AD 2007-10-01

We are adopting a new airworthiness directive (AD) for certain Air Tractor, Inc. (Air Tractor) Model AT-602 airplanes. This AD requires you to install access holes to do repetitive detailed visual inspections for cracks in the horizontal stabilizer brace tube assembly, and if any cracks are found as a result of a visual inspection, to replace the horizontal stabilizer brace tube assembly with a new design horizontal stabilizer brace tube assembly. The installation of the new design horizontal stabilizer brace tube assembly is terminating action for the repetitive inspection requirement. This AD results from two reports of Model AT-602 airplanes with cracked horizontal stabilizer brace tube assemblies. We are issuing this AD to detect and correct cracks in the horizontal stabilizer brace tube assembly, which could result in failure of the horizontal stabilizer. This failure could affect the ability to control pitch with consequent loss of control.

Final rule.

2007-10-01 Air Tractor Inc.: Amendment 39-15042; Docket No. FAA- 2006-26775; Directorate Identifier 2007-CE-01-AD.

Effective Date

(a) This AD becomes effective on June 12, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Model AT-602 airplanes, all serial numbers through 602-0695 that:
(1) Have horizontal stabilizer brace tube assembly, part number (P/N) 30012-7, installed; and
(2) Are certificated in any category.

Unsafe Condition

(d) This AD results from two reports of Model AT-602 airplanes with cracked horizontal stabilizer brace tube assemblies. We are issuing this AD to detect and correct cracks in the horizontal stabilizer brace tube assembly, which could result in failure of the horizontal stabilizer. This failure could affect the ability to control pitch with consequent loss of control.

Compliance

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

Actions
Compliance
Procedures
(1) Do the following:
(i) Install access holes for visual inspection of the P/N 30012-7, horizontal stabilizer brace tube assembly.
(ii) Conduct a detailed visual inspection for cracks in the P/N 30012-7 horizontal stabilizer brace tube assembly.
Install the access holes and do the initial inspection upon accumulating 2,000 hours time-in-service (TIS) or within the next 60 days after June 12, 2007 (the effective date of this AD), whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS. Replacement of the P/N 30012-7 horizontal stabilizer brace tube assembly with a new design P/N 30766-1 horizontal stabilizer brace tube assembly following paragraph (e)(2) of this AD is terminating action for the repetitive inspection requirement of this AD.
Follow Snow Engineering Co. Service Letter #235, dated August 25, 2004, revised October 24, 2006.
(2) Replace the P/N 30012-7 horizontal stabilizer brace tube assembly with a new design P/N 30766-1 horizontal stabilizer brace tube assembly.
Before further flight after any inspection required by paragraph (e)(1) of this AD where cracks are found. The installation of a new design P/N 30766-1 horizontal stabilizer brace tube assembly is terminating action for the repetitive inspection requirement of this AD.
Follow Snow Engineering Co. Service Letter #129A, dated August 7, 2004, revised November 15, 2005; Snow Engineering Co. Service Letter #235, dated August 25, 2004, revised October 24, 2006; and Snow Engineering Co. Drill Template 602, Drawing Number SL129-602, dated August 2, 2004.
(3) Do not install any P/N 30012-7 horizontal stabilizer brace tube assembly.
As of June 12, 2007 (the effective date of this AD).
Not Applicable.

Alternative Methods of Compliance (AMOCs)

(f) The Manager, Fort Worth Airplane Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Andrew McAnaul, Aerospace Engineer, ASW-150 (c/o MIDO-43), 10100 Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: (210) 308-3365; fax: (210) 308-3370. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

Related Information

(g) To get copies of the service information referenced in this AD, contact Air Tractor Inc., P.O. Box 485, Olney, Texas 76374; telephone: (940) 564-5616; fax: (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, or on the Internet at http://dms.dot.gov. The docket number is Docket No. FAA-2006-26775; Directorate Identifier 2007-CE-01-AD.

Material Incorporated by Reference

(h) You must use Snow Engineering Co. Service Letter 129A, dated August 7, 2004, revised November 15, 2005; Snow Engineering Co. Service Letter 235, dated August 25, 2004, revised October 24, 2006; and Snow Engineering Co. Drill Template-- 602, Drawing Number SL129-602, dated August 2, 2004, to do the actions required by this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.

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

(3) You may review copies at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Kansas City, Missouri 64106; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202- 741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html .

Discussion

On January 31, 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 certain Air Tractor Model AT-602 airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on February 6, 2007 (72 FR 5359). The NPRM proposed to require you to install access holes to do repetitive detailed visual inspections for cracks in the horizontal stabilizer brace tube assembly, and if any cracks are found as a result of a visual inspection, to replace the horizontal stabilizer brace tube assembly with a new design horizontal stabilizer brace tube assembly. The installation of the new design horizontal stabilizer brace tube assembly is terminating action for the repetitive inspection requirement.

Comments

We provided the public the opportunity to participate in developing this AD. We received no comments on the proposal or on thedetermination of the cost to the public.

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 128 airplanes in the U.S. registry.
We estimate the following costs to do the installation of access holes to do visual inspections:

Labor Cost
Parts Cost
Total Cost Per Airplane
Total Cost on U.S. Operators
1 work-hour X $80 per hour = $80
$5
$85
$10,880

We estimate the following costs to do each visual inspection for cracks of the horizontal stabilizer brace tube assembly:

Labor Cost
Parts Cost
Total Cost Per Airplane
Total Cost on U.S. Operators for Initial Inspection
1 work-hour X $80 per hour = $80
Not Applicable
$80
$10,240

We estimate the following costs to do any necessary replacement of the horizontal stabilizer brace tube assembly with a new design horizontal stabilizer brace tube assembly that will be required based on the results of the inspection or as the terminating action for the repetitive inspection requirement. We have no way of determining the number of airplanes that will need this replacement:

Labor Cost
Parts Cost
Total Cost Per Airplane
35 work-hours X $80 per hour = $2,800
$896
$3,696

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 describedin 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-2006-26775; Directorate Identifier 2007-CE-01-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. FAA amends Sec. 39.13 by adding the following new AD: