05-3271. Airworthiness Directives; Air Tractor Inc. Model AT-602 Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all Air Tractor Inc. Model AT-602 airplanes. This proposed AD would require you to repetitively inspect (using the eddy current methods) the two outboard holes in the lower wing spar caps for cracks and repair or replace any cracked spar cap. This proposed AD results from fatigue cracking of the wing main spar lower cap at the centerline joint outboard fastener hole. We are issuing this proposed 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:

We must receive any comments on this proposed AD by April 21, 2005.

ADDRESSES:

Use one of the following to submit comments 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 20590-001.
• 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.

To get the service information identified in this proposed AD, contact Air Tractor Inc.; P.O. Box 485, Olney, Texas 76374; telephone: [phone]; facsimile: [phone].

To view the comments to this proposed AD, go to http://dms.dot.gov. The docket number is FAA-2004-20007.

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

How do I comment on this proposed AD? We invite you to submit any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include the docket number, “FAA-2004-20007; Directorate Identifier 2004-CE-50-AD” at the beginning of your 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 with FAA personnel concerning this proposed rulemaking. Using the search function of our docket Web site, anyone can find and read the comments received into any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). This is docket number FAA-2004-20007. You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78) or you may visit http://dms.dot.gov.

Are there any specific portions of this proposed AD I should pay attention to? We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. If you contact us through a nonwritten communication and that contact relates to a substantive part of this proposed AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend this proposed AD in light of those comments and contacts.

Docket Information

Where can I go to view the docket information? You may view the AD docket that contains the proposal, any comments received, and any final disposition in person at the DMS Docket Offices between 9 a.m. and 5 p.m. (eastern standard time), Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) is located on the plaza level of the Department of Transportation NASSIF Building at the street address stated in ADDRESSES. You may also view the AD docket on the Internet at http://dms.dot.gov. The comments will be available in the AD docket shortly after the DMS receives them.

Discussion

What events have caused this proposed AD? The FAA received a report of fatigue cracking of the wing main spar lower cap at the centerline outboard fastener hole on one Air Tractor Model AT-602 airplane. The airplane had 2,895 hours time-in-service at the time the cracking was discovered. The fatigue cracking was similar to that found on Air Tractor Models AT-502, AT-502A, and AT-502B airplanes. The FAA previously issued AD 2002-26-05, Amendment 39-12991 (68 FR 18, January 2, 2003), to address the condition on the Models AT-502, AT-502A, and AT-502B airplanes.

What is the potential impact if FAA took no action? Cracks in the wing main spar lower cap could result in failure of the spar cap and lead to wing separation and loss of control of the airplane.

Is there service information that applies to this subject? Snow Engineering Co. has issued Process Specification #197, revised June 4, 2002; Process Specification #205, dated April 26, 2004; Service Letter #204, dated November 13, 2003; Service Letter #240, dated September 30, 2004; and Drawing 20998, Revision B, dated September 28, 2004.

What are the provisions of this service information? The service letters, process specifications, and drawing include procedures for:

—Preparing the airplane and the eddy current machine for inspection of the lower wing spar caps;

—Inspecting the lower wing spar caps for cracks;

—Verifying suspected cracks for steel and aluminum lower wing spars caps;

—Repairing the cracks by installing a web plate and 8-bolt splice block; and

—Replacing the spar caps and associated hardware.

FAA's Determination and Requirements of This Proposed AD

What has FAA decided? We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. For this reason, we are proposing AD action.

What would this proposed AD require? This proposed AD would require you to incorporate the actions in the previously-referenced service information.

How does the revision to 14 CFR part 39 affect this proposed AD? On July 10, 2002, we published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.

Costs of Compliance

How many airplanes would this proposed AD impact? We estimate that this proposed AD affects 107 airplanes in the U.S. registry.

What would be the cost impact of this proposed AD on owners/operators of the affected airplanes? We estimate the following costs to accomplish this proposed inspection:

Labor cost	Parts cost	Total cost per airplane	Total cost on U.S. operators
2 workhours × $65 = $130	N/A	$130	$13,910

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

Labor cost	Parts cost	Total cost per airplane
* Install access panels: 22 workhours × $65 per hour = $1,430	$425	$1,855
** Install web plate, 8-bolt splice blocks, and cold work fastener holes: 130 workhours × $65 = $8,450	5,000	13,450
*Access panels are incorporated into production starting with serial number 602-0670.
**If 8-bolt attach blocks (part number 20985-1/-2) are not installed with a web plate, then reduce the cost by $900.

Authority for This Rulemaking

What authority does FAA have for issuing this rulemaking action? 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

Would this proposed AD impact various entities? 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.

