Airworthiness Directives; Air Tractor Incorporated Models AT-301, AT-401, and AT-501 Airplanes

[Federal Register Volume 65, Number 107 (Friday, June 2, 2000)]
[Rules and Regulations]
[Pages 35267-35270]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-13445]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-CE-21-AD; Amendment 39-11753; AD 2000-11-05]
RIN 2120-AA64


Airworthiness Directives; Air Tractor Incorporated Models AT-301, 
AT-401, and AT-501 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to certain Air Tractor Incorporated (Air Tractor) Models AT-
301, AT-401, and AT-501 airplanes that are equipped with a \3/16\-inch 
thick aluminum fin front spar fitting and an all metal rudder. This AD 
requires that you repetitively inspect the vertical fin front spar 
attachment fittings for fatigue cracks, and rework the vertical fin if 
any cracks are found. This AD is the result of reports of a vertical 
fin front spar fitting failure on a Model AT-401 airplane. The actions 
specified by this AD are intended to detect and correct cracks in the 
vertical fin front spar attachment fittings, which could result in 
failure of the vertical fin. This condition could lead to loss of 
directional control and eventual loss of airplane control.

DATES: This AD becomes effective on June 23, 2000.
    The Director of the Federal Register previously approved the 
incorporation by reference of Snow Engineering Company Service Letter 
#138, Revised August 7, 1996, as of August 25, 1997.
    The Director of the Federal Register approved the incorporation by 
reference of Snow Engineering Company Service Letter #196, Revised 
March 7, 2000, as of June 23, 2000.
    The Federal Aviation Administration (FAA) must receive any comments 
on this rule on or before July 28, 2000.

ADDRESSES: Submit comments in triplicate to FAA, Central Region, Office 
of the Regional Counsel, Attention: Rules Docket No. 2000-CE-21-AD, 901 
Locust, Room 506, Kansas City, Missouri 64106.
    You may get the service information referenced in this AD from Air 
Tractor Incorporated, P.O. Box 485, Olney, Texas 76374. You may examine 
this information at FAA, Central Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 2000-CE-21-AD, 901 Locust, Room 
506, Kansas City, Missouri 64106; or at the Office of the Federal 
Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Rob Romero, Aerospace Engineer, 
Airplane Certification Office, FAA, 2601 Meacham Boulevard, Fort Worth, 
Texas 76137; telephone: (817) 222-5102; facsimile: (817) 222-5960.

SUPPLEMENTARY INFORMATION:

Discussion

    What events have caused this AD? The FAA has received a report of 
an incident involving an Air Tractor Model AT-401 airplane. The 
following describe this incident:
    1. The vertical fin front spar plate cracked and caused failure of 
the vertical fin front spar fitting;
    2. The rear spar consequently failed and the fin contacted the 
elevator, which caused difficulty in controlling the airplane; and
    3. The front spar failure occurred in the \3/16\-inch thick 
aluminum fin front spar fitting across one of the bolt holes where the 
fitting attaches to the fuselage frame.

[[Page 35268]]

    What are the consequences if the condition is not corrected? 
Fatigue cracking of the vertical fin front spar attachment fittings, if 
not detected and corrected, could result in structural failure of the 
front spar and consequently the rear spar. This could result in loss of 
directional control and loss of control of the airplane.
    Is there service information that applies to this subject? Snow 
Engineering Company has issued the following service information that 
relates to this subject:

------------------------------------------------------------------------
      Service letter #        Issue/revision dates     Procedures for
------------------------------------------------------------------------
Service Letter #196.........  Issued February 9,    Reworking the
                               2000; Revised March   vertical fin.
                               7, 2000.
Service Letter #138.........  Issued July 29,       Repetitively
                               1995; Revised         inspecting the
                               August 7, 1996.       vertical fin front
                                                     spar attachment
                                                     fittings for
                                                     fatigue cracks.
------------------------------------------------------------------------

The FAA's Determination and an Explanation of the Provisions of the 
AD

    What has FAA decided? After examining the circumstances and 
reviewing all available information related to the incidents described 
above, including the relevant service information, we determined that:

