FR Doc E7-23229

[Federal Register: November 30, 2007 (Volume 72, Number 230)]
[Proposed Rules]
[Page 67687-67690]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30no07-19]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-0258; Directorate Identifier 2007-CE-090-AD]
RIN 2120-AA64

Airworthiness Directives; Air Tractor, Inc. Models AT-400, AT-
500, AT-600, and AT-800 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to supersede Airworthiness Directive (AD) 2007-13-
17, which applies to all Air Tractor, Inc. (Air Tractor) Models AT-602,
AT-802, and AT-802A airplanes. AD 2007-13-17 currently requires you to
repetitively inspect the engine mount for any cracks, repair or replace
any cracked engine mount, and report any cracks found to the FAA. Since
we issued AD 2007-13-17, Air Tractor has learned of a Model AT-502B
with a crack located where the lower engine mount tube is welded to the
engine mount ring. In addition, Snow Engineering Co. has developed
gussets that, when installed according to their service letter,
terminate the repetitive inspection requirement. Consequently, this
proposed AD would retain the inspection actions of AD 2007-13-17 for
Model AT-602, AT-802, and AT-802A airplanes, including the compliance
times and effective dates; establish new inspection actions for the AT-
400 and AT-500 series airplanes; incorporate a mandatory terminating
action for all airplanes; and terminate the reporting requirement of AD
2007-13-17. We are proposing this AD to detect and correct cracks in
the engine mount, which could result in failure of the engine mount.
Such failure could lead to separation of the engine from the airplane.

DATES: We must receive comments on this proposed AD by January 29,
2008.

ADDRESSES: Use one of the following addresses to comment on this
proposed AD:
Federal eRulemaking Portal: Go to http://www.regulations.gov.
Follow the instructions for submitting comments.

Fax: (202) 493-2251.
Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590.
Hand Delivery: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
For service information identified in this proposed AD, contact Air
Tractor Inc., P.O. Box 485, Olney, Texas 76374; telephone: (940) 564-
5616; fax: (940) 564-5612.

FOR FURTHER INFORMATION CONTACT: Andy McAnaul, Aerospace Engineer, ASW-
150, FAA San Antonio MIDO-43, 10100 Reunion Pl, San Antonio, Texas
78216; phone: (210) 308-3365; fax: (210) 308-3370.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or
arguments regarding this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include the docket number, ``FAA-
2007-0258; Directorate Identifier 2007-CE-090-AD'' at the beginning of
your comments. We specifically invite comments on the overall
regulatory, economic, environmental, and energy aspects of the proposed
AD. We will consider all comments received by the closing date and may
amend the proposed AD in light of those comments.
We will post all comments we receive, without change, to http://www.regulations.gov
, including any personal information you provide. We

will also post a report summarizing each substantive verbal contact we
receive concerning this proposed AD.

Discussion

Two reports of Model AT-802A airplanes with cracked engine mounts
(at 2,815 hours time-in-service (TIS) and 1,900 hours TIS) caused us to
issue AD 2007-13-17, Amendment 39-15121 (72 FR 36863, July 6, 2007). AD
2007-13-17 currently requires the following on all Air Tractor Models
AT-602, AT-802, and AT-802A airplanes:
Inspect (initially and repetitively) the engine mount for
any cracks;
Repair or replace any cracked engine mount; and
Report any cracks found to the FAA.

[[Page 67688]]

Since we issued AD 2007-13-17, Air Tractor notified the FAA of a
Model AT-502B airplane with a crack located where the lower engine
mount tube is welded to the engine mount ring. The airplane had 8,436
total hours TIS. The cracking is similar to what prompted us to issue
AD 2007-13-17.
The Model AT-502B engine mount is the same design used in the
Models AT-400, AT-400A, AT-402, AT-402A, AT-402B, AT-502, and AT-503A
airplanes. The Model AT-502A airplane uses the same engine mount design
as the airplanes affected by AD 2007-13-17. Therefore, we determined
that these airplane models should be subject to the actions of AD 2007-
13-17.
Currently, the FAA is aware of the following airplanes that have
had cracked engine mounts:
1 Model AT-502B;
3 Model AT-602; and
11 Model AT-802/802A.
This condition, if not corrected, could result in failure of the
engine mount. Such failure could lead to separation of the engine from
the airplane.
In addition, Snow Engineering Co. developed gussets for an FAA-
approved repair scheme to AD 2007-13-17. Snow Engineering Co. tested
the engine mount with the gussets installed; and based on their test
data, which has been approved by the FAA, installation of the gussets
terminates the repetitive inspection requirement.

