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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

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Start Preamble

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This amendment supersedes Airworthiness Directive (AD) 2002-11-03, which applies to certain Air Tractor, Inc. (Air Tractor) Models AT-502, AT-502A, AT-502B, and AT-503A airplanes. AD 2002-11-03 lowered the safe life for the wing lower spar cap and further reduced the safe life for airplanes that incorporate or have incorporated Marburger Enterprises, Inc. winglets. AD 2002-11-03 also currently 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). Field inspections on the affected airplanes have revealed wings with cracks below the currently established safe life. This AD would further reduce the safe life of the Models AT502, AT-502B, and AT-503A airplanes and would add airplanes recently manufactured to the Applicability of the AD. 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.

DATES:

This AD becomes effective on January 15, 2003.

The Director of the Federal Register previously approved the incorporation by reference of certain publications listed in the regulation as of June 8, 2001 (66 FR 27014, May 16, 2001).

The FAA must receive any comments on this rule on or before February 14, 2003.

ADDRESSES:

Submit comments to FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2002-CE-54-AD, 901 Locust, Room 506, Kansas City, Missouri 64106. You may view any comments at this location between 8 a.m. and 4 p.m., Monday through Friday, except Federal holidays. You may also send comments electronically to the following address: 9-ACE-7-Docket@faa.gov. Comments sent electronically must contain “Docket No. 2002-CE-54-AD” in the subject line. If you send comments electronically as attached electronic files, the files must be formatted in Microsoft Word 97 for Windows or ASCII text.

You may get the service information referenced in this AD from 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. You may view this information at FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2002-CE-54-AD, 901 Locust, Room 506, Kansas City, Missouri 64106; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

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:

Discussion

Has FAA taken any action to this point? On December 17, 2001, FAA issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to certain Air Tractor, Inc. (Air Tractor) AT-400, AT-500, and AT-800 series airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on December 27, 2001 (66 FR 66823). The NPRM proposed to supersede AD 2001-10-04 R1 with a new AD that would retain the safe life for the wing lower spar cap and require 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. The NPRM also proposed to further reduce the safe life for those AT-400 and AT-500 series airplanes that incorporate or have incorporated Marburger Enterprises, Inc. winglets.

After issuing that NPRM, we received 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. This caused us to issue AD 2002-11-03, Amendment 39-12764 (67 FR 38371, June 4, 2002). AD 2002-11-03 lowers 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 reduces the safe life for airplanes that incorporate or have incorporated Marburger Enterprises, Inc. winglets.

We issued a separate AD for the Air Tractor AT-400 and AT-800 series airplanes.

What has happened since AD 2002-11-03 to initiate This action? Field inspections have revealed wings with cracks below the currently established safe life on Air Tractor Models AT 502, AT-502B, and AT-503A airplanes.

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

The FAA's Determination and an Explanation of the Provisions of This AD

What has FAA decided? The FAA has reviewed all available information and determined that:

—The unsafe condition referenced in this document exists or could develop on other Air Tractor Models AT-502, AT-502A, AT-502B, and AT-503A airplanes of the same type design;

—The safe life on the Models AT-502, AT-502B, and AT-503A airplanes should be further reduced;

—The serial number range of the Models AT-502A and AT-502B airplanes should be expanded to Start Printed Page 19include future manufactured airplanes; and

—Final rule; request for comments (immediately adopted rule) AD action should be taken to address this condition.

What does this AD require? This AD will supersede AD 2002-11-03 and will:

—Maintain the requirements of a lowered safe life, inspection, replacement/modification, and reporting the results to FAA;

—Further lower the safe life for the wing lower spar cap established in AD 2002-11-03 for the Models AT-502, AT-502B, and AT-503A airplanes; and

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

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

In preparation of this rule, we contacted type clubs and aircraft operators to obtain technical information and information on operational and economic impacts. We did not receive any information through these contacts. If received, we would have included, in the rulemaking docket, a discussion of any information that may have influenced this action.

Will I have the opportunity to comment prior to the issuance of the rule? Because the unsafe condition described in this document could result in the wing separating from the airplane during flight, we find that notice and opportunity for public prior comment are impracticable. Therefore, good cause exists for making this amendment effective in less than 30 days.

Comments Invited

How do I comment on this AD? Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, FAA invites your comments on the rule. You may submit whatever written data, views, or arguments you choose. You need to include the rule's docket number and submit your comments to the address specified under the caption ADDRESSES. We will consider all comments received on or before the closing date specified above. We may amend this rule in light of comments received. Factual information that supports your ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether we need to take additional rulemaking action.

Are there any specific portions of the AD I should pay attention to? We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. You may view all comments we receive before and after the closing date of the rule in the Rules Docket. We will file a report in the Rules Docket that summarizes each FAA contact with the public that concerns the substantive parts of this AD.

