E6-9639. Airworthiness Directives; Air Tractor, Inc. Models 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 certain Air Tractor, Inc. Models AT-802 and AT-802A airplanes. This proposed AD would require you to repetitively inspect the attach angles on the firewall mounted hopper rinse tank shelf for damage and/or cracks and replace damaged and/or cracked attach angles. Replacing the attach angles with steel attach angles would terminate the proposed repetitive inspection requirement. Reports of an uncommanded change in the engine power setting caused by separation of the hopper rinse tank shelf from the firewall prompted this proposed AD. We are proposing this AD to detect and correct damage and/or cracks in the attach angles on the firewall mounted hopper rinse tank shelf, which could result in failure of the attach angles. This failure could lead to shelf movement under maneuver load and shifting of the engine power cables, which could result in an uncommanded engine power setting change.

DATES:

We must receive comments on this proposed AD by August 18, 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-2006-24710; Directorate Identifier 2006-CE-29-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 reports of cracks in the aluminum attach angles on the firewall mounted hopper rinse tank shelf. The cracks caused the attach angles to fail, allowing the shelf to move during in-flight maneuvering.

Movement of the shelf during in-flight maneuvering caused the engine power cables, which attach to the hopper rinse tank shelf by a bracket, to shift and resulted in an uncommanded engine power setting change.

This condition, if not corrected, could result in failure of the attach angles. This failure could cause the hopper rinse tank shelf to separate from the firewall, allowing the shelf to move under maneuver load. This movement could cause the engine power cables to shift and result in an uncommanded change to the engine power setting.

Relevant Service Information

We have reviewed Snow Engineering Co. Service Letter #248, dated August 31, 2005.

The service information describes procedures for:

• Inspecting the hopper rinse tank shelf attach angles for damage and/or cracks; and
• Replacing all three attach angles with steel attach angles, part number (P/N) 60568-3, if any damage and/or cracks are found on any of the attach angles.

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 attach angles on the firewall mounted hopper rinse tank shelf for damage and/or cracks and replace damaged and/or cracked attach angles. Replacing the attach angles with steel attach angles, P/N 60568-3, would terminate the proposed repetitive inspection requirement.

Costs of Compliance

We estimate that this proposed AD would affect 219 airplanes in the U.S. registry.

We estimate the following costs to do each proposed inspection:

Labor cost	Parts cost	Total cost for each airplane	Total cost on U.S. operators
1 work-hour × $80 an hour = $80	Not applicable	$80	$80 × 219 = $17,520

We estimate the following costs to do any necessary replacements that would be required based on the results of the proposed inspection. We have no way of determining the number of airplanes that may need this replacement:

Labor cost	Parts cost	Total cost for each airplane
3 work-hours × $80 an hour = $240	$105	$240 + $105 = $345

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 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-2006-24710; Directorate Identifier 2006-CE-29-AD.

Comments Due Date

(a) We must receive comments on this proposed airworthiness directive (AD) action by August 18, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD affects Models AT-802 and AT-802A airplanes, all serial numbers beginning with 802/802A-0001 through 802/802A-0219, that are certificated in any category.

Unsafe Condition

(d) This AD results from reports of an uncommanded change in engine power setting caused by separation of a hopper rinse tank shelf from the firewall. We are proposing this AD to detect and correct damage and/or cracks in the attach angles on the firewall mounted hopper rinse tank shelf, which could result in failure of the attach angles. This failure could lead to shelf movement under maneuver load and shifting of the engine power cables, which could result in an uncommanded engine power setting change.

Compliance

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

Actions	Compliance	Procedures
(1) Visually inspect the three attach angles on the firewall mounted hopper rinse tank shelf for damage and/or cracks	Initially inspect within the next 100 hours time-in-service (TIS) after the effective date of this AD. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS. Replacing all three attach angles with steel attach angles, part number (P/N) 60568-3 (or FAA-approved equivalent P/N), terminates the repetitive inspection requirement of this AD	Follow Snow Engineering Co. Service Letter #248, dated August 31, 2005.
(2) If you find any damage and/or cracks on any of the three attach angles during any inspection required in paragraph (e)(1) of this AD, replace all three attach angles with steel attach angles, P/N 60568-3 (or FAA-approved equivalent P/N)	Before further flight after the inspection in which damage and/or cracks are found. Replacing all three attach angles with steel attach angles, P/N 60568-3 (or FAA-approved equivalent P/N), terminates the repetitive inspection requirement of paragraph (e)(1) of this AD	Follow Snow Engineering Co. Service Letter #248, dated August 31, 2005.
(3) You may replace the aluminum attach angles on the firewall mounted hopper rinse tank shelf with steel attach angles, P/N 60568-3 (or FAA-approved equivalent P/N), at any time to terminate the repetitive inspections required in paragraph (e)(1) of this AD	As of the effective date of this AD	Follow Snow Engineering Co. Service Letter #248, dated August 31, 2005.
(4) Do not install aluminum attach angles on the hopper rinse tank shelf attach angles	As of the effective date of this AD	Not applicable.

(f) 14 CFR 21.303 allows for replacement parts through parts manufacturer approval (PMA). The phrase “or FAA-approved equivalent P/N” in this AD is intended to allow for the installation of parts approved through identicality to the design of the replacement parts. Equivalent replacement parts to correct the unsafe condition under PMA (other than identicality) may also be installed provided they meet current airworthiness standards, which include those actions cited in this AD.

Alternative Methods of Compliance (AMOCs)

(g) 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

(h) 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-2006-24710; Directorate Identifier 2006-CE-29-AD.

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

James E. Jackson,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.