FR Doc 04-8056

[Federal Register: April 9, 2004 (Volume 69, Number 69)]
[Proposed Rules]
[Page 18848-18851]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr09ap04-15]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2004-CE-05-AD]
RIN 2120-AA64

Airworthiness Directives; Air Tractor, Inc. Models AT-401, AT-
401B, AT-402, AT-402A, AT-402B, AT-501, AT-502, AT-502A, AT-502B, AT-
503A, 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 supersede Airworthiness Directive (AD)
2002-19-10, which applies to certain Air Tractor, Inc. (Air Tractor)
Models AT-402, AT-402A, AT-402B, AT-602, AT-802, and AT-802A airplanes.
AD 2002-19-10 currently 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 proposed AD is the result of reports
of the same cracks recently found on AT-500 series airplanes. The
manufacturer has also issued new and revised service information that
incorporates a modification to terminate the repetitive inspection
requirements. Consequently, this proposed AD would retain the
inspection actions required in AD 2002-19-10, would add certain AT-500
series airplanes to the applicability section, would change the
compliance times, and would incorporate new and revised manufacturer
service information that contains a terminating action for the
repetitive inspection requirement. We are issuing this proposed AD to
detect and correct cracks in the upper aft longeron, which could cause
the fuselage to fail. Such failure could result in loss of control of
the airplane.

DATES: We must receive any comments on this proposed AD by June 7,
2004.

ADDRESSES: Use one of the following to submit comments on this proposed
AD:
By mail: FAA, Central Region, Office of the
Regional Counsel, Attention: Rules Docket No. 2004-CE-05-AD, 901
Locust, Room 506, Kansas City, Missouri 64106.
By fax: (816) 329-3771.
By e-mail: 9-ACE-7-Docket@faa.gov. Comments sent
electronically must contain ``Docket No. 2004-CE-05-AD'' in the subject
line. If you send comments electronically as attached electronic files,
the files must be formatted in Microsoft Word 97 for Windows or ASCII.
You may get the service information identified in this proposed AD
from Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374.
You may view the AD docket at FAA, Central Region, Office of the
Regional Counsel, Attention: Rules Docket No. 2004-CE-05-AD, 901
Locust, Room 506, Kansas City, Missouri 64106. Office hours are 8 a.m.
to 4 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Andrew D. McAnaul, Aerospace Engineer,
FAA, Fort Worth Airplane Certification Office (ACO), 2601 Meacham
Boulevard, Fort Worth, Texas 76193-0150. Current duty station: San
Antonio Manufacturing Inspection District Office (MIDO), 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 ``AD
Docket No. 2004-CE-05-AD'' in the subject line of your comments. If you
want us to acknowledge receipt of your mailed comments, send us a self-
addressed, stamped postcard with the docket number written on it. We
will date-stamp your postcard and mail it back to you.
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.

Discussion

Has FAA taken any action to this point? We received reports 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. Additional cracking was later reported
on AT-400, AT-602, and AT-802 series airplanes.
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 loads away from the joint. However, an AT-802
airplane with the extended reinforcement gusset installed during
factory production was discovered cracked in service at the forward end
of the gusset.
These conditions caused us to issue AD 2002-19-10, Amendment 39-
12890 (67 FR 61481, October 1, 2002). AD 2002-19-10 currently requires
you to do the following on certain Air Tractor Models AT-402, AT-402A,
AT-402B, AT-602, AT-802, and AT-802A airplanes:

--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.

What has happened since AD 2002-19-10 to initiate this proposed
action? We have received additional reports of the same cracks found on
an Air Tractor Model AT-502 and AT-502A airplane.
The manufacturer has also issued new and revised service
information. The new service information contains procedures for
replacing and modifying the upper aft longeron as a terminating action
for the repetitive inspection requirement.
What is the potential impact if FAA took no action? This condition,
if not detected and 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? Snow

[[Page 18849]]

Engineering Co. has issued the following Service Letters:

--Service Letter 195, reissued: November 10, 2003;
--Service Letter 195A, revised: November 10, 2003;
--Service Letter 195B, dated November 10, 2003;
--Service Letter 213A, dated November 10, 2003;
--Service Letter 213B, revised November 10, 2003;
--Service Letter 217A, dated November 10, 2003;
--Service Letter 217B, revised November 10, 2003;
--Service Letter 218A, dated November 10, 2003; and
--Service Letter 218B, revised November 10, 2003.

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

--Service Letter 195 specifies inspecting the upper longeron
in the aft fuselage structure on all the affected model airplanes;
--Service Letter 195B, Service Letter 213A, Service
Letter 217A, and Service Letter 218A provides the
inspection requirements for all affected model airplanes; and
--Service Letter 195A, Service Letter 213B, Service
Letter 217B, and Service Letter 218B give the
procedures for replacing and modifying the upper aft longeron if cracks
are found for all affected model airplanes and is the terminating
action for the repetitive inspection requirements.

