[Federal Register Volume 67, Number 125 (Friday, June 28, 2002)]
[Proposed Rules]
[Pages 43568-43570]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-16309]


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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. Models AT-402, AT-
402A, AT-402B, AT-602, AT-802, and AT-802A Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking (NPRM); Reopening of 
the comment period.

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SUMMARY: This document proposes to revise an earlier proposed 
airworthiness directive (AD) that would apply to certain Air Tractor, 
Inc. (Air Tractor) Model AT-602 airplanes. The earlier NPRM would have 
required you to repetitively inspect the left hand upper longeron and 
upper diagonal tube of the fuselage frame for cracks and repair any 
cracks found. The earlier NPRM would have also required eventual 
modification of this area to terminate the repetitive inspection. The 
manufacturer has identified additional airplane models on which the 
unsafe condition exists or could develop and has determined that the 
required modification is not eliminating the cracks from occurring. 
This proposed AD adds additional airplanes to the applicability and 
makes the inspection repetitive for all airplanes even if the 
modification is incorporated. Since these actions impose an additional 
burden over that proposed in the NPRM, we are reopening the comment 
period to allow the public the chance to comment on these additional 
actions.

DATES: The Federal Aviation Administration (FAA) must receive any 
comments on this proposed rule on or before August 26, 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 Is the Background of the Subject Matter?

    The FAA received reports of three occurrences of cracks found on 
the left hand upper longeron and upper diagonal support tubes where 
they intersect on the left hand side of the fuselage frame just forward 
of the vertical fin front spar attachment point on Air Tractor Model 
AT-602 airplanes. The crack starts at the forward edge of the weld 
where the tubes come together. We initially determined that the cracks 
resulted from 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.

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 Model AT-602 airplanes. This proposal was published 
in the Federal Register as a notice of proposed rulemaking (NPRM) on 
March 11, 2002 (67 FR 10862).
    The NPRM proposed to require you to repetitively inspect the upper 
longeron and upper diagonal tube on the left hand side of the aft 
fuselage structure

[[Page 43569]]

for cracks, repair any cracks found, and modify this area by installing 
reinforcement parts.
    You would have to accomplish the proposed actions in accordance 
with the following service information:

--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;
--Snow Engineering Co. Process Specification #125, dated November 28, 
1993; and
--the applicable maintenance manual.

Was the Public Invited To Comment?

    The FAA encouraged interested persons to participate in the making 
of this amendment. We did not receive any comments on the proposed rule 
or on our determination of the cost to the public.

What Events Have Caused FAA To Issue a Supplemental NPRM?

    Since we issued the earlier NPRM, further cracking has been 
reported on 3 more AT-602 airplanes, as well as 1 AT-402 series and 3 
AT-802 series airplanes. One of the AT-802 airplanes had the extended 
reinforcement gusset installed during factory production.
    Air Tractor discovered that the factory installed extended 
reinforcement gusset, which runs further forward than the original 
gusset, is also cracking at the forward end of the extended gusset. 
Therefore, we have determined that installing the reinforcement gussets 
is not transferring the loads away from the joint and does not 
alleviate the crack condition from occurring.

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-402, AT-402A, AT-402B, AT-602, 
AT-802, and AT-802A airplanes of the same type design;
--The originally proposed modification should not be considered as a 
terminating action for the repetitive inspections and all referenced 
airplanes should be repetitively inspected; and
--AD action should be taken in order to correct this unsafe condition.

The Supplemental NPRM

How Will the Changes to the NPRM Impact the Public?

    Proposing that the NPRM apply to certain Air Tractor Models AT-402, 
AT-402A, AT-402B, AT-602, AT-802, and AT-802A airplanes and requiring 
you to repetitively inspect without a terminating action present 
actions that go beyond the scope of what was already proposed. 
Therefore, we are issuing a supplemental NPRM and reopening the comment 
period to allow the public additional time to comment on the proposed 
AD.

What Are the Provisions of the Supplemental NPRM?

    The 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 and contact the manufacturer for a repair 
scheme if cracks are found.

Is There a Modification I Can Incorporate Instead of Repetitively 
Inspecting the Left Hand Upper Longeron and Upper Diagonal Tube of the 
Fuselage Frame for Cracks?

    The FAA has determined that long-term continued operational safety 
would be better assured by design changes that remove the source of the 
problem rather than by repetitive inspections or other special 
procedures. With this in mind, FAA will continue to work with Air 
Tractor in performing further tests to determine the cause of the 
cracking and to provide a corrective action for terminating the need 
for repetitive inspections.

Why Are Air Tractor AT-500 Series Airplanes Not Included in This 
Proposed AD?

    The Air Tractor AT-500 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 AT-402 
series airplanes, Model AT-602 airplanes, and AT-802 series airplanes.
    Air Tractor is currently researching this subject on the AT-500 
series airplanes. Based on this research and if justified, we may 
propose additional rulemaking on this subject for these other 
airplanes.

How Many Airplanes Would This Proposed AD Impact?

    We estimate that this proposed AD affects 248 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):

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                                                            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  248 = $14,880.
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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.

[[Page 43570]]

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 the 
following airplane models and serial numbers that are certificated 
in any category.

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                Model                             Serial No.
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AT-402..............................  All serial numbers beginning with
                                       402-0694.
AT-402A.............................  All serial numbers beginning with
                                       402A-0738.
AT-402B.............................  All serial numbers beginning with
                                       402B-0966.
AT-602..............................  All serial numbers
AT-802..............................  All serial numbers.
AT-802A.............................  All serial numbers.
------------------------------------------------------------------------

    (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:

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                   Actions                                Compliance                        Procedures
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(1) Inspect the upper longeron and upper       Initially inspect within the      In accordance with Snow
 diagonal tube on the left hand side of the     next 100 hours time-in-service    Engineering Co. Service Letter
 fuselage frame, just forward of the vertical   (TIS) after the effective date    #195, dated February 4, 2000,
 fin front spar attachment, for cracks          of this AD and thereafter at      and the applicable maintenance
                                                intervals not to 100 hours TIS.   exceed manual.
(2) If cracks are found during any inspection  Obtain and incorporate the        In accordance with the repair
 required in paragraph (d)(1) of this AD,       repair scheme prior to further    scheme obtained from Air
 accomplish the following:                      flight after the inspection in    Tractor, Incorporated, P.O.
    (i) Obtain a repair scheme from the         which the cracks are found.       Box 485, the Olney, Texas
 manufacturer through the FAA at address        Continue to inspect as            76374. Obtain this repair
 specified in paragraph (f) of this AD; and     specified in paragraph (d)(1)     scheme through the FAA at the
    (ii) Incorporate this repair scheme         of this AD.                       address specified in paragraph
                                                                                  (f) of this AD.
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    (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 June 20, 2002.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 02-16309 Filed 6-27-02; 8:45 am]
BILLING CODE 4910-13-P