Document ID: chunk:federal_register_of_legislation:F2007L00122:body:0:p1
Version: federal_register_of_legislation:F2007L00122
Segment Type: other
Provision Reference: 
Character Range: 0–3436

AIRWORTHINESS DIRECTIVE
On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AT/21 Amdt 2 and issues the following 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.

Airtractor AT-300, 400 and 500 Series Aeroplanes
AD/AT/21 Amdt 3  Wing Lower Spar Cap Safe Life - 2  2/2007

Applicability:  Models AT-501, AT-502, AT-502A, AT-502B, and AT-503A aircraft.
Requirement:       1. The following table specifies the safe life of the wing lower spar cap for affected aircraft that do not incorporate and never have incorporated Marburger Enterprises Inc. winglets.  Retire at or before reaching the safe lives listed.
                Model    Serial Numbers                  Safe Life
                AT-501   0002 through 0061               4,531 hours TIS
                AT-501   0062 and subsequent             7,693 hours TIS
                AT-502   0003 and subsequent             1,650 hours TIS
                AT-502A  0158 and subsequent             1,650 hours TIS
                AT-502B  0187 through 0654, except 0643  1,650 hours TIS
                AT-502B  6243, and 0655 through 0692     9,000 hours TIS
                AT-502B  0693 through 0701               9,500 hours TIS
                AT-502B  0702 and subsequent             9,800 hours TIS
                AT-503A  0067 and subsequent             1,650 hours TIS

                   2. If piston powered aircraft have been converted to turbine power, use the limits for the corresponding serial number turbine powered aircraft.

                   3. Aircraft that have been modified to install lower spar caps, part numbers 21058-1 and 21058-2, should have a safe life of 9,800 hours TIS.

                   4. Some aircraft at some stage could have been fitted with Marburger Enterprises Inc. winglets.  These winglets are installed in accordance with Supplemental Type Certificate (STC) SA00490LA.  Use the winglet usage factor indicated in the table below, the wing lower spar cap safe life specified above, and the instructions included in FAA AD 2006-24-10 Appendix 1, to determine the new safe life for aircraft that incorporate or have incorporated Marburger winglets.
                Model    Serial Numbers       Winglet Usage Factor
                AT-501   0002 through 0061    1.6
                AT-501   0062 and subsequent  1.6
                AT-502   0003 through 0236    1.6
                AT-502A  0158 through 0238    1.6
                AT-502A  0239 and subsequent  1.2
                AT-502B  0187 and subsequent  1.2

                Note 1:  FAA AD 2006-24-10 Appendix 1 and Appendix 2 may be obtained from the FAA Internet web site www.airweb.faa.gov/rgl or by request to the Authority Internet address airworthiness.directives@casa.gov.au

                   5. Model AT-502B aircraft, serial number 0643, serial number 0655 and subsequent, and all