How can I be sure FAA receives my comment? If you want us to acknowledge the receipt of your comments, you must include a self-addressed, stamped postcard. On the postcard, write “Comments to Docket No. 2002-CE-54-AD.” We will date stamp and mail the postcard back to you.

Regulatory Impact

Does this AD impact various entities? These regulations 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. Therefore, FAA has determined that this final rule does not have federalism implications under Executive Order 13132.

Does this AD involve a significant rule or regulatory action? We have determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a significant regulatory action under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket (otherwise, an evaluation is not required). A copy of it, if filed, may be obtained from the Rules Docket.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

Adoption of the Amendment

Start Amendment Part

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (

End Amendment Part Start Part

PART 39—AIRWORTHINESS DIRECTIVES

End Part Start Amendment Part

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

End Amendment Part Start Authority

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

End Authority
[Amended]
Start Amendment Part

2. FAA amends § 39.13 by removing Airworthiness Directive (AD) 2002-11-03, Amendment 39-12764 (

End Amendment Part

2002-26-05 Air Tractor, Inc.: Amendment 39-12991; Docket No. 2002-CE-54-AD. Supersedes AD 2002-11-03, Amendment 39-12764.

(a) What airplanes are affected by this AD? This AD applies to certain Models AT-502, AT-502A, AT-502B, and AT-503A airplanes. Use paragraph (a)(1) of this AD for airplanes that do not incorporate and never have incorporated winglets. Use paragraph (a)(3) 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 Nos.Safe life
AT-5020003 through 02361,650 hours TIS
AT-502AAll serial numbers beginning with 01581,650 hours TIS
AT-502BAll serial numbers beginning with 01871,650 hours TIS
AT-503AAll serial numbers beginning with 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.Start Printed Page 20

(3) 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 Nos.Winglet usage factor
AT-5020003 through 02361.6
AT-502A0158 through 02381.6
AT-502AAll serial numbers beginning with 02391.2
AT-502BAll serial numbers beginning with 01871.2

(b) Who must comply with this AD? Anyone who wishes to operate any of the airplanes identified in paragraph (a) of this AD must comply with this AD.

(c) What problem does this AD address? 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.

(d) What must I do to address this problem? To address this problem, you must accomplish the following actions:

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 (a)(1) and (a)(3) of this AD and the Appendix to this AD, as applicable): (i) Incorporate the following into the Aircraft Logbook “In accordance with AD 2002-26-05, the wing lower spar cap is life limited to _.” Insert the applicable safe life number from the applicable tables in paragraphs (a)(1) and (a)(3) of this AD and the Appendix to this AD. (ii) If, as of the time of the logbook entry requirement of paragraph (d)(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 accomplish the replacement/modification.Accomplish the logbook entry within the next 10 hours TIS after January 15, 2003 (the effective date of this AD)The 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 (d)(1)(i) and (d)(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). Accomplish the actual replacement/modification in accordance with Snow Engineering Service Letter #197 or #205, both Revised March 26, 2001, as applicable. The owner/operator may not accomplish the replacement/modification, unless he/she holds the proper mechanic authorization.
(2) You may eddy-current inspect the wing lower spar cap instead of accomplishing the replacement/modification provided you have ordered parts from the factory and scheduled a replacement/modification date when it is time to replace the wing lower spar cap (as required when you reach the established safe life). These inspections are allowed until one of the following occurs, at which time the replacement/modification must be accomplished: (i) Crack(s) is/are found; or (ii) Not more than three inspections or 1,200 hours TIS go by: the first inspection would have to be accomplished upon accumulating the safe life; the second inspection would have to be accomplished within 400 hours TIS after accumulating the safe life; the third inspection would have to be accomplished 400 hours TIS after the second inspection; and the replacement/modification would have to be accomplished within 400 hours TIS after the third inspection (maximum elapsed time would be 1,200 hours TIS).Inspect prior to further flight after ordering the parts and scheduling a replacement/modification date, and inspect thereafter at intervals not to exceed 400 hours TIS until one of the criteria in paragraphs (d)(2)(i) and (d)(2)(ii) of this AD is metIn accordance with the procedures in Snow Engineering Service Letter #197 or #205, both Revised March 26, 2001, as applicable.
Start Printed Page 21
(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 accomplished 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 perform AD work who has completed and passed the Air Tractor, Inc. training course on Eddy Current Inspection on wing lower spar caps.Immediately prior to the replacement/modification required when you reach the new safe life. For airplanes that had this replacement/modification accomplished in accordance with either AD 2001-10-04 or AD 2001-10-04 R1, accomplish 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 accomplished (have the mechanic who accomplished the work mark the logbooks accordingly)In accordance with the procedures in Snow Engineering Service Letter #197 or #205, both Revised March 26, 2001, as applicable.
(4) Report to FAA the results of each inspection required by paragraph (d)(3) 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 2120-0056Within 10 days after the inspection required in paragraph (d)(3) of this AD or within 10 days after June 14, 2002 (the effective date of AD 2002-11-03), whichever occurs laterSubmit the form (Figure 1 of this AD) to FAA, Fort Worth Airplane Certification Office, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0150; telephone: (817) 222-5102; facsimile: (817) 222-5960.

