Airworthiness Directives; Thrush Aircraft, Inc. Models S2R Series Airplanes, 41042-41045 [E7-14433]

Download as PDF 41042 Federal Register / Vol. 72, No. 143 / Thursday, July 26, 2007 / Proposed Rules (d) The Cooperator shall promptly refund any balance of unobligated cash advanced or paid by the REE Agency that it is not authorized to retain for use in other projects. OMB Circular A–129 governs unreturned amounts that become delinquent debts. (e) When authorized by the terms and conditions of the award, the REE Agency shall make a settlement for any upward or downward adjustments to the Federal share of costs after closeout reports are received. (f) The Cooperator shall account for any personal property acquired with Federal funds or received from the Federal Government in accordance with § 550.36 through § 550.42. (g) In the event a final audit has not been performed prior to the closeout of an award, the REE Agency shall retain the right to recover an appropriate amount after fully considering the recommendations on disallowed costs resulting from the final audit. § 550.61 Subsequent adjustments and continuing responsibilities. The closeout of an award does not affect any of the following. (a) The right of the REE Agency to disallow costs and recover funds on the basis of a later audit or other review. (b) The obligation of the Cooperator to return any funds due as a result of later refunds, corrections, or other transactions. (c) Audit requirements in § 550.24. (d) Property management requirements in § 550.36 through § 550.42. (e) Records retention as required in § 550.56. rmajette on PROD1PC64 with PROPOSALS § 550.62 Collection of amounts due. (a) Any funds paid to a Cooperator in excess of the amount to which the Cooperator is finally determined to be entitled under the terms and conditions of the award constitute a debt to the Federal Government. If not paid within a reasonable period after the demand for payment, the REE Agency may in accordance with 7 CFR Part 3, reduce the debt by— (1) Making an administrative offset against other requests for reimbursements or (2) Withholding advance payments otherwise due to the Cooperator, or (3) Taking other action permitted by statute. (b) Except as otherwise provided by law, the REE Agency shall charge interest on an overdue debt in accordance with 31 CFR Part 900, ‘‘Federal Claims Collection Standards.’’ VerDate Aug<31>2005 15:44 Jul 25, 2007 Jkt 211001 Dated: July 5, 2007. Edward B. Knipling, Administrator, Agricultural Research Service. [FR Doc. E7–13550 Filed 7–25–07; 8:45 am] BILLING CODE 3410–03–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2007–28432; Directorate Identifier 2007–CE–051–AD] RIN 2120–AA64 Airworthiness Directives; Thrush Aircraft, Inc. Models S2R Series Airplanes Federal Aviation Administration (FAA), Department of Transportation (DOT). ACTION: Notice of proposed rulemaking (NPRM). AGENCY: SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain Thrush Aircraft, Inc. (Thrush) Model S2R series airplanes. This proposed AD would require repetitive visual inspections of the vertical and horizontal stabilizer attach fitting, attach fitting bolts, and the vertical fin aft spar for cracks or corrosion and require immediate replacement of cracked or corroded parts and eventual replacement if no cracks or corrosion is found as terminating action for the repetitive inspections. This proposed AD results from reports of cracks in the empennage of Thrush S2R series airplanes. We are proposing this AD to detect and correct these cracks, which could cause the vertical stabilizer to lose structural integrity. This condition could lead to loss of control. DATES: We must receive comments on this proposed AD by September 24, 2007. Use one of the following addresses to comment on this proposed AD: • DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically. • 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. • Fax: (202) 493–2251. • Hand Delivery: U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue, SE., ADDRESSES: PO 00000 Frm 00016 Fmt 4702 Sfmt 4702 Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. • Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments. For service information identified in this proposed AD, contact: Thrush Aircraft, Inc., P.O. Box 3149, 300 Old Pretoria Road, Albany, Georgia 31706– 3149; telephone: 229–883–1440; facsimile: 229–436–4856; or on the Internet at: http:// www.thrushaircraft.com. FOR FURTHER INFORMATION, CONTACT ONE OF THE FOLLOWING: —Cindy Lorenzen, Aerospace Engineer, ACE–115A, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Blvd., Suite 450, Atlanta, Georgia 30349; telephone: (770) 703–6078; facsimile: (770) 703–6097; e-mail: cindy.lorenzen@faa.gov; or —Mike Cann, Aerospace Engineer, ACE–117A, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Blvd., Suite 450, Atlanta, Georgia 30349; telephone: (770) 703–6038; facsimile: (770) 703–6097; e-mail: michael.cann@faa.gov. 