E7-23860. Airworthiness Directives; Taylorcraft Aviation, LLC A, B, and F Series Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to supersede Airworthiness Directive (AD) AD 2007-16-14, which applies to all Taylorcraft Aviation, LLC (Taylorcraft) A, B, and F series airplanes. AD 2007-16-14 currently requires you to do an initial visual inspection of the left and right wing front and aft lift struts for cracks and corrosion and replace any cracked strut or strut with corrosion that exceeds certain limits. If the strut is replaced with an original design vented strut, AD 2007-16-14 requires you to repetitively inspect those struts thereafter. Since we issued AD 2007-16-14, we determined that the eddy current inspection method does not address the unsafe condition for the long term. We also determined that Models FA-III and TG-6 airplanes are not equipped with the affected struts. Consequently, this proposed AD would retain the actions required in AD 2007-16-14, except it removes the eddy current inspection method (provides 24-month credit if already done using this method), adds the radiograph method as an inspection method, changes the Applicability section, and changes the compliance time between the repetitive inspections. We are issuing this proposed AD to detect and correct cracks and corrosion in the right and left wing front and aft lift struts. This condition, if not corrected, could result in failure of the lift strut and lead to in-flight separation of the wing.

DATES:

We must receive comments on this proposed AD by January 9, 2008.

ADDRESSES:

Use one of the following addresses to comment on this proposed AD:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Taylorcraft Aviation, LLC, 2124 North Central Avenue, Brownsville, Texas 78521; telephone: [phone].

FOR FURTHER INFORMATION CONTACT:

Andrew McAnaul, Aerospace Engineer, ASW-150 (c/o MIDO-43), 10100 Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: [phone]; fax: [phone].

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-2007-0286; Directorate Identifier 2007-CE-086-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive concerning this proposed AD.

Discussion

Reports of several corroded vented wing lift struts from different Taylorcraft series airplanes caused us to issue AD 2007-16-14, Amendment 39-15153 (72 FR 45153, August 13, 2007). AD 2007-16-14 currently requires the following on all Taylorcraft A, B, and F series airplanes:

• Initial visual inspection of the left and right wing front and aft lift struts for cracks and corrosion;
• Replacement of any cracked strut or strut with corrosion that exceeds certain limits with either sealed or vented struts; and
• Repetitive eddy current or ultrasound inspection of any vented lift struts.

Since issuing AD 2007-16-14, we received several comments concerning the AD. We reviewed all comments submitted to the docket. The following are significant comments that influenced our decision to propose superseding AD 2007-16-14 with a new AD:

Comment	FAA discussion
We received several requests to use the radiograph inspection method as an alternative method of compliance (AMOC) for doing the repetitive strut inspection	We approved the radiograph inspection procedure as an AMOC for the repetitive inspections required in AD 2007-16-14, and the manufacturer has added the procedures for the radiograph inspection to their revised service bulletin.
We received several requests to increase the compliance time between repetitive inspections because the Taylorcraft service information requires the application of corrosion inhibitor to the interior of the strut at each inspection. The commenters also requested a longer compliance time between repetitive inspections for land planes compared to float equipped planes	Based on the inspection methods used and the requirement to apply corrosion inhibitor to the strut interior at each inspection, we believe there is not an increased safety risk to the public by increasing the compliance time between the repetitive inspections from 24 months to 48 months for all airplanes. We do not have sufficient information to determine if a different inspection interval for land and float equipped airplanes is valid.
We received a request to use Univair part numbers (P/N) UA-A815 and UA-854 as a terminating action for the repetitive inspection requirement on Taylorcraft Models BC12-D/D1 and BCS12-D/D1 airplanes	We have approved using these parts as an AMOC to AD 2007-16-14.
We received several requests to install used vented lift struts that have been inspected using the criteria specified in paragraph (e)(2) of AD 2007-16-14	We did not intend to preclude owners from installing these parts. Vented lift struts that are inspected using the ultrasound or radiograph inspection method, that meet the Acceptance/Rejection Criteria specified in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007, and that are treated with internal corrosion protection are considered new struts.

