E6-6584. Airworthiness Directives; Air Tractor, Inc. Models AT-602, AT-802, and AT-802A Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for all Air Tractor, Inc. Models AT-602, AT-802, and AT-802A airplanes. This proposed AD would 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. This proposed AD results from reports of cracked engine mounts. We are proposing 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:

We must receive comments on this proposed AD by June 27, 2006.

ADDRESSES:

Use one of the following addresses to comment on this proposed AD:

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-0001.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

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

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:

Comments Invited

We invite you to send any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include the docket number, “FAA-2006-24228; Directorate Identifier 2006-CE-22-AD” at the beginning 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 we receive concerning this proposed AD.

Discussion

We received two reports from Air Tractor, Inc. of cracked engine mounts resulting from fatigue. One report was for a Model AT-602 airplane. The specific airplane model with the other crack is unverified. This AD applies to Air Tractor, Inc. Models AT-602, AT-802, and AT-802A airplanes due to design similarity.

A cracked engine mount, if not detected and corrected, could result in failure of the engine mount. Such failure could lead to separation of the engine from the airplane.

Relevant Service Information

We have reviewed Snow Engineering Co. Service Letter #253, dated December 12, 2005.

The service information describes procedures for performing a visual inspection for cracks of the engine mount and requesting a repair scheme from the manufacturer.

Snow Engineering Co. has a licensing agreement with Air Tractor, Inc. that allows them to produce technical data to use for Air Tractor, Inc. products.

FAA's Determination and Requirements of the Proposed AD

We are proposing this AD because we evaluated all information and determined the unsafe condition described previously is likely to exist or develop on other products of the same type design. This proposed AD would 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. To repair a cracked engine mount, you would obtain an FAA-approved repair scheme from Air Tractor, Inc. following the instructions in the service information.

Costs of Compliance

We estimate that this proposed AD would affect 368 airplanes in the U.S. registry.

We estimate the following costs to do the proposed inspection of the engine mount for cracks:

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 repair/replacement of the engine mount as a result of the proposed inspection. We have no way of determining the cost of an engine mount repair. To replace the engine mount would take 81 work hours at $80 per hour (estimated total labor = $6,480), parts cost of $3,982, and a total replacement cost of $10,462 per 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 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. 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 regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket.

Examining the AD Docket

You may examine the AD docket that contains the proposed AD, the regulatory evaluation, any comments received, and other information on the Internet at http://dms.dot.gov; or in person at the Docket Management Facility between 9 a.m. and 5:00 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) is located at the street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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. The FAA amends § 39.13 by adding the following new AD:

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

Comments Due Date

(a) We must receive comments on this proposed airworthiness directive (AD) action by June 27, 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.

What Must I do to Address This Problem?

(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 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 from the manufacturer 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	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 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 of 1980 (44 U.S.C. 3501 et seq.) 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.

Related Information

(g) To get copies of the documents referenced 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, or on the Internet at http://dms.dot.gov. The docket number is Docket No. FAA-2006-24228; Directorate Identifier 2006-CE-22-AD.

Issued in Kansas City, Missouri, on April 26, 2006.

John R. Colomy,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.