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Proposed Rule

Airworthiness Directives; Air Tractor, Inc. Models AT-802 and AT-802A Airplanes

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Start Preamble

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to supersede Airworthiness Directive (AD) 2006-08-09, which applies to all Air Tractor, Inc. (Air Tractor) Models AT-802 and AT-802A airplanes. AD 2006-08-09 currently requires you to repetitively inspect (using the eddy current method) the two outboard fastener holes in both of the wing main spar lower caps at the center splice joint for cracks and repair or replace any cracked spar cap. Since we issued AD 2006-08-09, we have determined we need to clarify the applicability of Models AT-802 and AT-802A airplanes affected serial number (SN) ranges. Additionally, we propose to add an option of modifying the wing main spar lower caps to extend the safe life limit on the affected airplanes. Consequently, this proposed AD would keep the actions of AD 2006-08-09, clarify the applicability of Models AT-802 and AT-802A affected SN ranges, and add a modification option to extend the safe life limit. We are proposing this AD to detect and correct cracks in the wing main spar lower cap at the center splice joint, 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 comments on this proposed AD by September 21, 2009.

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: (202) 493-2251.
  • 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: (940) 564-5616; fax: (940) 564-5612; e-mail: airmail@airtractor.com; Internet: http://www.airtractor.com.

Start Further Info

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: (210) 308-3365; fax: (210) 308-3370.

End Further Info End Preamble Start Supplemental Information

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-2009-0707; Directorate Identifier 2009-CE-035-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

Since 2000, we have issued several airworthiness directives (ADs) related to the wing spar inspection and safe life on Air Tractor AT-400, AT-500, AT-600, and AT-800 series airplanes.

In 2001, we issued AD 2001-10-04, Amendment 39-12230 (66 FR 27014, May 16, 2001) to lower the safe life for the wing lower spar cap on Air Tractor AT-400, AT-500, and AT-800 series airplanes. This AD allowed for inspection (using eddy current methods) of the wing lower spar cap for airplanes that were at or over the lower safe life and for which parts were not available. Later that same year we revised that AD to remove AT-800 series airplanes from the applicability that were equipped with the factory-supplied computerized fire gate (part number 80540) and engaged in full-time firefighting.

In 2002, we issued AD 2002-11-05, Amendment 39-12766 (67 FR 37967, May 31, 2002) to further reduce the safe life for certain AT-400 series airplanes and certain AT-500 series airplanes that either incorporate or have incorporated Marburger winglets.

After receiving reports of fatigue cracking found on three Model AT-802A airplanes that were below the reduced safe life established in AD 2002-11-05, we issued AD 2006-08-09, Amendment 39-14565 (71 FR 27784, May 12, 2006). AD 2006-08-09 currently requires the following on Air Tractor Models AT-802 and AT-802A airplanes:

  • Repetitively inspecting (using the eddy current method) the two outboard fastener holes in both of the wing main spar lower caps at the center splice joint for cracks; and
  • Repairing or replacing any cracked spar cap.

Since we issued AD 2006-08-09, we have determined we need to clarify the applicability of Models AT-802 and AT-802A airplanes affected SN ranges. The manufacturer, Air Tractor, shared a common SN range for the Models AT-802 and AT-802A. Sometimes service information listed only one of the models with a starting or ending SN within an SN range, depending on which model was produced with that specific SN, even though the service information applied to both models.

Additionally, we propose to add an option of modifying the wing main spar Start Printed Page 39244lower caps to extend the safe life limit on the affected airplanes.

This condition, if not corrected, could result in failure of the spar cap and lead to wing separation and loss of control of the airplane.

Relevant Service Information

We have reviewed the following Snow Engineering Co. service information:

  • Process Specification #197, page 1, revised June 4, 2002; pages 2 through 4, dated February 23, 2001; and page 5, dated May 3, 2002;
  • Process Specification #204, Rev. C, dated November 16, 2004;
  • Service Letter #215, page 5, titled “802 Spar Inspection Holes and Vent Tube Mod,” dated November 19, 2003;
  • Service Letter #240, dated September 30, 2004;
  • Service Letter #244, dated April 25, 2005;
  • Drawing Number 20975, Sheet 2, Rev. A, dated September 1, 2004;
  • Drawing Number 20975, Sheet 3, dated January 6, 2005; and
  • Drawing Number 20995, Sheet 2, Rev. C., dated September 28, 2004.