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–2007–28432; Directorate Identifier 2007–CE–051–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:// dms.dot.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 We have received reports of cracks in the empennage of Thrush S2R series airplanes. Cracks may occur in the vertical stabilizer attach fitting, the horizontal stabilizer attach fitting, attach fitting bolts, and/or the vertical fin aft spar on airplanes with metal empennages. A metallurgy report suggests stress corrosion cracking is the E:\FR\FM\26JYP1.SGM 26JYP1 Federal Register / Vol. 72, No. 143 / Thursday, July 26, 2007 / Proposed Rules cause of these cracks. A report was received from the field that a 5⁄16-inch vertical attach bolt, part number (P/N) NAS1105–68, was found broken in two places, causing the rear spar of the vertical fin to crack. A separate incident found the attach fitting on the stabilizer itself cracked in both lugs from stress corrosion. This condition, if not corrected, could cause the vertical stabilizer to lose structural integrity. This condition could lead to loss of control. Relevant Service Information We have reviewed Thrush Aircraft, Inc., Service Bulletin No. SB–AG–45, Revision B, dated June 1, 2007. The service information describes procedures for inspecting and upgrading the fin spar and attach fittings. 41043 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 require repetitive visual inspections of the vertical and horizontal stabilizer attach fitting, attach fitting bolts, and the vertical fin aft spar for cracks or corrosion and require immediate replacement of cracked or corroded parts and eventual replacement if no cracks or corrosion is found as terminating action for the repetitive inspections. upon receipt action to be an urgent safety of flight compliance time. Because our risk assessment does not indicate this unsafe condition to be an urgent safety of flight condition, we propose to require an initial inspection within the next 50 hours time-in-service (TIS). The initial inspection time of 50 hours TIS is an adequate compliance for this AD action and meets the FAA requirements of an NPRM. We propose to require a terminating action of replacing the parts within the next 2 years or 2,000 hours TIS, whichever occurs first. This is recommended because there is historic evidence that inspections alone can eventually miss detecting a crack. Differences Between This Proposed AD and the Service Information Thrush Aircraft, Inc. SB–AG–45, Revision B, dated June 1, 2007, recommends an immediate initial inspection. We consider immediately Costs of Compliance We estimate that this proposed AD would affect 910 airplanes in the U.S. registry. We estimate the following costs to do the proposed inspection: Labor cost Parts cost Total cost per airplane Total cost on U.S. operators 8 work-hours × $80 per hour = $640 ...................................................... Not applicable ................................ $640 $582,400 We estimate the following costs to do any necessary replacements of the vertical fin aft spar that would be required based on the results of the proposed inspection. We have no way of determining the number of airplanes that may need this replacement: Labor cost Parts cost Total cost per airplane 12 work-hours × $80 per hour = $960 ................................................................................................................ $3,800 $4,760 We estimate the following costs to replace the vertical and horizontal stabilizer attach fittings and attachment bolt: Parts cost Total cost per airplane Total cost on U.S. operators 30 work-hours × $80 per hour = $2,400 ............................................................................... rmajette on PROD1PC64 with PROPOSALS Labor cost $1,550 $3,950 $3,594,500 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 VerDate Aug<31>2005 15:44 Jul 25, 2007 Jkt 211001 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. PO 00000 Frm 00017 Fmt 4702 Sfmt 4702 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. E:\FR\FM\26JYP1.SGM 26JYP1 41044 Federal Register / Vol. 72, No. 143 / Thursday, July 26, 2007 / Proposed Rules 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://dms.dot.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. 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) (2) (3) (4) (5) (6) (a) We must receive comments on this airworthiness directive (AD) action by September 24, 2007. (b) None. Applicability Authority: 49 U.S.C. 106(g), 40113, 44701. [Amended] 2. The FAA amends § 39.13 by adding the following new AD: Model Comments Due Date Affected ADs 1. The authority citation for part 39 continues to read as follows: § 39.13 Thrush Aircraft, Inc.: Docket No. FAA– 2007–28432; Directorate Identifier 2007– CE–051–AD. (c) This AD applies to the following airplane models and serial numbers that are certificated in any category and are equipped with metal empennage part numbers (P/N) 40220 or 95400 (applies to serial numbers with or without a ‘‘DC’’ suffix): Serial Nos. S2R ................................................................ S2R–R1340 ................................................... S2R–R1820 ................................................... S2R–T11 ........................................................ S2R–T15 ........................................................ S2R–T34 ........................................................ (7) S2RHG–T34 .................................................. (8) S2R–T45 ........................................................ (9) S2R–T65 ........................................................ (10) S2RHG–T65 ................................................ (11) S2R–G1 ....................................................... (12) S2R–G5 ....................................................... (13) S2R–G6 ....................................................... (14) S2R–G10 ..................................................... (15) S2R–T660 .................................................... Unsafe Condition (d) This proposed AD results from reports of cracks in the empennage of Thrush Aircraft, Inc., S2R series airplanes. We are 1416R through 5100R. R1340–001 through R1340–035. R1820–001 through R1820–036. T11–001 through T11–005. T15–001 through T15–044 and T27–001 through T27–044. 6000 through 6049, T34–001 through T34–279, T36–001 through T36–279, T41–001 through T41–279, T42–001 through T42–279. T34HG–101 through T34HG–107. T45–001 through T45–015. T65–001 through T65–018. T65–001 through T65–018 and T65HG–011 through T65HG–019. G1–101 through G1–115. G5–101 through G5–105. G6–101 through G6–155. G10–101 through G10–168. T660–101 through T660–120. proposing this AD to detect and correct these cracks, which could cause the vertical stabilizer to lose structural integrity. This condition could lead to loss of control. Compliance (e) To address this problem, you must do the following, unless already done: Compliance Procedures (1) Perform a visual inspection of the vertical stabilizer attach fitting (P/N 40301–7), the horizontal stabilizer attach fitting (P/N 40303– 1/–4/–7 or 95267–1), attachment bolt (P/N NAS1105–68), and vertical fin aft spar (P/N 40261–24 or P/N 95253–1), for cracks or corrosion. (2) If cracks or corrosion are found in P/N 40301–7, 40303–1/–4/–7, 95267–1, or NAS1105–68 during any inspection required in paragraph (e)(1) of this AD, replace all three parts with new P/Ns 95266–3, 95267–5 and NAS6207–68. (3) If cracks or corrosion are found in P/N 40261–24 or 95253–1 during any inspection required in paragraph (e)(1) of this AD, replace with a new P/N 40261–24 or 95253–1, or repair in accordance with Thrush SB–AG– 45, Revision B. rmajette on PROD1PC64 with PROPOSALS Actions Within the next 50 hours time-in-service (TIS) after the effective date of this AD and repetitively thereafter at intervals not to exceed every 100 hours TIS for up to 2 years or a total of 2,000 hours TIS, whichever occurs first. Follow Thrush Aircraft, Inc. Service Bulletin No. SB–AG–45, Revision B, dated June 1, 2007. Before further flight after any inspection where cracks or corrosion are found. Follow Thrush Aircraft, Inc. Service Bulletin No. SB–AG–45, Revision B, dated June 1, 2007. Before further flight after any inspection where cracks or corrosion are found. Follow Thrush Aircraft, Inc. Service Bulletin No. SB–AG–45, Revision B, dated June 1, 2007. VerDate Aug<31>2005 15:44 Jul 25, 2007 Jkt 211001 PO 00000 Frm 00018 Fmt 4702 Sfmt 4702 E:\FR\FM\26JYP1.SGM 26JYP1 Federal Register / Vol. 72, No. 143 / Thursday, July 26, 2007 / Proposed Rules 41045 Actions Compliance Procedures (4) Replace vertical stabilizer attach fitting P/N 40301–7 with P/N 95266–3, replace horizontal stabilizer attach fitting P/N 40303–1/– 4/–7 or 95267–1 with P/N 95267–5, and replace attachment bolt NAS1105–68 with NAS6207–68 bolt. Within the next 2,000 hours TIS after the effective date of this AD or within 2 years after the effective date of this AD, whichever occurs first. This action terminates the repetitive inspections required in paragraph (e)(1) of this AD, including the inspections of the vertical fin aft spar, P/N 40261–24 or 95253–1. Follow Thrush Aircraft, Inc. Service Bulletin