E8-25286. Airworthiness Directives; Air Tractor, Inc. Models AT-200, AT-300, AT-400, AT-500, AT-600, and AT-800 Series Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to supersede Airworthiness Directive (AD) 2008-11-17, which applies to certain Air Tractor, Inc. Models AT-200, AT-300, AT-400, AT-500, AT-600, and AT-800 series airplanes. AD 2008-11-17 currently requires you to install an overturn skid plate kit or a modification to the overturn skid plate already installed. Since we issued AD 2008-11-17, the manufacturer has notified us that Model AT-401B airplanes also require a modification to the overturn skid plate. Consequently, this proposed AD would retain the actions of AD 2008-11-17 and add the requirement to modify the overturn skid plate installed on Model AT-401B airplanes. We are proposing this AD to prevent the front and rear connections of the overturn skid plate to the airplane from breaking, which could allow foreign debris to enter the cockpit during an airplane overturn. This condition, if not corrected, could lead to pilot injury.

DATES:

We must receive comments on this proposed AD by November 24, 2008.

ADDRESSES:

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

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, 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]; fax: [phone]; e-mail: [e-mail]; Internet: http://www.airtractor.com.

FOR FURTHER INFORMATION CONTACT:

Andy McAnaul, Aerospace Engineer, ASW-150, FAA San Antonio MIDO-43, 10100 Reunion Pl., Ste. 650, San Antonio, Texas 78216; telephone: [phone]; fax: [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-2008-1120; Directorate Identifier 2008-CE-064-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://www.regulations.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

Reports of foreign material entering the cabin area during an overturn skid on Air Tractor, Inc. (Air Tractor) AT-301 and AT-401 series airplanes caused us to issue AD 2002-25-09, Amendment 39-12985 (67 FR 78156, December 23, 2002). AD 2002-25-09 required you to install overturn skid plate, part number (P/N) 11411-1-500 or an FAA-approved equivalent P/N. The manufacturer incorporated skid plates in some production models including Models AT-401B, AT-402B, AT-502B, AT-602, and AT-802A airplanes.

Since we issued AD 2002-25-09, we received a report of the bolts breaking in an overturn accident where they attach the forward end of the original design overturn skid plate to the airframe. This allowed the skid plate to rotate around the rear attach point and the forward end of the plate to enter the cockpit area. This report caused us to issue AD 2008-11-17, Amendment 39-15540 (73 FR 31351, June 2, 2008). AD 2008-11-17 currently retains the actions of AD 2002-25-09 and requires you to install a modification kit if certain overturn skid plates are already installed.

Since we issued AD 2008-11-17, the manufacturer has notified us that Model AT-401B airplanes also require a modification to the overturn skid plane. Consequently, this proposed AD would retain the actions of AD 2008-11-17 and add the requirement to modify the overturn skid plate installed on Model AT-401B airplanes.

We are proposing this AD to prevent the front and rear connections of the overturn skid plate to the airplane from breaking, which could allow foreign debris to enter the cockpit during an airplane overturn. This condition, if not corrected, could lead to pilot injury.

Relevant Service Information

We have reviewed Snow Engineering Company Service Letter #97, Revised September 19, 2008.

The service information describes procedures for:

• Modifying the overturn skid plate by enlarging the mounting holes and replacing existing clamps and hardware on airplanes with the overturn skid plate installed; and
• Installing the overturn skid plate for airplanes that do not have the overturn skid plate currently installed.

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 supersede AD 2008-11-17 with a new AD that would retain the actions of AD 2008-11-17 and add the requirement to modify the overturn skid plate installed on Model AT-401B airplanes. This proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

We estimate that this proposed AD would affect 1,309 airplanes in the U.S. registry.

In determining the total cost on U.S. operators, we presume all airplanes in the U.S. fleet have an overturn skid plate installed (as required by AD 2002-25-09) and the only cost is to incorporate the modification kit P/N 11411-1-501. We estimate the following costs to do the proposed modification of installing the overturn skid plate modification kit P/N 11411-1-501 to those planes that currently have the overturn skid plate installed:

Labor cost	Parts cost	Total cost per airplane	Total cost on U.S. operators
2 work-hours × $80 per hour = $160	$42	$202	$264,418

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://www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 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
• Incorporation by reference
• 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 removing Airworthiness Directive (AD) 2008-11-17, Amendment 39-15540 (73 FR 31351, June 2, 2008), and adding the following new AD:

Air Tractor, Inc.: Docket No. FAA-2008-1120; Directorate Identifier 2008-CE-064-AD.

Comments Due Date

(a) We must receive comments on this airworthiness directive (AD) action by November 24, 2008.

Affected ADs

(b) This AD supersedes AD 2008-11-17, Amendment 39-15540.

Applicability

(c) This AD applies to the following airplane models and serial numbers that are certificated in any category:

Group 1 models	Serial Nos.
AT-250, AT-300, AT-301, AT-302, AT-400, AT-400A, AT-401, AT-401A, AT-402, AT-402A, and AT-402B	-0001 through -1196.
AT-501, AT-502, AT-502A, and AT-502B	-0001 through -2620.
AT-602	-0337 through -1153.
AT-802A	-0003 through -0282.

Group 2 model	Serial Nos.
AT-401B	-0952 through -1196.

Unsafe Condition

(d) Since we issued AD 2008-11-17, the manufacturer has notified us that Model AT-401B airplanes also require a modification to the overturn skid plate. Consequently, this proposed AD retains the actions of AD 2008-11-17 and adds the requirement to modify the overturn skid plate installed on Model AT-401B airplanes. We are issuing this AD to prevent the front and rear connections of the overturn skid plate to the airplane from breaking, which could allow foreign debris to enter the cockpit during an airplane overturn. This condition, if not corrected, could lead to pilot injury.

Compliance

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

Actions	Compliance	Procedures
(1) For Group 1 airplanes: If overturn skid plate part number (P/N) 11411-1-500 or an FAA-approved equivalent P/N is already installed then install P/N 11411-1-501 modification kit	Within the next 180 days after July 7, 2008 (the effective date of AD 2008-11-17)	Follow Snow Engineering Co. Service Letter #97, revised November 7, 2007; or Snow Engineering Co. Service Letter #97, revised September 19, 2008.
(2) For Group 1 airplanes: If there is no overturn skid plate installed, then install overturn skid plate kit P/N 11411-1-502 or an FAA-approved equivalent part number	Within the next 180 days after July 7, 2008 (the effective date of AD 2008-11-17)	Follow Snow Engineering Co. Service Letter #97, revised November 7, 2007; or Snow Engineering Co. Service Letter #97, revised September 19, 2008.
(3) For Group 2 airplanes: Install P/N 11411-1-501 modification kit	Within the next 180 days after the effective date of this AD	Follow Snow Engineering Co. Service Letter #97, revised September 19, 2008.

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: Andy McAnaul, Aerospace Engineer, ASW-150, FAA San Antonio MIDO-43, 10100 Reunion Pl., Ste. 650, San Antonio, Texas 78216; telephone: [phone]; fax: [phone]. 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: [phone]; fax: [phone]; e-mail: [e-mail]; Internet: http://www.airtractor.com. To view the AD docket, go to U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, or on the Internet at http://www.regulations.gov.

Issued in Kansas City, Missouri, on October 14, 2008.

John Colomy,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.