Costs of Compliance

We estimate that this AD affects 910 airplanes in the U.S. registry.

We estimate the following costs to do the inspection: Total cost per Total cost on Labor cost Parts cost airplane U.S. operators 8 workhours 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 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 workhours 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:
[[Page 71205]]
Total cost per Total cost on Labor cost Parts cost airplane U.S. operators 30 workhours 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 AD. Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD 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.

For the reasons discussed above, I certify that this 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 AD (and other information as included in the Regulatory Evaluation) 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 ``Docket No. FAA200728432; Directorate Identifier 2007CE051AD'' in your request.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
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 39AIRWORTHINESS 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. FAA amends Sec. 39.13 by adding the following new AD:
20072601 Thrush Aircraft, Inc.: Amendment 3915303; Docket No. FAA200728432; Directorate Identifier 2007CE051AD.
Effective Date
(a) This AD becomes effective on January 22, 2008.
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) S2RR1340..................... R1340001 through R1340035. (3) S2RR1820..................... R1820001 through R1820036. (4) S2RT11....................... T11001 through T11005.
(5) S2RT15....................... T15001 through T15044 and T27001 through T27044.
(6) S2RT34....................... 6000 through 6049, T34001 through T34279, T36001 through T36279, T41001 through T41279, and T42 001 through T42279.
(7) S2RHGT34..................... T34HG101 through T34HG107. (8) S2RT45....................... T45001 through T45015.
(9) S2RT65....................... T65001 through T65018.
(10) S2RHGT65.................... T65001 through T65018 and T65HG 011 through T65HG019.
(11) S2RG1....................... G1101 through G1115.
(12) S2RG5....................... G5101 through G5105.
(13) S2RG6....................... G6101 through G6155.
(14) S2RG10...................... G10101 through G10168.
(15) S2RT660..................... T660101 through T660120. Unsafe Condition
(d) This AD results from reports of cracks in the empennage of Thrush Aircraft, Inc., S2R series airplanes. We are issuing 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:
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Actions Compliance Procedures (1) Perform a visual inspection of the Within the next 50 hours timein Follow Thrush Aircraft, Inc. vertical stabilizer attach fitting (P/N service (TIS) after January 22, Service Bulletin No. SBAG45, 403017), the horizontal stabilizer attach 2008 (the effective date of this Revision B, dated June 1, 2007. fitting (P/N 403031/4/7 or 952671), AD) and repetitively thereafter attachment bolt (P/N NAS110568), and the at intervals not to exceed 100 vertical fin aft spar (P/N 4026124 or P/N hours TIS.
952531) for corrosion and cracks.
(2) If corrosion or cracks are found in P/N Before further flight after any Follow Thrush Aircraft, Inc. 403017, 403031/4/7, 952671, NAS1105 inspection where corrosion or Service Bulletin No. SBAG45, 68, 4026124, or 952531 during any cracks are found. This action Revision B, dated June 1, 2007. inspection required in paragraph (e)(1) of terminates the repetitive this AD: inspections required in (i) Replace the vertical stabilizer attach paragraph (e)(1) of this AD. fitting with new P/N 952663; the
horizontal stabilizer attach fitting with
new P/N 952675; and the attachment bolt
with NAS620768; and.
(ii) If corrosion or cracks are found in
the P/N 4026124 or P/N 952531 vertical
fin aft spar, repair in accordance with
Thrush SBAG45, Revision B, or replace
with a new P/N 4026124 or new P/N 952531.
(3) If no corrosion or cracks are found in Within the next 2,000 hours TIS Follow Thrush Aircraft, Inc. P/N 403017, 403031/4/7, 952671, after January 22, 2008 (the Service Bulletin No. SBAG45, NAS110568, 4026124, or 952531 during effective date of this AD) or Revision B, dated June 1, 2007. any inspection required in paragraph within 2 years after January 22, (e)(1) of this AD: 2008 (the effective date of this (i) Replace the vertical stabilizer attach AD), whichever occurs first. fitting with new P/N 952663; the This action terminates the horizontal stabilizer attach fitting with repetitive inspections required new P/N 952675; and the attachment bolt in paragraph (e)(1) of this AD. with NAS620768; and.
(ii) Perform a visual inspection of the
vertical fin aft spar (P/N 4026124 or P/N
952531) for corrosion and cracks, and.
(iii) If corrosion or cracks are found in
the P/N 4026124 or P/N 952531 vertical
fin aft spar, repair in accordance with
Thrush SBAG45, Revision B, or replace
with a new P/N 4026124 or new P/N 952531.
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) 7036097; email: cindy.lorenzen@faa.gov; or Mike Cann, Aerospace Engineer, ACE117A, Atlanta Aircraft
Certification Office, One Crown Center, 1895 Phoenix Blvd., Suite 450, Atlanta, Georgia 30349; telephone: (770) 7036038; facsimile: (770) 7036097; email: 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.
Material Incorporated by Reference
(h) You must use Thrush Aircraft, Inc. Service Bulletin No. SB AG45, Revision B, dated June 1, 2007, to do the actions required by this AD, unless the AD specifies otherwise.
(1) The Director of the Federal Register approved the
incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact Thrush Aircraft, Inc., P.O. Box 3149, 300 Old Pretoria Road, Albany, Georgia 317063149; telephone: 2298831440; facsimile: 229436 4856; or on the Internet at: http://www.thrushaircraft.com. (3) You may review copies at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Kansas City, Missouri 64106; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202 7416030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html .

Issued in Kansas City, Missouri, on December 10, 2007. John R. Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. E724218 Filed 121407; 8:45 am]
BILLING CODE 491013P