In addition to the comments above, we also received several reports of the following:

• The eddy current inspection method currently required in AD 2007-16-14 may not adequately address the unsafe condition for the long term; and
• Models FA-III (Airphibian) and TG-6 Conversion airplanes do not have the affected struts installed.

The following is a significant comment that did not influence our decision to propose superseding AD 2007-16-14 with a new AD:

Comment

FAA discussion

We received several requests to use the Maule Fabric Tester as an AMOC for doing the repetitive strut inspection

Testing of Taylorcraft strut samples with the Maule Fabric Tester shows that both 1025 steel material, and to a greater degree 4130 steel material, resist showing a positive dent indication until a major portion of the wall thickness is consumed. Taylorcraft used 4130 steel in a majority of their wing struts during production. We have not received any data substantiating that Taylorcraft wing struts can still carry required certification loads at the reduced strut wall material thickness indicated in the testing.

Cracks and corrosion in the right and left wing front and aft lift struts, if not detected and corrected, could result in failure of the wing lift strut and lead to in-flight separation of the wing.

Relevant Service Information

We reviewed Taylorcraft Aviation, LLC Service Bulletin (SB) No. 2007-001, Revision B, dated October 15, 2007.

The service information describes procedures for wing lift strut assembly corrosion inspection and/or replacement.

FAA's Determination and Requirements of the Proposed AD

We are proposing this AD because we evaluated all information and determined the unsafe condition described previously is likely to exist or develop on other products of the same type design. This proposed AD would supersede AD 2007-16-14 with a new AD that would do the following:

• Retain the actions of AD 2007-16-14;
• Remove the eddy current inspection method, but allow a 24-month credit for those who already inspected once using the eddy current method;
• Remove Models FA-III (Airphibian) and TG-6 Conversion airplanes from the Applicability section;
• Add the radiograph inspection method;
• Increase the time interval between the repetitive inspections;
• Allow the installation of Univair P/Ns UA-A815 and UA-854 on Taylorcraft Models BC12-D/D1 and BCS12-D/D1 airplanes as a terminating action for the repetitive inspection requirement; and
• Allow the installation of used vented lift struts that have been inspected using ultrasound or radiograph inspection methods, meet the Acceptance/Rejection Criteria specified in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007, and have corrosion inhibitor applied to the interior of the strut. These lift struts are then subject to the repetitive 48-month inspection thereafter.

We have determined that the Maule Fabric Tester is not a viable AMOC to this AD.

This proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

We estimate that this proposed AD would affect 3,119 airplanes in the U.S. registry.

We estimate the following costs to do the proposed visual inspection:

Labor cost	Parts cost	Total cost per airplane	Total cost on U.S. operators
1 work-hour × $80 per hour = $80	Not applicable	$80	$249,520

We estimate the following costs to do the proposed repetitive ultrasound or radiograph inspection:

Labor cost	Parts cost	Total cost per airplane
4 work-hours × $80 per hour = $320	Not applicable	$320

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

Labor cost	Parts cost	Total cost per airplane to replace all 4 wing lift struts
4 work-hours to replace all 4 struts × $80 per hour = $320	Sealed front lift strut: $835 per strut. 2 per airplane = $1,670 Sealed aft lift strut: $638 per strut. 2 per airplane = $1,276	$1,670 + $1,276 + $320 = $3,266.

Original design vented lift struts are no longer manufactured. We have no way of determining the cost associated with obtaining a useable vented strut.

The estimated total cost on U.S. operators includes the cumulative costs associated with AD 2007-16-14 and any actions being added in this proposed AD.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that the proposed regulation:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

3. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket.

Examining the AD Docket

You may examine the AD docket that contains the proposed AD, the regulatory evaluation, any comments received, and other information on the Internet at http://www.regulations.gov;​; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by removing Airworthiness Directive (AD) 2007-16-14, Amendment 39-15153 (72 FR 45153, August 13, 2007), and by adding a new AD to read as follows:

Taylorcraft Aviation, LLC: Docket No. FAA-2007-0286; Directorate Identifier 2007-CE-086-AD.

