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Airworthiness Directives; Thrush Aircraft, Inc. Model 600 S2D and S2R (S-2R) Series Airplanes

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Start Preamble Start Printed Page 16691

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) to supersede AD 2003-07-01, which applies to certain Thrush Aircraft, Inc. Model 600 S2D and S2R (S-2R) series airplanes (type certificate previously held by Quality Aerospace, Inc. and Ayres Corporation). AD 2003-07-01 currently requires you to repetitively inspect the 1/4-inch and 5/16-inch bolt hole areas on the lower wing spar caps for fatigue cracking; replace or repair any lower wing spar cap where fatigue cracking is found; and report any fatigue cracking found. This AD is the result of the analysis of data from 112 cracks found in the last 8 years on similar design Model 600 S2D and S2R (S-2R) series airplanes, and FAA's determination that an immediate initial inspection and more frequent repetitive inspections are necessary to address the unsafe condition for certain airplanes. Consequently, this AD would require you to increase the frequency of the repetitive inspections on Groups 1, 2, 3, and 6 airplanes; and decrease the hours time-in-service (TIS) for the initial inspection on Group 2 airplanes. We are issuing this AD to prevent lower wing spar cap failure caused by undetected fatigue cracks. Such failure could result in loss of a wing with consequent loss of airplane control.

DATES:

This AD becomes effective on April 18, 2006.

As of July 25, 2000 (65 FR 36055), the Director of the Federal Register previously approved the incorporation by reference of Ayres Corporation Service Bulletin No. SB-AG-39, dated September 17, 1996; and Ayres Corporation Custom Kit No. CK-AG-29, dated December 23, 1997.

As of May 20, 2003 (68 FR 15653), the Director of the Federal Register previously approved the incorporation by reference of Quality Aerospace, Inc. Custom Kit No. CK-AG-30, dated December 6, 2001, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

We must receive any comments on this AD by May 16, 2006.

ADDRESSES:

Use one of the following to submit comments on this AD:

  • DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
  • Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-001.
  • Fax: 1-202-493-2251.
  • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

To get the service information identified in this proposed AD, contact Thrush Aircraft, Inc. at 300 Old Pretoria Road, PO Box 3149, Albany, Georgia 31706-3149. You can also find service information on their Web site at http://www.thrushaircraft.com.

To view the comments to this AD, go to http://dms.dot.gov. The docket number is FAA-2006-23649; Directorate Identifier 2006-CE-08-AD.

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.

End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

History of AD Actions

An accident on a Thrush S2R series airplane (type certificate previously held by Quality Aerospace, Inc. and Ayres Corporation), where the wing separated from the airplane in flight, caused us to issue AD 97-13-11, Amendment 39-10071 (62 FR 36978, July 10, 1997). AD 97-13-11 required you to do the following:

—Inspect the 1/4-inch and 5/16-inch bolt hole areas on the lower wing spar caps for fatigue cracking;

—Replace any lower wing spar cap where fatigue cracking is found; and

—Report any fatigue cracking to FAA.

AD 97-17-03, Amendment 39-10195 (62 FR 43926, August 18, 1997) superseded AD 97-13-11. AD 97-13-11 incorrectly referenced the Model S2R-R1340 airplanes as Model S2R-1340R. AD 97-17-03 corrected the model designation and retained the actions of AD 97-13-11.

AD 2000-11-16, Amendment 39-11764 (65 FR 36055, June 7, 2000) superseded AD 97-17-03. AD 2000-11-16 made the inspections required in AD 97-17-03 repetitive, added airplanes to the applicability of the AD, changed the initial compliance time for all airplanes, and arranged the affected airplanes into six groups based on usage and configuration. AD 2000-11-16 required you to do the following:

—Repetitively inspect the 1/4-inch and 5/16-inch bolt hole areas on the lower wing spar caps for fatigue cracking;

—Replace or repair any lower wing spar cap where fatigue cracking is found; and

—Report any fatigue cracking to FAA.

AD 2003-07-01, Amendment 39-13097 (68 FR 15653, April 1, 2003) superseded AD 2000-11-16. AD 2003-07-01 added some airplanes that were manufactured with a similar design to the applicability table and added a third repair option. Start Printed Page 16692

Recent Events That Initiated This Current AD Action

AD 2003-07-01 required submitting reports to FAA when any crack was found on the affected airplanes. Recent FAA analysis of data from those reports and other historical and statistical data indicate that the current AD inspections are not completely addressing the unsafe condition. Specifically, the data indicate a risk that some airplanes in the Thrush fleet may currently have cracks. The airplanes with cracks may be unable to meet ultimate strength requirements.

