Document ID: FAA-2007-0258-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Air Tractor, Inc. Models AT-400, AT- 500, AT-600, and AT-800 Series Airplanes
Posted Date: 2007-11-30T05:00Z

[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).

-----------------------------------------------------------------------

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:

----------------------------------------------------------------------------------------------------------------
                                                                                 Total cost per   Total cost on
                          Labor cost                              Parts cost        airplane      U.S. operators
----------------------------------------------------------------------------------------------------------------
1.5 work-hours x $80 per hour = $120.........................              $0             $120         $151,680
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do the repair/modification:

----------------------------------------------------------------------------------------------------------------
                                                                                 Total cost per   Total cost on
                          Labor cost                              Parts cost        airplane      U.S. operators
----------------------------------------------------------------------------------------------------------------
24 work-hours x $80 per hour = $1,920........................             $80           $2,000       $2,528,000
----------------------------------------------------------------------------------------------------------------

    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

    (c) This AD applies to the following airplane models and serial 
numbers that are certificated in any category:

------------------------------------------------------------------------
                Model                            Serial numbers
------------------------------------------------------------------------
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.
------------------------------------------------------------------------

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:

------------------------------------------------------------------------
     Affected airplanes            Compliance            Procedures
------------------------------------------------------------------------
(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.
------------------------------------------------------------------------

    (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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