[Federal Register Volume 70, Number 119 (Wednesday, June 22, 2005)]
[Rules and Regulations]
[Pages 36005-36008]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-12177]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19837; Directorate Identifier 2004-CE-43-AD; 
Amendment 39-14149; AD 2005-13-12]
RIN 2120-AA64


Airworthiness Directives; Air Tractor, Inc. Models AT-300, AT-
301, AT-302, AT-400, AT-400A, AT-401, AT-402, AT-602, AT-802, and AT-
802A Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: The FAA adopts a new airworthiness directive (AD) for certain 
Air Tractor, Inc. (Air Tractor) Models AT-300, AT-301, AT-302, AT-400, 
AT-400A, AT-401, AT-402, AT-602, AT-802, and AT-802A airplanes. This AD 
requires you to repetitively tighten the four eyebolts that attach the 
front and rear spar of the horizontal stabilizer to the respective 
stabilizer strut to the specified torque, and repetitively replace at 
specified intervals any eyebolts that attach the front and rear spar of 
the horizontal stabilizer to the respective stabilizer strut. An option 
for replacing the steel brace assembly inside the stabilizer with a new 
steel brace assembly with larger bushings and stronger eyebolts that 
increases the interval for replacement of eyebolts for AT-602, AT-802, 
and AT-802A airplanes is also included in this AD. This AD results from 
reports of failures of the subject eyebolt. We are issuing this AD to 
detect, correct, and prevent future fatigue failure in any eyebolt that 
attaches the front and rear spar of the horizontal stabilizer to the 
respective stabilizer strut. Failure of the eyebolt could lead to an 
abrupt change or complete loss of pitch control and/or the airplane 
departing from controlled flight.

DATES: This AD becomes effective on August 5, 2005.
    As of August 5, 2005, the Director of the Federal Register approved 
the incorporation by reference of certain publications listed in the 
regulation.

ADDRESSES: To get the service information identified in this AD, 
contact Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374.
    To view the AD docket, go to the Docket Management Facility; U.S. 
Department of Transportation, 400 Seventh Street, SW., Nassif Building, 
Room PL-401, Washington, DC 20590-001 or on the Internet at http://dms.dot.gov. The docket number is FAA-2004-19837; Directorate 
Identifier 2004-CE-43-AD.

FOR FURTHER INFORMATION CONTACT: Andrew D. McAnaul, Aerospace Engineer, 
FAA, Fort Worth Airplane Certification Office (ACO), ASW-150, 2601 
Meacham Boulevard, Fort Worth, Texas 76193-0150. Current duty station: 
San Antonio Manufacturing Inspection District Office (MIDO-43), 10100 
Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: (210) 
308-3365; facsimile: (210) 308-3370.

SUPPLEMENTARY INFORMATION:

Discussion

    What events have caused this AD? In December 1985, Snow Engineering 
Co. issued Service Letter 62 to recommend the inspection of 
eyebolts. This was in response to several reports of eyebolt failures 
on Models AT-301 and AT-400 airplanes.
    In response to another failure of an eyebolt on an AT-400 airplane, 
Snow Engineering Co. issued Service Letter 129 in September 
1994. This service letter recommended eyebolt replacement every 2,000 
hours time-in-service (TIS) for Models AT-301 and AT-400 airplanes. 
After a report of an eyebolt failure on a Model AT-602 airplane, Snow 
Engineering Co. revised Service Letter 129 in November 2003 to 
recommend replacing eyebolts for Models AT-602, AT-802, and AT-802A 
airplanes every 1,350 hours TIS.
    In December 2003, FAA issued Special Airworthiness Information 
Bulletin (SAIB) CE-04-23. This SAIB recommended periodic eyebolt 
replacement following Snow Engineering Co. Service Letter 129.
    In April 2004, we received a report of both eyebolts that attach 
the left hand stabilizer failing in flight on a Model AT-602 airplane. 
These eyebolts had accumulated 1,675 hours TIS.
    Engineering analysis concludes that the eyebolts failed as a result 
of high-cycle, low-nominal stress. This is most likely due to the loss 
of torque during service.
    Air Tractor has since redesigned the horizontal stabilizer 
structure for Models AT-802 and AT-602 airplanes to accommodate a new, 
stronger eyebolt.
    Snow Engineering Co. also revised Service Letter 129 with 
new eyebolt replacement intervals and issued Service Letter 
129A to include procedures for optional replacement of the 
steel brace assembly inside the stabilizer with a new steel brace 
assembly with larger bushings to accommodate new stronger eyebolts on

[[Page 36006]]

existing Models AT-602, AT-802, and AT-802A airplanes. This 
modification provides for increased safety and extends eyebolt 
replacement intervals.
    What is the potential impact if FAA took no action? Failure of an 
eyebolt could lead to an abrupt change or complete loss of pitch 
control and/or aircraft departure from controlled flight.
    Has FAA taken any action to this point? We issued a proposal to 
amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to 
include an AD that would apply to certain Air Tractor, Inc. (Air 
Tractor) Models AT-300, AT-301, AT-302, AT-400, AT-400A, AT-401, AT-
402, AT-602, AT-802, and AT-802A airplanes. This proposal was published 
in the Federal Register as a notice of proposed rulemaking (NPRM) on 
March 4, 2005 (70 FR 10513). The NPRM proposed to require you to 
repetitively tighten the four eyebolts that attach the front and rear 
spar of the horizontal stabilizer to the respective stabilizer strut to 
the specified torque, and repetitively replace at specified intervals 
any eyebolts that attach the front and rear spar of the horizontal 
stabilizer to the respective stabilizer strut. An option for replacing 
the steel brace assembly inside the stabilizer with a new steel brace 
assembly with larger bushings and stronger eyebolts that increases the 
interval for replacement of eyebolts for AT-602, AT-802, and AT-802A 
airplanes was also included in this proposed AD.

Comments

    Was the public invited to comment? We provided the public the 
opportunity to participate in developing this AD. The following 
presents the comments received on the proposal and FAA's response to 
each comment:

Comment Issue No. 1: Correct the Date for Service Letter 129 
in Discussion

    What is the commenter's concern? One commenter writes that the 
original date of Snow Engineering Co. Service Letter 129 is 
September 1994 (not September 1995) and requests use of the correct 
date in the Discussion section.
    What is FAA's response to the concern? We concur. We will correct 
all reference in the final rule of the service letter to read, ``Snow 
Engineering Co. issued Service Letter 129 in September 1994.''

Comment Issue No. 2: Cases of Cracks in Model AT-802 Airplane Eyebolts

    What is the commenter's concern? Mr. Leland Snow, Air Tractor, 
Inc., writes that the Discussion section of the NPRM is incorrect in 
reporting, ``The FAA also received two service difficulty reports 
(SDRs) in November 2003. Both SDRs referenced Model AT-802 airplane 
eyebolt cracks.'' Also, Mr. Snow notes that Air Tractor inspected 
eyebolts that were reported to be cracked and found that the eyebolts 
were not cracked but instead had a groove caused by washer edge 
contact.
    What is FAA's response to the concern? The FAA is not able to 
verify with certainty that the eyebolts that Air Tractor inspected are 
the same or not as those eyebolts identified in the two SDRs. However, 
both the eyebolts Air Tractor inspected and the eyebolts reported to 
FAA were from the same sources, making Air Tractor's claim a strong 
possibility.
    We have deleted the reference to the two SDRs from the Discussion 
section of the final rule.

Comment Issue No. 3: Initial and Repetitive Tightening of the Eyebolts

    What is the commenter's concern? Mr. Leland Snow, Air Tractor, 
requests that the compliance times for initial and repetitive 
tightening of the eyebolts follow the times required in Snow 
Engineering Service Letter 129, initial inspection and 
tightening of the eyebolts within 100 hours TIS, and repetitively 
tighten the eyebolts every 12 calendar months thereafter.
    What is FAA's response to the concern? We agree to add the 
requirement to initially inspect within 100 hours TIS after the 
effective date of the AD. However, we will retain the initial 12 
calendar months requirement with whichever occurs first as the 
prevalent time. We agree the repetitive inspections should remain every 
12 calendar months thereafter.

Conclusion

    What is FAA's final determination on this issue? We have carefully 
reviewed the available data and determined that air safety and the 
public interest require adopting the AD as proposed except for the 
changes discussed above and minor editorial corrections. We have 
determined that these changes and minor corrections:

--Are consistent with the intent that was proposed in the NPRM for 
correcting the unsafe condition; and
--Do not add any additional burden upon the public than was already 
proposed in the NPRM.

Changes to 14 CFR Part 39--Effect on the AD

    How does the revision to 14 CFR part 39 affect this AD? On July 10, 
2002, the FAA published a new version of 14 CFR part 39 (67 FR 47997, 
July 22, 2002), which governs the FAA's AD system. This regulation now 
includes material that relates to altered products, special flight 
permits, and alternative methods of compliance. This material 
previously was included in each individual AD. Since this material is 
included in 14 CFR part 39, we will not include it in future AD 
actions.