The repetitive inspection interval required by AD 2003-07-01 was designed to give owners/operators two opportunities to detect a crack before the critical crack length is reached. The high rate of cracking in the fleet combined with the industry standard of a 90-percent probability of detection with the inspection methods used means that eventually an inspection will not find an existing crack. A completely severed spar cap was found on one of the affected airplanes. Analysis indicates a crack existed during the last two repetitive inspections of that spar cap, but the crack was undetected by the inspections. Fortunately, the wing remained intact until the crack was found.

This in-service incident correlates with other historical probability data that indicate there may be cracks in other lower wing spar caps in the fleet now, and those cracks may go undetected with current inspection intervals. The FAA used a probability approach when analyzing the risks from data obtained from reports of 112 lower wing spar cap cracks found on Model 600 S2D and S2R (S-2R) series airplanes since 1997. This analysis indicates there is an ever-increasing risk of another crack being missed during an inspection.

To increase the chances of detecting a crack in the lower wing spar cap prior to the crack reaching critical length, we are increasing the frequency of the repetitive inspections on Groups 1, 2, 3, and 6 airplanes and decreasing the hours TIS for the initial inspection on Group 2 airplanes. These actions are necessary to ensure the continued airworthiness of Groups 1, 2, 3, and 6 airplanes. There has been one crack reported on Groups 4 and 5 airplanes; however, this is not enough statistical data to show an increasing risk for these airplanes at this time. Until additional information is obtained, we are not changing the initial inspection times or the repetitive inspection intervals for Groups 4 and 5 airplanes.

Wing spar cap failure caused by undetected fatigue cracks could result in loss of a wing with consequent loss of airplane control.

Relevant Service Information

The following service information was included in AD 2003-07-01 and will remain in effect for this AD:

—Ayres Corporation Service Bulletin No. SB-AG-39, dated September 17, 1996;

—Ayres Corporation Custom Kit No. CK-AG-29, dated December 23, 1997; and

—Quality Aerospace, Inc. Custom Kit No. CK-AG-30, dated December 6, 2001.

The service information includes procedures for:

—Inspecting the 1/4-inch and 5/16-inch bolt hole areas on the lower wing spar caps for fatigue cracking;

—Reworking the spar cap if a small crack is found in the 1/4-inch spar cap hole;

—Replacing the butterfly center splice plate, part number 20211-3, from the aft surface of the wing spar join area; and

—Installing Kaplan splice blocks that repair small cracks in the 1/4-inch and 5/16-inch bolt holes.

FAA's Determination and Requirements of the AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other Thrush Aircraft, Inc. Model 600 S2D and S2R (S-2R) series airplanes of the same type design. Therefore, we are issuing this AD to prevent lower wing spar cap failure caused by undetected fatigue cracks. Such failure could result in loss of a wing with consequent loss of airplane control.

This AD supersedes AD 2003-07-01 with a new AD that retains the actions of the previous AD, but increases the frequency of the repetitive inspections on Groups 1, 2, 3, and 6 airplanes; and decreases the hours TIS for the initial inspection on Group 2 airplanes.

In preparing this rule, we contacted type clubs and aircraft operators to get technical information and information on operational and economic impacts. We have included a discussion of information that may have influenced this action in the rulemaking docket.

For any of the affected airplanes that exceed the new repetitive inspection interval at the effective date of this AD, the compliance times are graduated based on the increasing risk of the airplanes with the most hours since their last inspection. Graduated compliance times will help alleviate overcrowding at inspection facilities while still addressing the increased risk for airplanes that have accumulated the most flight hours since the last inspection. We are working with Thrush to develop a future terminating action.

Comments Invited

This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2006-23649; Directorate Identifier 2006-CE-08-AD” in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it; we will date-stamp your postcard and mail it back to you. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify it. If a person contacts us through a nonwritten communication, and that contact relates to a substantive part of this AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend the AD in light of those comments.

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. Start Printed Page 16693

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 “AD Docket FAA-2006-23649; Directorate Identifier 2006-CE-08-AD” in your request.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

Adoption of the Amendment

Start Amendment Part

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (

End Amendment Part Start Part

PART 39—AIRWORTHINESS DIRECTIVES

End Part Start Amendment Part

1. The authority citation for part 39 continues to read as follows:

End Amendment Part Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]
Start Amendment Part

2. The FAA amends § 39.13 by removing Airworthiness Directive (AD) 2003-07-01, Amendment 39-13097 (

End Amendment Part

2006-07-15 Thrush Aircraft, Inc. (Type Certificate Previously Held by Quality Aerospace, Inc. and Ayres Corporation): Amendment 39-14542; Docket No. FAA-2006-23649; Directorate Identifier 2006-CE-08-AD.