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 products of this same type design. Therefore, we are proposing
AD action.
What would this proposed AD require? This proposed AD would
supersede 2002-19-10 with a new AD that 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. If cracks are
found, this proposed AD would also require you to replace and modify
the upper aft longeron. Replacing and modifying the upper aft longeron
would terminate the repetitive inspection requirement.
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 1,194 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 inspections:

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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 $65 per hour = $65....... No parts required........ $65 $65 x 1,194 = $77,610.
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We estimate the following costs to accomplish any necessary
replacements that would be required based on the results of the
proposed inspection(s). We have no way of determining the number of
airplanes that may need this replacement:

------------------------------------------------------------------------
Total cost per
Labor cost Parts cost airplane
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27 workhours x $65 per hour For AT-400, AT-500, For AT-400, AT-500,
= $1,755. and AT-600 series and AT-600 series
airplanes: $35. airplanes: $1,755 +
$35 = $1,790.
For AT-800 series For AT-800 series
airplanes: $45. airplanes: $1,755 +
$45 = $1,800.
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What is the difference between the cost impact of this proposed AD
and the cost impact of AD 2002-19-10? The difference is the addition of
certain Model AT-501, AT-502, AT-502A, AT-502B, and AT-503A airplanes
to the applicability section of this proposed AD and the cost of
replacing any cracked upper aft longeron. There is no difference in
cost to perform the proposed inspection.

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 a copy of this summary by
sending a request to us at the address listed under ADDRESSES. Include
``AD Docket No. 2004-CE-05-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.

[[Page 18850]]

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by removing Airworthiness Directive
(AD) 2002-19-10, Amendment 39-12890 (67 FR 61481, October 1, 2002), and
by adding a new AD to read as follows:

Air Tractor, Inc.: Docket No. 2004-CE-05-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 June 7, 2004.

What Other ADs Are Affected by This Action?

(b) This AD supersedes AD 2002-19-10.

What Airplanes Are Affected by This AD?

------------------------------------------------------------------------
Model Serial Nos.
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AT-401, AT-401B, AT-402, AT-402A, and AT- 0716 through 1144.
402B.
AT-501, AT-502, AT-502A, AT-502B, and AT- 0037 through 0658.
503A.
AT-602.................................... 0337 through 0664.
AT-802 and AT-802A........................ 0001 through 0139.
------------------------------------------------------------------------

What Is the Unsafe Condition Presented in This AD?

(d) This AD is the result of reports of cracks in the aft
fuselage upper longeron, originally detected as excessive movement
in the empennage due to the loss of fuselage torsional rigidity. The
actions specified in this AD are intended to detect and correct
cracks in the upper aft longeron, which could cause the fuselage to
fail. Such failure could result in loss of control of the airplane.

What Must I Do To Address This Problem?

(e) To address this problem, you must inspect the upper longeron
and upper diagonal tube on the left hand side of the fuselage frame
just forward of the vertical fin front spar attachment for cracks at
the times specified below. You must also replace and modify any
cracked upper and diagonal longerons found during any inspection
required by this AD before further flight after the inspection in
which cracks are found.

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Affected models and serial numbers Inspection compliance times Procedures
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(1) AT-401, AT-401B, AT-402, AT- Initially inspect upon the Inspect following Snow Engineering
402A, and AT-402B: serial numbers accumulation of 1,250 total hours Co. Service Letter 218A,
(S/Ns) 0716 through 1144. time-in-service (TIS) or within the dated November 10, 2003, as
next 100 hours TIS after the specified in Snow Engineer Co.
effective date of this AD, Service Letter 195,
whichever occurs later. reissued November 10, 2003.
Repetitively inspect thereafter at Replace and modify following Snow
intervals not to exceed 100 hours Engineering Co. Service Letter
TIS until the upper and diagonal 218B, dated November 10,
longerons are replaced and 2003.
modified.
Replacing and modifying the upper
and diagonal longerons is the
terminating action for the
repetitive inspection requirement
in this AD.
(2) AT-501, AT-502, AT-502B, and AT- Initially inspect upon the Inspect following Snow Engineering
503A, S/Ns 0037 through 0658. accumulation of 4,800 total hours Co. Service Letter 218A,
TIS or within the next 100 hours dated November 10, 2003, as
TIS after the effective date of specified in Snow Engineer Co.
this AD, whichever occurs later. Service Letter 195,
Repetitively inspect thereafter at reissued November 10, 2003.
intervals not to exceed 100 hours Replace and modify following Snow
TIS until the upper and diagonal Engineering Co. Service Letter
longerons are replaced and 195A, revised November 10,
modified. 2003.
Replacing and modifying the upper
and diagonal longerons is the
terminating action for the
repetitive inspection requirement
in this AD.
(3) AT-502A, S/Ns 0037 through 0658. Initially inspect upon the Inspect following Snow Engineering
accumulation of 2,800 total hours Co. Service Letter 195B,
TIS or within the next 100 hours dated November 10, 2003, as
TIS after the effective date of specified in Snow Engineer Co.
this AD, whichever occurs later. Service Letter 195,
Repetitively inspect thereafter at reissued November 10, 2003.
intervals not to exceed 100 hours Replace and modify following Snow
TIS until the upper and diagonal Engineering Co. Service Letter
longerons are replaced and 195A, revised November 10,
modified. 2003.
Replacing and modifying the upper
and diagonal longerons is the
terminating action for the
repetitive inspection requirement
in this AD.
(4) AT-602, S/Ns 0337 through 0661. Initially inspect upon the Inspect following Snow Engineering
accumulation of 700 total hours TIS Co. Service Letter 213A,
or within the next 100 hours TIS dated November 10, 2003, as
after the last inspection required specified in Snow Engineer Co.
by AD 2002-19-10, whichever occurs Service Letter 195,
later. reissued November 10, 2003.
Repetitively inspect thereafter at Replace and modify following Snow
intervals not to exceed 100 hours Engineering Co. Service Letter
TIS until the upper and diagonal 218B, dated November 10,
longerons are replaced and 2003.
modified.
Replacing and modifying the upper
and diagonal longerons is the
terminating action for the
repetitive inspection requirement
in this AD.

