[Federal Register Volume 67, Number 47 (Monday, March 11, 2002)]
[Proposed Rules]
[Pages 10862-10864]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-5690]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-CE-03-AD]
RIN 2120-AA64


Airworthiness Directives; Air Tractor, Inc. Model AT-602 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to adopt a new airworthiness directive 
(AD) that would apply to certain Air Tractor, Inc. (Air Tractor) Model 
AT-602 airplanes. This proposed AD would require you to repetitively 
inspect the left hand upper longeron and upper diagonal tube of the 
fuselage frame for cracks and repair any cracks found. This proposed AD 
would also require eventual modification of this area to terminate the 
repetitive inspection. This proposed AD is the result of reports of 
excessive movement in the empennage due to the loss of fuselage 
torsional rigidity. The actions specified by this proposed AD are 
intended to prevent failure of the fuselage caused by cracks. Such 
failure could result in loss of control of the airplane.

DATES: The Federal Aviation Administration (FAA) must receive any 
comments on this proposed rule on or before May 10, 2002.

ADDRESSES: Submit comments to FAA, Central Region, Office of the 
Regional Counsel, Attention: Rules Docket No. 2002-CE-03-AD, 901 
Locust, Room 506, Kansas City, Missouri 64106. You may view any 
comments at this location between 8 a.m. and 4 p.m., Monday through 
Friday, except Federal holidays. You may also send comments 
electronically to the following address: [email protected]. 
Comments sent electronically must contain ``Docket No. 2002-CE-03-AD'' 
in the subject line. If you send comments electronically as attached 
electronic files, the files must be formatted in Microsoft Work 97 for 
Windows or ASCII text.
    You may get service information that applies to this proposed AD 
from Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374. You 
may also view this information at the Rules Docket at the address 
above.

FOR FURTHER INFORMATION CONTACT: Andrew D. McAnaul, Aerospace Engineer, 
FAA, Fort Worth Airplane Certification Office, 2601 Meacham Boulevard, 
Fort Worth, Texas 76193-0150; telephone: (817) 222-5156; facsimile: 
(817) 222-5960.

SUPPLEMENTARY INFORMATION:

Comments Invited

How Do I Comment on This Proposed AD?

    The FAA invites comments on this proposed 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 to the 
address specified under the caption ADDRESSES. We will consider all 
comments received on or before the closing date. We may amend this 
proposed rule in light of comments received. Factual information that 
supports your ideas and suggestions is extremely helpful in evaluating 
the effectiveness of this proposed AD action and determining whether we 
need to take additional rulemaking action.

Are There Any Specific Portions of This Proposed AD I Should Pay 
Attention to?

    The FAA specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed rule that 
might suggest a need to modify the rule. You may view 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 
contact we have with the public that concerns the substantive parts of 
this proposed AD.

How Can I Be Sure FAA Receives My Comment?

    If you want FAA to acknowledge the receipt of your comments, you 
must include a self-addressed, stamped postcard. On the postcard, write 
``Comments to Docket No. 2002-CE-03-AD.'' We will date stamp and mail 
the postcard back to you.

Discussion

What Events Have Caused This Proposed AD?

    The FAA has received reports of three occurrences where cracks were 
found on the left hand upper longeron and upper diagonal support tubes 
intersect on the left hand side of the fuselage frame just forward of 
the vertical fin front spar attachment point on Model AT-602 airplanes. 
The crack starts at the forward edge of the weld where the tubes come 
together. We have determined that the cracks are a result of high 
vertical tail loads during repeated hard turns. The cracks were found 
by the pilot and/or ground crew when they noticed excessive movement in 
the empennage due to the loss of torsional rigidity.

What Are the Consequences if the Condition Is Not Corrected?

    This condition, if not corrected, could cause the fuselage to fail. 
Such failure could result in loss of control of the airplane.

Is There Service Information That Applies to This Subject?

    Air Tractor has issued the following:

--Snow Engineering Co. Service Letter #195, dated February 4, 2000;
--Snow Engineering Co. Service Letter #213, dated November 13, 2001;
--Snow Engineering Co. Process Specification #102, Revised January 5, 
2001;
--Snow Engineering Co. Process Specification #120, Revised December 16, 
1997; and
--Snow Engineering Co. Process Specification #125, dated November 28, 
1993.

What Are the Provisions of This Service Information?

    These service bulletins include procedures for:

--Repetitively inspecting the upper longeron and upper diagonal tube on 
the left hand side of the aft fuselage structure for cracks; and
--Modifying this area by installing reinforcement parts.

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

What Has FAA Decided?

    After examining the circumstances and reviewing all available 
information related to the incidents described above, we have 
determined that:

--The unsafe condition referenced in this document exists or could 
develop on other Air Tractor Model AT-602 airplanes of the same type 
design;
--The actions specified in the previously-referenced service 
information should be accomplished on the affected airplanes; and
--AD action should be taken in order to correct this unsafe condition.

[[Page 10863]]

What Would This Proposed AD Require?

    This proposed AD would require you to repetitively inspect the 
upper longeron and upper diagonal tube on the left hand side of the aft 
fuselage structure for cracks, repair any cracks found, and modifying 
this area by installing reinforcement parts.

Why Are the Air Tractor AT-400, AT-500, and AT-800 Series Airplanes Not 
Included in This Proposed AD?

