[Federal Register Volume 79, Number 29 (Wednesday, February 12, 2014)]
[Proposed Rules]
[Pages 8350-8358]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-03024]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2014-0077; Directorate Identifier 2013-CE-021-AD]
RIN 2120-AA64


Airworthiness Directives; Air Tractor, Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to supersede Airworthiness Directive (AD) 2010-17-
18 R1, which applies to certain Air Tractor, Inc. Models AT-802 and AT-
802A airplanes. AD 2010-17-18 R1 currently requires repetitively 
inspecting (using the eddy current method) the two outboard fastener 
holes in both of the wing main spar lower caps at the center splice 
joint for cracks; repairing or replacing any cracked spar; changing the 
safe life for certain serial number ranges; and sending the inspection 
results, only if cracks are found, to the FAA. Since we issued AD 2010-
17-18 R1, we have determined that the safe life for the wing main spar 
lower caps should apply to all AT-802 and AT-802A airplanes regardless 
of configuration or operational use. This proposed AD would retain all 
actions of AD 2010-17-18 R1 and expand the applicability to include all 
serial numbers regardless of configuration or operational use. We are 
proposing this AD to correct the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by March 31, 2014.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact Air 
Tractor, Inc., P.O. Box 485, Olney, Texas 76374; telephone: (940) 564-
5616; fax: (940) 564-5612; email: [email protected]; Internet: 
www.airtractor.com. You may review copies of the referenced service 
information at the FAA, Small Airplane Directorate, 901 Locust, Kansas 
City, Missouri 64106. For information on the availability of this 
material at the FAA, call (816) 329-4148.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating it in Docket No. FAA-
2014-0077; or in person at the Docket Management Facility between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD 
docket contains this proposed AD, the regulatory evaluation, any 
comments received, and other information. The street address for the 
Docket Office (phone: (800) 647-5527) is in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Andrew McAnaul, Aerospace Engineer, 
ASW-150 (c/o MIDO-43), 10100 Reunion Place, Suite 650, San Antonio, 
Texas 78216; phone: (210) 308-3365; fax: (210) 308-3370; email: 
[email protected].

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2014-0077; 
Directorate Identifier

[[Page 8351]]

2013-CE-021-AD'' at the beginning of your comments. We specifically 
invite comments on the overall regulatory, economic, environmental, and 
energy aspects of this proposed AD. We will consider all comments 
received by the closing date and may amend this proposed AD because of 
those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    On December 16, 2010, we issued AD 2010-17-18 R1, Amendment 39-
16552 (75 FR 82219, December 30, 2010) (``AD 2010-17-18 R1''), for 
certain Air Tractor Models AT-802 and AT-802A airplanes. AD 2010-17-18 
R1 requires repetitively inspecting (using the eddy current method) the 
two outboard fastener holes in both of the wing main spar lower caps at 
the center splice joint for cracks; repairing or replacing any cracked 
spar; changing the safe life for certain serial number ranges; and 
sending the inspection results, only if cracks are found, to the FAA.
    AD 2010-17-18 R1 resulted from our evaluation of a comment from 
David Ligon, Air Tractor, and our determination that we should reduce 
the applicability from that already required by AD 2010-17-18, 
Amendment 39-16412 (75 FR 52255, August 25, 2010) (``AD 2010-17-18''), 
because the safe life limit already existed through other regulatory 
methods for airplanes equipped for agricultural dispersal beginning 
with serial number (SN) -0270.
    Therefore, the Applicability section of AD 2010-17-18 R1 was 
changed to SNs -0001 through -0269 that are certificated in any 
category and engaged in agricultural dispersal operations. AD 2010-17-
18 R1 included those airplanes that had been converted from 
firefighting to agricultural dispersal or airplanes that convert 
between firefighting and agricultural dispersal, not equipped with the 
factory-supplied computerized fire gate P/N 80540 and not engaged in 
only full-time firefighting.
    We issued AD 2010-17-18 R1 to detect and correct cracks in the wing 
main spar lower cap at the center splice joint, which could result in 
failure of the spar cap and lead to wing separation and loss of 
control.

Actions Since AD 2010-17-18 R1 Was Issued

    Since we issued AD 2010-17-18 R1, we have further determined that 
we do not have sufficient information to show what, if any, fatigue 
development and crack growth differences there are between the 
different operating environments. Airplanes without agricultural 
dispersal equipment, used in such operations as firefighting and 
patrol, all share the same wing main spar design and may develop the 
same fatigue cracks that are addressed in AD 2010-17-18 R1. Since we do 
not have information to determine that the operating environments for 
the agricultural, firefighting, and patrol airplanes affect the wing 
fatigue life differently, we consider it appropriate to treat all 
Models AT-802 and AT-802A airplanes similar regardless of how the 
airplane is configured or operated.

