AD 2007-26-01

We are adopting a new airworthiness directive (AD) for certain Thrush Aircraft, Inc. (Thrush) Model S2R series airplanes. This AD requires you to do repetitive visual inspections of the vertical and horizontal stabilizer attach fitting, attach fitting bolts, and the vertical fin aft spar for cracks or corrosion. This AD also requires immediate replacement of the vertical and horizontal stabilizer attach fittings and attach fitting bolts if cracked or corroded parts are found, and the inspection of the vertical fin aft spar with repair or replacement if cracks or corrosion are found. This AD requires the eventual replacement of the vertical and horizontal stabilizer attach fittings and attach fitting bolts if no corrosion or cracks are found as terminating action for the repetitive inspections. This AD results from reports of cracks in the empennage of Thrush 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 failure could lead to loss of control.

Final rule.

2007-26-01 Thrush Aircraft, Inc.: Amendment 39-15303; Docket No. FAA-2007-28432; Directorate Identifier 2007-CE-051-AD.

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 Numbers
(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, and 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 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:

Actions
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 the vertical fin aft spar (P/N 40261-24 or P/N 95253-1) for corrosion and cracks.
Withinthe next 50 hours time-in-service (TIS) after January 22, 2008 (the effective date of this AD) and repetitively thereafter at intervals not to exceed 100 hours TIS.
Follow Thrush Aircraft, Inc. Service Bulletin No. SB-AG-45, Revision B, dated June 1, 2007.
(2) If corrosion or cracks are found in P/N 40301-7, 40303-1/-4/-7, 95267-1, NAS1105-68, 40261-24,
or 95253-1 during any inspection required in paragraph (e)(1) of this AD:
(i) Replace the vertical stabilizer attach fitting with new P/N 95266-3; the horizontal stabilizer attach fitting with new P/N
95267-5; and the attachment bolt with NAS6207-68; and
(ii) If corrosion or cracks are found in the P/N 40261-24 or
P/N 95253-1 vertical fin aft spar, repair in accordance with Thrush SB-AG-45, Revision B, or replace with a new P/N 40261-24 or new P/N 95253-1.
Before further flight after any inspection where corrosion or cracks are found. This action terminates the repetitive inspections required in paragraph (e)(1) of this AD.Follow Thrush Aircraft, Inc. Service Bulletin No. SB-AG-45, Revision B, dated June 1, 2007.
(3) If no corrosion or cracks are found in P/N 40301-7, 40303-1/-4/-7, 95267-1, NAS1105-68, 40261-24, or 95253-1 during any inspection required in paragraph (e)(1) of this AD:
(i) Replace the vertical stabilizer attach fitting with new P/N 95266-3; the horizontal stabilizer attach fitting with new P/N
95267-5; and the attachment bolt with NAS6207-68; and
(ii) Perform a visual inspection of the vertical fin aft spar (P/N 40261-24 or P/N 95253-1) for corrosion and cracks, and
(iii) If corrosion or cracks are found in the P/N 40261-24 or P/N 95253-1 vertical fin aft spar, repair in accordance with Thrush
SB-AG-45, Revision B, or replace with a new P/N 40261-24 or new P/N 95253-1.
Within the next 2,000 hours TIS after January 22, 2008 (the effective date of this AD) or within 2 years after January 22, 2008 (the effective date of this AD), whichever occurs first. This action terminates the repetitive inspections required in paragraph (e)(1) of this AD.
Follow Thrush Aircraft, Inc. Service Bulletin No. SB-AG-45, Revision B, dated June 1, 2007.

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.

Material Incorporated by Reference

(h) You must use Thrush Aircraft, Inc. Service Bulletin No. SB- AG-45, 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 31706-3149; telephone: 229-883-1440; facsimile: 229-436- 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- 741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html .

Discussion

On July 26, 2007, 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 S2R series airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on July 26, 2007 (72 FR 41042). The NPRM proposed to require repetitive visual inspections of the vertical and horizontal stabilizer attach fitting, attach fitting bolts, and the vertical fin aft spar for corrosion or cracks. The NPRM also proposed to require immediate replacement of the vertical and horizontal stabilizer attach fittings and attach fitting bolts if cracked or corroded parts are found, and inspection of the vertical fin aft spar with repair or replacement if cracks or corrosion are found. This AD requires the eventual replacement of the vertical and horizontal stabilizer attach fittings and attach fitting bolts if no corrosion or cracks are found as terminating action for the repetitive inspections.

Comments

We provided the public the opportunity to participate in developing this AD. We received no comments on the proposal or on the determination of the cost to the public.

Conclusion

We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed except for minor editorial corrections. We have determined that these minor corrections:
Are consistent with 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.

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:

Labor Cost
Parts Cost
Total Cost Per Airplane
Total Cost on 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 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 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:

Labor Cost
Parts Cost
Total Cost Per Airplane
Total Cost on 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 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. FAA-2007-28432; Directorate Identifier 2007-CE-051-AD'' 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 39--AIRWORTHINESS DIRECTIVES

1. Theauthority 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: