[Federal Register Volume 70, Number 26 (Wednesday, February 9, 2005)]
[Proposed Rules]
[Pages 6786-6792]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-2507]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19961; Directorate Identifier 2004-CE-48-AD]
RIN 2120-AA64


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

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.

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:

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.

[[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:

----------------------------------------------------------------------------------------------------------------
                                                        Total cost per
           Labor cost                  Parts cost          airplane           Total cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
2 workhours x $65 per hour =      No parts required              $130   $130 x 350 = $45,500.
 $130.                             for inspection.
----------------------------------------------------------------------------------------------------------------

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

----------------------------------------------------------------------------------------------------------------
              Labor cost                         Parts cost                     Total cost per airplane
----------------------------------------------------------------------------------------------------------------
120 workhours x $65 per hour =         Approximately $3,700.........  $7,800 + $3,700 = $11,500
 $7,800..
----------------------------------------------------------------------------------------------------------------

    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.

[[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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

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

PART 39--AIRWORTHINESS DIRECTIVES

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

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


Sec.  39.13  [Amended]

    2. FAA amends Sec.  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:

----------------------------------------------------------------------------------------------------------------
                 Model                            Serial numbers                          Safe Life
----------------------------------------------------------------------------------------------------------------
AT-502................................  all serial numbers beginning with   1,650 hours TIS.
                                         502-0003.
AT-502A...............................  all serial numbers beginning with   1,650 hours TIS.
                                         502A-0158.
AT-502B...............................  502B-0187 through 502B-0654,        1,650 hours TIS.
                                         except 502B-0643.
AT-502B...............................  502B-0643 and all serial numbers    2,100 hours TIS.
                                         beginning with 502B-0655.
AT-503A...............................  all serial numbers beginning with   1,650 hours TIS.
                                         503A-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) 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:

------------------------------------------------------------------------
                                                                Winglet
              Model                      Serial numbers          usage
                                                                 factor
------------------------------------------------------------------------
AT-502..........................  502-0003 through 502-0236..        1.6
AT-502A.........................  502A-0158 through 502A-0238        1.6
AT-502A.........................  all serial numbers                 1.2
                                   beginning with 502-0239.
AT-502B.........................  all serial numbers                 1.2
                                   beginning with 502B-0187.
------------------------------------------------------------------------

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:

[[Page 6789]]



------------------------------------------------------------------------
           Actions                 Compliance            Procedures
------------------------------------------------------------------------
(1) Modify the applicable     For airplanes         The owner/operator
 aircraft records (logbook)    previously affected   holding at least a
 as follows to show the        by AD 2002-26-05:     private pilot
 reduced safe life for the     Do the logbook        certificate as
 wing lower spar cap (use      entry within the      authorized by
 the information from          next 10 hours TIS     section 43.7 of the
 paragraphs (c)(1) and         after January 15,     Federal Aviation
 (c)(4) of this AD and         2003 (the effective   Regulations (14 CFR
 Appendix 1 to this AD, as     date of AD 2002-26-   43.7) may modify
 applicable):                  05). For airplanes    the aircraft
(i) Incorporate the            not previously        records as
 following into the Aircraft   affected by AD 2002-  specified in
 Logbook ``In accordance       26-05: Do the         paragraphs
 with AD **-**-** (or AD       logbook entry         (e)(1)(i) and
 2002-26-05, as applicable):   within the next 10    (e)(1)(ii) of this
 the wing lower spar cap is    hours TIS after       AD. Make an entry
 life limited to --------.''   effective date of     into the aircraft
 Insert the applicable safe    this AD.              records showing
 life number from the                                compliance with
 applicable tables in                                this portion of the
 paragraphs (c)(1) and                               AD in accordance
 (c)(4) of this AD and                               with section 43.9
 Appendix 1 to this AD..                             of the Federal
(ii) If, as of the time of                           Aviation
 the logbook entry                                   Regulations (14 CFR
 requirement of paragraph                            43.9). Do the
 (e)(1)(i) of this AD, your                          actual replacement/
 airplane is over or within                          modification
 50 hours of the safe life,                          following the
 an additional 50 hours TIS                          applicable Snow
 is allowed to do the                                Engineering Service
 replacement/modification..                          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      Inspection schedule   Procedures included
 inspect the wing lower spar   included as part of   as part of the AMOC
 cap instead of doing the      the AMOC in           in Appendix 2 to
 replacement/modification.     Appendix 2 to this    this AD.
 The inspection schedule and   AD.
 procedures are included in
 Appendix 2 to this AD.
-----------------------------
(3) Eddy-current inspect the  Immediately before    Following the
 wing lower spar cap in        the replacement/      applicable Snow
 order to detect any crack     modification          Engineering Service
 before it extends to the      required when you     Letter 197
 modified center section of    reach the new safe    or 205,
 the wing and repair any       life. For airplanes   both revised March
 crack or replace the wing     that had this         26, 2001, or
 section. The inspection       replacement/          following Snow
 must be done by one of the    modification done     Engineering Process
 following:                    following either AD   Specification
(i) A Level 2 or Level 3       2001-10-04 or AD      Number 197, revised
 inspector that is certified   2001-10-04 R1: do     June 4, 2002.
 for eddy-current inspection   this inspection and
 using the guidelines          any necessary
 established by the American   corrective action
 Society for Nondestructive    within the next 400
 Testing or MIL-STD-410; or.   hours TIS after
(ii) A person authorized to    June 14, 2002 (the
 do AD work who has            effective date of
 completed and passed the      AD 2002-11-03),
 Air Tractor, Inc. training    unless already done
 course on Eddy Current        (have the mechanic
 Inspection on wing lower      who did the work
 spar caps..                   mark the logbooks
                               accordingly).
-----------------------------
(4) Report to FAA any cracks  Send the report       If cracks are found,
 detected as the result of     within 10 days        send the form
 each inspection required by   after the             (Figure 1 of this
 paragraph (e)(3) of this AD   inspection required   AD) to FAA, Fort
 on the form in Figure 1 of    in paragraph (e)(3)   Worth Airplane
 this AD. The Office of        of this AD only if    Certification
 Management and Budget (OMB)   cracks are found.     Office, Attn: Rob
 approved the information                            Romero, 2601
 collection requirements                             Meacham Boulevard,
 contained in this                                   Fort Worth, Texas
 regulation under the                                76193-0150;
 provisions of the Paperwork                         telephone: (817)
 Reduction Act of 1980 (44                           222-5102;
 U.S.C. 3501 et seq.) and                            facsimile: (817)
 assigned OMB Control Number                         222-5960.
 2120-0056.
------------------------------------------------------------------------


    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.


BILLING CODE 4910-13-P

[[Page 6790]]

[GRAPHIC] [TIFF OMITTED] TP09FE05.013

BILLING CODE 4910-13-C

[[Page 6791]]

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 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 (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

[[Page 6792]]

life 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{time}  
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{time}  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.

    Issued in Kansas City, Missouri, on February 3, 2005.
Nancy C. Lane,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.

[FR Doc. 05-2507 Filed 2-8-05; 8:45 am]
BILLING CODE 4910-13-P