Costs of Compliance

    How many airplanes does this AD impact? We estimate that this AD 
affects 1,011 airplanes in the U.S. registry.
    What is the cost impact of this AD on owners/operators of the 
affected airplanes? We estimate the following costs to do the 
tightening of the four eyebolt nuts to the specified torque:

----------------------------------------------------------------------------------------------------------------
                                                            Total cost per
             Labor cost                    Parts cost          airplane         Total cost on  U.S. operators
----------------------------------------------------------------------------------------------------------------
1 workhour x $65 per hour = $65....  No parts required....             $65  $65 x 1,011= $65,715
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary replacement of 
the four eyebolts for the Models AT-300, AT-301, AT-302, AT-400, AT-
400A, AT-401, AT-402 AT-602, AT-802, and AT-802A airplanes:

----------------------------------------------------------------------------------------------------------------
                                                    Average total
        Average labor cost          Average parts     cost per         Average total cost on  U.S. operators
                                        cost          airplane
----------------------------------------------------------------------------------------------------------------
1 workhour x $65 per hour = $65..         $186.30         $251.30  1,011 x $251.30 = $254,064.30
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[[Page 36007]]

    We estimate the following costs to do any necessary replacement of 
the steel brace assembly inside the stabilizer with a new steel brace 
assembly with larger bushings on existing Models AT-602, AT-802, and 
AT-802A airplanes:

----------------------------------------------------------------------------------------------------------------
                                                    Average total
        Average labor cost          Average parts     cost per         Average total cost on  U.S. operators
                                        cost          airplane
----------------------------------------------------------------------------------------------------------------
22 workhours x $65 per hour =             $901.65       $2,331.65  312 x $2,331.65 = $727,474.80
 $1,430.
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

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

Regulatory Findings

    Will this AD impact various entities? 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.
    Will this AD involve a significant rule or regulatory action? 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 the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979); and
    3. Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a summary of the costs to comply with this AD (and 
other information as included in the Regulatory Evaluation) and placed 
it in the AD Docket. You may get a copy of this summary by sending a 
request to us at the address listed under ADDRESSES. Include ``Docket 
No. FAA-2004-19837; Directorate Identifier 2004-CE-43-AD'' in your 
request.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration amends part 39 of the Federal 
Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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. FAA amends Sec.  39.13 by adding a new AD to read as follows:

2005-13-12 Air Tractor, Inc.: Amendment 39-14149; Docket No. FAA-
2004-19837; Directorate Identifier 2004-CE-43-AD.

When Does This AD Become Effective?

    (a) This AD becomes effective on August 5, 2005.

What Other ADs Are Affected by This Action?

    (b) None.

What Airplanes Are Affected by This AD?

    (c) This AD affects the following airplane models and serial 
numbers that are certificated in any category:

------------------------------------------------------------------------
              Models                             Serial Nos.
------------------------------------------------------------------------
AT-300, AT-301, AT-302, AT-400,     All serial numbers.
 and AT-400A.
AT-401/AT-402.....................  All through 401-0700.
AT-602............................  All through 602-0695 that have any 7/
                                     16-inch eyebolt (part number (P/N)
                                     AN47-22A) installed; all beginning
                                     with 602-0703; and all that have
                                     any 9/16-inch eyebolt (P/N 30774-1)
                                     installed.
AT-802 and AT-802A................  All through 802A-0188 that have any
                                     7/16-inch eyebolt (P/N AN47-30A)
                                     installed; all beginning with 802A-
                                     0189; and all that have any 9/16-
                                     inch eyebolt (P/N 30775-1)
                                     installed.
------------------------------------------------------------------------

What Is the Unsafe Condition Presented in This AD?

    (d) This AD is the result of reports of failures of the subject 
eyebolt. The actions specified in this AD are intended to detect, 
correct, and prevent future fatigue failure in any eyebolt that 
attaches the front and rear spar of the horizontal stabilizer to the 
respective stabilizer strut. Failure of the eyebolt could lead to an 
abrupt change or complete loss of pitch control and/or the airplane 
departing from controlled flight.

What Must I Do To Address This Problem?

    (e) To address this problem, you must do the following:

------------------------------------------------------------------------
           Actions                 Compliance            Procedures
------------------------------------------------------------------------
(1) Tighten the four          Within the next 100   Follow Snow
 eyebolts that attach the      hours time-in-        Engineering Co.
 front and rear spar of the    service (TIS) or 12   Service Letter
 horizontal stabilizer to      calendar months       129,
 the respective stabilizer     after August 5,       Issued September
 strut using the torque        2005 (the effective   26, 1994, Revised
 values referenced in Snow     date of this AD),     October 21, 2004.
 Engineering Co. Service       whichever occurs
 Letter 129,          first, unless
 revised October 21, 2004.     already done.
                               Repetitively
                               tighten thereafter
                               at every 12
                               calendar months
                               after the date of
                               the initial
                               tightening to the
                               specified torque.
-----------------------------

[[Page 36008]]

 
(2) Repetitively replace any  Initially replace     Follow Snow
 eyebolts that attach the      upon accumulating     Engineering Co.
 front and rear spar of the    the applicable        Service Letter
 horizontal stabilizer to      number of hours TIS   129,
 the respective stabilizer     referenced in Snow    Issued September
 strut.                        Engineering Co.       26, 1994, Revised
                               Service Letter        October 21, 2004.
                               129,
                               revised October 21,
                               2004, or within 50
                               hours TIS after
                               August 5, 2005 (the
                               effective date of
                               this AD), whichever
                               occurs later.
                               Replace
                               repetitively
                               thereafter at the
                               intervals
                               referenced in Snow
                               Engineering Co.
                               Service Letter
                               129,
                               revised October 21,
                               2004.
-----------------------------
(3) For Model AT-602          At any time after     Follow Snow
 airplanes through serial      August 5, 2005 (the   Engineering Co.
 number 602-0695 and AT-802,   effective of this     Service Letter
 and 802A airplanes through    AD). Use the          129A,
 serial number 802A-0188: As   applicable time in    Dated August 7,
 an alternative in order to    Snow Engineering      2004.
 use the increased             Co. Service Letter
 replacement compliance        129A,
 times in paragraph (e)(2)     dated August 7,
 of this AD, you may replace   2004. The
 the steel brace assembly      repetitive
 inside the stabilizer with    replacement of
 a new steel brace assembly    paragraph (e)(2) of
 with larger bushings, and     this AD is still
(i) For the Model AT-602       required.
 airplane: replace any 7/16-
 inch eyebolt with the 9/16-
 inch eyebolt (P/N 30774-1)
(ii) For the Model AT-802
 and AT-802A airplanes:
 replace any 7/16-inch
 eyebolt with the 9/16-inch
 eyebolt (P/N 30775-1)
-----------------------------
(4) Do not install any 5/16-  As of August 5, 2005  Not Applicable.
 inch eyebolt (P/N AN44-17A    (the effective date
 or AN44-21A), 7/16-inch       of this AD).
 eyebolt (AN47-22A or AN47-
 30A), or 9/16-inch eyebolt
 (P/N 30774-1 or 30775-1)
 that exceeds the
 corresponding cumulative
 hours TIS specified in
 paragraphs (e)(2) or (e)(3)
 of this AD.
------------------------------------------------------------------------

May I Request an Alternative Method of Compliance?

    (f) You may request a different method of compliance or a 
different compliance time for this AD by following the procedures in 
14 CFR 39.19. Unless FAA authorizes otherwise, send your request to 
your principal inspector. The principal inspector may add comments 
and will send your request to the Manager, Fort Worth Airplane 
Certification Office (ACO), FAA. For information on any already 
approved alternative methods of compliance, contact Andrew D. 
McAnaul, Aerospace Engineer, FAA, Fort Worth ACO, ASW-150, 2601 
Meacham Boulevard, Fort Worth, Texas 76193-0150. Current duty 
station: San Antonio Manufacturing Inspection District Office (MIDO-
43), 10100 Reunion Place, Suite 650, San Antonio, Texas 78216; 
telephone: (210) 308-3365; facsimile: (210) 308-3370.

Does This AD Incorporate Any Material by Reference?

    (g) You must do the actions required by this AD following the 
instructions in Snow Engineering Co. Service Letter 129, 
Issued September 26, 1994, Revised October 21, 2004, and Snow 
Engineering Co. Service Letter 129A, dated August 7, 2004. 
The Director of the Federal Register approved the incorporation by 
reference of this service bulletin in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51. To get a copy of this service information, 
contact Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374. 
To review copies of this service information, go to the National 
Archives and Records Administration (NARA). For information on the 
availability of this material at NARA, go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html or call (202) 741-6030. To view the AD docket, 
go to the Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-
401, Washington, DC 20590-001 or on the Internet at http://dms.dot.gov. The docket number is FAA-2004-19837; Directorate 
Identifier 2004-CE-43-AD.


    Issued in Kansas City, Missouri, on June 14, 2005.
John R. Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-12177 Filed 6-21-05; 8:45 am]
BILLING CODE 4910-13-P