Effective Date

(a) This AD becomes effective on April 18, 2006.

Affected ADs

(b) The following lists a history of the ADs affected by this AD action:

(1) This AD supersedes AD 2003-07-01; Amendment 39-13097;

(2) AD 2003-07-01 superseded AD 2000-11-16, Amendment 39-11764;

(3) AD 2000-11-16 superseded AD 97-17-03, Amendment 39-10195; and

(4) AD 97-17-03 superseded AD 97-13-11, Amendment 39-10071.

Applicability

(c) This AD affects the following airplane models and serial numbers that are certificated in any category. The table also identifies the group that each airplane belongs in when determining inspection compliance times:

Table 1.—Applicability and Airplane Groups

ModelSerial Nos.Group
(1) S-2R5000R through 5100R, except 5010R, 5031R, 5038R, 5047R, and 5085R1
(2) S2R-G1G1-101 through G1-1061
(3) S2R-R1820R1820-001 through R1820-0351
(4) S2R-T15T15-001 through T15-0331
(5) S2R-T346000R through 6049R, T34-001 through T34-143, T34-145, T34-147 through T34-167, T34-171, T34-180, and T34-1811
(6) S2R-G10G10-101 through G10-136, G10-138, G10-140, and G10-1412
(7) S2R-G5G5-101 through G5-1052
(8) S2R-G6G6-101 through G6-1472
(9) S2RHG-T65T65-002 through T65-0182
(10) S2R-R1820R1820-0362
(11) S2R-T34T34-144, T34-146, T34-168, T34-169, T34-172 through T34-179, and T34-189 through T34-232, and T34-2342
(12) S2R-T45T45-001 through T45-0142
(13) S2R-T65T65-001 through T65-0182
(14) 600 S2DAll serial numbers beginning with 600-1311D3
(15) S-2R1380R, 1416R through 2592R, 3000R, and 3002R3
(16) S2R-R1340R1340-001 through R1340-0353
(17) S2R-R3SR3S-001 through R3S-0113
(18) S2R-T11T11-001 through T11-0053
(19) S2R-G1G1-107, G1-108, and G1-1094
(20) S2R-G10G10-137, G10-139, and G10-1424
(21) S2R-T34T34-225, T34-236, T34-237, and T34-2384
(22) S2R-G1G1-110 through G1-1155
(23) S2R-G10G10-143 through G10-1655
(24) S2R-G6G6-148 through G6-1555
(25) S2RHG-T34T34HG-1025
(26) S2R-T15T15-034 through T15-0405
(27) S2R-T34T34-239 through T34-2705
(28) S2R-T45T45-0155
(29) S-2R5010R, 5031R, 5038R, 5047R, and 5085R6

Note 1:

The serial numbers of the Model S2R-T15 airplanes could incorporate T15-xxx and T27-xxx (xxx is the variable for any of the serial numbers beginning with T15- and T27-). This AD applies to both of these serial number designations as they are both Model S2R-T15 airplanes.

Note 2:

The serial numbers of the Model S2R-T34 airplanes could incorporate T34-xxx, T36-xxx, T41-xxx, or T42-xxx (xxx is the variable for any of the serial numbers beginning with T34-, T36-, T41- and Start Printed Page 16694T42-). This AD applies to all of these serial number designations as they are all Model S2R-T34 airplanes.

Note 3:

Any Group 3 airplane that has been modified with a hopper of a capacity more than 410 gallons, a piston engine greater than 600 horsepower, or any gas turbine engine, makes the airplane a Group 1 airplane for the purposes of this AD. Inspect the airplane at the Group 1 compliance time specified in this AD.

Note 4:

Group 6 airplanes were originally manufactured with turbine engines, but were converted to radial engines. They are now configured identical to Group 3 airplanes.

Unsafe Condition

(d) This AD is the result of the analysis of data from 112 cracks found in the last 8 years on similar design Model 600 S2D and S2R (S-2R) series airplanes, and FAA's determination that an immediate initial inspection and more frequent repetitive inspections are necessary to address the unsafe condition for certain airplanes. We are issuing this AD to prevent lower wing spar cap failure caused by undetected fatigue cracks. Such failure could result in loss of a wing with consequent loss of airplane control.

