[Federal Register Volume 70, Number 42 (Friday, March 4, 2005)]
[Proposed Rules]
[Pages 10513-10517]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-4238]


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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]
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: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for

[[Page 10514]]

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 proposed AD would 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 is 
also included in this proposed AD. This proposed AD results from 
reports of failures of the subject eyebolt. We are issuing this 
proposed 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: We must receive any comments on this proposed AD by May 6, 2005.

ADDRESSES: Use one of the following to submit comments on this proposed 
AD:
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-001.
     Fax: 1-202-493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    To get the service information identified in this proposed AD, 
contact Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374.
    To view the comments to this proposed AD, go to http://dms.dot.gov. 
The docket number is FAA-2004-19837.

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:

Comments Invited

    How do I comment on this proposed AD? We invite you to submit any 
written relevant data, views, or arguments regarding this proposal. 
Send your comments to an address listed under ADDRESSES. Include the 
docket number, ``FAA-2004-19837; Directorate Identifier 2004-CE-43-AD'' 
at the beginning of your comments. We will post all comments we 
receive, without change, to http://dms.dot.gov, including any personal 
information you provide. We will also post a report summarizing each 
substantive verbal contact with FAA personnel concerning this proposed 
rulemaking. Using the search function of our docket Web site, anyone 
can find and read the comments received into any of our dockets, 
including the name of the individual who sent the comment (or signed 
the comment on behalf of an association, business, labor union, etc.). 
This is docket number FAA-2004-19837. You may review the DOT's complete 
Privacy Act Statement in the Federal Register published on April 11, 
2000 (65 FR 19477-78) or you may visit http://dms.dot.gov.
    Are there any specific portions of this proposed AD I should pay 
attention to? We specifically invite comments on the overall 
regulatory, economic, environmental, and energy aspects of this 
proposed AD. If you contact us through a nonwritten communication and 
that contact relates to a substantive part of this proposed AD, we will 
summarize the contact and place the summary in the docket. We will 
consider all comments received by the closing date and may amend this 
proposed AD in light of those comments and contacts.

Docket Information

    Where can I go to view the docket information? You may view the AD 
docket that contains the proposal, any comments received, and any final 
disposition in person at the DMS Docket Offices between 9 a.m. and 5 
p.m. (eastern standard time), Monday through Friday, except Federal 
holidays. The Docket Office (telephone 1-800-647-5227) is located on 
the plaza level of the Department of Transportation NASSIF Building at 
the street address stated in ADDRESSES. You may also view the AD docket 
on the Internet at http://dms.dot.gov. The comments will be available 
in the AD docket shortly after the DMS receives them.

Discussion

    What events have caused this proposed 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 
1995. 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.
    The FAA also received two service difficulty reports (SDRs) in 
November 2003. Both SDRs referenced Model AT-802 airplane eyebolt 
cracks. 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 
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.

[[Page 10515]]

    Is there service information that applies to this subject? As 
discussed earlier, Snow Engineering Co. has issued the following 
Service Letters:

--Service Letter 129, revised: October 21, 2004; and
--Service Letter 129A, dated August 7, 2004.

    What are the provisions of this service information? These service 
letters include procedures for:

--Service Letter 129 recommends tightening the eyebolt nut to 
a specified torque, replacing the eyebolt, and includes the inspection 
procedures when replacing any eyebolt; and
--Service Letter 129A, for certain eyebolts, recommends 
replacing eyebolts with larger eyebolts, tightening the eyebolt nut to 
a specified torque, and procedures for replacing the steel brace 
assembly inside the stabilizer with a new steel brace assembly with 
larger bushings.

FAA's Determination and Requirements of This Proposed AD

    What has FAA decided? We have evaluated all pertinent information 
and identified an unsafe condition that is likely to exist or develop 
on other airplanes of this same type design. For this reason, we are 
proposing AD action.
    What would this proposed AD require? This proposed AD would require 
you to incorporate the actions in the previously-referenced service 
information.
    How does the revision to 14 CFR part 39 affect this proposed AD? On 
July 10, 2002, we published a new version of 14 CFR part 39 (67 FR 
47997, July 22, 2002), which governs FAA's AD system. This regulation 
now includes material that relates to altered products, special flight 
permits, and alternative methods of compliance. This material 
previously was included in each individual AD. Since this material is 
included in 14 CFR part 39, we will not include it in future AD 
actions.

Costs of Compliance

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

----------------------------------------------------------------------------------------------------------------
                                                                  Total
              Labor cost                      Parts cost         cost per      Total  cost on  U.S. operators
                                                                 airplane
----------------------------------------------------------------------------------------------------------------
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
                                        Average    total  cost
         Average labor cost            parts cost      per           Average total  cost on U.S.  operators
                                                     airplane
----------------------------------------------------------------------------------------------------------------
1 workhour x $65 per hour = $65.....      $186.30      $251.30  1,011 x $251.30 = $254,064.30
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    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
                                        Average     total cost
         Average labor cost            parts cost      per           Average total  cost on U.S.  operators
                                                     airplane
----------------------------------------------------------------------------------------------------------------
22 workhours x $65 per hour = $1,430      $901.65    $2,331.65  312 x $2,331.65 = $727,474.80
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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

    Would this proposed AD impact various entities? We have determined 
that this proposed AD would not have federalism implications under 
Executive Order 13132. This proposed AD would not have a substantial 
direct effect on the States, on the relationship between the national 
Government and the States, or on the distribution of power and 
responsibilities among the various levels of government.
    Would this proposed AD involve a significant rule or regulatory 
action? For the reasons discussed above, I certify that this proposed 
AD:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979); and
    3. Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a summary of the costs to comply with this proposed AD 
and placed it in the AD Docket. You may get

[[Page 10516]]

a copy of this summary by sending a request to us at the address listed 
under ADDRESSES. Include ``AD Docket 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, Safety.

The Proposed Amendment

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

PART 39--AIRWORTHINESS DIRECTIVES

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

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


Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

Air Tractor, Inc.: Docket No. FAA-2004-19837; Directorate Identifier 
2004-CE-43-AD.

When Is the Last Date I Can Submit Comments on This Proposed AD?

    (a) We must receive comments on this proposed airworthiness 
directive (AD) by May 6, 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 numbers
------------------------------------------------------------------------
AT-300, AT-301, AT-302, AT-400, and AT-  All serial numbers.
 400A.
AT-401/AT-402..........................  All through 401-0700.
AT-602.................................  All through 602-0695 that have
                                          any 7/16-inch eyebolt (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
                                          AN74-30A) 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 12    Follow Snow
 eyebolts that attach the      calendar months       Engineering Co.
 front and rear spar of the    after the effective   Service Letter
 horizontal stabilizer to      date of this AD,      129,
 the respective stabilizer     unless already        revised October 21,
 strut using the torque        done. Repetitively    2004.
 values referenced in Snow     tighten thereafter
 Engineering Co. Service       at every 12
 Letter 129,          calendar months
 revised October 21, 2004.     after the date of
                               the initial
                               tightening to the
                               specified torque.
(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       129,
 the respective stabilizer     time-in-service       revised October 21,
 strut.                        (TIS) referenced in   2004.
                               Snow Engineering
                               Co. Service Letter
                               129,
                               revised October 21,
                               2004, or within 50
                               hours TIS after 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      the effective date    Engineering Co.
 number 602-0695 and AT-802,   of this AD. Use the   Service Letter
 and 802A airplanes through    applicable time in    129A,
 serial number 802A-0188: As   Snow Engineering      dated August 7,
 an alternative in order to    Co. Service Letter    2004.
 use the increased             129A,
 replacement compliance        dated August 7,
 times in paragraph (e)(2)     2004. The
 of this AD, you may replace   repetitive
 the steel brace assembly      replacement of
 inside the stabilizer with    paragraph (e)(2) of
 a new steel brace assembly    this AD is still
 with larger bushings, and.    required.
    (i) For the Model AT-602
     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).

[[Page 10517]]

 
(4) Do not install any 5/16-  As of the effective   Not Applicable.
 inch eyebolt (P/N AN44-17A    date of this AD..
 or AN44-21A), 7/16-inch
 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 Aircraft Certification 
Office (ACO), FAA. For information on any already approved alternative 
methods of compliance, 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.

May I Get Copies of the Documents Referenced in This AD?

    (g) To get copies of the documents referenced in this AD, contact 
Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374. To view 
the AD docket, go to the Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, S.W., Nassif Building, Room PL-401, 
Washington, DC, or on the Internet at http://dms.dot.gov. The docket 
number is FAA-2004-19837.

    Issued in Kansas City, Missouri, on February 28, 2005.
David R. Showers,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-4238 Filed 3-3-05; 8:45 am]
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