AD/Taylorcraft/1 Wing Struts (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Taylorcraft Series Aeroplanes

AD/TAYLORCRAFT/1 Wing Struts 10/2007 DM

Applicability:

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,  BF (Army L-2G), BFS, BF-60, BFS-60, BF-65, BFS-65, BF12-65 (Army L-2K), BL, BLS, BL-65 (Army L-2F), BLS-65, BL12-65 (Army L-2J), BLS12-65, FA-III (Amphibian), 19, F19, F21, F21A, F21B, F22, F22A, F22B, F22C, and TG-6 Conversion aircraft, all serial numbers; and,

The affected models do not incorporate in all struts, new sealed front lift struts (part number MA-A815 or FAA-approved equivalent part number) and new sealed aft lift struts (part number MA-A854 or FAA-approved equivalent part number).

Note:  This Directive applies to all Taylorcraft models listed above, including those not listed in Taylorcraft Aviation, LLC Service Bulletin No.2007-001 Revision A, dated 1 August 2007.  If there are any other differences between the requirements of this Directive and the above service bulletin, this Directive takes precedence.

Requirement:

1.    Visually inspect for corrosion or cracking in the lower 12-inches of the left and right wing front lift struts part number A-A815 or FAA-approved equivalent part number, and aft lift struts part number A-A854 or FAA-approved equivalent part number; in accordance with Part 1 of the Instructions in Taylorcraft Aviation, LLC Service Bulletin (SB) No. 2007-001 Revision A, or later FAA approved revision.

2.    Inspect using eddy current or ultrasound inspection methods to detect corrosion or cracking in the lower 12-inches of the left and right wing front lift struts part number A-A815 or FAA-approved equivalent part number, and aft lift struts part number A-A854 or FAA-approved equivalent part number; in accordance with Part 2 of the Instructions in Taylorcraft Aviation, LLC Service Bulletin (SB)
No. 2007-001 Revision A, or later FAA approved revision.

3.    Repetitively inspect in accordance with Requirement 2.

If cracking or corrosion is found during any inspection that exceeds the acceptance/rejection criteria in Taylorcraft Aviation, LLC Service Bulletin (SB)
No. 2007-001 Revision A, or later FAA approved revision, before further flight, replace the original design (vented) front lift struts part number A-815 or FAA-approved equivalent part number and original design (vented) aft lift struts part number A-A854 or FAA-approved equivalent part number, with one of the following:

a.    new sealed front lift struts part number MA-A815 or FAA-approved equivalent part number and new sealed aft lift struts, part number MA-A854 or FAA-approved equivalent part number; or,

b.    new original design (vented) front lift struts part number A-815 or FAA-approved equivalent part number and new original design (vented) aft lift struts part number A-A854 or FAA-approved equivalent part number.

Replacement of all struts with new sealed front lift struts part number MA-A815 or FAA-approved equivalent part number, and new sealed aft lift struts part number MA-A854 or FAA-approved equivalent part number, eliminates the repetitive inspection requirements of this Directive.

If not all the vented lift struts are replaced with new sealed units, then the lift struts that are not new sealed units are still subject to the repetitive inspection requirements of this Directive.

Note:  FAA AD 2007-16-14 Amdt 39-15153 refers.

Compliance:

1.    Within 5 hours time in service after 20 August 2007, unless the strut has:

a.     been replaced with new sealed front lift struts part number MA-A815 or FAA-approved equivalent part number and new sealed aft lift struts, part number MA-A854 or FAA-approved equivalent part number; or,

b.    been replaced with new original design (vented) front lift struts part number A-815 or FAA-approved equivalent part number and new original design (vented) aft lift struts part number A-A854, and has been installed on the aircraft for less than 24 months.

2.    Initially inspect any original design (vented) strut or FAA-approved equivalent part number, at whichever of the following applies:

a.     Before further flight when corrosion or cracking is found during the Requirement 1 inspection; or,

b.    If no corrosion or cracking is found during the Requirement 1 inspection; within 3 months after 20 August 2007, or within 24 months of installation of the strut, whichever occurs later.

3.    Inspect at intervals not to exceed 24 months after the initial Requirement 2 inspection:

For original or replacement left and right wing front lift struts part number A-A815 or FAA-approved equivalent part number, and aft lift struts part number A-A854 or FAA-approved equivalent part number of original design (vented).

This Airworthiness Directive becomes effective on 20 August 2007.

Background:

The FAA received several reports of corroded wing lift struts from different Taylorcraft series aircraft.  Independent laboratory analysis of the struts revealed varying degrees of excessive internal and external corrosion, including through-the- thickness corrosion.  The struts exhibited corrosion severe enough to require strut replacement.  This condition, unless corrected, could result in failure of a wing strut and lead to separation of the wing from the aircraft with subsequent loss of control.

Charles Lenarcic
Delegate of the Civil Aviation Safety Authority

16 August 2007