No. SB–AG–45, Revision B, dated June 1, 2007. Special Flight Permit DEPARTMENT OF THE TREASURY (f) Under 14 CFR part 39.23, we are limiting the special flight permits authorized for this AD to ferry aircraft to a maintenance facility for inspection by the following conditions: (1) Hopper must be empty. (2) Vne reduced to 126 m.p.h. (109 knots); and (3) No flight into known turbulence. Alternative Methods of Compliance (AMOCs) (g) The Manager, 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: Cindy Lorenzen, Aerospace Engineer, ACE–115A, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Blvd., Suite 450, Atlanta, GA 30349; telephone: (770) 703– 6078; facsimile: (770) 703–6097; e-mail: cindy.lorenzen@faa.gov; or Mike Cann, Aerospace Engineer, ACE–117A, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Blvd., Suite 450, Atlanta, Georgia 30349; telephone: (770) 703– 6038; facsimile: (770) 703–6097; e-mail: michael.cann@faa.gov. 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 rmajette on PROD1PC64 with PROPOSALS (h) To get copies of the service information referenced in this AD, contact Thrush Aircraft, Inc., P.O. Box 3149, 300 Old Pretoria Road, Albany, Georgia 31706–3149; telephone: 229–883–1440; facsimile: 229– 436–4856; or on the Internet at: http:// www.thrushaircraft.com. 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://dms.dot.gov. The docket number is Docket No. FAA–2007–28432; Directorate Identifier 2007–CE–051–AD. Issued in Kansas City, Missouri, on July 20, 2007. Kim Smith, Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. E7–14433 Filed 7–25–07; 8:45 am] BILLING CODE 4910–13–P VerDate Aug<31>2005 15:44 Jul 25, 2007 Jkt 211001 Internal Revenue Service 26 CFR Part 301 Zone Act of 2005, the Tax Relief and Health Care Act of 2006, and the Small Business and Work Opportunity Tax Act of 2007. The regulations provide’’. RIN 1545–BE07 Application of Section 6404(g) of the Internal Revenue Code Suspension Provisions; Correction LaNita Van Dyke, Chief, Publications and Regulations Branch, Legal Processing Division, Associate Chief Counsel (Procedure and Administration). [FR Doc. E7–14400 Filed 7–25–07; 8:45 am] BILLING CODE 4830–01–P [REG–149036–04] Internal Revenue Service (IRS), Treasury. ACTION: Correction to notice of proposed rulemaking by cross-reference to temporary regulations. DEPARTMENT OF THE TREASURY SUMMARY: This document contains corrections to notice of proposed rulemaking by cross-reference to temporary regulations (REG–149036–04) that were published in the Federal Register on Thursday, June 21, 2007 (72 FR 34204) relating to the application of section 6404(g) of the Internal Revenue Code suspension provisions. FOR FURTHER INFORMATION CONTACT: Stuart Spielman, (202) 622–7950 (not a toll-free number). SUPPLEMENTARY INFORMATION: [REG–149036–04] AGENCY: Background The notice of proposed rulemaking by cross-reference to temporary regulations that are the subject of this correction are under section 6404(g) of the Internal Revenue Code. Need for Correction As published, proposed regulations (REG–149036–04) contains an error that may prove to be misleading and is in need of clarification. Correction of Publication Accordingly, the publication of the proposed regulations (REG–149036–04), which was the subject of FR Doc. E7– 12085, is corrected as follows: On page 34204, column 1, in the preamble, under the caption SUMMARY:, lines 11 through 13, the language ‘‘the gulf Opportunity zone act of 2005, and the Tax Relief and Health Care Act of 2006. The regulations provide’’ is corrected to read ‘‘the Gulf Opportunity PO 00000 Frm 00019 Fmt 4702 Sfmt 4702 Internal Revenue Service 26 CFR Part 301 RIN 1545–BG75 Application of Section 6404(g) of the Internal Revenue Code Suspension Provisions; Correction Internal Revenue Service (IRS), Treasury. ACTION: Correction to notice of proposed rulemaking. AGENCY: SUMMARY: This document contains corrections to the notice of proposed rulemaking (REG–149036–04) that were published in the Federal Register on Thursday, June 21, 2007 (72 FR 34199) proposing regulations for the suspension of interest, penalties, additions to tax or additional amounts under section 6404(g) of the Internal Revenue Code that explain the general rules for suspension as well as exceptions to those general rules. FOR FURTHER INFORMATION CONTACT: Stuart Spielman, (202) 622–7950 (not a toll-free number). SUPPLEMENTARY INFORMATION: Background The notice of proposed rulemaking that is the subject of this correction is under section 6404(g) of the Internal Revenue Code. Need for Correction As published, the proposed regulations (REG–149036–04) contain errors that may prove to be misleading and are in need of clarification. E:\FR\FM\26JYP1.SGM 26JYP1

Agencies

[Federal Register Volume 72, Number 143 (Thursday, July 26, 2007)]
[Proposed Rules]
[Pages 41042-41045]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-14433]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28432; Directorate Identifier 2007-CE-051-AD]
RIN 2120-AA64


Airworthiness Directives; Thrush Aircraft, Inc. Models S2R Series 
Airplanes

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

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain Thrush Aircraft, Inc. (Thrush) Model S2R series airplanes. This 
proposed AD would require repetitive visual inspections of the vertical 
and horizontal stabilizer attach fitting, attach fitting bolts, and the 
vertical fin aft spar for cracks or corrosion and require immediate 
replacement of cracked or corroded parts and eventual replacement if no 
cracks or corrosion is found as terminating action for the repetitive 
inspections. This proposed AD results from reports of cracks in the 
empennage of Thrush S2R series airplanes. We are proposing this AD to 
detect and correct these cracks, which could cause the vertical 
stabilizer to lose structural integrity. This condition could lead to 
loss of control.

DATES: We must receive comments on this proposed AD by September 24, 
2007.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD:
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     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.
     Fax: (202) 493-2251.
     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.
     Federal eRulemaking Portal: Go to http://
www.regulations.gov. Follow the instructions for submitting comments.
    For service information identified in this proposed AD, contact: 
Thrush Aircraft, Inc., P.O. Box 3149, 300 Old Pretoria Road, Albany, 
Georgia 31706-3149; telephone: 229-883-1440; facsimile: 229-436-4856; 
or on the Internet at: http://www.thrushaircraft.com.

FOR FURTHER INFORMATION, CONTACT ONE OF THE FOLLOWING:
--Cindy Lorenzen, Aerospace Engineer, ACE-115A, Atlanta Aircraft 
Certification Office, One Crown Center, 1895 Phoenix Blvd., Suite 450, 
Atlanta, Georgia 30349; telephone: (770) 703-6078; facsimile: (770) 
703-6097; e-mail: cindy.lorenzen@faa.gov; or
--Mike Cann, Aerospace Engineer, ACE-117A, Atlanta Aircraft 
Certification Office, One Crown Center, 1895 Phoenix Blvd., Suite 450, 
Atlanta, Georgia 30349; telephone: (770) 703-6038; facsimile: (770) 
703-6097; e-mail: michael.cann@faa.gov.

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-
2007-28432; Directorate Identifier 2007-CE-051-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://
dms.dot.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

    We have received reports of cracks in the empennage of Thrush S2R 
series airplanes. Cracks may occur in the vertical stabilizer attach 
fitting, the horizontal stabilizer attach fitting, attach fitting 
bolts, and/or the vertical fin aft spar on airplanes with metal 
empennages. A metallurgy report suggests stress corrosion cracking is 
the

[[Page 41043]]

cause of these cracks. A report was received from the field that a \5/
16\-inch vertical attach bolt, part number (P/N) NAS1105-68, was found 
broken in two places, causing the rear spar of the vertical fin to 
crack. A separate incident found the attach fitting on the stabilizer 
itself cracked in both lugs from stress corrosion.
    This condition, if not corrected, could cause the vertical 
stabilizer to lose structural integrity. This condition could lead to 
loss of control.

Relevant Service Information

    We have reviewed Thrush Aircraft, Inc., Service Bulletin No. SB-AG-
45, Revision B, dated June 1, 2007. The service information describes 
procedures for inspecting and upgrading the fin spar and attach 
fittings.

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 require repetitive visual inspections of the vertical and 
horizontal stabilizer attach fitting, attach fitting bolts, and the 
vertical fin aft spar for cracks or corrosion and require immediate 
replacement of cracked or corroded parts and eventual replacement if no 
cracks or corrosion is found as terminating action for the repetitive 
inspections.

Differences Between This Proposed AD and the Service Information

    Thrush Aircraft, Inc. SB-AG-45, Revision B, dated June 1, 2007, 
recommends an immediate initial inspection. We consider immediately 
upon receipt action to be an urgent safety of flight compliance time. 
Because our risk assessment does not indicate this unsafe condition to 
be an urgent safety of flight condition, we propose to require an 
initial inspection within the next 50 hours time-in-service (TIS). The 
initial inspection time of 50 hours TIS is an adequate compliance for 
this AD action and meets the FAA requirements of an NPRM.
    We propose to require a terminating action of replacing the parts 
within the next 2 years or 2,000 hours TIS, whichever occurs first. 
This is recommended because there is historic evidence that inspections 
alone can eventually miss detecting a crack.

Costs of Compliance

    We estimate that this proposed AD would affect 910 airplanes in the 
U.S. registry.
    We estimate the following costs to do the proposed inspection:

----------------------------------------------------------------------------------------------------------------
                                                                               Total cost per     Total cost on
                 Labor cost                             Parts cost                airplane       U.S. operators
----------------------------------------------------------------------------------------------------------------
8 work-hours x $80 per hour = $640..........  Not applicable................             $640          $582,400
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary replacements of 
the vertical fin aft spar that would be required based on the results 
of the proposed inspection. We have no way of determining the number of 
airplanes that may need this replacement:

------------------------------------------------------------------------
                                                         Total cost per
             Labor cost                  Parts cost         airplane
------------------------------------------------------------------------
12 work-hours x $80 per hour = $960.           $3,800            $4,760
------------------------------------------------------------------------

    We estimate the following costs to replace the vertical and 
horizontal stabilizer attach fittings and attachment bolt:

----------------------------------------------------------------------------------------------------------------
                                                                               Total cost per     Total cost on
                        Labor cost                             Parts cost         airplane       U.S. operators
----------------------------------------------------------------------------------------------------------------
30 work-hours x $80 per hour = $2,400.....................           $1,550            $3,950        $3,594,500
----------------------------------------------------------------------------------------------------------------

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.

[[Page 41044]]

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://dms.dot.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.

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 adding the following new AD:

Thrush Aircraft, Inc.: Docket No. FAA-2007-28432; Directorate 
Identifier 2007-CE-051-AD.

Comments Due Date

    (a) We must receive comments on this airworthiness directive 
(AD) action by September 24, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to the following airplane models and serial 
numbers that are certificated in any category and are equipped with 
metal empennage part numbers (P/N) 40220 or 95400 (applies to serial 
numbers with or without a ``DC'' suffix):

------------------------------------------------------------------------
               Model                             Serial Nos.
------------------------------------------------------------------------
(1) S2R...........................  1416R through 5100R.
(2) S2R-R1340.....................  R1340-001 through R1340-035.
(3) S2R-R1820.....................  R1820-001 through R1820-036.
(4) S2R-T11.......................  T11-001 through T11-005.
(5) S2R-T15.......................  T15-001 through T15-044 and T27-001
                                     through T27-044.
(6) S2R-T34.......................  6000 through 6049, T34-001 through
                                     T34-279, T36-001 through T36-279,
                                     T41-001 through T41-279, T42-001
                                     through T42-279.
(7) S2RHG-T34.....................  T34HG-101 through T34HG-107.
(8) S2R-T45.......................  T45-001 through T45-015.
(9) S2R-T65.......................  T65-001 through T65-018.
(10) S2RHG-T65....................  T65-001 through T65-018 and T65HG-
                                     011 through T65HG-019.
(11) S2R-G1.......................  G1-101 through G1-115.
(12) S2R-G5.......................  G5-101 through G5-105.
(13) S2R-G6.......................  G6-101 through G6-155.
(14) S2R-G10......................  G10-101 through G10-168.
(15) S2R-T660.....................  T660-101 through T660-120.
------------------------------------------------------------------------

Unsafe Condition

    (d) This proposed AD results from reports of cracks in the 
empennage of Thrush Aircraft, Inc., S2R series airplanes. We are 
proposing this AD to detect and correct these cracks, which could 
cause the vertical stabilizer to lose structural integrity. This 
condition could lead to loss of control.