Relevant Service Information

We have reviewed Snow Engineering Co. Service Letter 253
Rev. A, dated October 16, 2007.
The service information describes procedures for:
Performing a visual inspection of the engine mount for
cracks;
Repairing the engine mount if cracks are found; and
Adding gussets to reinforce the engine mount and terminate
the inspection requirement.

FAA's Determination and Requirements of the Proposed AD

We are proposing this AD because we evaluated all information and
determined the unsafe condition described previously is likely to exist
or develop on other products of the same type design. This proposed AD
would supersede AD 2007-13-17 with a new AD that would retain the
inspection actions of AD 2007-13-17 for Models AT-602, AT-802, and AT-
802A airplanes, including the compliance times and effective dates;
establish new inspection actions for the AT-400 and AT-500 series
airplanes; incorporate a mandatory terminating action for all
airplanes; and terminate the reporting requirement of AD 2007-13-17.
This proposed AD would require you to use the service information
described previously to perform these actions.

Costs of Compliance

We estimate that this proposed AD would affect 1,264 airplanes in
the U.S. registry, including those airplanes affected by AD 2007-13-17.
We estimate the following costs to do the proposed inspection:

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Total cost per Total cost on
Labor cost Parts cost airplane U.S. operators
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1.5 work-hours x $80 per hour = $120......................... $0 $120 $151,680
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We estimate the following costs to do the repair/modification:

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Total cost per Total cost on
Labor cost Parts cost airplane U.S. operators
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24 work-hours x $80 per hour = $1,920........................ $80 $2,000 $2,528,000
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The estimated total cost on U.S. operators includes the cumulative
costs associated with AD 2007-13-17 and those airplanes and actions
being added in this AD.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, Section 106, describes the
authority of the FAA Administrator. Subtitle VII, Aviation Programs,
describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701, ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.

Regulatory Findings

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.
For the reasons discussed above, I certify that the proposed
regulation:
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 regulatory evaluation of the estimated costs to
comply with this proposed AD and placed it in the AD docket.

Examining the AD Docket

You may examine the AD docket that contains the proposed AD, the
regulatory evaluation, any comments received, and other information on
the Internet at http://www.regulations.gov; or in person at the Docket

Management Facility between 9 a.m. and 5 p.m., Monday through Friday,
except Federal holidays. The Docket Office (telephone (800) 647-5527)
is located at the street address stated in the ADDRESSES section.
Comments will be available in the AD docket shortly after receipt.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

[[Page 67689]]

The Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA 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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by removing Airworthiness Directive
(AD) 2007-13-17, Amendment 39-15121 (72 FR 36863, July 6, 2007), and
adding the following new AD:

Air Tractor, Inc.: Docket No. FAA-2007-0258; Directorate Identifier
2007-CE-090-AD.

Comments Due Date

(a) We must receive comments on this airworthiness directive
(AD) action by January 29, 2008.

Affected ADs

(b) This AD supersedes AD 2007-13-17, Amendment 39-15121.

Applicability

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Model Serial numbers
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AT-400, AT-400A, AT-402, AT-402A, and -0001 through -1175.
AT-402B.
AT-502, AT-502A, AT-502B, and AT-503A -0001 through -2597.
AT-602............................... -0001 through -1141.
AT-802 and AT-802A................... -0001 through -0227.
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Unsafe Condition

(d) This AD results from a report of a Model AT-502B airplane
with a crack located where the lower engine mount tube is welded to
the engine mount ring. The airplane had 8,436 total hours time-in-
service (TIS). We are issuing this AD to detect and correct cracks
in the engine mount, which could result in failure of the engine
mount. Such failure could lead to separation of the engine from the
airplane.

