow states that installation of a welded gusset following Snow Engineering Co. Service Letter 253, dated December 12, 2005, revised January 22, 2007, would eliminate the need for such inspections.
Based on the information presented in Report 1727, the FAA finds that the installation of the welded gusset does not fully address the unsafe condition and cannot be considered as a terminating action for the repetitive inspection.
We are making no changes to the final rule AD action based on this comment.
Comment Issue No. 2: FAA Has Overstated the Consequences of Cracks in the Engine Mount
Mr. Snow also states that the FAA overstates the events that would occur should cracks found in service result in the engine mount tube separating from the engine mount ring. He also states that the engine mount ring would remain attached to the remaining tube connections and prevent the engine from separating from the airplane.
The commenter did not provide any analysis or data to show that this situation would not occur. Based on the FAA's evaluation of the unsafe condition, we believe there is potential for the engine mount tube to separate from the engine mount ring.
Without the data to show that the engine mount ring would remain attached to the remaining tube connections, the FAA cannot change the potential end result condition of the engine separating from the airplane.
We are not changing the final rule AD action as a result of these comments.
Conclusion
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.
Costs of ComplianceWe estimate that this AD affects 368 airplanes in the U.S. registry.
We estimate the following costs to do each required inspection:
Labor Cost
Parts Cost
Total Cost Per Airplane Per Inspection
Total Cost on U.S. Operators for Initial Inspection
1.5 work-hours X $80 per hour = $120
Not Applicable
$120
$44,160
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:
Labor Cost
Parts Cost
Total Cost Per Airplane Per Replacement
81 work-hours X $80 per hour = $6,480
$3,982
$10,462
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 AD.
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 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-2007-27212; Directorate Identifier 2007-CE-011-AD" in your request.
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 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.
Sec. 39.13 [Amended]
2. The FAA amends Sec. 39.13 by removing Airworthiness Directive (AD) 2006-22-08, Amendment 39-14805 (71 FR 62910, October 27, 2006), and adding the following new AD: