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Proposed Rule

Airworthiness Directives; Air Tractor, Inc. Models AT-502, AT-502A, AT-502B, and AT-503A Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede Airworthiness Directive (AD) 2002-26-05, which applies to certain Air Tractor, Inc. (Air Tractor) Models AT-502, AT-502A, AT-502B, and AT-503A airplanes. AD 2002-26-05 lowers the safe life for the wing lower spar cap for Models AT-502, AT-502A, AT-502B, and AT-503A airplanes and those that incorporate or have incorporated Marburger Enterprises, Inc. winglets. AD 2002-26-05 also requires you to eddy-current inspect the wing lower spar cap immediately prior to the replacement/modification to detect and correct any crack in a bolthole before it extends to the modified center section of the wing and report the results of this inspection to the Federal Aviation Administration (FAA). Since we issued AD 2002-26-05, we have determined that additional airplanes should be added to the applicability section. We also developed an alternative method of compliance (AMOC) to the requirements of AD 2002-26-05. This proposed AD retains the action required in AD 2002-26-05, adds additional airplanes to the applicability, and includes an AMOC. We are issuing this proposed AD to prevent fatigue cracks from occurring in the wing lower spar cap before the established safe life is reached. Fatigue cracks in the wing lower spar cap could result in the wing separating from the airplane during flight.

DATES:

We must receive any comments on this proposed AD by April 5, 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: 1-202-493-2251.
  • 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, Incorporated, P.O. Box 485, Olney, Texas 76374; or Marburger Enterprises, Inc., 1227 Hillcourt, Williston, North Dakota 58801; telephone: (800) 893-1420 or (701) 774-0230; facsimile: (701) 572-2602.

To view the comments to this proposed AD, go to http://dms.dot.gov. The docket number is FAA-2004-19961.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Direct all questions to:

—For the airplanes that do not incorporate and never have incorporated Marburger Enterprises, Inc. winglets: Rob Romero, Aerospace Engineer, FAA, Fort Worth Airplane Certification Office, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0150; telephone: (817) 222-5102; facsimile: (817) 222-5960; and

—For airplanes that incorporate or have incorporated Marburger Enterprises, Inc. winglets: John Cecil, Aerospace Engineer, Los Angeles Aircraft Certification Office, FAA, 3960 Paramount Boulevard, Lakewood, California 90712; telephone: (562)

627-5228; facsimile: (562) 627-5210.

End Further Info End Preamble Start Supplemental Information

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-2004-19961; Directorate Identifier 2004-CE-48-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-2004-19961. 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. Start Printed Page 6787

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 1-800-647-5227) 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

Has FAA taken any action to this point? On January 2, 2003, we issued AD 2002-26-05, Amendment 39-12991 (6 FR 18), which applies to certain Air Tractor Models AT-502, AT-502A, AT-502B, and AT-503A airplanes. AD 2002-26-05 supersedes AD 2002-11-03.

Reports of several cracks originating in the outboard 3/8-inch hole of the main spar lower cap on Air Tractor Models AT-502, AT-502A, and AT-502B airplanes at hours time-in-service (TIS) lower than the established safe life caused us to issue AD 2002-11-03, Amendment 39-12764 (67 FR 38371, June 4, 2002).

We issued AD 2002-11-03 to lower the safe life for the wing lower spar cap established in AD 2001-10-04 R1 on Air Tractor Models AT-502, AT-502A, AT-502B, and AT-503A airplanes and further reduce the safe life for airplanes that incorporate or have incorporated Marburger Enterprises, Inc. winglets.

Additional field inspections revealed wings with cracks below the safe life limits established in AD 2002-11-03 for Air Tractor Models AT 502, AT-502B, and AT-503A airplanes. This caused us to issue AD 2002-26-05.

In addition, the applicability section of AD 2002-11-03 covered only Models AT-502A and AT-502B serial number airplanes that were already manufactured. The applicability did not account for airplanes manufactured after the issuance of the AD.

AD 2002-26-05 currently requires the following on certain Air Tractor Models AT-502, AT-502A, AT-502B, and AT-503A airplanes:

—maintaining the original requirements from AD 2002-11-03 for a lowered safe life, inspection, replacement/modification, and reporting the results to FAA;

—further lowering the safe life for the wing lower spar cap established in AD 2001-11-03 for Models AT-502, AT-502B, and AT-503A airplanes; and

—expanding the applicability of Models AT-502A and AT-502B airplanes to account for future manufactured airplanes.

You must do these actions in accordance with Snow Engineering Service Letter #197 or #205, both Revised March 26, 2001, as applicable.

What has happened since AD 2002-26-05 to initiate this proposed AD action? Since we issued AD 2002-26-05, FAA has identified additional airplanes that need to be added to the applicability. We have also developed an alternative method of compliance (AMOC) to the actions of AD 2002-26-05.

What is the potential impact if FAA took no action? If not detected and corrected, fatigue cracks in the wing lower spar cap could cause the wing to separate from the airplane during flight.

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 supersede AD 2002-26-05 with a new AD that would retain the actions required in AD 2002-26-05, add additional airplanes to the applicability, and incorporate an AMOC to the actions required by AD 2002-26-05.

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 approximately 350 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 do this proposed inspection:

Labor costParts costTotal cost per airplaneTotal cost on U.S. operators
2 workhours × $65 per hour = $130No parts required for inspection$130$130 × 350 = $45,500.

We estimate the following costs to do the proposed replacement/modification:

Labor costParts costTotal cost per airplane
120 workhours × $65 per hour = $7,800.Approximately $3,700$7,800 + $3,700 = $11,500

What is the difference between the cost impact of this proposed AD and the cost impact of AD 2002-26-05? The only difference is the change in the applicability to add later-manufactured airplanes to the proposed AD. There is no difference in cost to do the actions required by this proposed AD.

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. Start Printed Page 6788

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 No. 2004-CE-48-AD” in your request.

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 Federal Aviation Administration 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. FAA amends § 39.13 by removing Airworthiness Directive (AD) 2002-26-05, Amendment 39-12991 (68 FR 18, January 2, 2003), and by adding a new AD to read as follows:

Air Tractor, Inc.: Docket No. FAA-2004-19961; Directorate Identifier 2004-CE-48-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 5, 2005.

What Other ADs Are Affected By This Action?

(b) This AD supersedes AD 2002-26-05, Amendment 39-12991.

What Airplanes Are Affected by This AD?

(b) This AD applies to certain Models AT-502, AT-502A, AT-502B, and AT-503A airplanes. Use paragraph (c)(1) of this AD for airplanes that do not incorporate and never have incorporated winglets. Use paragraph (c)(4) of this AD for certain AT-500 series airplanes that incorporate or have incorporated Marburger Enterprises, Inc. winglets.

(1) The following presents airplanes (certificated in any category) that are affected by this AD, along with the new safe life (presented in hours time-in-service (TIS)) of the wing lower spar cap for all affected airplane models and serial numbers:

ModelSerial numbersSafe Life
AT-502all serial numbers beginning with 502-00031,650 hours TIS.
AT-502Aall serial numbers beginning with 502A-01581,650 hours TIS.
AT-502B502B-0187 through 502B-0654, except 502B-06431,650 hours TIS.
AT-502B502B-0643 and all serial numbers beginning with 502B-06552,100 hours TIS.
AT-503Aall serial numbers beginning with 503A-00671,650 hours TIS.

(2) If piston powered aircraft have been converted to turbine power, you must use the limits for the corresponding serial number turbine-powered aircraft.

(3) Aircraft that have been modified to install lower spar caps, either part number 21026-1/-2, 21078-1/-2, or 21094-1/-2, should use the limits for Model AT-502B airplanes, serial number 0643 and all serial numbers beginning with 0655.

(4) The following presents airplanes (certificated in any category) that could incorporate or could have incorporated Marburger Enterprises, Inc. winglets. These winglets are installed in accordance with Supplemental Type Certificate (STC) SA00490LA. Use the winglet usage factor in the table below, the safe life specified in paragraph (a)(1) of this AD, and the instructions included in the Appendix to this AD to determine the new safe life of these airplanes:

ModelSerial numbersWinglet usage factor
AT-502502-0003 through 502-02361.6
AT-502A502A-0158 through 502A-02381.6
AT-502Aall serial numbers beginning with 502-02391.2
AT-502Ball serial numbers beginning with 502B-01871.2

What Is the Unsafe Condition Presented in This AD?

(d) The actions specified by this AD are intended to prevent fatigue cracks from occurring in the wing lower spar cap before the established safe life is reached. Fatigue cracks in the wing lower spar cap, if not detected and corrected, could result in the wing separating from the airplane during flight.

What Must I Do To Address This Problem?

(e) To address this problem, you must do the following unless you do the alternative method of compliance (AMOC) in Appendix 2 of this AD: Start Printed Page 6789

ActionsComplianceProcedures
(1) Modify the applicable aircraft records (logbook) as follows to show the reduced safe life for the wing lower spar cap (use the information from paragraphs (c)(1) and (c)(4) of this AD and Appendix 1 to this AD, as applicable): (i) Incorporate the following into the Aircraft Logbook “In accordance with AD **-**-** (or AD 2002-26-05, as applicable): the wing lower spar cap is life limited to ____.” Insert the applicable safe life number from the applicable tables in paragraphs (c)(1) and (c)(4) of this AD and Appendix 1 to this AD. (ii) If, as of the time of the logbook entry requirement of paragraph (e)(1)(i) of this AD, your airplane is over or within 50 hours of the safe life, an additional 50 hours TIS is allowed to do the replacement/modification.For airplanes previously affected by AD 2002-26-05: Do the logbook entry within the next 10 hours TIS after January 15, 2003 (the effective date of AD 2002-26-05). For airplanes not previously affected by AD 2002-26-05: Do the logbook entry within the next 10 hours TIS after effective date of this ADThe owner/operator holding at least a private pilot certificate as authorized by section 43.7 of the Federal Aviation Regulations (14 CFR 43.7) may modify the aircraft records as specified in paragraphs (e)(1)(i) and (e)(1)(ii) of this AD. Make an entry into the aircraft records showing compliance with this portion of the AD in accordance with section 43.9 of the Federal Aviation Regulations (14 CFR 43.9). Do the actual replacement/modification following the applicable Snow Engineering Service Letter #197 or #205, both revised March 26, 2001, or following the applicable sheet of Snow Engineering Modification—Wing Center- splice—502, Drawing Number 20989. The owner/operator may not do the replacement/modification, unless he/she holds the proper mechanic authorization.
(2) You may eddy-current inspect the wing lower spar cap instead of doing the replacement/modification. The inspection schedule and procedures are included in Appendix 2 to this ADInspection schedule included as part of the AMOC in Appendix 2 to this ADProcedures included as part of the AMOC in Appendix 2 to this AD.
(3) Eddy-current inspect the wing lower spar cap in order to detect any crack before it extends to the modified center section of the wing and repair any crack or replace the wing section. The inspection must be done by one of the following: (i) A Level 2 or Level 3 inspector that is certified for eddy-current inspection using the guidelines established by the American Society for Nondestructive Testing or MIL-STD-410; or (ii) A person authorized to do AD work who has completed and passed the Air Tractor, Inc. training course on Eddy Current Inspection on wing lower spar caps.Immediately before the replacement/modification required when you reach the new safe life. For airplanes that had this replacement/modification done following either AD 2001-10-04 or AD 2001-10-04 R1: do this inspection and any necessary corrective action within the next 400 hours TIS after June 14, 2002 (the effective date of AD 2002-11-03), unless already done (have the mechanic who did the work mark the logbooks accordingly)Following the applicable Snow Engineering Service Letter #197 or #205, both revised March 26, 2001, or following Snow Engineering Process Specification Number 197, revised June 4, 2002.
(4) Report to FAA any cracks detected as the result of each inspection required by paragraph (e)(3) of this AD on the form in Figure 1 of this AD. 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 et seq.) and assigned OMB Control Number 2120-0056.Send the report within 10 days after the inspection required in paragraph (e)(3) of this AD only if cracks are foundIf cracks are found, send the form (Figure 1 of this AD) to FAA, Fort Worth Airplane Certification Office, Attn: Rob Romero, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0150; telephone: (817) 222-5102; facsimile: (817) 222-5960.

Note:

Upon completion of the replacement/modification required by this AD, the safe life of the new/modified wing spar is limited to the applicable hours listed in paragraph (c)(1) of this AD. This new life limit starts at the time of the replacement/modification.

Start Printed Page 6790

May I Request a Different Alternative Method of Compliance?

(f) 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.

(1) 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 or Los Angeles Airplane Certification Office (ACO), FAA. For information on any already approved alternative methods of compliance, contact:

(2) For the airplanes that do not incorporate and never have incorporated Marburger Enterprises, Inc. winglets: Rob Romero, Aerospace Engineer, FAA, Fort Worth Airplane Certification Office, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0150; telephone: (817) 222-5102; facsimile: (817) 222-5960.

(3) For airplanes that incorporate or have incorporated Marburger Enterprises, Inc. winglets: John Cecil, Aerospace Engineer, Los Angeles Aircraft Certification Office, FAA, 3960 Paramount Boulevard, Lakewood, California 90712; telephone: (562) 627-5228; facsimile: (562) 627-5210.

(4) Alternative methods of compliance approved in accordance with AD 2002-26-05, which is superseded by this AD, are approved as alternative methods of compliance with this AD.

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

(g) To get copies of the documents referenced in this AD, contact Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374; or Marburger Enterprises, Inc., 1227 Hillcourt, Williston, North Dakota 58801. To view the AD docket, go to the Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, S.W., Nassif Building, Room PL-401, Washington, DC, or on the Internet at http://dms.dot.gov. The docket number is FAA-2004-19961.

Appendix 1 to Docket No. FAA-2004-19961 (as Retained From AD 2002-26-05)

The following provides procedures for determining the safe life for Models AT-502, AT-502A, and AT-502B airplanes that incorporate or have incorporated Marburger Enterprises, Inc. winglets. These winglets are installed in accordance with Supplemental Type Certificate (STC) SA00490LA.

What if I removed the Marburger winglets prior to further flight after the effective date of this AD or prior to the effective date of this AD?

1. Review your airplane's logbook to determine your airplane's time-in-service (TIS) with winglets installed per Marburger Enterprises STC SA00490LA. This includes all time spent with the winglets currently installed and any previous installations where the winglet was installed and later removed.

Example: A review of your airplane's logbook shows that you have accumulated 350 hours TIS since incorporating the Marburger STC. Further review of the airplane's logbook shows that a previous owner had installed the STC and later removed the winglets after accumulating 150 hours TIS. Therefore, your airplane's TIS with the winglets installed is 500 hours.

If you determine that the winglet STC has never been incorporated on your airplane, then your safe life is presented in paragraph (c)(1) of this AD. Any future winglet installation will be subject to a reduced safe life per these instructions.

2. Determine your airplane's unmodified safe life from paragraph (c)(1) of this AD.

Example: Your airplane is a Model AT-502B, serial number 0292. From paragraph (c)(1) of this AD, the safe life of your airplane is 1,650 hours TIS.

All examples from hereon will be based on the Model AT-502B, serial number 0292 airplane.

3. Determine the winglet usage factor from paragraph (c)(4) of this AD.

Example: Again, your airplane is a Model AT-502B, serial number 0292. From paragraph (c)(4) of this AD, your winglet usage factor is 1.2.

4. Adjust the winglet TIS to account for the winglet usage factor. Multiply the winglet TIS (result of Step 1 above) by the winglet usage factor (result of Step 3 above).

Example: Winglet TIS is 500 hours × a winglet usage factor of 1.2. The adjusted winglet TIS is 600 hours.

5. Calculate the winglet usage penalty. Subtract the winglet TIS (result of Step 1 above) from the adjusted winglet TIS (result of Step 4 above).