Comments Due Date

(a) We must receive comments on this airworthiness directive (AD) action by January 9, 2008.

Affected ADs

(b) This AD supersedes AD 2007-16-14, Amendment 39-15153.

Applicability

(c) This AD applies to all serial numbers of Taylorcraft Models A, BC, BCS, BC-65, BCS-65, BC12-65 (Army L-2H), BCS12-65, BC12-D, BCS12-D, BC12-D1, BCS12-D1, BC12D-85, BCS12D-85, BC12D-4-85, BCS12D-4-85, (Army L-2G) BF, BFS, BF-60, BFS-60, BF-65, (Army L-2K) BF 12-65, BFS-65, BL, BLS, (Army L-2F) BL-65, BLS-65, (Army L-2J) BL12-65, BLS12-65, 19, F19, F21, F21A, F21B, F22, F22A, F22B, and F22C airplanes that:

(1) Are certificated in any category; and

(2) Do not incorporate sealed wing front lift struts, part number (P/N) MA-A815, Univair P/N UA-A815 (for Models BC12-D/D1 and BCS12-D/D1 only), or FAA-approved equivalent P/N, and sealed aft lift struts, P/N MA-A854, Univair P/N UA-854 (for Models BC12-D/D1 and BCS12-D/D1 only), or FAA-approved equivalent P/N, for all struts.

Note 1:

This AD applies to all Taylorcraft models listed above, including those models not listed in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007. If there are any other differences between this AD and the above service bulletin, this AD takes precedence.

Note 2:

For the purposes of this AD, a used strut that has been inspected using the ultrasound or radiograph inspection method, meets the Acceptance/Rejection Criteria specified in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007, and is treated with internal corrosion protection, is considered a new strut.

Unsafe Condition

(d) This AD results from our determination that the radiograph inspection method should be used in place of the eddy current inspection method currently required in AD 2007-16-14. We are issuing this AD to detect and correct corrosion or cracks in the right and left wing front and aft lift struts, which could result in failure of the lift strut and lead to in-flight separation of the wing with consequent loss of control.

Compliance

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

Actions	Compliance	Procedures
(1) Visually inspect the right and left wing front and aft lift struts, (P/N A-A815 and P/N A-A854, or FAA-approved equivalent P/Ns), along the entire bottom 12 inches of each strut for cracks and corrosion	Within the next 5 hours TIS after August 20, 2007 (the effective date of AD 2007-16-14), unless one of the following conditions is met: (i) The struts have been replaced with parts specified in paragraph (e)(2)(i) of this AD. No further action is required on those struts (ii) The struts have been replaced with parts specified in paragraph (e)(2)(ii) of this AD and have been installed for less than 48 months. No visual inspection is required. These parts are now subject to the repetitive inspection requirement specified in paragraph (e)(4) of this AD	Follow Part 1 of the Instructions in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision A, dated August 1, 2007; or Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007.
(2) If any cracks are found during the visual inspection required in paragraph (e)(1) of this AD, replace the cracked strut with the following applicable strut:	Before further flight after the visual inspection required in paragraph (e)(1) of this AD	Following the Instructions in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007.
(i) A sealed front lift strut, P/N MA-A815, Univair P/N UA-A815 (for Models BC12-D/D1 and BCS12-D/D1 only), or FAA-approved equivalent P/N, a sealed aft lift strut, P/N MA-A854, Univair P/N UA-854 (for Models BC12-D/D1 and BCS12-D/D1 only), or FAA-approved equivalent P/N. Installing these lift struts terminates the repetitive inspections required by this AD for that strut and no further action is required
(ii) A new vented front lift strut, P/N A-A815, a new vented aft lift strut, P/N A-A854, or FAA-approved equivalent P/Ns, that is treated with internal corrosion protection specified in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007. Installing one of these lift struts is subject to the repetitive inspections required in paragraph (e)(4) of this AD
(3) If corrosion is found during the inspection required in paragraph (e)(1) of this AD, do an ultrasound or radiograph inspection to determine if the corrosion exceeds the Acceptance/Rejection Criteria specified in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007	Before further flight after the visual inspection required in paragraph (e)(1) of this AD	Follow Part 2 of the Instructions in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007. All ultrasound or radiograph inspections required by this AD must be done by one of the following: (i) A Level II or III inspector certified in the applicable ultrasound or radiograph inspection method using the guidelines established by the American Society of Nondestructive Testing or NAS 410 (formerly MIL-STD-410); (ii) An inspector certified to specific FAA or other acceptable government or industry standards, such as Air Transport Association (ATA) Specifications 105-Guidelines for Training and Qualifying Personnel in Nondestructive Testing Methods; or (iii) An FAA Repair Station or a Testing/ Inspection Laboratory qualified to do ultrasound or radiograph inspections.
(4) If no corrosion or cracks are found during the visual inspection required in paragraph (e)(1) of this AD, or if the inspection required in paragraph (e)(3) reveals that the corrosion does not exceed the Acceptance/Rejection Criteria specified in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007, repetitively inspect thereafter using the ultrasound or radiograph inspection method and treat with internal corrosion protection until all struts are replaced with the sealed struts specified in paragraph (e)(2)(i) of this AD. If any cracks are found or corrosion is found that exceeds the Acceptance/Rejection Criteria specified in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007, during any of the repetitive inspections required by this AD, take the necessary corrective actions as applicable in paragraph (e)(5) of this AD	(i) Initially inspect within the next 3 months after August 20, 2007 (the effective date of AD 2007-16-14) or within 48 months after installing a lift strut specified in paragraph (e)(2)(ii) of this AD, whichever occurs later (ii) Repetitively inspect thereafter at intervals not to exceed 48 months, except as required by paragraph (e)(4)(iii) of this AD (iii) If the initial inspection was done using the eddy current method as specified in AD 2007-16-14, the first ultrasound or radiograph repetitive inspection must be done within the next 24 months after doing the eddy current inspection. Repetitively inspect thereafter at intervals not to exceed 48 months using the ultrasound or radiograph inspection method	Follow Part 2 of the Instructions in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007, using the ultrasound or radiograph inspection method.
(5) If, during any inspection required in paragraphs (e)(3) or (e)(4) of this AD, any cracks are found or it is determined that the corrosion exceeds the Acceptance/Rejection Criteria specified in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007, replace the lift strut with the applicable lift strut specified in paragraph (e)(2)(i) or (e)(2)(ii) of this AD	Before further flight after the inspection required in paragraph (e)(3) or (e)(4) of this AD	Following the Instructions in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007.
(6) Do not install P/N A-A815, P/N A-A854, or FAA-approved equivalent P/N, unless:	As of 5 hours TIS after the effective date of this AD	Not applicable.
(i) within the last 48 months it has been inspected using the ultrasound or radiograph method;
(ii) meets the Acceptance/Rejection Criteria; and
(iii) is treated with internal corrosion protection as specified in Taylorcraft Aviation, LLC Service Bulletin No. 2007-001, Revision B, dated October 15, 2007
(7) As a terminating action for the repetitive inspections required by this AD, all vented lift struts (P/Ns A-A815, A-A854, and FAA-approved equivalent P/Ns) may be replaced with sealed lift struts (P/Ns MA-A815, UA-A815 (for Models BC12-D/D1 and BCS12-D/D1 only), MA-A854, UA-854 (for Models BC12-D/D1 and BCS12-D/D1 only), or FAA-approved equivalent P/Ns)	At any time after the effective date of this AD	Not applicable.

Alternative Methods of Compliance (AMOCs)

(f) The Manager, Fort Worth Airplane Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Andrew McAnaul, Aerospace Engineer, ASW-150 (c/o MIDO-43), 10100 Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: [phone]; fax: [phone]. 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.

(g) AMOCs approved for AD 2007-16-14 are approved for this AD.

Related Information

(h) To get copies of the service information referenced in this AD, contact Taylorcraft Aviation, LLC, 2124 North Central Avenue, Brownsville, Texas 78521; telephone: [phone]. To view the AD docket, go to U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, or on the Internet at http://www.regulations.gov.

Issued in Kansas City, Missouri, on December 3, 2007.

John R. Colomy,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.