Compliance

(e) To address this problem, you must do the following, unless
already done:
(1) For all airplanes with less than 5,000 hours total TIS that
do not have gussets installed on the engine mount in accordance with
Snow Engineering Co. Service Letter #253 Rev. A, dated October 16,
2007: Visually inspect the engine mount as follows:

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Affected airplanes Compliance Procedures
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(i) For all Models AT-602, Initially before the Follow Snow
AT-802, and AT-802A airplane reaches a Engineering Co.
airplanes. total of 1,300 Service Letter
hours TIS or within 253 Rev.
the next 100 hours A, dated October
TIS after August 16, 2007, or Snow
10, 2007 (the Engineering Co.
effective date of Service Letter
AD 2007-13-17), 253,
whichever occurs revised January 22,
later. Repetitively 2007.
thereafter at
intervals not to
exceed 300 hours
TIS.
(ii) For all Model AT-502A Initially before the Follow Snow
airplanes. airplane reaches a Engineering Co.
total of 1,300 Service Letter
hours TIS or within 253 Rev.
the next 100 hours A, dated October
TIS after the 16, 2007.
effective date of
this AD, whichever
occurs later.
Repetitively
thereafter at
intervals not to
exceed 300 hours
TIS.
(iii) For all Models AT-400, Initially within the Follow Snow
AT-400A, AT-402, AT-402A, next 12 months Engineering Co.
AT-402B, AT-502, AT-502B, after the effective Service Letter
and AT-503A airplanes. date of this AD. 253 Rev.
Repetitively A, dated October
thereafter at 16, 2007.
intervals not to
exceed 12 months.
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(2) For all airplanes: Before further flight after any
inspection required by paragraph (e)(1) of this AD where crack
damage is found, repair and modify the engine mount by installing
gussets following Snow Engineering Co. Service Letter 253
Rev. A, dated October 16, 2007. This modification terminates the
repetitive inspections required in paragraphs (e)(1)(i), (e)(1)(ii),
and (e)(1)(iii) of this AD.
(3) For all airplanes: Before the airplane reaches 5,000 hours
total TIS after the effective date of this AD or within the next 100
hours TIS after the effective date of this AD, whichever occurs
later; inspect, repair if cracked, and modify the engine mount by
installing gussets following Snow Engineering Co. Service Letter
253 Rev. A, dated October 16, 2007. This modification
terminates the repetitive inspections required in paragraphs
(e)(1)(i), (e)(1)(ii), and (e)(1)(iii) of this AD.

Note: As a terminating action to the repetitive inspections
required in paragraphs (e)(1)(i), (e)(1)(ii), and (e)(1)(iii) of
this AD, you may install the gussets before finding cracks or
reaching 5,000 hours total TIS.

Alternative Methods of Compliance (AMOCs)

(f) The Manager, Forth Worth Aircraft Certification Office, FAA,
has the authority to approve AMOCs for this AD, if requested using
the procedures found in 14 CFR 39.19. Send information to ATTN: Andy
McAnaul, Aerospace Engineer, ASW-150, FAA San Antonio MIDO-43, 10100
Reunion Pl, San Antonio, Texas 78216; phone: (210) 308-3365; fax:
(210) 308-3370. Before using any approved AMOC on any airplane to
which the AMOC applies, notify your appropriate principal inspector
(PI) in the FAA Flight Standards District Office (FSDO), or lacking
a PI, your local FSDO.

Related Information

(g) To get copies of the service information referenced in this
AD, contact Air Tractor Inc., P.O. Box 485, Olney, Texas 76374;
telephone: (940) 564-5616; fax: (940) 564-5612. To view the AD
docket, go to U.S. Department of Transportation, Docket Operations,
M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey
Avenue, SE., Washington, DC 20590, or on the Internet at http://www.regulations.gov.
The docket number is Docket No. FAA-2007-0258;

Directorate Identifier 2007-CE-090-AD.

[[Page 67690]]

Issued in Kansas City, Missouri, on November 23, 2007.
Steven W. Thompson,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-23229 Filed 11-29-07; 8:45 am]

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