Compliance

(e) To address the problem, do the following:

(1) If you have already done an inspection per AD 2003-07-01, identify the number of hours time-in-service (TIS) since your last inspection per AD 2003-07-01. You will need this to establish the inspection interval for next inspection required by this AD.

(2) Inspect the 1/4-inch and 5/16-inch bolt hole areas on each wing lower spar cap for fatigue cracking using magnetic particle, ultrasonic, or eddy current procedures. If Kaplan splice blocks, part number (P/N) 22515-1/-3 or 88-251 per Quality Aerospace, Inc. Custom Kit No. CK-AG-30, dated December 6, 2001, are installed, inspect the three bolt hole areas on each wing lower spar cap for fatigue cracking using magnetic particle, ultrasonic, or eddy current procedures. Use the compliance times listed in paragraph (e)(3) of this AD for the initial inspection and the compliance time listed in paragraphs (e)(5), (e)(6), or (e)(7) of this AD for the repetitive inspections. The cracks may emanate from the bolt hole on the face of the spar cap or they may occur in the shaft of the hole. You must inspect both of those areas.

(i) If using the magnetic particle method for the inspection, inspect using the “Inspection” portion of the “Accomplishment Instructions” and “Lower Splice Fitting Removal and Installation Instructions” in Ayres Corporation Service Bulletin No. SB-AG-39, dated September 17, 1996. You must follow American Society for Testing and Materials E 1444-01, using wet particles meeting the requirements of the Society for Automotive Engineers AMS 3046. CAUTION: You must firmly support the wings during the inspection to prevent movement of the spar caps when the splice blocks are removed. This will allow easier realignment of the splice block holes and the holes in the spar cap for bolt insertion.

(ii) The inspection must be done by or supervised by a Level 2 or Level 3 inspector certified following the guidelines established by the American Society for Nondestructive Testing or MIL-STD-410.

(iii) If using ultrasonic or eddy current methods for the inspection, a procedure must be sent to the FAA, Atlanta Aircraft Certification Office (ACO), for approval before doing the inspection. Send your proposed procedure to the FAA, Atlanta ACO, Attn: Cindy Lorenzen, One Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia 30349. You are not required to remove the splice block for either the ultrasonic or eddy current inspections, unless corrosion is visible.

(iv) If you change the inspection method used (magnetic particle, ultrasonic, or eddy current), the TIS intervals for repetitive inspections are based on the method used for the last inspection.

(3) If airplanes have not reached the threshold for the initial inspection required in AD 2003-07-01, AD 2000-11-16, AD 97-17-03, or AD 97-13-11, initially inspect following the wing lower spar cap hours TIS schedule below or within 50 wing lower spar cap hours TIS after April 18, 2006 (the effective date of this AD), whichever occurs later:

Table 2.—Initial Inspection

Airplane groupInitially inspect within the following lower wing spar cap hours TIS
(i) Group 12,000 hours TIS.
(ii) Group 21,400 hours TIS.
(iii) Group 36,400 hours TIS.
(iv) Group 42,500 hours TIS.
(v) Group 56,200 hours TIS.
(vi) Group 6(A) Serial number (S/N) 5010R: 5,530 hours TIS.
(B) S/N 5038R: 5,900 hours TIS.
(C) S/N 5031R: 6,400 hours TIS.
(D) S/N 5047R: 6,400 hours TIS.
(E) S/N 5085R: 6,290 hours TIS.

(4) Airplanes in all groups must meet the following conditions before doing the repetitive inspections required in paragraphs (e)(5), (e)(6), or (e)(7) of this AD:

(i) No cracks have been found previously on wing spar;

(ii) Small cracks have been repaired through cold work (or done as an option if never cracked) per SB-AG-39;

(iii) Small cracks have been repaired by reaming the 1/4-inch bolt hole to 5/16 inches diameter (or done as an option if never cracked) per Ayres Corporation Custom Kit No. CK-AG-29, Part I, dated December 23, 1997;

(iv) Small cracks have been repaired through previous alternative methods of compliance (AMOC); or

(v) Small cracks have been repaired by the installation of Kaplan splice blocks, P/N 22515-1/-3 or 88-251 (or done as an option if never cracked) per Quality Aerospace, Inc. Custom Kit No. CK-AG-30, dated December 6, 2001.