Example:

Adjusted winglet TIS−the winglet TIS = winglet usage penalty.

(600 hours)−(500 hours TIS) = (100 hours TIS).

6. Adjust the safe life of your airplane to account for winglet usage. Subtract the winglet usage penalty (result of Step 5 above) result from the unmodified safe life from paragraph (c)(1) of this AD (result of Step 2 above).

Example:

Unmodified safe life−winglet usage penalty = adjusted safe life.

(1,650 hours TIS)−(100 hours TIS) = (1,550 hours TIS).

7. If you remove the winglets from your airplane prior to further flight or no longer have the winglets installed on your airplane, the safe life of your airplane is the adjusted safe life (result of Step 6 above). Enter this number in paragraph (e)(1)(i) of this AD and the airplane logbook.

What if I have the Marburger winglet installed as of the effective date of this AD and plan to operate my airplane without removing the winglet?

1. Review your airplane's logbook to determine your airplane's TIS without the winglets installed.

Example: A review of your airplane's logbook shows that you have accumulated 1,500 hours TIS, including 500 hours with the Marburger winglets installed. Therefore, your airplane's TIS without the winglets installed is 1,000 hours.

2. Determine your airplane's unmodified safe life from paragraph (c)(1) of this AD.

Example: Your airplane is a Model AT-502B, serial number 0292. From paragraph (c)(1) of this AD, the safe life of your airplane is 1,650 hours TIS.

All examples from hereon will be based on the Model AT-502B, serial number 0292 airplane.

3. Determine the winglet usage factor from paragraph (c)(4) of this AD.

Example: Again, your airplane is a Model AT-502B, serial number 0292. From paragraph (c)(4) of this AD, your winglet usage factor is 1.2.

4. Determine the potential winglet TIS. Subtract the TIS without the winglets installed (result of Step 1 above) from the unmodified safe life (result of Step 2 above).

Example:

Unmodified safe life−TIS without winglets = Potential winglet TIS.

(1,650 hours TIS)−(1,000 hours TIS) = (650 hours TIS).

5. Adjust the potential winglet TIS to account for the winglet usage factor. Divide the potential winglet TIS (result of Step 4 above) by the winglet usage factor (result of Step 3 above).

Example:

Potential winglet TIS ÷ Winglet usage factor = Adjusted potential winglet TIS.

(650 hours TIS) ÷ (1.2) = (542 hours TIS).

6. Calculate the winglet usage penalty. Subtract the adjusted potential winglet TIS (result of Step 5 above) from the potential winglet TIS (result of Step 4 above).

Example:

Potential winglet TIS−Adjusted potential winglet TIS = Winglet usage penalty.

(650 hours TIS)−(542 hours TIS) = (108 hours TIS).

7. Adjust the safe life of your airplane to account for the winglet installation. Subtract the winglet usage penalty (result of Step 6 above) from the unmodified safe life from paragraph (c)(1) of this AD (result of Step 2 above).

Example:

Unmodified safe life − Winglet usage penalty = Adjusted safe life.

(1,650 hours TIS) − (108 hours TIS) = (1,542 hours TIS).

8. Enter the adjusted safe life (result of Step 7 above) in paragraph (e)(1)(i) of this AD and the airplane logbook.

What if I install or remove the Marburger winglet from my airplane in the future?

If, at anytime in the future, you install or remove the Marburger winglet STC from your airplane, you must repeat the procedures in this Appendix to determine the airplane's safe life.

Appendix 2—Alternative Method Of Compliance (AMOC) to Docket No. FAA-2004-19961

Optional Inspection Program

For all airplanes listed in this AD; except for Model AT-502B airplanes, serial number 0643 and all serial numbers beginning with 0655; you may begin a repetitive inspection interval program as an alternative to the safe Start Printed Page 6792life requirement of this AD with the following provisions:

1. Upon accumulating 1,600 hours time-in-service (TIS), inspect the outboard two lower spar cap bolt holes following Snow Engineering Process Specification PS 197, dated June 4, 2002.

