E6-18688. Airworthiness Directives; Air Tractor, Inc. Model AT-602 Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

The FAA adopts a new airworthiness directive (AD) for all Air Tractor, Inc. (Air Tractor) Model AT-602 airplanes. This AD requires you to repetitively inspect (using the eddy current method) the wing center splice joint two outboard fastener holes on both of the wing main spar lower caps for fatigue cracking; repair or replace any wing main spar lower cap where fatigue cracking is found; and report any fatigue cracking found. This AD results from fatigue cracking at the wing center splice joint outboard fastener hole in one of the wing main spar lower caps. We are issuing this AD to detect and correct cracks in the wing main spar lower cap, which could result in failure of the spar cap and lead to wing separation and loss of control of the airplane.

DATES:

This AD becomes effective on December 14, 2006.

As of December 14, 2006, the Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulation.

ADDRESSES:

To get the service information identified in this AD, contact Air Tractor, Inc. at P.O. Box 485, Olney, Texas 76374; telephone: [phone]; or fax: [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 20590-0001 or on the Internet at http://dms.dot.gov. The docket number is FAA-2004-20007; Directorate Identifier 2004-CE-50-AD.

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]; fax: [phone].

SUPPLEMENTARY INFORMATION:

Discussion

On August 3, 2006, 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 all Air Tractor, Inc. (Air Tractor) Model AT-602 airplanes. This proposal was published in the Federal Register as a supplemental notice of proposed rulemaking (NPRM) on August 9, 2006 (71 FR 45467). The supplemental NPRM proposed to require you to repetitively inspect (using the eddy current method) the wing center splice joint two outboard fastener holes on both of the wing main spar lower caps for fatigue cracking; repair or replace any wing main spar lower cap where fatigue cracking is found; and report any fatigue cracking found.

The following table contains AD actions that address the wing spar safe life of the Air Tractor airplane fleet:

Related Ad Actions

AD No.	Affected air tractor model airplanes	Status
2000-14-51	AT-501, AT-502, and AT-502A	Superseded by AD 2001-10-04.
2001-10-04	AT-400, AT-500, and AT-800 Series	Revised by AD 2001-10-04 R1.
2001-10-04 R1	AT-400, AT-500, and AT-800 Series	Superseded by AD 2002-11-05.
2002-11-05	AT-400, AT-401, AT-401B, AT-402, AT-402A, AT-402B, AT-501, AT-802, and AT-802A	Revised by AD 2002-11-05 R1.
2002-13-02	AT-300, AT-301, AT-302, AT-400, and AT-400A Airplanes	Superseded by AD 2003-06-01.
2002-11-03	AT-502, AT-502A, AT-502B, and AT-503A	Superseded by AD 2002-26-05.
2002-26-05	AT-502, AT-502A, AT-502B, and AT-503A	Current.
2003-06-01	AT-300, AT-301, AT-302, AT-400, and AT-400A	Current.
2002-11-05 R1	AT-501	Current.
2006-08-08	AT-400, AT-401, AT-401B, AT-402, AT-402A, and AT-402B	Current.
2006-08-09	AT-802 and AT-802A	Current.

You may view these ADs at the following Internet Web site addresses: http://www.airweb.faa.gov/​Regulatory_​and_​Guidance_​Library/​rgAD.nsf/​MainFrame?​OpenFrameSet or http://www.gpoaccess.gov/​fr/​index.html.

Comments

We provided the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and FAA's response to each comment:

Comment Issue No. 1: Publish the Manufacturer Service Information

Jack Buster with the Modification and Replacement Parts Association (MARPA) provides comments on how the FAA addresses publishing manufacturer service information as part of a proposed AD action. The commenter states that the proposed rule attempts to require compliance with a public law by reference to a private writing (as referenced in paragraph (e) of the proposed AD). The commenter would like the FAA to incorporate by reference (IBR) the Snow Engineering Company service information.

We agree with Mr. Buster. However, we do not IBR any document in a proposed AD action, instead we IBR the document in the final rule. Since we are issuing the proposal as a final rule AD action, the service information referenced in the NPRM is incorporated by reference.

Comment Issue No. 2: Availability of IBR Documents in the Docket Management System (DMS)

Mr. Buster requests IBR documents be made available to the public by publication in the Federal Register or in the Docket Management System (DMS).

We are currently reviewing issues surrounding the posting of service bulletins in the Department of Transportation's DMS as part of the AD docket. Once we have thoroughly examined all aspects of this issue and have made a final determination, we will consider whether our current practice needs to be revised.

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 107 airplanes in the U.S. registry.

We estimate the following costs to do the inspection:

Labor cost	Parts cost	Eddy current inspection	Total cost per airplane	Total cost on U.S. operators
Initial inspection and installation of access panels—24 work-hours × $80 = $1,920	$645	*$500	$3,065	$327,955
Repetitive Inspection (each)	60	*800	860	92,020
* Eddy current inspections are an estimated flat cost that includes labor and use of equipment.

We estimate the following costs to do any necessary repairs 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 repair:

Labor cost	Parts cost	Total cost per airplane
Install web plate, 8-bolt splice blocks, and cold work fastener holes: Air Tractor estimated a labor cost of $12,100. When broken down into work-hours, we estimated 151 work-hours to complete the task. 151 work-hours × $80 = $12,080	$6,900	$18,980
Cold work fastener holes following Snow Engineering Co. Service Letter #244, dated April 25, 2005: 19 work-hours × $80 = $1,520	1,350	2,870

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-2004-20007; Directorate Identifier 2004-CE-50-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.