[[Page 18851]]

(5) AT-602, S/Ns 0662 through 0664. Initially inspect upon the Inspect following Snow Engineering
accumulation of 1,750 total hours Co. Service Letter 213A,
TIS or within the next 100 hours dated November 10, 2003, as
TIS after the last inspection specified in Snow Engineer Co.
required by AD 2002-19-10, Service Letter 195,
whichever occurs later. reissued November 10, 2003.
Repetitively inspect thereafter at Replace and modify following Snow
intervals not to exceed 100 hours Engineering Co. Service Letter
TIS until the upper and diagonal 213B, revised November 10,
longerons are replaced and 2003.
modified.
Replacing and modifying the upper
and diagonal longerons is the
terminating action for the
repetitive inspection requirement
in this AD.
(6) AT-802 and AT-802A, S/Ns 0001 Initially inspect upon the Inspect following Snow Engineering
through 0004 and 0012 through 0118. accumulation of 250 total hours TIS Co. Service Letter 217A,
or within the next 100 hours TIS dated November 10, 2003, as
after the last inspection required specified in Snow Engineer Co.
by AD 2002-19-10, whichever occurs Service Letter 195,
later. reissued November 10, 2003.
Repetitively inspect thereafter at Replace and modify following Snow
intervals not to exceed 100 hours Engineering Co. Service Letter
TIS until the upper and diagonal 217B, revised November 10,
longerons are replaced and 2003.
modified.
Replacing and modifying the upper
and diagonal longerons is the
terminating action for the
repetitive inspection requirement
in this AD.
(7) AT-802 and AT-802A, S/Ns 0005 Initially inspect upon the Inspect following Snow Engineering
through 0011. accumulation of 900 total hours TIS Co. Service Letter 217A,
or within the next 100 hours TIS dated November 10, 2003, as
after the last inspection required specified in Snow Engineer Co.
by AD 2002-19-10, whichever occurs Service Letter 195,
later. reissued November 10, 2003.
Repetitively inspect thereafter at Replace and modify following Snow
intervals not to exceed 100 hours Engineering Co. Service Letter
TIS until the upper and diagonal 217B, dated November 10,
longerons are replaced and 2003.
modified.
Replacing and modifying the upper
and diagonal longerons is the
terminating action for the
repetitive inspection requirement
in this AD.
(8) AT-802 and AT-802A, S/Ns 0119 Initially inspect upon the Inspect following Snow Engineering
through 0139. accumulation of 1,750 total hours Co. Service Letter 217A,
TIS or within the next 100 hours dated November 10, 2003, as
TIS after the last inspection specified in Snow Engineer Co.
required by AD 2002-19-10, Service Letter 195,
whichever occurs later. reissued November 10, 2003.
Repetitively inspect thereafter at Replace and modify following Snow
intervals not to exceed 100 hours Engineering Co. Service Letter
TIS until the upper and diagonal 217B, revised November 10,
longerons are replaced and 2003.
modified.
Replacing and modifying the upper
and diagonal longerons is the
terminating action for the
repetitive inspection requirement
in this AD.
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(f) You may replace and modify the upper and diagonal longeron
at any time as a terminating action for the repetitive inspection
requirement in this AD. However, you must replace and modify the
upper and diagonal longeron before further flight after any
inspection in which cracks are found.

May I Request an Alternative Method of Compliance?

(g) 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 ACO, 2601 Meacham
Boulevard, Fort Worth, Texas 76193-0150. Current duty station: San
Antonio Manufacturing Inspection District Office (MIDO), 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?

(h) 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 April 1, 2004.
David R. Showers,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-8056 Filed 4-8-04; 8:45 am]

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