AD 2008-21-08

We are adopting a new airworthiness directive (AD) for certain Air Tractor, Inc. (Air Tractor) Models AT-402, AT-402A, and AT-402B airplanes. This AD requires you to repetitively visually inspect the rudder and vertical fin hinge attaching structure for loose fasteners and inspect the rudder or vertical fin skins, spars, hinges, or brackets for cracks and/or corrosion. This AD also requires you to replace any damaged parts found as a result of the inspections and install an external doubler at the upper rudder hinge. Installation of the external doubler at the upper rudder hinge is terminating action for the repetitive inspection requirements. This AD results from a report of a Model AT-402 airplane with a loose upper rudder hinge caused by fatigue. We are issuing this AD to detect and correct loose fasteners; any cracks in the rudder or vertical fin skins, spars, hinges, or brackets; or corrosion of the rudder and vertical fin hinge attaching structure. Hinge failure adversely affects ability to control yaw and has led to the rudder folding over in flight. This condition could allow the rudder to contact the elevator and affect ability to control pitch with consequent loss of control.

Final rule.

2008-21-08 Air Tractor, Inc.: Amendment 39-15692; Docket No. FAA- 2008-0749; Directorate Identifier 2008-CE-044-AD.

Effective Date

(a) This AD becomes effective on November 20, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Models AT-402, AT-402A, and AT-402B airplanes, serial numbers 0694 through 1176, that are certificated in any category.

Unsafe Condition

(d) This AD results from a report of a Model AT-402 airplane with a loose upper rudder hinge caused by fatigue. We are issuing this AD to detect and correct loose fasteners; any cracks in the rudder or vertical fin skins, spars, hinges, or brackets; or corrosion of the rudder and vertical fin hinge attaching structure. Hinge failure adversely affects ability to control yaw and has led to the rudder folding over in flight. This condition could allow the rudder to contact the elevator and affect 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) Inspect visually the rudder and vertical fin hinge attachment for loose fasteners; and inspect the rudder or vertical fin skins, spars, hinges, and brackets for cracks and/or corrosion.
Initially inspect when the airplane reaches a total of 3,500 hours time-in-service (TIS) or within the next 100 hours TIS after November 20, 2008 (the effective date of this AD), whichever occurs later. Thereafter, repetitively inspect at intervals not to exceed every 100 hours TIS. Installation of the external doubler at the upper rudder hinge required by paragraph (e)(2)(ii) or (e)(3) of this AD is terminating action for the repetitive inspections required by this AD.
Follow Snow Engineering Co. Service Letter #247, revised June 2, 2008.
(2) If you find any damage as a result of any inspection required by paragraph (e)(1) of this AD, you must:
(i) Replace any damaged parts with newparts; and
(ii) Do the installation of the external doubler at the upper rudder hinge.
Before further flight after any inspection required by paragraph (e)(1) of this AD where you find any damaged parts. The installation of the external doubler at the upper rudder hinge required by paragraph (e)(2)(ii) or (e)(3) of this AD terminates the repetitive inspections required by this AD.
Follow Snow Engineering Co. Service Letter #247, revised June 2, 2008; and Snow Engineering Co. Process Specification Number 145, dated December 6, 1991.
(3) Do the installation of the external doubler at the upper rudder hinge.
When the airplane reaches a total of 5,000 hours TIS after November 20, 2008 (the effective date of this AD) or within the next 100 hours TIS after November 20, 2008 (the effective date of this AD), whichever occurs later. The installation of the external doubler at the upper rudder hinge required by paragraph (e)(2)(ii) or (e)(3) of this AD terminates the repetitive inspections required by this AD.
Follow Snow Engineering Co. Service Letter #247, revised June 2, 2008; and Snow Engineering Co. Process Specification Number 145, dated December 6, 1991.
(4) Do not install any rudder without the external doubler at the upper rudder hinge required by paragraph (e)(3) of this AD.
As of November 20, 2008 (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; facsimile: (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.

Material Incorporated by Reference

(g) You must use Snow Engineering Co. Service Letter 247, revised June 2, 2008; and Snow Engineering Co. Process Specification Number 145, dated December 6, 1991, 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 Snow Engineering Co. Service Letter 247, revised June 2, 2008, under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) On December 21, 2006 (71 FR 66661, November 16, 2006), the Director of the Federal Register approved the incorporation by reference of Snow Engineering Co. Process Specification Number 145, dated December 6, 1991.
(3) For 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; E-mail: parts@airtractor.com; Web site: http://www.airtractor.com.
(4) 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 July 1, 2008, 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 Models AT-402, AT-402A, and AT-402B airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on July 8, 2008 (73 FR 38933). The NPRM proposed to require you to repetitively visually inspect the rudder and vertical fin hinge attaching structure for loose fasteners and inspect the rudder or vertical fin skins, spars, hinges, or brackets for cracks and/or corrosion. This AD would also require you to replace any damaged parts found as a result of the inspections and install an external doubler at the upper rudder hinge. Installation of the external doubler at the upper rudder hinge is terminating action for the repetitive inspection requirements.

Comments

We provided the public the opportunity to participate in developing this AD. We received no comments on the proposal or on the determination 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 220 airplanes in the U.S. registry.
We estimate the following costs to do the inspection:

Labor Cost
Parts Cost
Total Cost Per Airplane
Total Cost on U.S. Operators
1 work-hour X $80 per hour = $80
Not applicable
$80
$17,600

Any required replacements will vary depending upon the damage found, and any replacements required will vary based on the results of the inspection. Based on this, we have no way of determining the potential replacement costs for each airplane or the number of airplanes that will need the replacements based on the result of the inspections.
We estimate the following costs to do installation of the external doubler at the upper rudder hinge:

Labor Cost
Parts Cost
Total Cost Per Airplane
Total Cost on U.S. Operators
5 work-hours X $80 per hour = $400
$217
$617
$135,740

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-2008-0749; Directorate Identifier 2008 CE-044-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: