Document ID: FAA-2014-0077-0004
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Air Tractor, Inc. Airplanes
Posted Date: 2014-08-25T04:00Z

[Federal Register Volume 79, Number 164 (Monday, August 25, 2014)]
[Rules and Regulations]
[Pages 50542-50549]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-20098]

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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; 
Amendment 39-17941; AD 2014-16-17]
RIN 2120-AA64

Airworthiness Directives; Air Tractor, Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are superseding 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 required 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. This new AD retains all actions of AD 
2010-17-18 R1 and expands the applicability to include all serial 
numbers regardless of configuration or operational use. This AD was 
prompted by our determination that the safe life for the wing main spar 
lower caps should apply to all Models AT-802 and AT-802A airplanes 
regardless of configuration or operational use. We are issuing this AD 
to correct the unsafe condition on these products.

DATES: This AD is effective September 29, 2014.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of September 9, 
2010 (75 FR 52255, August 25, 2010).
    The Director of the Federal Register approved the incorporation by 
reference of certain other publications listed in this AD as of April 
21, 2006 (71 FR 19994, April 19, 2006).

ADDRESSES: 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: airmail@airtractor.com; 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 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 AD, the regulatory evaluation, any comments received, and 
other information. The address for the Docket Office (phone: 800-647-
5527) is Document Management Facility, U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.

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

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to supersede AD 2010-17-18 R1, Amendment 39-16552 (75 FR 82219, 
December 30, 2010) (``AD 2010-17-18 R1''), for certain Air Tractor, 
Inc. Models AT-802 and AT-802A airplanes. The NPRM published in the 
Federal Register on February 12, 2014 (79 FR 8350). The NPRM was 
prompted by our determination that the safe life for the wing main spar 
lower caps should apply to all Models AT-802 and AT-802A airplanes 
regardless of configuration or operational use. The NPRM proposed to 
continue to require 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. The NPRM also proposed to expand the applicability 
to include all serial numbers regardless of configuration or 
operational use. We are issuing this AD to correct the unsafe condition 
on these products.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comment received on the NPRM (79 FR 
8350, February 12, 2014) and the FAA's response to that comment.

Request To Withdraw Proposed Rulemaking

    David Ligon of Air Tractor, Inc. requested the FAA to withdraw the 
proposed AD.
    David Ligon stated that he (Air Tractor, Inc.) believes the FAA 
does not have relevant information or objective evidence to establish 
that an unsafe condition is likely to exist or develop in Models AT-802 
and AT-802A air tanker (fire-fighting) airplanes. Air Tractor, Inc. 
stated that the safe life of the wing on the land-based Models AT-802 
and AT-802A air tanker airplanes far exceeds that of their agricultural 
application counterparts and will continue to work to establish an 
appropriate wing safe life.
    Included with the comment from Air Tractor, Inc. were two graphs 
showing firebomber and agricultural airplane exceedance curves from a 
single Model AT-802 air tanker airplane, their validated Model AT-802 
agricultural application airplane spectrum, and one set of generic air 
tanker and agricultural application exceedance curves from Report No. 
DOT/FAA/AR-05/035, Consolidation and Analysis of Loading Data in 
Firefighting Operations: Analysis of Existing Data and Definition of 
Preliminary Air Tanker and Lead Aircraft Spectra, which can be found on 
the Internet at http://www.tc.faa.gov/its/worldpac/techrpt/ar05-35.pdf, 
and FAA Advisory Circular 23-13A, which can be found on the internet at 
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/CCAE8A15127D66408625708C00710BA4?OpenDocument&Highlight=23-13a, 
respectively.
    Air Tractor, Inc. does not disagree 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. Air Tractor, 
Inc. also stated that they are concerned that issuing this AD will 
result in unneeded additional cost to the industry that could possibly 
hinder the establishment of an appropriate wing safe life in the 
future.
    We do not agree with the commenter. The wing main spar centerline 
joint is a design detail that has demonstrated in-

[[Page 50543]]

service fatigue cracking on Models AT-802 and AT-802A agricultural 
application airplanes. We have determined that this design detail shows 
a demonstrated risk that fatigue cracking is expected to also occur on 
the same type design airplanes used for other purposes such as fire-
fighting and patrolling. The guidance for addressing known safety risk 
through a fatigue management program that includes establishing 
appropriate inspection, modification, and/or life limits is outlined in 
the appendices of FAA Advisory Circular 91-82A, which can be found on 
the Internet at http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/A07DDCB245AD6B43862578F8006F82E9?OpenDocument&Highlight=91-82a. These 
aspects are currently addressed for the agricultural application Models 
AT-802 and AT-802A airplanes in AD 2010-17-18 R1. We believe it is 
appropriate to expand the applicability of AD 2010-17-18 R1 to include 
all Models AT-802 and AT-802A airplanes used in other operational roles 
since they have the same type design detail and share the same 
demonstrated risk.
    We have not received validated data from Air Tractor, Inc. that 
provides inspection intervals, modification times, or safe life limits 
for the Models AT-802 and AT-802A airplanes wing main spar for 
operational usages other than for agricultural application. The 
exceedance data provided by Air Tractor, Inc. does not provide those 
inspection intervals, modification times, or life limit replacement 
times. Report No. DOT/FAA/AR-05/035, which can be found on the Internet 
at http://www.tc.faa.gov/its/worldpac/techrpt/ar05-35.pdf, includes 
exceedance data for air tanker (fire-fighting) airplanes of various 
weights. The data shows a trend of increasing severity in the flight 
spectrum as airplane size and gross weight decrease. In Report No. DOT/
FAA/AR-05/035, the exceedance data does not include airplanes having a 
gross weight as low as Models AT-802 and AT-802A airplanes; therefore, 
the exceedance data may not be representative of the lighter gross 
weight AT-802/802A air tanker airplane fleet. Additionally, limited 
exceedance curves we received earlier from Air Tractor, Inc. include 
data for one land-based and two float-equipped Model AT-802 air tanker 
airplanes. The two float-equipped airplane's exceedance curves closely 
match the severity of the validated Model AT-802 airplane agricultural 
application exceedance curves. We question why the two float-equipped 
airplanes have a more severe spectrum than the single land-based Model 
AT-802 air tanker airplane. We would expect the float-equipped 
airplanes to be less maneuverable, and therefore less severely flown 
than their land-based counterpart.
    We agree with the need to establish life limits for the Models AT-
802 and AT-802A air tanker fleet, as well as those used in other 
operations such as patrolling. Further, we evaluated the information 
presented by Air Tractor and determined it is appropriate to apply the 
same inspections, modification, and safe life limitations addressed in 
the current AD to Models AT-802 and AT-802A airplanes engaged in other 
operational roles. We arrived at this decision based on (1) the time in 
service those fleets have now accumulated, and (2) because they have 
the same wing main spar design feature as the agricultural applications 
airplanes and share the same demonstrated safety risk.. We remain open 
to working with Air Tractor, Inc. to obtain data that reflects an 
adequate pilot mix and operational conditions, that appropriately 
differentiates Models AT-802 and AT-802A airplane wing main spar 
inspection and modification times, and includes a safe life based on 
operational usage.
    We are not changing the final rule AD action based on this comment.

Conclusion

    We reviewed the relevant data, considered the comment received, and 
determined that air safety and the public interest require adopting 
this AD as proposed except for minor editorial changes. We have 
determined that these minor changes:
     Are consistent with the intent that was proposed in the 
NPRM (79 FR 8350, February 12, 2014) for correcting the unsafe 
condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM (79 FR 8350, February 12, 2014).

Costs of Compliance

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

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
               Action                      Labor cost              Parts cost                 Cost per product               Cost on U.S.  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 $85    $39,100 (two spars)...  $81,175..........................  $12,500,950.
                                      per hour = $42,075.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary repairs/
modifications that will be required based on the results of the 
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     $4,300...........................         $20,025
                                       per hour = $15,725.
Extended splice block installation..  70 work-hours x $85 per  3,200............................           9,150
                                       hour = $5,950.
Cold-work lower spar cap fastener     16 work-hours x $85 per  Not Applicable...................           1,360
 holes.                                hour = $1,360.
----------------------------------------------------------------------------------------------------------------

[[Page 50544]]

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 AD is 2120-
0056. The paperwork cost associated with this AD has been 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 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 AD will not have federalism 
implications under Executive Order 13132. This AD 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.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under 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.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 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:

2014-16-17 Air Tractor, Inc.: Amendment 39-17941; Docket No. FAA-
2014-0077; Directorate Identifier 2013-CE-021-AD.

(a) Effective Date

    This AD is effective September 29, 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 19994, 
April 19, 2006; corrected 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 paragraphs (g)(5)(i) 
through (g)(5)(iii) 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 September 29, 2014 (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 
September 29, 2014 (the effective date of this AD), then 
repetitively inspect following the compliance times in paragraphs 
(g)(6)(i) through (g)(6)(iii) 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 paragraphs 
(g)(5) and (g)(6) 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 October 4, 2009; Snow Engineering Co.

[[Page 50545]]

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 is 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 September 29, 2014 (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) For airplanes previously affected by AD 2010-17-18 R1: 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 paragraphs (g)(5)(i) through (g)(5)(iii) of this AD, as 
applicable.
    (i) If the airplane already had the center splice plate and 
extended 8-bolt splice blocks installed at or after 3,200 hours TIS 
but the fastener holes have not been cold worked, you may cold work 
the fastener holes at any time to terminate the repetitive 
inspection requirements of this paragraph. Initially inspect when 
the airplane reaches a total of 2,400 hours TIS after the 
modification or within the next 100 days after September 9, 2010 
(the effective date retained from AD 2010-17-18), whichever occurs 
later. Repetitively thereafter inspect at intervals not to exceed 
1,200 hours TIS until the 8,000 hours TIS spar replacement time.
    (ii) If the airplane already had the center splice plate and 
extended 8-bolt splice blocks already installed before reaching 
3,200 hours TIS but the fastener holes have not been cold worked, 
initially inspect when the airplane reaches a total of 2,400 hours 
TIS after the modification or within the next 100 days after 
September 9, 2010 (the effective date retained from AD 2010-17-18), 
whichever occurs later. Repetitively thereafter inspect at intervals 
not to exceed 1,200 hours TIS. Upon reaching 4,800 hours TIS after 
the modification, repetitively thereafter inspect at intervals not 
to exceed 600 hours TIS until the 8,000 hours TIS spar replacement 
time.
    (iii) If the airplane had the center splice plate and extended 
8-bolt splice blocks installed before reaching 3,200 hours TIS and 
the fastener holes have been cold worked, initially inspect when the 
airplane reaches a total of 4,800 hours TIS after the modification 
or within the next 100 days after September 9, 2010 (the effective 
date retained from AD 2010-17-18), whichever occurs later. 
Repetitively thereafter inspect at intervals not to exceed 600 hours 
TIS until the 8,000 hours TIS spar replacement time.
    (6) For airplanes not previously affected by AD 2010-17-18 R1: 
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, and your, you must do the eddy current inspections required 
in paragraph (g)(1) of this AD following the compliance times 
specified in paragraphs (g)(6)(i) through (g)(6)(iii) of this AD, as 
applicable.
    (i) If the airplane already had the center splice plate and 
extended 8-bolt splice blocks installed at or after 3,200 hours TIS 
but the fastener holes have not been cold worked, you may cold work 
the fastener holes at any time to terminate the repetitive 
inspection requirements of this paragraph. Initially inspect when 
the airplane reaches a total of 2,400 hours TIS after the 
modification or within the next 50 hours TIS after September 29, 
2014 (the effective date of this AD), whichever occurs later. 
Repetitively thereafter inspect at intervals not to exceed 1,200 
hours TIS until the 8,000 hours TIS spar replacement time.
    (ii) If the airplane had the center splice plate and extended 8-
bolt splice blocks already installed before reaching 3,200 hours TIS 
but the fastener holes have not been cold worked, initially inspect 
when the airplane reaches a total of 2,400 hours TIS after the 
modification or within the next 50 hours TIS after September 29, 
2014 (the effective date of this AD), whichever occurs later. 
Repetitively thereafter inspect at intervals not to exceed 1,200 
hours TIS. Upon reaching 4,800 hours TIS after the modification, 
repetitively thereafter inspect at intervals not to exceed 600 hours 
TIS until the 8,000 hours TIS spar replacement time.
    (iii) If the airplane had the center splice plate and extended 
8-bolt splice blocks installed before reaching 3,200 hours TIS and 
the fastener holes have been cold worked, initially inspect when the 
airplane reaches a total of 4,800 hours TIS after the modification 
or within the next 50 hours TIS after September 29, 2014 (the 
effective date of this AD), whichever occurs later. Repetitively 
thereafter inspect at intervals not to exceed 600 hours TIS until 
the 8,000 hours TIS spar replacement time.
    (7) If you find any cracks during any inspection required by 
paragraphs (g)(5) and (g)(6) 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 September 29, 2014 (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,

[[Page 50546]]

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 September 29, 2014 (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 September 29, 2014 (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, 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) For airplanes previously affected by AD 2010-17-18 R1: 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 (i)(1)(i) and 
(i)(1)(ii) 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.
    (i) If the center splice joint outboard two fastener holes in 
both the left and right wing main spar lower caps have not been cold 
worked, initially inspect when the airplane reaches a total of 5,500 
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 
1,100 hours TIS until the 8,000 hours TIS spar replacement time.
    (ii) If the center splice joint outboard two fastener holes in 
both the left and right wing main spar lower caps have been cold 
worked, initially inspect when the airplane reaches a total of 5,500 
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 
2,200 hours TIS until the 8,000 hours TIS spar replacement time.
    (2) For airplanes not previously affected by AD 2010-17-18 R1: 
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 (i)(2)(i) and 
(i)(2)(ii) 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.
    (i) If the center splice joint outboard two fastener holes in 
both the left and right wing main spar lower caps have not been cold 
worked, initially inspect when the airplane reaches a total of 5,500 
hours TIS or within the next 50 hours TIS after September 29, 2014 
(the effective date of this AD), whichever occurs later. 
Repetitively thereafter inspect at intervals not to exceed 1,100 
hours TIS until the 8,000 hours TIS spar replacement time.
    (ii) If the center splice joint outboard two fastener holes in 
both the left and right wing main spar lower caps have been cold 
worked initially inspect when the airplane reaches a total of 5,500 
hours TIS or within the next 50 hours TIS after September 29, 2014 
(the effective date of this AD), whichever occurs later. 
Repetitively thereafter inspect at intervals not to exceed 2,200 
hours TIS until the 8,000 hours TIS spar replacement time.
    (3) If no cracks are found during the initial inspections 
required in paragraphs (i)(1)(i)

[[Page 50547]]

and (i)(2)(i) of this AD, to use the longer repetitive inspection 
intervals specified in paragraphs (i)(1)(ii) and (i)(2)(ii) 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.
    (4) If any cracks are found during any inspection required in 
paragraphs (i)(1) and (i)(2) of this AD, before further flight after 
the inspection where a crack is found, do the actions specified in 
paragraphs (i)(4)(i) or (i)(4)(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 
paragraphs (i)(1) and (i)(2) 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)(4)(i) of this AD, replace the lower spar 
caps and associated parts listed following paragraph (i)(5) of this 
AD, including all subparagraphs.
    (5) 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)(5)(i), (i)(5)(ii), 
or (i)(5)(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)(4)(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 September 29, 2014 (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 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 September 29, 2014 (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 R1

    (1) As of September 29, 2014 (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 September 29, 2014 (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 any crack is found using 
the form in Figure 1 of this AD. Send your report to Andrew McAnaul, 
Aerospace Engineer, ASW-150 (c/o San Antonio MIDO), 10100 Reunion 
Place, Suite 650, San Antonio, Texas 78216; phone: (210) 308-3365; 
fax: (210) 308-3370.
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[[Page 50548]]

[GRAPHIC] [TIFF OMITTED] TR25AU14.003

BILLING CODE 4910-13-C

(m) Special Flight Permit

    Special flight permits are permitted in accordance with 14 CFR 
39.23 provided the following limitations are adhered to:
    (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 50549]]

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 R1 are approved as AMOCs 
for this AD.

(p) Related Information

    For more information about this AD, contact Andrew McAnaul, 
Aerospace Engineer, ASW-150 (c/o San Antonio MIDO), 10100 Reunion 
Place, Suite 650, San Antonio, Texas 78216; phone: (210) 308-3365; 
fax: (210) 308-3370; email: andrew.mcanaul@faa.gov.

(q) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (3) The following service information was approved for IBR on 
September 9, 2010 (75 FR 52255, August 25, 2010).
    (i) Snow Engineering Co. Service Letter 80GG, dated 
December 21, 2005.
    (ii) Snow Engineering Co. Service Letter 284, dated 
October 4, 2009.
    (iii) Snow Engineering Co. Service Letter 281, dated 
August 1, 2009.
    (iv) Snow Engineering Co. Service Letter 245, dated 
April 25, 2005.
    (v) Snow Engineering Co. Drawing Number 20995, Sheet 2, Rev. D., 
dated November 25, 2005.
    (vi) Snow Engineering Co. Drawing Number 20995, Sheet 3, dated 
November 25, 2005.
    (vii) Snow Engineering Co. Drawing Number 20975, Sheet 4, Rev. 
A., dated January 7, 2009
    (4) The following service information was approved for IBR on 
April 21, 2006 (71 FR 19994, April 19, 2006).
    (i) 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.
    (ii) Snow Engineering Co. Service Letter 240, dated 
September 30, 2004.
    (5) For Air Tractor, Inc. 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: 
airmail@airtractor.com; Internet: www.airtractor.com.
    (6) You may view this service information at 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.
    (7) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Kansas City, Missouri, on August 7, 2014.
Earl Lawrence,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2014-20098 Filed 8-22-14; 8:45 am]
BILLING CODE 4910-13-C