    The Air Tractor AT-400, AT-500, and AT-800 series airplanes have a 
similar design in the upper longeron in the aft fuselage structure. 
However, we have not received any reports of damage to this area on 
those airplanes. The only reports of damage are those previously 
referenced on the Model AT-602 airplanes.
    Air Tractor is currently researching this subject on the AT-400, 
AT-500, and AT-800 series airplanes. Based on this research and if 
justified, we may propose additional rulemaking on this subject for 
these other airplanes.

Cost Impact

How Many Airplanes Would This Proposed AD Impact?

    We estimate that this proposed AD affects 91 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 accomplish the proposed 
inspection(s):

----------------------------------------------------------------------------------------------------------------
                                                            Total cost per
             Labor cost                    Parts cost          airplane         Total cost on U.S.  operators
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1 workhour  x  $60 = $60...........  No parts required....             $60  $60  x  91 = $5,460
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    We estimate the following costs to accomplish the proposed 
modification:

------------------------------------------------------------------------
                                                          Total cost per
            Labor cost                   Parts cost          airplane
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8 workhours  x  $60 = $480........  Manufacturer will               $480
                                     provide parts at no
                                     charge.
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Regulatory Impact

Would This Proposed AD Impact Various Entities?

    The regulations proposed herein 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. Therefore, it 
is determined that this proposed rule would not have federalism 
implications under Executive Order 13132.

Would This Proposed AD Involve a Significant Rule or Regulatory Action?

    For the reasons discussed above, I certify that this proposed 
action (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); and (3) if 
promulgated, 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. A copy of the draft regulatory 
evaluation prepared for this action has been placed in the Rules 
Docket. A copy of it may be obtained by contacting the Rules Docket at 
the location provided under the caption ADDRESSES.

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 
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.


Sec. 39.13  [Amended]

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

Air Tractor, Inc.: Docket No. 2002-CE-03-AD.

    (a) What airplanes are affected by this AD? This AD affects 
Model AT-602 airplanes, serial numbers 602-0337 through 602-0569, 
that are certificated in any category.
    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the airplanes identified in paragraph (a) of this AD must 
comply with this AD.
    (c) What problem does this AD address? The actions specified by 
this AD are intended to prevent failure of the empennage caused by 
cracks. Such failure could result in loss of control of the 
airplane.
    (d) What actions must I accomplish to address this problem? To 
address this problem, you must accomplish the following:

------------------------------------------------------------------------
             Actions                  Compliance          Procedures
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(1) Inspect the upper longeron    Initially inspect   In accordance with
 and upper diagonal tube on the    within the next     Snow Engineering
 left hand side of the fuselage    50 hours time-in-   Co. Service
 frame, just forward of the        service (TIS)       Letter #195,
 vertical fin front spar           after the           dated February 4,
 attachment, for cracks.           effective date of   2000, and
                                   this AD and         applicable
                                   thereafter at       maintenance
                                   intervals not to    manual.
                                   exceed 100 hours
                                   TIS until 12
                                   months after the
                                   effective date of
                                   this AD.

[[Page 10864]]

 
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(2) If cracks are found during    Prior to further    In accordance with
 any inspection required in        flight after the    the repair scheme
 paragraph (d)(1) of this AD,      inspection in       obtained from Air
 accomplish the following:.        which the cracks    Tractor,
(i) Obtain a repair scheme from    are found. The      Incorporated,
 the manufacturer through the      incorporation of    P.O. Box 485,
 FAA at the address specified in   the repair scheme   Olney, Texas
 paragraph (f) of this AD; and.    will terminate      76374. Obtain
(ii) Incorporate this repair       the repetitive      this repair
 scheme.                           inspections.        scheme through
                                                       the FAA at the
                                                       address specified
                                                       in paragraph (f)
                                                       of this AD.
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(3) If no cracks were found       Within the next 12  In accordance with
 during any inspection required    calendar months     Snow Engineering
 in paragraph (d)(1) of this AD,   after the           Co. Service
 accomplish the following:.        effective date of   Letter #213,
(i) Inspect as required in         this AD. You may    dated November
 paragraph (d)(1) to ensure        install the         13, 2001, Snow
 there are no cracks; and.         reinforcement       Engineering Co.
(ii) Install gusset part numbers   gussets at any      Process
 11946-1 and 11686-1 (or FAA-      time to terminate   Specification
 approved equivalent part          the repetitive      #102, revised
 numbers).                         inspections         January 5, 2001,
                                   provided that you   Snow Engineering
                                   inspect prior to    Co. Process
                                   installation and    Specification
                                   no cracks are       #120, revised
                                   found.              December 16,
                                                       1997, and Snow
                                                       Engineering Co.
                                                       Process
                                                       Specification
                                                       #125, dated
                                                       November 28,
                                                       1993, as
                                                       specified in
                                                       Service Letter
                                                       #213, and the
                                                       applicable
                                                       maintenance
                                                       manual.
------------------------------------------------------------------------

    (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 Aircraft 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, specific 
actions you propose to address it.

    (f) Where can I get information about any already-approved 
alternative methods of compliance? Contact Andrew D. McAnaul, 
Aerospace Engineer, FAA, Fort Worth Airplane Certification Office, 
2601 Meacham Boulevard, Fort Worth, Texas 76193-0150; telephone: 
(817) 222-5156; 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) How do I get copies of the documents referenced in this AD? 
You may get copies of the documents referenced in this AD from Air 
Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374. You may 
view these documents at FAA, Central Region, Office of the Regional 
Counsel, 901 Locust, Room 506, Kansas City, Missouri 64106.


    Issued in Kansas City, Missouri, on March 4, 2002.
James E. Jackson,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-5690 Filed 3-8-02; 8:45 am]
BILLING CODE 4910-13-U