[Federal Register: April 3, 2003 (Volume 68, Number 64)]
[Rules and Regulations]
[Page 16198-16200]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr03ap03-7]
[[Page 16198]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2000-CE-59-AD; Amendment 39-13100; AD 2003-07-04]
RIN 2120-AA64
Airworthiness Directives; Air Tractor, Inc. Models AT-300, AT-
400, AT-400A, AT-401, AT-401B, AT-402, AT-402A, AT-402B, AT-501, AT-
502, and AT-502B 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-300, AT-
400, AT-400A, AT-401, AT-401B, AT-402, AT-402A, AT-402B, AT-501, AT-
502, and AT-502B airplanes. This AD requires you to repetitively
inspect the vertical fin front spar fitting for cracks and replace any
cracked fitting found. This AD also requires you to install a steel
doubler as a terminating action for the repetitive inspections. This AD
is the result of a report of failure of a \1/4\-inch thick vertical fin
front spar fitting. The actions specified by this AD are intended to
prevent failure of the vertical fin front spar fitting, which could
result in failure of the rear spar fitting. Such failures could lead to
loss of directional control of the airplane.
DATES: This AD becomes effective on May 22, 2003.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in the regulations as of May
22, 2003.
ADDRESSES: You may get the service information referenced in this AD
from Air Tractor, Inc., PO 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.
2000-CE-59-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: Andy 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 two incidents, one in 1994 and one in
1995, in which the vertical fin front spar fitting and rear spar
fitting failed, while in flight, on an Air Tractor Model AT-402 and a
Model AT-502 airplane. Failure of the vertical fin front spar fitting
causes the rear spar fitting to fail. These failures result in the
vertical tail lying over against the elevator creating difficulty in
controlling the airplane.
These vertical fin front spar fittings were made of \3/16\-inch
thick aluminum. Investigation revealed that Air Tractor models with the
\3/16\-inch front spar attach plates installed were subject to fatigue
failure.
This unsafe condition was addressed in AD 95-20-06, Amendment 39-
9384. AD 95-20-06 applied to airplanes with \3/16\-inch thick and \1/
4\-inch thick aluminum fin front spar fittings installed.
In 1997, we issued AD 97-14-05, Amendment 39-10063, that supersedes
AD 95-20-06. Further investigation revealed that only Air Tractor
models with a \3/16\-inch thick fin front spar fitting installed were
developing cracks. Therefore, we issued AD 97-14-05 to remove Air
Tractor models with a \1/4\-inch thick fin front spar fitting installed
from the applicability.
Recently, a Model AT-502 airplane was found with a cracked \1/4\-
inch thick fin front spar fitting. The crack was found during a routine
inspection. The rear spar had not yet failed. This recent finding
demonstrates that Air Tractor models with a \1/4\-inch thick fin front
spar fitting are subject to fatigue failure.
What Is the Potential Impact if FAA Took No Action?
This condition, if not detected and corrected, could result in
structural failure of the vertical fin front spar fitting and
eventually the rear spar fitting. Such failure could result in loss of
directional 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 Models AT-300, AT-400, AT-400A, AT-401, AT-401B,
AT-402, AT-402A, AT-402B, AT-501, AT-502, and AT-502B airplanes. This
proposal was published in the Federal Register as a notice of proposed
rulemaking (NPRM) on December 27, 2002 (67 FR 79008). The NPRM proposed
to require you to repetitively inspect the vertical fin front spar
fitting for cracks and replace any cracked fitting found. The NPRM also
proposed to require you to install a steel doubler as a terminating
action for the repetitive inspections.
Was the Public Invited To Comment?
The FAA encouraged interested persons to participate in the making
of this amendment. The following presents the comment received on the
proposal and FAA's response:
Comment Issue: Change the Serial Number Applicability for Certain
Affected Airplane Models
What Is the Commenter's Concern?
The commenter states that the serial number affectivity for Air
Tractor Models AT-401 and AT-401B should include the notation that
specifically designates serial numbers that have been converted to
turbine powerplants as specified in Snow Engineering Co. Service Letter
155, Revised November 27, 2002.