2. Repeat these inspections at intervals of (as applicable):

a. 800 hours TIS (all serial numbers except as noted in b).

b. 600 hours TIS (serial numbers AT502B-0187 through AT502B-0618 that do not have the part number 20998-1/-2 web plate installed).

c. If the outboard two lower spar cap bolt holes have been cold worked following Snow Engineering Service Letter # 233 or #234, both dated May 18, 2004, then you may double (1,600 hours TIS or 1,200 hours TIS, as applicable) the inspection interval (See Note 1—re: mid cycle cold work).

3. If at any time a crack is found, and:

a. If the crack indication goes away by drilling the hole to the next larger size, then you may modify your center splice following Snow Engineering Drawing 20989. After modification, proceed to step 5.

b. If the crack indication does not go away, then you must replace your lower spar caps before further flight.

4. For all serial numbers, upon accumulating 4,000 hours TIS, you must modify your center splice connection following ATI drawing 20989, unless previously done. Prior to the modification perform an eddy-current inspection following PS #197 (See Note 2).

5. Upon accumulating 1,600 hours TIS after modification, inspect the outboard two lower spar cap bolt holes following Snow Engineering Process Specification PS 197.

6. Repeat the inspection at intervals of:

a. 800 hours TIS; or

b. 1,600 hours TIS if the outboard two lower spar cap bolt holes have been cold worked following Snow Engineering Service Letter #233 or #234, both dated May 18, 2004 (See Note 1).

c. If at any time a crack is found, you must replace before further flight your lower spar caps, splice blocks, and wing attach angles and hardware.

7. Upon accumulating 8,000 hours TIS, you must replace before further flight your lower spar caps, splice blocks, and wing attach angles (P/N 20693-1) and associated hardware.

Note 1:

If you decide to cold work your bolt holes following Snow Engineering Service Letter #233 or #234, both dated May 18, 2002, at a TIS that does not coincide with a scheduled inspection following this AD, then inspect at the time of cold working and then begin the 1,600/1,200 hour TIS inspection intervals.

Note 2:

If you have modified your airplane prior to accumulating 4,000 hours TIS, then you may continue to fly your airplane past modification + 4,000 hours TIS provided you cut your inspection intervals in half. Upon accumulating 8,000 hours TIS, you must comply with step 7 above. See example:

Example: An AT-502B had the two-part modification installed at 3,000 hours TIS and the bolt holes have not been cold worked. The first inspection would occur at 4,600 hours TIS, followed by inspections at 5,400, 6,200 and 7,000 hours TIS. This airplane may continue to fly if inspected again at 7,400 and 7,800 hours TIS (this is at 400 hour TIS intervals instead of 800 hours TIS intervals). Upon accumulating 8,000 hours TIS, you must modify the wing following Step 7 above.

8. If you have elected to use repetitive inspections in this AMOC instead of the safe life, you must make a logbook entry as follows:

“Following AD 2002-26-05, at XXXX {insert hours TIS} hours TIS an eddy-current inspection has been performed. As of now, the safe life listed in the AD no longer applies to this airplane. This airplane must be eddy-current inspected at intervals not to exceed {800/600/1,200/1,600 as applicable} hours TIS.”

For Model AT-502B airplanes, serial number 0643 and all serial numbers beginning with 0655, you may extend your safe life as an alternative to the safe life requirement of AD 2002-26-05, as follows:

1. Upon accumulating 2,100 hours TIS, perform an eddy-current inspection of the outboard two bolt holes of the lower spar wing center splice following PS #197, dated June 4, 2002.

2. If no cracks are found, then you may fly an additional 1,000 hours TIS.

3. You must replace the lower spar caps before further flight if cracks are found or upon accumulating the additional 1,000 hours TIS, whichever occurs first.

Start Signature

Issued in Kansas City, Missouri, on February 3, 2005.

Nancy C. Lane,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.

End Signature
End Part End Supplemental Information

BILLING CODE 4910-13-P

BILLING CODE 4910-13-CStart Printed Page 6791

[FR Doc. 05-2507 Filed 2-8-05; 8:45 am]

BILLING CODE 4910-13-P