Would this proposed AD involve a significant rule or regulatory action? For the reasons discussed above, I certify that this proposed 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 proposed AD 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 “AD Docket 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
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration 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 airworthiness directive (AD):

Air Tractor Inc.: Docket No. FAA-2004-20007; Directorate Identifier 2004-CE-50-AD.

When Is the Last Date I Can Submit Comments on This Proposed AD?

(a) We must receive comments on this proposed airworthiness directive (AD) by April 21, 2005.

What Other ADs Are Affected by This Action?

(b) None.

What Airplanes Are Affected by This AD?

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

What Is the Unsafe Condition Presented in This AD?

(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.

What Must I Do To Address This Problem?

(e) At the initial inspection time specified in paragraph (e)(2) or (e)(3) of this AD, do the following:

(1) For all affected airplanes, gain access for the required inspection listed below by installing cover plates. Follow Snow Engineering Co. Service Letter #204 (page 3), dated November 13, 2003.

(2) For all affected airplanes not having cold-worked fastener holes as described in Snow Engineering Co. Service Letter #240, dated September 30, 2004; or Process Specification #205, dated April 26, 2004: Eddy current inspect the two outboard holes in both the right and left lower wing spar caps following Snow Engineering Co. Process Specification #197, revised June 4, 2002. For these non cold-worked airplanes, use the following wing spar lower cap hours time-in-service (TIS) schedule to do the initial and repetitive inspections:

Serial Nos.	Condition	Initially inspect upon accumulating the following or within 50 hours TIS after the effective date of this AD, whichever occurs later:	Repetitively inspect thereafter at the intervals following:
(i) 602-0337 through 602-0584	As manufactured	2,500 hours TIS	1,000 hours TIS.
(ii) 602-0337 through 602-0584	When modified by installing Web Plate, part number (P/N) 20996-2, following Drawing Number 20998 or 20776, Sheet 2	2,500 hours TIS	1,600 hours TIS.
(iii) 602-0585 through 602-0694	As manufactured	2,500 hours TIS	1,600 hours TIS.

(3) For all affected airplanes that have cold-worked fastener holes by either Snow Engineering Co. Service Letter #240, dated September 30, 2004; or Snow Engineering Co. Process Specification #205, dated April 26, 2004: Upon accumulating 5,000 hours TIS after cold-working the lower spar caps or within 50 hours TIS after the effective date of the AD, whichever occurs later, perform a one-time eddy current inspection of the two outboard holes in both the right and left lower wing spar caps following Snow Engineering Co. Process Specification #197, revised June 4, 2002.

(4) For all serial number airplanes beginning with 602-0695 (excludes 602-0337 through 602-0694), upon accumulating 5,000 hours TIS on the lower spar caps or within 50 hours TIS after the effective date of the AD, whichever occurs later, perform a one-time eddy current inspection of the two outboard holes in both the right and left lower wing spar caps following Snow Engineering Co. Process Specification #197, revised June 4, 2002.

(5) 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 MIL-STD-410; or

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

(f) For all affected airplanes, repair or replace any cracked spar cap prior to further flight. For repair or replacement, do one of the following:

(1) Repair small cracks by reaming the cracked hole to the next larger size and installing P/N 20985-1 and 20985-2 extended 8-bolt splice blocks (and P/N 20996-2 web plate if not already installed) following Snow Engineering Co. drawing 20998.

(2) For large cracks or cracks that can not be removed with the 8-bolt splice blocks, replace the lower spar caps, splice blocks and hardware, and wing attach angles and hardware following Snow Engineering Co. drawing 20776, Sheet 2.

(g) For all affected airplanes, upon accumulating 6,500 hours TIS on the wing spar lower caps or within the next 50 hours TIS after the effective date of this AD, whichever occurs later, replace the wing lower spar caps, splice blocks and hardware, and wing attach angles and hardware. Follow Snow Engineering Co. Drawing 20776, Sheet 2.

(h) Report any cracks you find within 10 days after the cracks are found or within 10 days after the effective date of this AD, whichever occurs later. Include in your report the aircraft serial number, aircraft 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].

May I Request an Alternative Method of Compliance?

(i) You may request a different method of compliance or a different compliance time for this AD by following the procedures in 14 CFR 39.19. Unless FAA authorizes otherwise, send your request to your principal inspector. The principal inspector may add comments and will send your request to the Manager, Fort Worth Airplane Certification Office, FAA, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0150. For information on any already approved alternative methods of compliance, contact Andrew McAnaul, Aerospace Engineer, ASW-150 (c/o MIDO-43), 10100 Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: [phone]; facsimile: [phone].

May I Get Copies of the Documents Referenced in This AD?

(j) 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 FAA-2004-20007.

Issued in Kansas City, Missouri, on February 11, 2005.

Nancy C. Lane,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.