--An unsafe condition exists or could develop on certain Air Tractor 
Models AT-301, AT-401, and AT-501 airplanes of the same type design to 
the incident airplane that are equipped with a \3/16\-inch thick 
aluminum fin front spar fitting and an all metal rudder; and
--AD action should be taken in order to detect and correct cracks in 
the vertical fin front spar attachment fittings, which could result in 
failure of the vertical fin. This condition could lead to loss of 
directional control and eventual loss of airplane control.
    What does this AD require? This AD requires you to:
    1. repetitively inspect vertical fin front spar attachment fittings 
for fatigue cracks; and
    2. rework the vertical fin if any cracks are found.
    Once you rework the vertical fin, you may discontinue the 
repetitive inspections.
    The applicability of Snow Engineering Company Service Letter #138 
refers to different airplanes than are referenced in this AD action. AD 
97-14-05, Amendment 39-10063 (62 FR 38445, July 18, 1997), covers the 
airplanes referenced in Service Letter #138. The inspection procedures 
also apply for the airplanes referenced in this AD action. Therefore, 
Snow Engineering Company Service Letter #138 also applies to this AD, 
as well as AD 97-14-05. This service letter also specifies repetitive 
inspection intervals of 25 hours time-in-service (TIS). Paragraph 
(d)(2) of this AD requires the repetitive inspections at 100 hours TIS.
    Will I have the opportunity to comment prior to the issuance of the 
rule? Because the unsafe condition described in this document could 
result in loss of directional control and eventual loss of airplane 
control, FAA finds that notice and opportunity for public prior comment 
are impracticable. Therefore, good cause exists for making this 
amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule and was not 
preceded by notice and opportunity for public comment, FAA invites 
comments on this rule. You may submit whatever written data, views, or 
arguments you choose. You need to include the rule's docket number and 
submit your comments in triplicate to the address specified under the 
caption ADDRESSES. The FAA will consider all comments received on or 
before the closing date. We may amend this rule in light of comments 
received. Factual information that supports your ideas and suggestions 
is extremely helpful in evaluating the effectiveness of the AD action 
and determining whether we need to take additional rulemaking action.
    The FAA is re-examining the writing style we currently use in 
regulatory documents, in response to the Presidential memorandum of 
June 1, 1998. That memorandum requires federal agencies to communicate 
more clearly with the public. We are interested in your comments on 
whether the style of this document is clearer, and any other 
suggestions you might have to improve the clarity of FAA communications 
that affect you. You can get more information about the Presidential 
memorandum and the plain language initiative at http://www.plainlanguage.gov.
    The FAA specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. You may examine all comments we 
receive before and after the closing date of the rule in the Rules 
Docket. We will file a report in the Rules Docket that summarizes each 
FAA contact with the public that concerns the substantive parts of this 
AD.
    If you want us to acknowledge the receipt of your comments, you 
must include a self-addressed, stamped postcard. On the postcard, write 
``Comments to Docket No. 2000-CE-21-AD.'' We will date stamp and mail 
the postcard back to you.

Regulatory Impact

    These regulations 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. Therefore, FAA has determined that this 
final rule does not have federalism implications under Executive Order 
13132.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a significant regulatory action under 
Executive Order 12866. We have determined that this action involves an 
emergency regulation under DOT Regulatory Policies and Procedures (44 
FR 11034, February 26, 1979). If FAA determines that this emergency 
regulation otherwise would be significant under DOT Regulatory Policies 
and Procedures, we will prepare a final regulatory evaluation. You may 
obtain a copy of the evaluation (if required) from the Rules Docket.

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 Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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.

[[Page 35269]]

Sec. 39.13  [Amended]

    2. FAA amends Section 39.13 by adding a new airworthiness directive 
(AD) to read as follows:

2000-11-05  Air Tractor Incorporated: Amendment 39-11753; Docket No. 
2000-CE-21-AD.
    (a) What airplanes are affected by this AD? The following 
airplane models and serial numbers that are:
    (1) Certificated in any category; and
    (2) Equipped with a \3/16\-inch fin front spar fitting and an 
all metal rudder.

------------------------------------------------------------------------
                  Models                           Serial numbers
------------------------------------------------------------------------
AT-301....................................  301-0100 through 301-0736
AT-401....................................  401-0662 through 401-0736
AT-501....................................  501-0002 through 501-0030
------------------------------------------------------------------------


    Note: This AD does not affect the requirements of AD 97-14-05, 
Amendment 39-10063 (62 FR 38445, July 18, 1997). AD 97-14-05 
requires similar actions to this AD on Models AT-302, AT-400, AT-
400A airplanes, and certain Models AT301, AT-401, and AT-501 
airplanes that are not affected by this AD.

    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the above airplanes on the U.S. Register.
    (c) What problem does this AD address? The actions required by 
this AD are intended to detect and correct cracks in the spar 
plates, which could result in failure of the vertical fin. This 
condition could lead to loss of directional control and eventual 
loss of control of the airplane.
    (d) What must I do to address this problem? To address this 
problem, you must accomplish the following:

