AD/At/21 Amdt 2 Wing Lower Spar Cap Safe Life 2 (Cth)
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 1 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 2 | Wing Lower Spar Cap Safe Life - 2 | 3/2005 |
Applicability: | Models 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. Retire at or before reaching the safe lives listed.
2. If piston powered aircraft have been converted to turbine power, use the limits for the corresponding serial number turbine powered aircraft. 3. Some aircraft at some stage could have been fitted with Marburger Enterprises Inc. winglets. These winglets are installed in accordance with Supplemental Type Certificate 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 2002-26-05 Appendix, to determine the new safe life for affected aircraft.
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| Note 1: FAA AD 2002-26-05 Appendix may be obtained from the FAA Internet web site or by request to the Authority Internet address [email protected]. | |
| 4. Modify the applicable aircraft records as follows to show the reduced safe life for the wing lower spar cap by using the information contained in Requirement paragraph 1 and paragraph 3 of this Directive, and FAA AD 2002-26-05 Appendix, as applicable: Incorporate the following into the Aircraft Logbook, “In accordance with AD/AT/21 Amdt 1, the wing lower spar cap is life limited to ___”(the life calculated from Requirement 4). 5. Accomplish the actual replacement /modification in accordance with Snow Engineering Service Letter No. 197 or No. 205, both revised 26 March 2001, as applicable. 6. If parts have been ordered from the manufacturer as a result of the wing lower spar cap reaching the safe life limit, but the parts are not available, an eddy current inspection of the wing lower spar cap is to be accomplished in accordance with Snow Engineering Service Letter No. 197 or No. 205, both revised 26 March 2001, as applicable. a. The Requirement 6 inspections are allowed until one of the following occurs, at which time the replacement /modification must be accomplished: (i) Crack(s) is/are found; (ii) Not more than three inspections or 1,200 hours time in service are accumulated: the first inspection must be accomplished upon accumulating the safe life; the second inspection would have to be accomplished within 400 hours time in service after accumulating the safe life; the third inspection would have to be accomplished 400 hours time in service after the second inspection; and the replacement/modification would have to be accomplished within 400 hours time in service after the third inspection. 7. Eddy current inspect the wing lower spar cap in accordance with the procedures in Snow Engineering Service Letter No. 197 or No. 205, as applicable; in order to detect any crack before it extends to the modified centre section of the wing. If found cracked, repair cracking or replace the wing section. Note 2: FAA AD 2002-26-05 Amdt 39-12991 refers. | |
| Alternative Method of Compliance to this Airworthiness Directive An Alternative Method of Compliance (AMOC) for this AD is available to perform inspections and modifications, in lieu of retirement at the safe lives specified in Requirement 1 of this AD. If the AMOC is used, a safe life of up to 8,000 hrs TTIS is applicable. The specifics of the inspections and modifications are complex and lengthy and are contained in the FAA AMOC document - a copy of which is available from the CASA Tamworth office. When requesting a copy of the document from CASA, ask for “FAA AMOC (dated 13 Jan 2005 or later issue) to FAA AD 2002-26-05, Amendment 39-12991”. The FAA AMOC contains a table of a range of aircraft serial numbers that are eligible for the AMOC. You must ensure that your serial number is within the range listed in the AMOC. If it is not, the requirements of this AD still apply. The aircraft logbook entry for this alternative means of compliance must include the logbook entry as shown in paragraph 8 of the AMOC. A copy of the AMOC must be attached to the aircraft logbook. If it is not possible or desirable to use the AMOC provisions, then the requirements of this AD must be followed. For aircraft that have undergone a turbine conversion or have winglets installed, contact Airtractor engineering for advice on whether or not the AMOC can be used for your aircraft. | |
Compliance: | Requirements 1, 2 & 3: As listed in requirement section. Requirement 4: Within 10 hours time in service after 20 March 2003. Requirement 5: Upon reaching the safe life as calculated at Requirement 4. If, as of the time of logbook entry as required by Requirement 4, the aircraft wing lower spar cap(s) is/are over or within 50 hours of the safe life, an additional 50 hours time in service is allowed to accomplish the replacement /modification. Requirement 6: Before further flight after the parts have been ordered, and thereafter at intervals not to exceed 400 hours time in service; until one of the criteria in Requirement paragraph 6.a.(i) or 6.a.(ii) are met. Requirement 7: Immediately prior to the replacement /modification when the safe life is reached. For aircraft that had this replacement /modification accomplished in accordance with AD/AT/20, accomplish this inspection and any necessary corrective action within 400 hours time in service after 10 July 2002, unless already done. |
| This Amendment becomes effective on 17 March 2005. |
Background: | This Directive lowered the safe life for the wing lower spar cap for affected aircraft that was established in AD/AT/20, and further reduced the safe life for aircraft that incorporate or have incorporated Marburger Enterprises Inc. winglets. This Directive also requires an eddy current inspection immediately prior to the replacement/modification to detect and correct any crack in a bolthole before it extends to the modified centre section of the wing. This Directive is the result of reports the FAA received of cracks originating in the outboard 3/8-inch hole of the main spar lower cap on affected aircraft at times lower than the established safe life. This amendment is issued to allow the use of an alternative method of compliance (AMOC) which involves the use of inspections and modifications and a new extended retirement life (8,000 Hours TTIS), in lieu of the safe lives specified in this AD. Amendment 1, effective 20 March 2003, was issued in response to a new FAA AD which further reduces the safe life of the Models AT-502, AT-502B, and AT-503A aircraft, and added aircraft recently manufactured to the applicability of this Directive. The original issue of this Airworthiness Directive became effective on 10 July 2002. |
David Punshon
Delegate of the Civil Aviation Safety Authority
4 February 2005
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