Compliance

    (e) To address this problem, you must do the following, unless 
already done:

------------------------------------------------------------------------
           Actions                 Compliance            Procedures
------------------------------------------------------------------------
(1) Perform a visual          Within the next 50    Follow Thrush
 inspection of the vertical    hours time-in-        Aircraft, Inc.
 stabilizer attach fitting     service (TIS) after   Service Bulletin
 (P/N 40301-7), the            the effective date    No. SB-AG-45,
 horizontal stabilizer         of this AD and        Revision B, dated
 attach fitting (P/N 40303-1/  repetitively          June 1, 2007.
 -4/-7 or 95267-1),            thereafter at
 attachment bolt (P/N          intervals not to
 NAS1105-68), and vertical     exceed every 100
 fin aft spar (P/N 40261-24    hours TIS for up to
 or P/N 95253-1), for cracks   2 years or a total
 or corrosion.                 of 2,000 hours TIS,
                               whichever occurs
                               first.
(2) If cracks or corrosion    Before further        Follow Thrush
 are found in P/N 40301-7,     flight after any      Aircraft, Inc.
 40303-1/-4/-7, 95267-1, or    inspection where      Service Bulletin
 NAS1105-68 during any         cracks or corrosion   No. SB-AG-45,
 inspection required in        are found.            Revision B, dated
 paragraph (e)(1) of this                            June 1, 2007.
 AD, replace all three parts
 with new P/Ns 95266-3,
 95267-5 and NAS6207-68.
(3) If cracks or corrosion    Before further        Follow Thrush
 are found in P/N 40261-24     flight after any      Aircraft, Inc.
 or 95253-1 during any         inspection where      Service Bulletin
 inspection required in        cracks or corrosion   No. SB-AG-45,
 paragraph (e)(1) of this      are found.            Revision B, dated
 AD, replace with a new P/N                          June 1, 2007.
 40261-24 or 95253-1, or
 repair in accordance with
 Thrush SB-AG-45, Revision B.

[[Page 41045]]

 
(4) Replace vertical          Within the next       Follow Thrush
 stabilizer attach fitting P/  2,000 hours TIS       Aircraft, Inc.
 N 40301-7 with P/N 95266-3,   after the effective   Service Bulletin
 replace horizontal            date of this AD or    No. SB-AG-45,
 stabilizer attach fitting P/  within 2 years        Revision B, dated
 N 40303-1/-4/-7 or 95267-1    after the effective   June 1, 2007.
 with P/N 95267-5, and         date of this AD,
 replace attachment bolt       whichever occurs
 NAS1105-68 with NAS6207-68    first. This action
 bolt.                         terminates the
                               repetitive
                               inspections
                               required in
                               paragraph (e)(1) of
                               this AD, including
                               the inspections of
                               the vertical fin
                               aft spar, P/N 40261-
                               24 or 95253-1.
------------------------------------------------------------------------

Special Flight Permit

    (f) Under 14 CFR part 39.23, we are limiting the special flight 
permits authorized for this AD to ferry aircraft to a maintenance 
facility for inspection by the following conditions:
    (1) Hopper must be empty.
    (2) Vne reduced to 126 m.p.h. (109 knots); and
    (3) No flight into known turbulence.

Alternative Methods of Compliance (AMOCs)

    (g) The Manager, 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: Cindy Lorenzen, Aerospace Engineer, ACE-
115A, Atlanta Aircraft Certification Office, One Crown Center, 1895 
Phoenix Blvd., Suite 450, Atlanta, GA 30349; telephone: (770) 703-
6078; facsimile: (770) 703-6097; e-mail: cindy.lorenzen@faa.gov; or 
Mike Cann, Aerospace Engineer, ACE-117A, Atlanta Aircraft 
Certification Office, One Crown Center, 1895 Phoenix Blvd., Suite 
450, Atlanta, Georgia 30349; telephone: (770) 703-6038; facsimile: 
(770) 703-6097; e-mail: michael.cann@faa.gov. 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

    (h) To get copies of the service information referenced in this 
AD, contact Thrush Aircraft, Inc., P.O. Box 3149, 300 Old Pretoria 
Road, Albany, Georgia 31706-3149; telephone: 229-883-1440; 
facsimile: 229-436-4856; or on the Internet at: http://
www.thrushaircraft.com. 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://dms.dot.gov. The docket number 
is Docket No. FAA-2007-28432; Directorate Identifier 2007-CE-051-AD.

    Issued in Kansas City, Missouri, on July 20, 2007.
Kim Smith,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. E7-14433 Filed 7-25-07; 8:45 am]
BILLING CODE 4910-13-P