The service information describes procedures for:

  • Repetitively inspecting (using the eddy current method) the two outboard fastener holes in both of the wing main spar lower caps at the center splice joint for cracks; and
  • Repairing or replacing any cracked spar cap.

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 2006-08-09 with a new AD that would incorporate the actions in the previously-referenced service information. This proposed AD would require you to use the service information described previously to perform these actions.

Differences Between This Proposed AD and the Service Information

Sometimes service information lists only one of the models with a starting or ending SN within an SN range, depending on which of those models was produced with that SN, even though the service information applies to both models. The requirements of this proposed AD, if adopted as a final rule, would take precedence over the provisions in the service information.

Costs of Compliance

We estimate that this proposed AD would affect 187 airplanes in the U.S. registry.

We estimate the following costs to do the proposed inspection:

Labor costParts costTotal cost per airplaneTotal cost on U.S. operators
$500 to $800Not applicable$500 to $800$93,500 to $149,600.

We estimate the following costs to do any necessary repairs for two spars that may be required based on the results of the proposed inspection or the modification as an option. We have no way of determining the number of airplanes that may need this repair:

Labor cost (two spars)Parts cost (two spars)Total cost (two spars) per airplane
225 work-hours × $80 per hour = $18,000$7,500$25,500

We estimate the following costs to do any necessary spar cap replacement (two spars) 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 (two spars)Parts cost (two spars)Total cost (two spars) per airplane
495 work-hours × $80 per hour = $39,600$39,100$78,700

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.Start Printed Page 39245

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 (800) 647-5527) is located at the street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]

2. The FAA amends § 39.13 by removing Airworthiness Directive (AD) 2006-08-09, Amendment 39-14565 (71 FR 27784, May 12, 2006), and adding the following new AD:

Air Tractor, Inc.: Docket No. FAA-2009-0707; Directorate Identifier 2009-CE-035-AD.

Comments Due Date

(a) We must receive comments on this airworthiness directive (AD) action by September 21, 2009.

Affected ADs

(b) This AD supersedes AD 2006-08-09, Amendment 39-14565.

Applicability

(c) This AD affects Model AT-802 and AT-802A airplanes, all serial numbers (SNs) beginning with -0001, that are:

(1) Certificated in any category;

(2) Engaged in agricultural dispersal operations, including those airplanes that have been converted from fire fighting to agricultural dispersal or airplanes that convert between fire fighting and agricultural dispersal;

(3) Not equipped with the factory-supplied computerized fire gate (part number (P/N) 80540); and

(4) Not engaged in only full-time fire fighting.

Unsafe Condition

(d) This AD results from our determination that we need to clarify the applicability of Models AT-802 and AT-802A airplanes affected serial number (SN) ranges. Additionally, we are adding an option to modify the wing main spar lower caps to extend the safe life limit on the affected airplanes. We are issuing this AD to detect and correct cracks in the wing main spar lower cap at the center splice joint, which could result in failure of the spar cap and lead to wing separation and loss of control of the airplane.

Compliance

(e) For Models AT-802 and AT-802A airplanes, SNs -0001 through -0091, do the following actions, unless already done, using the wing main spar lower cap hours time-in-service (TIS) schedule found in Table 1 of this AD to do the initial and repetitive inspections:

(1) Install access cover plates following Snow Engineering Co. Service Letter #215, page 5, titled “802 Spar Inspection Holes and Vent Tube Mod,” dated November 19, 2003.

(2) Eddy current inspect for cracks the center splice joint outboard two fastener holes in both the right and left wing main spar lower caps following Snow Engineering Co. Process Specification #197, page 1, revised June 4, 2002; pages 2 through 4, dated February 23, 2001; and page 5, dated May 3, 2002.

Table 1—Inspection Times

SNsConditionInitially inspectRepetitively inspect thereafter at intervals not to exceed
(i) AT-802 and AT-802A, SNs -0001 through -0091As manufacturedUpon accumulating 1,700 hours TIS after April 21, 2006 (the effective date of AD 2006-08-09) or within the next 50 hours TIS after April 21, 2006 (the effective date of AD 2006-08-09), whichever occurs later850 hours TIS.
(ii) AT-802 and AT-802A, serial numbers SNs -0001 through -0091Modified with cold-worked fastener holes following Service Letter #244, dated April 25, 2005If performing the cold-working procedure in Service Letter #244, dated April 25, 2005, it includes the initial eddy current inspection1,700 hours TIS.

(f) One of the following must do the eddy current inspections required in paragraph (e)(2) of this AD:

(1) 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

(2) 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.

(g) If cracks are found during any inspection required in paragraph (e)(2) of this AD, repair or replace any cracked spar cap before further flight after the inspection in which cracks are found. For repair or replacement, do whichever of the following that applies:

(1) For cracks that can be repaired by incorporating the modification specified in paragraph (j) of this AD, do the actions following the procedures in paragraph (j) of this AD before further flight after the inspection in which cracks are found.

(2) For cracks that cannot be repaired by incorporating the modification specified in paragraph (j) of this AD, replace the lower spar caps and associated parts listed following the procedures identified in paragraph (h) of this AD before further flight after the inspection in which cracks are found.

(h) For all AT-802 and AT-802A airplanes, replace the wing main spar lower caps, the center joint splice blocks and hardware, the wing attach angles and hardware, and install the steel web splice plate (P/N 21106-1 for SNs -0001 through -0091, and P/N 20094-2 for all SNs beginning with -0092). Do the replacement upon accumulating the safe life hours TIS on the wing main spar lower caps as listed in Table 2 of this AD or within 50 hours TIS after April 21, 2006 (the effective date of AD 2006-08-09), whichever occurs later. For SNs -0001 through -0091, you may extend the safe life hours TIS of the wing main spar lower caps to 8,000 hours TIS before doing the replacement if you modified your wing as specified in paragraph (j) of this AD.

(1) Use the following service information for replacement:

(i) For airplane Models AT-802 and AT-802A, SNs -0001 through -0091, follow Start Printed Page 39246Snow Engineering Co. Drawing Number 20975, Sheet 3, dated January 6, 2005; and Process Specification #204, Rev. C, dated November 16, 2004.

(ii) For airplane Models AT-802 and AT-802A, SNs beginning with -0092, follow Drawing Number 20975, Sheet 2, Rev. A, dated September 1, 2004; and Process Specification #204, Rev. C, dated November 16, 2004.

(2) The following presents the safe life and replacement times as required in paragraph (h) of this AD:

Table 2—Safe Life and Replacement Times

SNsWing spar lower cap safe life
AT-802-0001 through AT-802-00594,132 hours TIS.
AT-802-0060 through AT-802-00914,188 hours TIS.
All beginning with AT-802-00928,163 hours TIS.
AT-802A-0001 through AT-802A-00594,969 hours TIS.
AT-802A-0060 through AT-802A-00914,531 hours TIS.
All beginning with AT-802A-00928,648 hours TIS.

(i) After replacing the wing main spar lower caps and hardware, installing the web splice plate, and cold working the fastener holes by following Snow Engineering Co. Drawing Number 20975, Sheet 3, dated January 6, 2005 (SNs -0001 through -0091); or Sheet 2, Rev. A, dated September 1, 2004 (all SNs beginning with -0092); and Process Specification #204, Rev. C, dated November 16, 2004, the new safe life for the wing main spar lower caps is as follows:

Table 3—New Safe Life for Wing Main Spar Lower Caps

SNsWing spar lower cap safe life
All beginning with AT-802-00018,163 hours TIS.
All beginning with AT-802A-00018,648 hours TIS.

(j) For Models AT-802 and AT-802A airplanes, SNs -0001 through -0091, in lieu of replacing the wing main spar lower cap at the safe life hours TIS listed in Table 2 in paragraph (h) of this AD, you may extend the safe life of the wing main spar lower caps by doing the following actions. Between 3,200 hours TIS and the safe life hours TIS for your airplane currently listed in Table 2 of this AD, do the following, unless already done:

(1) Modify the wing by installing P/N 20997-2 web plate and P/N 20985-1 and 20985-2 extended 8-bolt splice blocks following Snow Engineering Co. Drawing 20995, Sheet 2, Rev. C, dated September 28, 2004.

(2) Cold-work the outboard two fastener holes in both the left and right hand lower spar caps at the center splice following Snow Engineering Co. Service Letter #240, dated September 30, 2004.

(3) Do an eddy current inspection of the wing center splice joint outboard two fastener holes in both the right and left wing main spar lower caps for cracks at the time of modification following Snow Engineering Co. Process Specification #197, page 1, revised June 4, 2002; pages 2 through 4, dated February 23, 2001; and page 5, dated May 3, 2002.

(4) If, before the effective date of this AD, an airplane has already been modified following paragraph (j)(1) of this AD but did not receive cold working in the outboard two fastener holes in both the left and right hand lower spar caps following paragraph (j)(2) of this AD, do the following:

(i) Initially do an eddy current inspection within the next 2,400 hours TIS after the modification, using the procedure in paragraph (j)(3) of this AD, and repetitively thereafter at intervals not to exceed every 1,200 hours TIS until the wing spar lower cap reaches 8,000-hour TIS safe life.

(ii) At any time after the modification, you may do the cold working in the outboard two fastener holes in both the left and right hand lower spar caps following paragraph (j)(2) of this AD to terminate the repetitive eddy current inspections required in paragraph (j)(4)(i) of this AD.

(5) If you have modified your airplane following paragraph (j)(1) of this AD prior to 3,200 hours TIS, you must do the following to reach the extended 8,000-hour TIS safe life:

(i) If you did not cold work in the outboard two fastener holes in both the left and right hand lower spar caps following paragraph (j)(2) of this AD, you must do the repetitive eddy current inspections following paragraph (j)(4)(i) of this AD until you accumulate 4,800 hours TIS after the modification on the wing spar lower cap. Upon accumulation of 4,800 hours TIS after the modification on the wing spar lower cap, do the repetitive eddy current inspections at intervals not to exceed every 600 hours TIS until you reach the extended safe life of 8,000-hour TIS.

(ii) If you did cold work the outboard two fastener holes in both the left and right hand lower spar caps following paragraph (j)(2) of this AD, upon accumulation of 4,800 hours TIS after the modification on the wing spar lower cap do the repetitive eddy current inspections at intervals not to exceed every 600 hours TIS until you reach the 8,000-hour TIS safe life.

(6) For the initial and repetitive eddy current inspections required in paragraphs (j)(3), (j)(4)(i), (j)(5)(i) and (j)(5)(ii) of this AD, follow the instructions as specified in Snow Engineering Co. Process Specification #197, page 1, revised June 4, 2002; pages 2 through 4, dated February 23, 2001; and page 5, dated May 3, 2002. For any cracks found, follow the instructions for repair or replacement as specified in paragraph (g) of this AD.

(k) If any cracks are found as a result of any inspection required in paragraphs (e)(2), (j)(3), (j)4)(i), (j)(5)(i), and (j)(5)(ii) of this AD, report any cracks you find within 10 days after the cracks are found or within 10 days after April 21, 2006 (the effective date of AD 2006-08-09), whichever occurs later.

(1) Include in your report the aircraft SN, aircraft hours TIS, wing spar cap hours 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: (210) 308-3365; facsimile: (210) 308-3370.

(2) The Office of Management and Budget (OMB) approved the information collection requirements contained in this regulation under the provisions of the Paperwork Reduction Act and assigned OMB Control Number 2120-0056.

Special Permit Flight

(l) Under 14 CFR part 39.23, we are allowing special flight permits for the purpose of compliance with this AD under the following conditions:

(1) Only operate in day visual flight rules (VFR).

(2) Ensure that the hopper is empty.

(3) Limit airspeed to 135 miles per hour (mph) indicated airspeed (IAS).

(4) Avoid any unnecessary g-forces.

(5) Avoid areas of turbulence.

(6) Plan the flight to follow the most direct route.

Alternative Methods of Compliance (AMOCs)

(m) The Manager, Fort Worth Airplane Certification Office, ASW-150, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 Start Printed Page 39247CFR 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: (210) 308-3365; fax: (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.

(n) AMOCs approved for AD 2006-08-09 are not approved for this AD.

Related Information

(o) To get copies of the service information referenced in this AD, contact Air Tractor, Inc., P.O. Box 485, Olney, Texas 76374; telephone: (940) 564-5616; fax: (940) 564-5612; e-mail: airmail@airtractor.com; Internet: 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.

Start Signature

Issued in Kansas City, Missouri, on July 31, 2009.

James E. Jackson,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. E9-18815 Filed 8-5-09; 8:45 am]

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