[Federal Register Volume 67, Number 190 (Tuesday, October 1, 2002)]
[Rules and Regulations]
[Pages 61481-61483]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-24404]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-CE-03-AD; Amendment 39-12890; AD 2002-19-10]
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: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to certain Air Tractor, Inc. (Air Tractor) Models AT-402, AT-
402A, AT-402B, AT-602, AT-802, and AT-802A airplanes. This AD requires 
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. This 
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: This AD becomes effective on November 15, 2002.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the regulations as of 
November 15, 2002.

ADDRESSES: You may get the service information referenced in this AD 
from Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374. You 
may view this information at the Federal Aviation Administration (FAA), 
Central Region, Office of the Regional Counsel, Attention: Rules Docket 
No. 2002-CE-03-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: 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:

Discussion

What Events Have Caused This AD?

    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.
    Air Tractor started installing extended reinforcement gussets on 
AT-402 and AT-802 series airplanes at the factory to alleviate the 
crack condition from occurring. The extended reinforcement gussets were 
intended to transfer the

[[Page 61482]]

loads away from the joint. However, 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.

What Is the Potential Impact if FAA Took No Action?

    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-402, AT-402A, AT-402B, AT-602, AT-802, and 
AT-802A airplanes. This proposal was published in the Federal Register 
as a supplemental notice of proposed rulemaking (NPRM) on June 28, 2002 
(67 FR 43568). The supplemental 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 for cracks and contact the 
manufacturer for a repair scheme if cracks are found.

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.

FAA's Determination

What Is FAA's Final Determination on This Issue?

    After careful review of all available information related to the 
subject presented above, we have determined that air safety and the 
public interest require the adoption of the rule as proposed except for 
minor editorial corrections. We have determined that these minor 
corrections:

--provide 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.

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, terminating the need for 
repetitive inspections.

Why Are Air Tractor AT-500 Series Airplanes Not Included in This 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 in 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.

Cost Impact

How Many Airplanes Does This AD Impact?

    We estimate that this AD affects 248 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 accomplish the inspection(s):

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                                                                              Total cost     Total cost on U.S.
                 Labor cost                            Parts cost            per airplane        operators
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1 workhour x $60 = $60.....................  No parts required.............         $60.    $60 X 248 = $14,880.
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    We have no method of determining the number of repairs or 
replacements each owner/operator would incur over the life of each of 
the affected airplanes based on the results of the proposed 
inspections. We have no way of determining the number of airplanes that 
may need such repair. The extent of damage may vary on each airplane.

Regulatory Impact

Does This AD Impact Various Entities?

    The regulations adopted herein 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, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.

Does This AD Involve a Significant Rule or Regulatory Action?

    For the reasons discussed above, I certify that this 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) 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 final evaluation prepared for this 
action is contained 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, 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.


Sec.  39.13  [Amended]

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


[[Page 61483]]


2002-19-10 Air Tractor, Inc.: Amendment 39-12890; 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.

------------------------------------------------------------------------
              Model                              Serial No.
------------------------------------------------------------------------
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    Initially inspect within the next     In accordance with Snow Engineering
 upper diagonal tube on the left       100 hours time-in-service (TIS)       Co. Service Letter 195,
 hand side of the fuselage frame,      after November 15, 2002 (the          dated February 4, 2000, and the
 just forward of the vertical fin      effective date of this AD) and        applicable maintenance manual.
 front spar attachment, for cracks.    thereafter at intervals not to
                                       exceed 100 hours TIS.
(2) If cracks are found during any    Obtain and incorporate the repair     In accordance the with the repair
 inspection required in paragraph      scheme prior to further flight        scheme obtained from Air Tractor,
 (d)(1) of this AD, accomplish the     after inspection in which the         Incorporated, P.O. Box 485, Olney,
 following:                            cracks are found. Continue to         Texas 76374. Obtain this repair
(i) Obtain a repair scheme from the    inspect as specified in paragraph     scheme through the FAA at the
 manufacturer through the FAA at the   (d)(1) of this AD.                    address specified in paragraph (f)
 address specified in paragrpah (f)                                          of this AD.
 of this AD; and
(ii) Incorporate this repair scheme.
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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) Are any service bulletins incorporated into this AD by 
reference? Actions required by this AD must be done in accordance 
with Snow Engineering Co. Service Letter 195, dated 
February 4, 2000. The Director of the Federal Register approved this 
incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 51. 
You may get copies from Air Tractor, Incorporated, P.O. Box 485, 
Olney, Texas 76374. You may view copies at the 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 November 15, 2002.

    Issued in Kansas City, Missouri, on September 18, 2002.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 02-24404 Filed 9-30-02; 8:45 am]
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