What Is FAA's Response to the Concern?
We concur with the commenter and will change the final rule AD
action to incorporate this change.
FAA's Determination
What Is FAA's Final Determination on This Issue?
We carefully reviewed all available information related to the
subject presented above and determined that air safety and the public
interest require the adoption of the rule as proposed except for the
changes discussed above and minor editorial corrections. We have
determined that these changes and 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.
How Does the Revision to 14 CFR Part 39 Affect This AD?
On July 10, 2002, FAA 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 special flight
permits, alternative methods of compliance, and altered products. 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.
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Cost Impact
How Many Airplanes Does This AD Impact?
We estimate that this AD affects 440 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:
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Total cost per
Labor cost Parts cost airplane Total cost on U.S. operators
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4 workhours x $60 = $240........... No parts required.... $240 $240 x 440 = $105,600
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We estimate the following costs to accomplish the modification:
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Total cost per
Labor cost Parts cost airplane
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7 workhours x $60 = $420....... Parts will be provided $420
by Air Tractor at no
charge to the
customer.
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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
0
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
0
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]
0
2. FAA amends Sec. 39.13 by adding a new AD to read as follows:
2003-07-04 Air Tractor, Inc.: Amendment 39-13100; Docket No. 2000-
CE-59-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 Nos.
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AT-300, AT-400, and AT-400A............ All serial numbers with a
turbine powerplant and is
retrofitted with a \1/4\inch
thick aluminum vertical fin
front spar fitting and an all-
metal rudder.
AT-401 and AT-401B..................... 401-0737 through 401-1015 and
401B-0737 through 401B-1015
that have been converted to
turbine powerplants.
AT-402, AT-402A, and AT-402B........... 402-0737 through 402B-1015.
AT-501................................. 501-0031 and subsequent that
have been converted to turbine
powerplants.
AT-502 and AT-502B..................... 502-0031 through 502B-0398.
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(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 vertical fin front
spar fittings, which could result in failure of the rear spar
fitting. Such failures could lead to loss of directional 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 vertical fin Upon the In accordance with
front spar fitting for accumulation of Snow Engineering
cracks. 2,000 hours time-in- Co. Service Letter
service (TIS) on 155,
the vertical fin Revised November
front or spar 27, 2002.
fitting next 100
hours TIS after May
22, 2003 (the
effective date of
this AD), whichever
occurs later. If no
cracks are found,
repetitively
inspect thereafter
at intervals not to
exceed 100 hours
TIS.
(2) If cracks are found Prior to further In accordance with
during any inspection flight after the Snow Engineering
required in paragraph crack is found. Co. Service Letter
(d)(1) of this AD, replace Continue with the 155,
the vertical fin front spar repetitive Revised November
fitting. inspection 27, 2002.
requirements in
paragraph (d)(1) of
this AD until the
terminating action
is accomplished.
(3) Modify the vertical fin Within the next In accordance with
front spar fitting by 2,000 hours TIS Snow Engineering
installing a steel doubler. after May 22, 2003 Co. Service Letter
(the effective date 155,
of this AD). Revised November
Installing the 27, 2002.
steel doubler is
considered
terminating action
for the repetitive
inspection
requirements of
this AD. The
installation may be
accomplished at any
time provided the
vertical fin front
spar fitting is
crack free.
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(e) Can I comply with this AD in any other way? To use an
alternative method of compliance or adjust the compliance time, use
the procedures in 14 CFR 39.19. Send these requests to the Manager,
Ft. Worth Aircraft Certification Office (ACO). For information on
any already approved alternative methods of compliance, contact Andy
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.
(f) 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 155, Revised
November 27, 2002. 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, Inc., 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.
(g) When does this amendment become effective? This amendment
becomes effective on May 22, 2003.
Issued in Kansas City, Missouri, on March 25, 2003.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 03-7747 Filed 4-2-03; 8:45 am]
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