(5) Repetitively inspect Groups 1, 2, 3, and 6 airplanes that do not have butterfly plates, P/N 20211-09 and P/N 20211-11, installed per Ayres Corporation Custom Kit No. CK-AG-29, Part II, dated December 23, 1997, and meet the conditions in paragraph (e)(4) of this AD. Follow the wing lower spar cap hours TIS compliance schedule below:

Table 3.—Repetitive Inspections for Airplane Groups 1, 2, 3, and 6 Without Butterfly Plates

When airplanes accumulate the following hours TIS on the wing lower spar cap, since the last inspection required in AD 2003-07-01,Inspect within the following hours TIS after April 18, 2006 (the effective date of this AD),Inspect thereafter at intervals of . . .
(i) Magnetic particle inspection250 hours TIS.
(A) 450 or more hours25 hours TIS
(B) 350 through 449 hours TIS50 hours TIS
(C) 175 through 349 hours TIS75 hours TIS
(D) Less than 175 hours TISupon accumulating 250 hours TIS
(ii) Ultrasonic inspection275 hours TIS.
(A) 500 or more hours TIS25 hours TIS
(B) 400 through 499 hours TIS50 hours TIS
(C) 200 through 399 hours TIS75 hours TIS
(D) Less than 200 hours TISupon accumulating 275 hours TIS
(iii) Eddy Current inspection350 hours TIS.
(A) 625 or more hours TIS25 hours TIS
(B) 500 through 624 hours TIS50 hours TIS
(C) 275 through 499 hours TIS75 hours TIS
Start Printed Page 16695
(D) Less than 275 hours TISupon accumulating 350 hours TIS

(6) Repetitively inspect Groups 1, 2, 3, and 6 airplanes that have butterfly plates, P/N 20211-09 and P/N 20211-11, installed per Ayres Corporation Custom Kit No. CK-AG-29, Part II, dated December 23, 1997, and meet the conditions in paragraph (e)(4) of this AD. Follow the wing lower spar cap hours TIS compliance schedule below:

Table 4.—Repetitive Inspections for Groups 1, 2, 3, and 6 With Butterfly Plates

When airplanes accumulate the following hours TIS on the wing lower spar cap, since the last inspection required in AD 2003-07-01,Inspect within the following hours TIS after April 18, 2006 (the effective date of this AD),Inspect thereafter at intervals of . . .
(i) Magnetic particle inspection450 hours TIS.
(A) 800 or more hours TIS25 hours TIS
(B) 650 through 799 hours TIS50 hours TIS
(C) 375 through 649 hours TIS75 hours TIS
(D) Less than 375 hours TISupon accumulating 450 hours TIS
(ii) Ultrasonic inspection475 hours TIS.
(A) 825 or more hours TIS25 hours TIS
(B) 675 through 824 hours TIS50 hours TIS
(C) 400 through 674 hours TIS75 hours TIS
(D) Less than 400 hours TISupon accumulating 475 hours TIS
(iii) Eddy Current inspection625 hours TIS
(A) 1125 or more hours TIS25 hours TIS
(B) 900 through 1124 hours TIS50 hours TIS
(C) 550 through 899 hours TIS75 hours TIS
(D) Less than 550 hours TISupon accumulating 625 hours TIS

(7) Repetitively inspect Groups 4 and 5 airplanes that meet the conditions in paragraph (e)(4) of this AD. Follow the wing lower spar cap hours TIS compliance schedule below:

Table 5.—Repetitive Inspection for Groups 4 and 5

When using the following inspection methods,Repetitively inspect at intervals of . . .
(i) Magnetic particle inspection900 hours TIS.
(ii) Ultrasonic inspection950 hours TIS.
(iii) Eddy current inspection1,250 hours TIS.

Note 5:

Groups 4 and 5 airplanes had the butterfly plates installed at the factory.

(f) If any cracks are found in any inspection required by this AD, you must repair the cracks or replace the lower wing spar before further flight.

(1) Use the cold work process to ream out small cracks as defined in Ayres Corporation Service Bulletin No. SB-AG-39, dated September 17, 1996; or

(2) Ream the 1/4-inch bolt holes to 5/16 inches diameter as defined in Part I of Ayres Corporation Custom Kit No. CK-AG-29, dated December 23, 1997; or

(3) Install Kaplan Splice Blocks as defined in Quality Aerospace, Inc. Custom Kit No. CK-AG-30, dated December 6, 2001; or

(4) Replace the affected spar cap in accordance with the maintenance manual.