Relevant Service Information

    Snow Engineering Co. has not issued any new service information to 
address the issue of this proposed AD. We retain the incorporation by 
reference of all the service information incorporated into AD 2010-17-
18 R1 into this proposed AD. That service information describes 
procedures for addressing the unsafe condition.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This proposed AD would retain all requirements of AD 2010-17-18 R1 
and add airplanes to the Applicability section as previously discussed.

Costs of Compliance

    We estimate that this proposed AD affects 154 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD. 
However, the only difference in the costs presented below and the costs 
associated with AD 2010-17-18 R1 is the proposed addition of 33 
airplanes, from 121 to 154, and the corresponding costs associated with 
those 33 airplanes:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                   Labor cost          Parts cost       Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Eddy current inspection.........  $500 to $800......  Not Applicable....  $500 to $800......  $77,000 to
                                                                                               $123,200.
Spar cap replacement (two spars)  495 work-hours x    $39,100 (two        $81,175...........  $12,500,950.
                                   $85 per hour =      spars).
                                   $42,075.
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary repairs/
modifications that would be required based on the results of the 
proposed inspections. We have no way of determining the number of 
aircraft that might need these repairs/modifications:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                Action                            Labor cost                   Parts cost             product
----------------------------------------------------------------------------------------------------------------
Center splice plate installation......  185 work-hours x $85 per hour   $4,300..................         $20,025
                                         = $15,725.
Extended splice block installation....  70 work-hours x $85 per hour =  $3,200..................           9,150
                                         $5,950.
Cold-work lower spar cap fastener       16 work-hours x $85 per hour =  Not Applicable..........           1,360
 holes.                                  $1,360.
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[[Page 8352]]

Paperwork Reduction Act

    A federal agency may not conduct or sponsor, and a person is not 
required to respond to, nor shall a person be subject to penalty for 
failure to comply with a collection of information subject to the 
requirements of the Paperwork Reduction Act unless that collection of 
information displays a current valid OMB control number. The control 
number for the collection of information required by this proposed AD 
is 2120-0056. The paperwork cost associated with this proposed AD is 
detailed in the Costs of Compliance section of this document and 
includes time for reviewing instructions, as well as completing and 
reviewing the collection of information. Therefore, all reporting 
associated with this proposed AD is mandatory. Comments concerning the 
accuracy of this burden and suggestions for reducing the burden should 
be directed to the FAA at 800 Independence Ave. SW., Washington, DC 
20591, ATTN: Information Collection Clearance Officer, AES-200.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would not 
have a substantial direct effect on the States, on the relationship 
between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify that the proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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.

List of Subjects in 14 CFR Part 39

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

The Proposed Amendment

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

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by removing Airworthiness Directive (AD) 
2010-17-18 R1, Amendment 39-16552 (75 FR 82219, December 30, 2010), and 
adding the following new AD:

Air Tractor, Inc.: Docket No. FAA-2014-0077; Directorate Identifier 
2013-CE-021-AD.

(a) Comments Due Date

    The FAA must receive comments on this AD action by March 31, 
2014.

(b) Affected ADs

    This AD supersedes AD 2010-17-18 R1, Amendment 39-16552 (75 FR 
82219, December 30, 2010) (``AD 2010-17-18 R1'').

(c) Applicability

    This AD applies to Air Tractor, Inc. Models AT-802 and AT-802A 
airplanes, all serial numbers that are certificated in any category.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 57: Wings.

(e) Unsafe Condition

    This AD was prompted by our determination that there is a need 
to establish a safe life for the wing main spar lower caps on all 
airplanes regardless of configuration or operational use. We are 
issuing this AD to detect and correct cracks in the wing main spar 
lower cap at the center splice joint, which could result in failure 
of the spar cap and lead to wing separation and loss of control of 
the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified in 
paragraphs (g) through (l) of this AD, including all subparagraphs, 
unless already done (compliance with AD 2010-17-18 R1).

(g) Actions for Airplanes Serial Numbers (SNs)--0001 Through -0091

    (1) Eddy current inspect the center splice joint outboard two 
fastener holes in both the left and right wing main spar lower caps 
for cracks at the compliance times specified in paragraphs (g)(1)(i) 
or (g)(1)(ii) of this AD. Do the inspections following Snow 
Engineering Co. Process Specification 197, page 1, revised 
June 4, 2002; pages 2 through 4, dated February 23, 2001; and page 
5, dated May 3, 2002.
    (i) For airplanes previously affected by AD 2010-17-18 R1: 
Initially inspect upon reaching 1,700 hours time-in-service (TIS) or 
within the next 50 hours TIS after April 21, 2006 (the effective 
date retained from AD 2006-08-09, Amendment 39-14565 (71 FR 27794, 
May 12, 2006)), whichever occurs later. Repetitively thereafter 
inspect at intervals not to exceed 800 hours TIS unless you 
installed the center splice plate and extended 8-bolt splice blocks 
before September 9, 2010 (the effective date retained from AD 2010-
17-18, Amendment 39-16412 (75 FR 52255, August 25, 2010)) (``AD 
2010-17-18''), then repetitively inspect following the compliance 
times in table 1 of paragraph (g)(5) of this AD.
    (ii) For airplanes not previously affected by AD 2010-17-18 R1: 
Initially inspect upon reaching 1,700 hours TIS or within the next 
50 hours TIS after the effective date of this AD, whichever occurs 
later. Repetitively thereafter inspect at intervals not to exceed 
800 hours TIS unless you installed the center splice plate and 
extended 8-bolt splice blocks before the effective date of this AD, 
then repetitively inspect following the compliance times in table 2 
of paragraph (g)(5) of this AD.
    (2) If any cracks are found as a result of any inspection 
required in paragraph (g)(1) of this AD, before further flight after 
the inspection where a crack was found, do the actions specified in 
paragraphs (g)(2)(i) or (g)(2)(ii) of this AD. If you repair your 
airplane following paragraph (g)(2)(i) of this AD before the 
airplane reaches a total of 3,200 hours TIS, you must do the eddy 
current inspections following the compliance times in table 1 and 
table 2 of paragraph (g)(5) of this AD, as applicable. If you repair 
your airplane following paragraph (g)(2)(i) of this AD at 3,200 
hours TIS or after, this repair terminates the repetitive 
inspections required in this AD.
    (i) For cracks that can be removed by repair, install center 
splice plate, P/N 20997-2, and extended 8-bolt splice blocks, P/N 
20985-1/-2; cold-work the lower spar cap fastener holes; and eddy 
current inspect the center splice joint outboard two fastener holes 
in both the left and right wing main spar lower caps for cracks. 
This eddy current inspection is required as part of the modification 
and is separate from the inspections required in paragraph (g)(1) of 
this AD. Incorporating this repair modification extends the safe 
life of the wing main spar lower cap to a total of 8,000 hours TIS. 
Do the repair following Snow Engineering Co. Service Letter 
284, dated

[[Page 8353]]

October 4, 2009; Snow Engineering Co. Process Specification 
197, page 1, revised June 4, 2002; pages 2 through 4, dated 
February 23, 2001; and page 5, dated May 3, 2002; Snow Engineering 
Co. Drawing Number 20995, Sheet 2, Rev. D., dated November 25, 2005; 
and Snow Engineering Co. Service Letter 240, dated 
September 30, 2004.
    (ii) For cracks that cannot be repaired by incorporating the 
repair modification specified in paragraph (g)(2)(i) of this AD, 
replace the lower spar caps and associated parts listed following 
paragraph (g)(3) of this AD.
    (3) Replace the wing main spar lower caps, the web plates, the 
center joint splice blocks and hardware, and the wing attach angles 
and hardware, and install the steel web splice plate at whichever of 
the compliance times specified in paragraphs (g)(3)(i), (g)(3)(ii), 
or (g)(3)(iii) of this AD that occurs first. If the wing main spar 
lower cap was replaced with P/N 21118-1/-2, the new spar safe life 
is 11,700 hours TIS. If the wing main spar lower cap was replaced 
with P/N 21083-1/-2 before September 9, 2010 (the effective date 
retained from AD 2010-17-18), the safe life for that P/N spar cap is 
8,000 hours TIS until the wing main spar lower cap is replaced with 
P/N 21118-1/-2. This replacement terminates the inspections required 
in this AD. Do the replacement following Snow Engineering Co. 
Service Letter 284, dated October 4, 2009; Snow Engineering 
Co. Service Letter 80GG, revised December 21, 2005; and 
Snow Engineering Co. Drawing Number 20975, Sheet 4, Rev. A, dated 
January 7, 2009.
    (i) For all airplanes: Before further flight when cracks are 
found that cannot be repaired by incorporating the repair 
modification specified in paragraph (g)(2)(i) of this AD.
    (ii) For airplanes previously affected by AD 2010-17-18 R1: 
Before or when the airplane reaches the wing main spar lower cap 
safe life of a total of 4,100 hours TIS or within the next 50 hours 
TIS after September 9, 2010 (the effective date retained from AD 
2010-17-18), whichever occurs later.
    (iii) For airplanes not previously affected by AD 2010-17-18 R1: 
Before or when the airplane reaches the wing main spar lower cap 
safe life of a total of 4,100 hours TIS or within the next 50 hours 
TIS after the effective date of this AD, whichever occurs later.
    (4) To extend the initial 4,100-hour TIS safe life of the wing 
main spar lower cap to a total of 8,000 hours TIS, you may 
incorporate the repair modification specified in paragraph (g)(2)(i) 
of this AD between 3,200 hours TIS and 4,100 hours TIS. This 
modification terminates the repetitive inspections required in 
paragraphs (g)(1)(i) and (g)(1)(ii) of this AD, unless you do the 
modification before the airplane reaches a total of 3,200 hours TIS 
to repair cracks.
    (5) If you modified your airplane to repair cracks before the 
airplane reached a total of 3,200 hours TIS, as required in 
paragraph (g)(2)(i) of this AD, or you previously modified your wing 
to extend the safe life but did not cold work the lower spar cap 
fastener holes, you must do the eddy current inspections required in 
paragraph (g)(1) of this AD following the compliance times specified 
in table 1 or table 2 of paragraph (g)(5) of this AD, as applicable.

 Table 1 of Paragraph (g)(5)--Modified Airplanes Previously Affected by
        AD 2010-17-18 R1 Eddy Current Inspection Compliance Times
------------------------------------------------------------------------
                                                        Repetitively
                                                     thereafter inspect
  Condition of the airplane     Initially inspect    at intervals not to
                                                           exceed
------------------------------------------------------------------------
(i) If the airplane already   When the airplane     1,200 hours TIS
 has the center splice plate   reaches a total of    until the 8,000
 and extended 8-bolt splice    2,400 hours TIS       hours TIS spar
 blocks installed at or        after the             replacement time.
 after 3,200 hours TIS but     modification or
 the fastener holes have not   within the next 100
 been cold worked. You may     days after
 cold work the fastener        September 9, 2010
 holes at any time to          (the effective date
 terminate the repetitive      retained from AD
 inspection requirements of    2010-17-18),
 this paragraph.               whichever occurs
                               later.
------------------------------------------------------------------------
(ii) Before reaching 3,200    When the airplane     1,200 hours TIS.
 hours TIS, the airplane had   reaches a total of    Upon reaching 4,800
 the center splice plate and   2,400 hours TIS       hours TIS after the
 extended 8-bolt splice        after the             modification,
 blocks already installed      modification or       repetitively
 but the fastener holes have   within the next 100   thereafter inspect
 not been cold worked.         days after            at intervals not to
                               September 9, 2010     exceed 600 hours
                               (the effective date   TIS until the 8,000
                               retained from AD      hours TIS spar
                               2010-17-18),          replacement time.
                               whichever occurs
                               later.
------------------------------------------------------------------------
(iii) Before reaching 3,200   When the airplane     600 hours TIS until
 hours TIS, the airplane had   reaches a total of    the 8,000 hours TIS
 the center splice plate and   4,800 hours TIS       spar replacement
 extended 8-bolt splice        after the             time.
 blocks installed and the      modification or
 fastener holes have been      within the next 100
 cold worked.                  days after
                               September 9, 2010
                               (the effective date
                               retained from AD
                               2010-17-18),
                               whichever occurs
                               later.
------------------------------------------------------------------------


 Table 2 of Paragraph (g)(5)--Modified Airplanes Not Previously Affected
      by AD 2010-17-18 R1 Eddy Current Inspection Compliance Times
------------------------------------------------------------------------
                                                        Repetitively
                                                     thereafter inspect
  Condition of the airplane     Initially inspect    at intervals not to
                                                           exceed
------------------------------------------------------------------------
(i) If the airplane already   When the airplane     1,200 hours TIS
 has the center splice plate   reaches a total of    until the 8,000
 and extended 8[dash]bolt      2,400 hours TIS       hours TIS spar
 splice blocks installed at    after the             replacement time.
 or after 3,200 hours TIS      modification or
 but the fastener holes have   within the next 50
 not been cold worked. You     hours TIS after the
 may cold work the fastener    effective date of
 holes at any time to          this AD, whichever
 terminate the repetitive      occurs later.
 inspection requirements of
 this paragraph.
------------------------------------------------------------------------
(ii) Before reaching 3,200    When the airplane     1,200 hours TIS.
 hours TIS, the airplane had   reaches a total of    Upon reaching 4,800
 the center splice plate and   2,400 hours TIS       hours TIS after the
 extended 8-bolt splice        after the             modification,
 blocks already installed      modification or       repetitively
 but the fastener holes have   within the next 50    thereafter inspect
 not been cold worked.         hours TIS after the   at intervals not to
                               effective date of     exceed 600 hours
                               this AD, whichever    TIS until the 8,000
                               occurs later.         hours TIS spar
                                                     replacement time.
------------------------------------------------------------------------

[[Page 8354]]

 
(iii) Before reaching 3,200   When the airplane     600 hours TIS until
 hours TIS, the airplane had   reaches a total of    the 8,000 hours TIS
 the center splice plate and   4,800 hours TIS       spar replacement
 extended 8-bolt splice        after the             time.
 blocks installed and the      modification or
 fastener holes have been      within the next 50
 cold worked.                  hours TIS after the
                               effective date of
                               this AD), whichever
                               occurs later.
------------------------------------------------------------------------

    (6) If you find any cracks during any inspection required by 
paragraph (g)(5) of this AD, before further flight, replace the 
lower spar caps and the associated parts following the procedures 
identified in paragraph (g)(3) of this AD.

(h) Actions for Airplanes SNs -0092 Through -0101

    (1) Eddy current inspect the center splice joint outboard two 
fastener holes in both the left and right wing main spar lower caps 
for cracks at the compliance times specified in paragraphs (h)(1)(i) 
or (h)(1)(ii) of this AD. Do the inspections following Snow 
Engineering Co. Service Letter 284, dated October 4, 2009; 
and Snow Engineering Co. Process Specification 197, page 1, 
revised June 4, 2002; pages 2 through 4, dated February 23, 2001; 
and page 5, dated May 3, 2002.
    (i) For airplanes previously affected by AD 2010-17-18 R1: 
Initially inspect upon reaching 1,700 hours TIS or within the next 
50 hours TIS after September 9, 2010 (the effective date retained 
from AD 2010-17-18), whichever occurs later. Repetitively thereafter 
inspect at intervals not to exceed 800 hours TIS unless the center 
splice plate, P/N 20994-2, is installed, then repetitively inspect 
at intervals not to exceed 2,000 hours TIS.
    (ii) For airplanes not previously affected by AD 2010-17-18 R1: 
Initially inspect upon reaching 1,700 hours TIS or within the next 
50 hours TIS after the effective date of this AD, whichever occurs 
later. Repetitively thereafter inspect at intervals not to exceed 
800 hours TIS unless the center splice plate, P/N 20994-2, is 
installed, then repetitively inspect at intervals not to exceed 
2,000 hours TIS.
    (2) If any cracks are found as a result of any inspection 
required by paragraph (h)(1) of this AD, before further flight after 
the inspection where a crack was found, do the actions specified in 
paragraphs (h)(2)(i) or (h)(2)(ii) of this AD.
    (i) For cracks that can be removed by repair, install the 9-bolt 
splice blocks; cold-work the lower spar cap fastener holes; install 
the center splice plate, P/N 20994-2, if not already installed; and 
eddy current inspect the center splice joint outboard two fastener 
holes in both the left and right wing main spar lower caps for 
cracks. This eddy current inspection is required as part of the 
repair and is separate from the inspections required in paragraph 
(h)(1) of this AD. Incorporating this repair modification extends 
the safe life of the wing main spar lower cap to a total of 8,000 
hours TIS and terminates the repetitive inspections required in this 
AD. Do the repair following Snow Engineering Co. Service Letter 
284, dated October 4, 2009; Snow Engineering Co. Process 
Specification 197, page 1, revised June 4, 2002; pages 2 
through 4, dated February 23, 2001; and page 5, dated May 3, 2002; 
Snow Engineering Co. Service Letter 281, dated August 1, 
2009; and Snow Engineering Co. Drawing Number 20995, Sheet 3, dated 
November 25, 2005.
    (ii) For cracks that cannot be repaired by incorporating the 
repair modification specified in paragraph (h)(2)(i) of this AD, 
replace the lower spar caps and associated parts listed following 
paragraph (h)(3) of this AD.
    (3) Replace the wing main spar lower caps, the web plates, the 
center joint splice blocks and hardware, and the wing attach angles 
and hardware, and install the steel web splice plate at whichever of 
the compliance times specified in paragraphs (h)(3)(i), (h)(3)(ii), 
or (h)(3)(iii) of this AD that occurs first. If the wing main spar 
lower cap is replaced with P/N 21118-1/-2, the new spar safe life is 
11,700 hours TIS. If the wing main spar lower cap was replaced with 
P/N 21083-1/-2 before September 9, 2010 (the effective date retained 
from AD 2010-17-18), the safe life for that P/N spar cap is 8,000 
hours TIS until the wing main spar lower cap is replaced with P/N 
21118-1/-2. This replacement terminates the inspections required in 
this AD. Do the replacement following Snow Engineering Co. Service 
Letter 284, dated October 4, 2009; Snow Engineering Co. 
Service Letter 80GG, revised December 21, 2005; and Snow 
Engineering Co. Drawing Number 20975, Sheet 4, Rev. A, dated January 
7, 2009.
    (i) For all airplanes: Before further flight when cracks are 
found that cannot be repaired by incorporating the modification 
specified in paragraph (h)(2)(i) of this AD.
    (ii) For airplanes previously affected by AD 2010-17-18 R1: 
Before or when the airplane reaches the wing main spar lower cap 
safe life of a total of 4,100 hours TIS or within the next 50 hours 
TIS after September 9, 2010 (the effective date retained from AD 
2010-17-18), whichever occurs later.
    (iii) For airplanes not previously affected by AD 2010-17-18 R1: 
Before or when the airplane reaches the wing main spar lower cap 
safe life of a total of 4,100 hours TIS or within the next 50 hours 
TIS after the effective date of this AD, whichever occurs later.
    (4) To extend the initial 4,100-hour TIS safe life of the wing 
main spar lower cap to a total of 8,000 hours TIS, before the 
airplane reaches a total of 4,100 hours TIS, as long as no cracks 
are found during any inspection required in paragraph (h)(1) of this 
AD, install center splice plate, P/N 20994-2, if not already 
installed as part of a repair; cold-work the lower spar cap fastener 
holes; and eddy current inspect the center splice joint outboard two 
fastener holes in both the left and right wing main spar lower caps 
for cracks. This eddy current inspection is required as part of the 
modification and is separate from the inspections required in 
paragraph (h)(1) of this AD. After installing P/N 20994-2, eddy 
current inspect the center splice joint outboard two fastener holes 
in both the left and right wing main spar lower caps for cracks 
repetitively at intervals not to exceed 2,000 hours TIS following 
the procedures specified in paragraph (h)(1) of this AD. Do the 
modification following Snow Engineering Co. Service Letter 
284, dated October 4, 2009; Snow Engineering Co. Process 
Specification 197, page 1, revised June 4, 2002; pages 2 
through 4, dated February 23, 2001; and page 5, dated May 3, 2002; 
Snow Engineering Co. Drawing Number 20975, Sheet 4, Rev. A., dated 
January 7, 2009; and Snow Engineering Co. Service Letter 
245, dated April 25, 2005.
    (i) For airplanes previously affected by AD 2010-17-18 R1: As of 
September 9, 2010 (the effective date retained from AD 2010-17-18), 
if you have already exceeded the 4,100-hour TIS threshold for 
extending the safe life to 8,000 hours TIS, you may be eligible for 
an alternative method of compliance following paragraph (o) in this 
AD.
    (ii) For airplanes not previously affected by AD 2010-17-18 R1: 
As of the effective date of this AD, if you have already exceeded 
the 4,100-hour TIS threshold for extending the safe life to 8,000 
hours TIS, you may be eligible for an alternative method of 
compliance following paragraph (o) in this AD.
    (5) If any cracks are found as a result of the eddy current 
inspection required by paragraph (h)(4) of this AD, do the actions 
specified in paragraphs (h)(5)(i) or (h)(5)(ii) of this AD.
    (i) For cracks that can be removed by repair, install the 9-bolt 
splice blocks, cold-work the lower spar cap fastener holes, and eddy 
current inspect the center splice joint outboard two fastener holes 
in both the left and right wing main spar lower caps for cracks. 
This eddy current inspection is required as part of the modification 
and is separate from the inspections required in paragraph (h)(1) of 
this AD. Incorporating this repair modification terminates the 
repetitive inspections required in paragraph (h)(4) of this AD. Do 
the repair following Snow Engineering Co. Service Letter 
284, dated October 4, 2009; and Snow Engineering Co. 
Process Specification 197, page 1,

