[Federal Register Volume 67, Number 107 (Tuesday, June 4, 2002)]
[Rules and Regulations]
[Pages 38371-38379]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-13423]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-CE-10-AD; Amendment 39-12764; AD 2002-11-03]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to certain Air Tractor, Inc. (Air Tractor) Models AT-502, AT-
502A, AT-502B, and AT-503A airplanes. This AD lowers the safe life for 
the wing lower spar cap established in AD 2001-10-04 R1 and further 
reduces the safe life for airplanes that incorporate or have 
incorporated Marburger Enterprises, Inc. winglets. This AD 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). This AD is the result of 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, AT-502B, and 
AT-503A airplanes at times lower than the established safe life. 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 June 14, 2002.
    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 July 5, 
2002.

ADDRESSES: Submit comments to FAA, Central Region, Office of the 
Regional Counsel, Attention: Rules Docket No. 2002-CE-10-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

[[Page 38372]]

through Friday, except Federal holidays. You may also send comments 
electronically to the following address: [email protected]. 
Comments sent electronically must contain ``Docket No. 2002-CE-10-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-10-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.

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.

SUPPLEMENTARY INFORMATION:

Discussion

What Events Have Caused This AD?

    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.
    Since issuance of 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, AT-502B, and AT-503A airplanes at 
hours time-in-service (TIS) lower than the established safe life.

What Are the Consequences if the Condition Is Not Corrected?

    This condition could result in fatigue cracks 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.

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 these airplanes should be further reduced;
--These airplanes should be removed from the previous NPRM; 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:

--Lowers the safe life for the wing lower spar cap established in AD 
2001-10-04 R1;
--Further reduces the safe life for the Models AT-502, AT-502A, AT-
502B, and AT-503A airplanes that incorporate or have incorporated 
Marburger Enterprises, Inc. winglets;
--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
--Requires you to report the results of this inspection to the FAA.

    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 have included, in the rulemaking 
docket, a discussion of 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-10-AD.'' We will date stamp and mail 
the postcard back to you.

[[Page 38373]]

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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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

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


Sec. 39.13  [Amended]

    2. FAA amends Sec. 39.13 by adding a new airworthiness directive 
(AD) to read as follows:

2002-11-03  Air Tractor, Inc.: Amendment 39-12764; Docket No. 2002-
CE-10-AD.

    (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:

----------------------------------------------------------------------------------------------------------------
                  Model                               Serial Nos.                          Safe life
----------------------------------------------------------------------------------------------------------------
AT-502...................................  0003 through 0236................  2,050 hours TIS.
AT-502A..................................  0158 through 0618................  1,650 hours TIS.
AT-502B..................................  0187 through 0618................  2,050 hours TIS.
AT-503A..................................  All serial numbers beginning with  2,050 hours TIS
                                            0067.
----------------------------------------------------------------------------------------------------------------

    (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) 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:

----------------------------------------------------------------------------------------------------------------
                  Model                               Serial Nos.                   Winglet  usage  factor
----------------------------------------------------------------------------------------------------------------
AT-502...................................  0003 through 0236................  1.6
AT-502A..................................  0158 through 0238................  1.6
AT-502A..................................  0239 through 0618................  1.2
AT-502B..................................  0187 through 0618................  1.2
----------------------------------------------------------------------------------------------------------------

    (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:

[[Page 38374]]



----------------------------------------------------------------------------------------------------------------
                   Actions                                Compliance                        Procedures
----------------------------------------------------------------------------------------------------------------
(1) Modify the applicable *COM001*aircraft     Accomplish the logbook entry      The owner/operator holding at
 records (logbook) as follows to show the       within the next 10 hours TIS      least a private pilot
 reduced safe life for the wing lower spar      after June 14, 2002 (the          certificate as authorized by
 cap (use the information from the table in     effective date of this AD).       section 43.7 of the Federal
 paragraph (a)(1) of this AD and utilize the                                      Aviation Regulations (14 CFR
 information in paragraph (a)(3) of this AD                                       43.7) may modify the aircraft
 and the Appendix to this AD, as applicable):                                     records as specified in
(i) Incorporate the following into the                                            paragraphs (d)(1)(i) and
 Aircraft Logbook ``In accordance with AD                                         (d)(1)(ii) of this AD. Make an
 2002-11-03, the wing lower spar cap is life                                      entry into the aircraft
 limited to ----.'' Insert the applicable                                         records showing compliance
 safe life number from the applicable tables                                      with this portion of AD in
 in paragraphs (a)(1) and (a)(3) of this AD                                       accordance with section 43.9
 and the Appendix to this AD)                                                     of the Federal Aviation
(ii) If, as of the time of the logbook entry                                      Regulations (14 CFR 43.9).
 requirement of paragraph (d)(1)(i) of this                                       Accomplish the actual
 AD, your airplane modification is over or                                        replacement/modification in
 within 50 hours of the safe life, an                                             accordance with Snow
 additional 50 hours TIS is allowed to                                            Engineering Service Letter
 accomplish the replacement/modification                                          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.
----------------------------------------------------------------------------------------------------------------

[[Page 38375]]

 
(2) If you have ordered parts from the         Inspect prior to further flight   In accordance with the
 factory when it is time to replace the wing    after ordering the parts and      procedures in Snow Engineering
 lower spar cap (as required when you reach     thereafter at intervals not to    Service Letter 197 or
 the established safe life), but the parts      exceed 400 hours TIS until one    205, both Revised
 are not available, you may eddy-current        of the criteria in paragraphs     March 26, 2001, as applicable.
 inspect the wing lower spar cap. These         (d)(2)(i), (d)(2)(ii), and
 inspections are allowed until one of the       (d)(2)(iii) of this AD is met.
 following occurs, at which time the
 replacement/modification must be
 accomplished:
(i) Crack(s) is/are found;
(ii) Parts become available from the
 manufacturer; or
(iii) 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)
----------------------------------------------------------------------------------------------------------------
(3) Eddy-current inspect the wing lower spar   Immediately prior to the          In accordance with the
 cap in order to detect any crack before it     replacement/modification          procedures in Snow Engineering
 extends to the modified center section of      required when you reach the new   Service Letter 197 or
 the wing and repair that crack or replace      safe life. For airplanes that     205, both Revised
 the wing section. The inspection must be       had this replacement/             March 26, 2001, as applicable.
 accomplished by one of the following:          modification accomplished in
(i) a Level 2 or Level 3 inspector that is      accordance with either AD 2001-
 certified for eddy-current inspection using    10-04 or AD 2001-10-04 R1,
 the guidelines established by the American     accomplish this inspection and
 Society for Nondestructive Testing or MIL-     any necessary corrective action
 STD-410; or                                    within the next 400 hours TIS
(ii) A person authorized to perform AD work     after June 14, 2002 (the
 who has completed and passed the Air           effective date of this AD),
 Tractor, Inc. training course on Eddy          unless already accomplished
 Current Inspection on wing lower spar caps     (have the mechanic who
                                                accomplished the work mark the
                                                logbooks accordingly).

[[Page 38376]]

 
(4) Report to FAA the results of each          Within 10 days after the          Submit the form (Figure 1 of
 inspection required by paragraph (d)(3) of     inspection required in            this AD) to FAA, Fort Worth
 this AD. The Office of Management and Budget   paragraph (d)(3) of this AD or    Airplane Certification Office,
 (OMB) approved the information collection      within 10 days after June 14,     2601 Meacham Boulevard, Fort
 requirements contained in this regulation      2002 (the effective date of       Worth, Texas 76193-0150;
 under the provisions of the Paperwork          this AD, whichever occurs later.  telephone: (817) 222-5102;
 Reduction Act of 1980 (44 U.S.C. 3501 et                                         facsimile: (817) 222-5960.
 seq.) and assigned OMB Control Number 2120-
 0056
----------------------------------------------------------------------------------------------------------------

BILLING CODE 4910-13-P

[[Page 38377]]

[GRAPHIC] [TIFF OMITTED] TR04JN02.000

BILLING CODE 4910-13-C
    (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 are considered approved for this AD.

    Note: 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 airplanes that have been modified, 
altered, or repaired so that the performance of the

[[Page 38378]]

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) Are there any alternative methods of compliance already 
approved or being considered for this AD? The FAA may approve, as an 
alternative method of compliance, inspection of the wing lower spar 
cap. You must submit the request in accordance with the procedures 
in paragraph (e) of this AD and adhere to the following:
    (1) If you are over or within 50 hours TIS of the safe life for 
the wing lower spar cap and you have ordered parts and scheduled a 
date for the replacement/modification, but having the replacement/
modification done on this date grounds the airplane, accomplish the 
following:
    (i) inspect the wing lower spar cap within 50 hours TIS after 
approval of the alternative method of compliance;
    (ii) reinspect thereafter at intervals not to exceed 400 hours 
TIS until either cracks are found, the date of the scheduled 
replacement/modification occurs, or 1,200 hours TIS after the 
initial inspection are accumulated, whichever occurs first; and
    (iii) accomplish the inspections in accordance with the 
procedures in Snow Engineering Service Letter 197 or 
205, both Revised March 26, 2001, as applicable.
    (2) Submit the following to the Fort Worth or Los Angeles ACO, 
as applicable, using the procedures described in paragraph (e) of 
this AD:
    (i) the airplane model serial number designation, and airplane 
registration number (N-number);
    (ii) the number of hours TIS on the airplane;
    (iii) the scheduled date for the replacement/modification; and
    (iv) the name and location of the authorized repair shop.
    (3) For more information about this issue, 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 
sections 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 June 14, 2002.

APPENDIX TO AD 2002-11-03

    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 
2,050 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:   
    [GRAPHIC] [TIFF OMITTED] TR04JN02.001
    

    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:   
    [GRAPHIC] [TIFF OMITTED] TR04JN02.002
    


[[Page 38379]]


    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 
2,050 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:
    [GRAPHIC] [TIFF OMITTED] TR04JN02.003
    
    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:   
    [GRAPHIC] [TIFF OMITTED] TR04JN02.004
    
    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:
    [GRAPHIC] [TIFF OMITTED] TR04JN02.005
    
    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:
    [GRAPHIC] [TIFF OMITTED] TR04JN02.006
    
    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.

    Issued in Kansas City, Missouri, on May 22, 2002.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 02-13423 Filed 6-3-02; 8:45 am]
BILLING CODE 4910-13-P