E6-17828. Airworthiness Directives; Air Tractor, Inc. Models AT-602, AT-802, and AT-802A Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

The FAA adopts a new airworthiness directive (AD) for all Air Tractor, Inc. Models AT-602, AT-802, and AT-802A airplanes. This AD requires 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. This AD results from reports of cracked engine mounts. We are issuing this AD to detect and correct cracks in the engine mount, which could result in failure of the engine mount. Such failure could lead to separation of the engine from the airplane.

DATES:

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.

ADDRESSES:

To get the service information identified in this AD, contact Air Tractor, Inc., P.O. Box 485, Olney, Texas 76374; telephone: [phone]; facsimile: [phone].

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.

FOR FURTHER INFORMATION CONTACT:

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

SUPPLEMENTARY INFORMATION:

Discussion

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.

Comments

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:

Comment Issue: Flight Test and Analysis

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.

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 Compliance

We 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 × $80 per hour = $120	Not Applicable	$120	368 × $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 inspection	Total cost on U.S. operators for initial inspection
81 work-hours × $80 per hour = $6,480	$3,982	$10,462	368 × $10,462 = $3,850,016.

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.

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-2006-24228; Directorate Identifier 2006-CE-22-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.

§ 39.13

[Amended]

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

2006-22-08 Air Tractor, Inc.: Amendment 39-14805; Docket No. FAA-2006-24228; Directorate Identifier 2006-CE-22-AD.

Effective Date

(a) This AD becomes effective on December 1, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD affects all Models AT-602, AT-802, and AT-802A airplanes, all serial numbers, that are certificated in any category.

Unsafe Condition

(d) This AD results from reports of cracked engine mounts. We are issuing this AD to detect and correct cracks in the engine mount, which could result in failure of the engine mount. Such failure could lead to separation of the engine from the airplane.

Compliance

(e) To address this problem, you must do the following:

Actions	Compliance	Procedures
(1) Visually inspect the engine mount for any cracks	Initially inspect upon accumulating 4,000 hours time-in-service (TIS) or within the next 100 hours TIS after December 1, 2006 (the effective date of this AD), whichever occurs later, unless already done. Thereafter, repetitively inspect every 300 hours TIS	Follow Snow Engineering Co. Service Letter #253, dated December 12, 2005.
(2) If you find any crack damage, do one of the following: (i) Obtain an FAA-approved repair scheme and incorporate this repair scheme; or (ii) Replace the engine mount with a new engine mount.	Before further flight after any inspection required by paragraph (e)(1) of this AD where crack damage is found. If you repair the cracked engine mount, then continue to reinspect at intervals not to exceed 300 hours TIS, unless the repair scheme states differently. If you replace the engine mount, then initially inspect upon accumulating 4,000 hours TIS and repetitively at intervals not to exceed 300 hours TIS thereafter	For obtaining a repair scheme: Follow Snow Engineering Co. Service Letter #253, dated December 12, 2005. For the replacement: The maintenance manual includes instructions for the replacement.
(3) Report any cracks that you find to the FAA at the address specified in paragraph (f) of this AD. Include in your report: (i) Airplane serial number; (ii) Airplane and engine mount hours TIS; (iii) Crack location(s) and size(s); (iv) Corrective action taken; and (v) Point of contact name and telephone number.	Within the next 10 days after you find the cracks or within the next 10 days after December 1, 2006 (the effective date of this AD), whichever occurs later	The Office of Management and Budget (OMB) approved the information collection requirements contained in this regulation under the provisions of the Paperwork Reduction Act and assigned OMB Control Number 2120-0056.

Alternative Methods of Compliance (AMOCs)

(f) The Manager, Fort Worth Airplane Certification Office, FAA, Attn: Andrew McAnaul, Aerospace Engineer, ASW-150 (c/o MIDO-43), 10100 Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: [phone]; facsimile: [phone], has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

Material Incorporated by Reference

(g) You must do the actions required by this AD following the instructions in Snow Engineering Co. Service Letter #253, dated December 12, 2005. The Director of the Federal Register approved the incorporation by reference of this service bulletin in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. To get a copy of this service information, contact Air Tractor, Inc., P.O. Box 485, Olney, Texas 76374; telephone: [phone]; facsimile: [phone]. To review copies of this service information, go to the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html or call [phone]. 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.

Issued in Kansas City, Missouri, on October 13, 2006.

James E. Jackson,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.