[[Page 8355]]

revised June 4, 2002; pages 2 through 4, dated February 23, 2001; 
and page 5, dated May 3, 2002; Snow Engineering Co. Service Letter 
281, dated August 1, 2009; and Snow Engineering Co. Drawing 
Number 20995, Sheet 3, dated November 25, 2005.
    (ii) For cracks that cannot be repaired by incorporating the 
repair modification specified in paragraph (h)(5)(i) of this AD, 
replace the lower spar caps and associated parts listed following 
paragraph (h)(3) of this AD.

(i) Actions for Airplanes, SNs -0102 through -0178

    (1) Eddy current inspect the center splice joint outboard two 
fastener holes in both the left and right wing main spar lower caps 
for cracks at the compliance times specified in table 3 or table 4 
of paragraph (i)(1) of this AD, as applicable. Do the inspections 
following Snow Engineering Co. Process Specification 197, 
page 1, revised June 4, 2002; pages 2 through 4, dated February 23, 
2001; and page 5, dated May 3, 2002; Snow Engineering Co. Service 
Letter 245 dated April 25, 2005; Snow Engineering Co. 
Service Letter 284, dated October 4, 2009.

 Table 3 of Paragraph (i)(1)--Modified Airplanes Previously Affected by
        AD 2010-17-18 R1 Eddy Current Inspection Compliance Times
------------------------------------------------------------------------
                                                        Repetitively
                                                     thereafter inspect
  Condition of the airplane     Initially inspect    at intervals not to
                                                           exceed
------------------------------------------------------------------------
(i) If the center splice      When the airplane     1,100 hours TIS
 joint outboard two fastener   reaches a total of    until the 8,000
 holes in both the left and    5,500 hours TIS or    hours TIS spar
 right wing main spar lower    within the next 50    replacement time.
 caps have not been cold       hours TIS after
 worked.                       September 9, 2010
                               (the effective date
                               retained from AD
                               2010-17-18),
                               whichever occurs
                               later.
------------------------------------------------------------------------
(ii) If the center splice     When the airplane     2,200 hours TIS
 joint outboard two fastener   reaches a total of    until the 8,000
 holes in both the left and    5,500 hours TIS or    hours TIS spar
 right wing main spar lower    within the next 50    replacement time.
 caps have been cold worked.   hours TIS after
                               September 9, 2010
                               (the effective date
                               retained from AD
                               2010-17-18),
                               whichever occurs
                               later.
------------------------------------------------------------------------


 Table 4 of Paragraph (i)(1)--Modified Airplanes Not Previously Affected
      by AD 2010-17-18 R1 Eddy Current Inspection Compliance Times
------------------------------------------------------------------------
                                                         Repetitively
                                                      thereafter inspect
    Condition of the airplane      Initially inspect   at intervals not
                                                           to exceed
------------------------------------------------------------------------
(i) If the center splice joint    When the airplane   1,100 hours TIS
 outboard two fastener holes in    reaches a total     until the 8,000
 both the left and right wing      of 5,500 hours      hours TIS spar
 main spar lower caps have not     TIS or within the   replacement time.
 been cold worked.                 next 50 hours TIS
                                   after the
                                   effective date of
                                   this AD,
                                   whichever occurs
                                   later.
(ii) If the center splice joint   When the airplane   2,200 hours TIS
 outboard two fastener holes in    reaches a total     until the 8,000
 both the left and right wing      of 5,500 hours      hours TIS spar
 main spar lower caps have been    TIS or within the   replacement time.
 cold worked.                      next 50 hours TIS
                                   after the
                                   effective date of
                                   this AD,
                                   whichever occurs
                                   later.
------------------------------------------------------------------------

    (2) If no cracks are found during the initial inspections 
required in paragraph (i)(1) of this AD, to use the longer 
repetitive inspection intervals specified in table 3 and table 4 of 
paragraph (i)(1) of this AD, as applicable, you may do the optional 
cold-working of the lower spar cap fastener holes following Snow 
Engineering Co. Service Letter 245, dated April 25, 2005.
    (3) If any cracks are found during any inspection required in 
paragraph (i)(1) of this AD, before further flight after the 
inspection where a crack is found, do the actions specified in 
paragraphs (i)(3)(i) or (i)(3)(ii) of this AD.
    (i) For cracks that can be removed by repair, install the 9-bolt 
splice blocks, cold-work the lower spar cap fastener holes, and eddy 
current inspect the center splice joint outboard two fastener holes 
in both the left and right wing main spar lower caps for cracks. 
This eddy current inspection is required as part of the repair 
modification and is separate from the inspections required in 
paragraph (i)(1) of this AD. This modification terminates the 
repetitive inspections required in this AD. Do the repair following 
Snow Engineering Co. Service Letter 281, dated August 1, 
2009; and Snow Engineering Co. Drawing Number 20995, Sheet 3, dated 
November 25, 2005.
    (ii) For cracks that cannot be repaired by doing the actions 
specified in paragraph (i)(3)(i) of this AD, replace the lower spar 
caps and associated parts listed following paragraph (i)(4) of this 
AD, including all subparagraphs.
    (4) Replace the wing main spar lower caps, the web plates, the 
center joint splice blocks and hardware, and the wing attach angles 
and hardware, and install the steel web splice plate at whichever of 
the compliance times specified in paragraphs (i)(4)(i), (i)(4)(ii), 
or (i)(4)(iii) of this AD that occurs first. This replacement 
terminates the inspections required in this AD, including all 
subparagraphs. After this replacement the new spar safe life is 
11,700 hours TIS. Do the replacement following Snow Engineering Co. 
Service Letter 284, dated October 4, 2009; Snow Engineering 
Co. Service Letter 80GG, revised December 21, 2005; Snow 
Engineering Co. Drawing Number 20975, Sheet 4, Rev. A, dated January 
7, 2009.
    (i) For all airplanes: Before further flight when cracks are 
found that cannot be repaired by doing the actions specified in 
paragraph (i)(3)(i) of this AD.
    (ii) For airplanes previously affected by AD 2010-17-18 R1: 
Before or when the airplane reaches the wing main spar lower cap 
safe life of a total of 8,000 hours TIS or within the next 50 hours 
TIS after September 9, 2010 (the effective date retained from AD 
2010-17-18), whichever occurs later.
    (iii) For airplanes not previously affected by AD 2010-17-18 R1: 
Before or when the airplane reaches the wing main spar lower cap 
safe life of a total of 8,000 hours TIS or within the next 50 hours 
TIS after the effective date of this AD, whichever occurs later.

(j) Actions for Airplanes SNs -0179 Through -0269

    Replace the wing main spar lower caps, the web plates, the 
center joint splice blocks and hardware, and the wing attach angles 
and hardware, and install the steel web splice plate at the 
compliance times specified in paragraphs (j)(1) or (j)(2) of this 
AD. Do the replacement following Snow Engineering Co. Service Letter 
284, dated October 4, 2009; Snow Engineering Co. Service 
Letter 80GG, revised December 21, 2005; and Snow 
Engineering Co. Drawing Number 20975, Sheet 4, Rev. A, dated January 
7, 2009. After

[[Page 8356]]

this replacement the new spar safe life is 11,700 hours TIS.
    (1) For airplanes previously affected by AD 2010-17-18 R1: 
Unless already done (compliance with AD 2010-17-18 R1), by the 
8,000-hour TIS safe life, or within the next 50 hours TIS after 
September 9, 2010 (the effective date retained from AD 2010-17-18), 
whichever occurs later.
    (2) For airplanes not previously affected by AD 2010-17-18 R1: 
Unless already done, by the 8,000-hour TIS safe life, or within the 
next 50 hours TIS after the effective date of this AD, whichever 
occurs later.

(k) Actions for Airplanes S/Ns -0270 and Subsequent Not Affected by AD 
2010-17-18

    (1) As of the effective date of this AD, this action establishes 
the safe life for the wing main spar to be 11,700 hours TIS.
    (2) Upon reaching the 11,700-hour TIS safe life or within the 
next 50 hours TIS after the effective date of this AD, whichever 
occurs later, replace the wing main spar lower caps, the web plates, 
the center joint splice blocks and hardware, and the wing attach 
angles and hardware, and install the steel web splice plate. After 
this replacement the subsequent new spar safe life is 11,700 hours 
TIS. Do the replacement following Snow Engineering Co. Service 
Letter 284, dated October 4, 2009; Snow Engineering Co. 
Service Letter 80GG, revised December 21, 2005; and Snow 
Engineering Co. Drawing Number 20975, Sheet 4, Rev. A, dated January 
7, 2009.

(l) Reporting Requirement for All Airplanes

    Report any crack from any inspection required in paragraphs (g) 
through (i) of this AD within 30 days after the cracks are found on 
the form in Figure 1 of this AD. Send your report to Andrew McAnaul, 
Aerospace Engineer, ASW-150 (c/o MIDO-43), 10100 Reunion Place, 
Suite 650, San Antonio, Texas 78216; phone: (210) 308-3365; fax: 
(210) 308-3370.

[[Page 8357]]

[GRAPHIC] [TIFF OMITTED] TP12FE14.000

(m) Special Flight Permit

    Special flight permits are permitted with the following 
limitations:
    (1) Only operate in day visual flight rules (VFR).
    (2) Ensure that the hopper is empty.
    (3) Limit airspeed to 135 miles per hour (mph) indicated 
airspeed (IAS).
    (4) Avoid any unnecessary g-forces.
    (5) Avoid areas of turbulence.
    (6) Plan the flight to follow the most direct route.

(n) Paperwork Reduction Act Burden Statement

    A federal agency may not conduct or sponsor, and a person is not 
required to respond to, nor shall a person be subject to a penalty 
for failure to comply with a collection of information subject to 
the

[[Page 8358]]

requirements of the Paperwork Reduction Act unless that collection 
of information displays a current valid OMB Control Number. The OMB 
Control Number for this information collection is 2120-0056. Public 
reporting for this collection of information is estimated to be 
approximately 5 minutes per response, including the time for 
reviewing instructions, completing and reviewing the collection of 
information. All responses to this collection of information are 
mandatory. Comments concerning the accuracy of this burden and 
suggestions for reducing the burden should be directed to the FAA 
at: 800 Independence Ave. SW., Washington, DC 20591, Attn: 
Information Collection Clearance Officer, AES-200.

(o) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Fort Worth Airplane Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested using 
the procedures found in 14 CFR 39.19. In accordance with 14 CFR 
39.19, send your request to your principal inspector or local Flight 
Standards District Office, as appropriate. If sending information 
directly to the manager of the ACO, send it to the attention of the 
person identified in paragraph (p) of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) AMOCs approved for AD 2010-17-18 are approved as AMOCs for 
this AD.

(p) Related Information

    (1) For more information about this AD, contact Andrew McAnaul, 
Aerospace Engineer, ASW-150 (c/o MIDO-43), 10100 Reunion Place, 
Suite 650, San Antonio, Texas 78216; phone: (210) 308-3365; fax: 
(210) 308-3370; email: [email protected].
    (2) For service information identified in this AD, contact Air 
Tractor, Inc., P.O. Box 485, Olney, Texas 76374; telephone: (940) 
564-5616; fax: (940) 564-5612; email: [email protected]; 
Internet: www.airtractor.com. You may review copies of the 
referenced service information at the FAA, Small Airplane 
Directorate, 901 Locust, Kansas City, Missouri 64106. For 
information on the availability of this material at the FAA, call 
816-329-4148.

    Issued in Kansas City, Missouri, on February 5, 2014.
Earl Lawrence,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2014-03024 Filed 2-11-14; 8:45 am]
BILLING CODE 4910-13-P