Note 1:

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 (a)(1) of this AD. This new life limit starts at the time of the replacement/modification.

AD 2002-26-05 Inspection Report

1. Inspection Performed By:2. Phone:
3. Aircraft Model4. Aircraft Serial Number:
5. Engine Model Number:6. Aircraft Total TIS:
7. Wing Total TIS:8. Lower Spar Cap TIS:
9. Has the lower spar cap been inspected before? (Eddy-current, Dye penetrant, magnetic particle, ultrasound)   ☐Yes     ☐No9a. If yes, Date: __________ Inspection Method: __________ Lower Spar Cap TIS: __________ Cracks found?  ☐     ☐No
10. Has there been any major repair or alteration performed to the spar cap?   ☐Yes     ☐No10a. If yes, specify (Description and TIS)
11. Date of AD inspection: ______________________________
12. Inspection Results: Note: Indicate even if no cracks are found.12a.   ☐Left Hand     ☐Right Hand
12b.   Crack Length: _______________12c. Does drilling hole to next larger size remove all traces of the crack(s)?   ☐Yes     ☐No
12d. Corrective Action Taken:
Figure 1 of paragraph (d)(4) of this AD

(e) Can I comply with this AD in any other way?

(1)You may use an alternative method of compliance or adjust the compliance time if:

(i) Your alternative method of compliance provides an equivalent level of safety; and

(ii) The Manager, Fort Worth or Los Angeles Airplane Certification Office (ACO), as applicable, approves your alternative. Submit your request through an FAA Principal Maintenance Inspector. The inspector may add comments before sending it to the Manager, Fort Worth or Los Angeles ACO.

(2) Alternative methods of compliance approved for AD 2001-10-04 and/or AD 2000-14-51 are not considered approved for this AD.

(3) Alternative methods of compliance approved for AD 2001-10-04 R1 or AD 2002-11-03 are considered approved for this AD.

Note 2:

This AD applies to each airplane identified in paragraphs (a)(1) and (a)(3) of this AD, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For Start Printed Page 22airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (e) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if you have not eliminated the unsafe condition, specific actions you propose to address it.

(f) Who can I contact with questions about this AD? For more information about the subject matter specified in this AD, contact:

(i) 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

(ii) For the airplanes that incorporate or have incorporated 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.

(g) What if I need to fly the airplane to another location to comply with this AD? The FAA can issue a special flight permit under §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate your airplane to a location where you can accomplish the requirements of this AD provided that the following is adhered to:

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

(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.

(h) Are any service bulletins incorporated into this AD by reference? Replacement and inspection actions required by this AD must be done in accordance with Snow Engineering Service Letter #197 or #205, both Revised March 26, 2001, as applicable. The Director of the Federal Register previously approved this incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 51, as of June 8, 2001 (66 FR 27014, May 16, 2001). You can get copies from Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374; or Marburger Enterprises, Inc., 1227 Hillcourt, Williston, North Dakota 58801. You may view copies at FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

(i) When does this amendment become effective? This amendment becomes effective on January 15, 2003.

Start Appendix

Appendix to 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 (a)(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 (a)(1) of this AD.

Example:

Your airplane is a Model AT-502B, serial number 0292. From paragraph (a)(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 (a)(3) of this AD.

Example:

Again, your airplane is a Model AT-502B, serial number 0292. From paragraph (a)(3) 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 X 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 (a)(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 (d)(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 (a)(1) of this AD.

Example:

Your airplane is a Model AT-502B, serial number 0292. From paragraph (a)(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 (a)(3) of this AD.

Example:

Again, your airplane is a Model AT-502B, serial number 0292. From paragraph (a)(3) 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 divided by 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 (a)(1) of this AD (result of Step 2 above).

Example:

Unmodified safe life—Winglet usage penalty = Adjusted safe life. Start Printed Page 23

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

8. Enter the adjusted safe life (result of Step 7 above) in paragraph (d)(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.

End Appendix Start Signature

Issued in Kansas City, Missouri, on December 20, 2002.

Michael Gallagher,

Manager, Small Airplane Directorate, Aircraft Certification Service.

End Signature End Supplemental Information

[FR Doc. 02-32684 Filed 12-31-02; 8:45 am]

BILLING CODE 4910-13-U