Note 6:

If a crack is found, the reaming associated with the cold work process may remove a crack if it is small enough. Some aircraft owners/operators were issued alternative methods of compliance with AD 97-17-03 to ream the 1/4-inch bolt hole to 5/16 inches diameter to remove small cracks. Ayres Corporation Custom Kit No. CK-AG-29, Part I, dated December 23, 1997, also provides procedures to ream the 1/4-inch bolt hole to 5/16 inches diameter, which may remove a small crack. Resizing the holes to the required size to install a Kaplan splice block may also remove small cracks. If you use any of these methods to remove cracks and the airplane is re-inspected immediately with no cracks found, you may continue to follow the repetitive inspection intervals for your airplane listed in paragraphs (e)(5), (e)(6), or (e)(7) of this AD.

(g) For all inspection methods (magnetic particle, ultrasonic, or eddy current), hours TIS for initial and repetitive inspections intervals start over when wing spar is replaced.

(1) If the wings or wing spars were replaced with new or used wings or wing spars during the life of the airplane and logbook records positively show the hours TIS of the wings or wing spars, then initially inspect at applicable wing or wing spar times in paragraph (e)(3) and repetitively inspect at intervals in paragraphs (e)(5), (e)(6), or (e)(7) of this AD.

(2) If the wings or wing spars were replaced with new or used wings or wing spars during the life of the airplane and logbook records cannot positively show the hours TIS of the wings or wing spars, then inspect within 25 hours TIS after April 18, 2006 (the effective date of this AD), unless already done, and repetitively inspect at intervals in paragraphs (e)(5), (e)(6), or (e)(7) of this AD.

(h) Report any cracks you find within 10 days after the cracks are found or within 10 days after April 18, 2006 (the effective date of this AD), whichever occurs later. Send your report to Cindy Lorenzen, Aerospace Engineer, ACE-115A, Atlanta ACO, 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. The Office of Management and Budget (OMB) approved the information collection requirements contained in this regulation under the provisions of the Paperwork Reduction Act and assigned OMB Control Number 2120-0056. Include in your report the following information:

(1) Aircraft model and serial number;

(2) Engine model;

(3) Aircraft hours TIS;

(4) Left and right wing lower spar cap hours TIS;

(5) Hours TIS on the spar cap since last inspection;

(6) Crack location and size;

(7) Procedure (magnetic particle, ultrasonic, or eddy current) used for the last inspection; and

(8) Information on corrective action taken, whether cold working has been done or modifications incorporated such as installation of butterfly plates, and when this corrective action was taken. Start Printed Page 16696

Alternative Methods of Compliance (AMOCs)

(i) The Manager, Atlanta Aircraft Certification Office, FAA, 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, has the authority to approve AMOCs for this AD, if requested using the procedures in 14 CFR 39.

(j) AMOCs approved for AD 2003-07-01, AD 2000-11-16, AD 97-13-11, and/or AD 97-17-03 are approved as AMOCs for this AD.

Material Incorporated by Reference

(k) You must do the actions required by this AD following the instructions in Ayres Corporation Service Bulletin No. SB-AG-39, dated September 17, 1996; Ayres Corporation Custom Kit No. CK-AG-29, dated December 23, 1997; and Quality Aerospace, Inc. Custom Kit No. CK-AG-30, dated December 6, 2001.

(1) As of July 25, 2000 (65 FR 36055), the Director of the Federal Register previously approved the incorporation by reference of Ayres Corporation Service Bulletin No. SB-AG-39, dated September 17, 1996; and Ayres Corporation Custom Kit No. CK-AG-29, dated December 23, 1997, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(2) As of May 20, 2003 (68 FR 15653), the Director of the Federal Register previously approved the incorporation by reference of Quality Aerospace, Inc. Custom Kit No. CK-AG-30, dated December 6, 2001, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(3) To get a copy of this service information, contact Thrush Aircraft, Inc. at 300 Old Pretoria Road, P.O. Box 3149, Albany, Georgia 31706-3149 or go to http://www.thrushaircraft.com. To review copies of this service information, go to the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html or call (202) 741-6030. To view the AD docket, go to the Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-001 or on the Internet at http://dms.dot.gov. The docket number is FAA-2006-23649; Directorate Identifier 2006-CE-08-AD.

Start Signature

Issued in Kansas City, Missouri, on March 28, 2006.

David R. Showers,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.

End Signature End Supplemental Information

[FR Doc. 06-3162 Filed 4-3-06; 8:45 am]

BILLING CODE 4910-13-P