------------------------------------------------------------------------
             Action                 Compliance time       Procedures
------------------------------------------------------------------------
(1) Initial inspection of the     At whichever of     Accomplish in
 fin front spar attachment         the following       accordance with
 fittings for fatigue cracks.      that occurs later.  the Inspection
                                  (i) Upon             Requirements
                                   accumulating        section of Snow
                                   4,000 hours time-   Engineering
                                   in-service (TIS);   Company Service
                                   or,.                Letter #138,
                                  (ii) Within the      Issued July 29,
                                   next 25 hours TIS   1995; Revised
                                   after the June      August 7, 1996.
                                   23, 2000 (the
                                   effective date of
                                   this AD).
(2) Repetitive inspections of     Within 100 hours    Accomplish in
 the fin front spar attachment     TIS after the       accordance with
 fittings. Repetitive inspection   initial             the Inspection
 requirement only applies if no    inspection and      Requirements
 cracks are found and you choose   thereafter at       section of Snow
 not to rework the fin front       intervals not to    Engineering
 spar attachment.                  exceed 100 hours    Company Service
                                   TIS if you have     Letter #138,
                                   no cracks and       Issued July 29,
                                   choose not to       1995; Revised
                                   rework the fin      August 7, 1996.
                                   front spar
                                   attachment.
(3) Rework the fin front spar     (i) Prior to        Accomplish in
 attachment fittings.              further flight      accordance with
                                   after any           the Vertical Fin
                                   inspection where    Rework
                                   a crack is found    Instructions
                                   in the front or     section of Snow
                                   rear spar area.     Engineering
                                  (ii) This            Company Service
                                   eliminates the      letter #196,
                                   repetitive          Issued February
                                   inspection          9, 2000; Revised
                                   requirement of      March 7, 2000.
                                   this AD.
(4) Optional rework of the fin    Any time to         Accomplish in
 front spar attachment fittings.   eliminate the       accordance with
                                   repetitive          the Vertical Fin
                                   inspection          Rework
                                   requirement of      Instructions
                                   this AD.            section of Snow
                                                       Engineering
                                                       Company Service
                                                       Letter #196,
                                                       Issued February
                                                       9, 2000; Revised
                                                       March 7, 2000.
------------------------------------------------------------------------


    Note: The applicability of Snow Engineering Company Service 
Letter #138 refers to different airplanes than are referenced in 
this document. AD 97-14-05, Amendment 39-10063 (62 FR 38445, July 
18, 1997), covers the airplanes referenced in Snow Engineering 
Company Service Letter #138. The inspection procedures also apply 
for the airplanes referenced in this AD. Therefore, Snow Engineering 
Company Service Letter #138 also applies to this AD, as well as AD 
97-14-05. This service letter also specifies repetitive inspection 
intervals of 25 hours TIS. Paragraph (d)(2) of this AD requires the 
repetitive inspections at 100 hours TIS.

    (e) Can I comply with this AD in any other way? You may use an 
alternative method of compliance or adjust the compliance time if:
    (1) Your alternative method of compliance provides an equivalent 
level of safety; and
    (2) The Manager, Fort Worth Airplane Certification Office (ACO), 
approves your alternative. Submit your request through an FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, Fort Worth ACO.

    Note: This AD applies to each airplane identified in paragraph 
(a) of this AD, regardless of whether it has been modified, altered, 
or repaired in the area subject to the requirements of this AD. For 
airplanes that have been modified, altered, or repaired so that the 
performance of the requirements of this AD is affected, the owner/
operator must request approval for an alternative method of 
compliance in accordance with paragraph (e) of this AD. The request 
should include an assessment of the effect of the modification, 
alteration, or repair on the unsafe condition addressed by this AD; 
and, if you have not eliminated the unsafe condition, specify 
actions you propose to address it.

    (f) Where can I get information about any already-approved 
alternative methods of compliance? Contact Rob Romero, Aerospace 
Engineer, FAA, Fort Worth ACO, 2601 Meacham Boulevard, Fort Worth, 
Texas 76193-0150; telephone: (817) 222-5102; facsimile: (817) 222-
5960.
    (g) What if I need to fly the airplane to another location to 
comply with this AD? The FAA can issue a special flight permit under 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate your airplane to a location where 
you can accomplish the requirements of this AD.
    (h) Are any service bulletins incorporated into this AD by 
reference? You must accomplish the actions required by this AD in 
accordance with Snow Engineering Company Service Letter #138, 
Revised August 7, 1996, and Snow Engineering Company Service Letter 
#196, Revised March 7, 2000.
    (1) The Director of the Federal Register previously approved the 
incorporation by

[[Page 35270]]

reference of Snow Engineering Company Service Letter #138, Revised 
August 7, 1996, as of August 25, 1997.
    (2) The Director of the Federal Register approved the 
incorporation by reference of Snow Engineering Company Service 
Letter #196, Revised March 7, 2000 under 5 U.S.C. 552(a) and 1 CFR 
part 51.
    (3) You may get copies from Air Tractor Incorporated, P.O. Box 
485, Olney, Texas 76374. You may look at copies at FAA, Central 
Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas 
City, Missouri, or at the Office of the Federal Register, 800 North 
Capitol Street, NW, suite 700, Washington, DC.
    (i) When does this amendment become effective? This amendment 
becomes effective on June 23, 2000.

    Issued in Kansas City, Missouri, on May 22, 2000.
Marvin R. Nuss,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-13445 Filed 6-1-00; 8:45 am]
BILLING CODE 4910-13-P

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