§ 39.13

[Amended]

2. FAA amends § 39.13 by adding a new AD to read as follows:

2006-23-01 Air Tractor, Inc.: Amendment 39-14798; Docket No. FAA-2004-20007; Directorate Identifier 2004-CE-50-AD.

Effective Date

(a) This AD becomes effective on December 14, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD affects Model AT-602 airplanes, all serial numbers beginning with 602-0337, that are certificated in any category.

Unsafe Condition

(d) This AD is the result of fatigue cracking of the wing main spar lower cap at the centerline splice joint outboard fastener hole. The actions specified in this AD are intended to detect and correct cracks in the wing main spar lower cap, which could result in failure of the spar cap and lead to wing separation and loss of control of the airplane.

Compliance

(e) To address the problem, do the following:

(1) Before doing the initial eddy current inspection required in paragraph (e)(2) of this AD, gain access for the inspection by cutting inspection holes, modifying the vent tube, and installing cover plates; unless already done. Follow Snow Engineering Co. Service Letter #204, revised March 26, 2001, Drawing titled “602 Spar Inspection Holes and Vent Tube Mod.,” dated November 13, 2003.

(2) Eddy current inspect the wing center splice joint outboard two fastener holes in both the right and left wing main spar lower caps for cracks. Follow Snow Engineering Co. Process Specification #197, Revised June 4, 2002. For the following airplanes, use the wing spar lower cap hours time-in-service (TIS) schedule below in Table 1 of this AD to do the initial and repetitive inspections:

Table 1.—Compliance Times for Inspection

Serial Nos.	Condition	Initially inspect	Repetitively inspect thereafter at the following intervals
(i) 602-0337 through 602-0584	As manufactured	Upon accumulating 2,000 hours TIS or within 50 hours TIS after December 14, 2006 (the effective date of this AD), whichever occurs later, unless already done	1,000 hours TIS.
(ii) 602-0337 through 602-0584	Modified with cold-worked fastener holes following Snow Engineering Co. Service Letter #244, dated April 25, 2005	If performing the cold-working procedure in Service Letter #244, it includes the eddy current inspection	2,000 hours TIS.

(3) Do an eddy current inspection as part of the cold working procedure in Service Letter #244, dated April 25, 2005, even if the wing spar was previously inspected.

(4) One of the following must do the inspection:

(i) A level 2 or 3 inspector certified in eddy current inspection using the guidelines established by the American Society for Nondestructive Testing or NAS 410; or

(ii) A person authorized to perform AD maintenance work and who has completed and passed the Air Tractor, Inc. training course on Eddy Current Inspection on wing lower spar caps.

(f) For the airplanes listed in paragraph (e)(2) of this AD, as terminating action for the inspection requirements, you may modify your wing by installing part number (P/N) 20996-2 steel web plate and P/N 20985-1/2 8-bolt splice blocks following Snow Engineering Co. Drawing 20998, Revision B, dated September 28, 2004, and cold work the lower spar cap two outboard fastener holes at the wing center section splice connection following Snow Engineering Co. Service Letter #240, dated September 30, 2004.

(g) For all affected airplanes listed in paragraph (e)(2) of this AD, repair or replace any cracked spar cap before further flight. For repair or replacement, do one of the following:

(1) For cracks that can be removed by performing the terminating action listed in paragraph (f) of this AD above, perform the actions in paragraph (f) of this AD.

(2) For cracks that can not be removed by performing the terminating action in paragraph (f) of this AD, you must replace the lower spar caps and associated parts listed in paragraph (h) of this AD before continued flight.

(h) For all Model AT-602 airplanes, upon accumulating 6,500 hours TIS on the wing spar lower caps or within the next 50 hours TIS after December 14, 2006 (the effective date of this AD), whichever occurs later, replace the wing lower spar caps, splice blocks and hardware, wing attach angles and hardware, and install the steel web plate, P/N 20996-2, if not already installed, following Snow Engineering Co. Drawing 20776, Sheet 2, Revision A, dated August 30, 2004. Compliance with this paragraph terminates the inspection requirements of paragraph (e)(2) of this AD.

(i) Report any cracks you find within 10 days after the cracks are found or within 10 days after December 14, 2006 (the effective date of this AD), whichever occurs later. Include in your report the airplane serial number, airplane TIS, wing spar cap TIS, crack location and size, corrective action taken, and a point of contact name and phone number. Send your report to Andrew McAnaul, Aerospace Engineer, ASW-150 (c/o MIDO-43), 10100 Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: [phone]; facsimile: [phone]. 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 and those following sections) and assigned OMB Control Number 2120-0056.

Alternative Methods of Compliance (AMOCs)

(j) 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

(k) None.

Material Incorporated by Reference

(l) You must use the service information specified in Table 2 of this AD 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. at address P.O. Box 485, Olney, Texas 76374; telephone: [phone]; or facsimile: [phone].

(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.

Table 2.—Material Incorporated by Reference

Snow Engineering Co. service information	Date
Process Specification #197	Revised June 4, 2002.
Drawing 20776, Sheet 2, Revision A	August 30, 2004.
Service Letter #204	Revised March 26, 2001.
Service Letter #240	September 30, 2004.
Drawing 20998, Revision B	September 28, 2004.
Service Letter #244	April 25, 2005.

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

James E. Jackson,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.