AD/At/29 Amdt 1 Engine Mount (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/29 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/29 Amdt 1 | Engine Mount | 8/2009 |
Applicability: | Model AT-400, AT-400A, AT-402, AT402A, and AT-402B aircraft, serial numbers 0001 through 1175. Model AT-502, AT-502A, AT-502B, and AT-503A aircraft, serial numbers 0001 through 2597. |
Requirement: | A. Model AT-400, AT-400A, AT-402, AT-402A, AT-402B, AT-502, AT-502B, and AT-503A aircraft. 1. For engine mounts without gussets installed, inspect the engine mount in accordance with Snow Engineering Co. SL No. 253 Revision C, dated a. For aircraft with less than 5,000 hours time in service; at the initial and repetitive times specified in the Compliance section. b. For aircraft with 5,000 hours time in service or more; at the initial and repetitive times specified in the Compliance section. 2. For engine mounts with gussets installed, inspect the engine mount in accordance with Snow Engineering Co. SL No. 253 Revision C, dated a. For aircraft with less than 5,000 hours time in service; at the initial and repetitive times specified in the Compliance section. b. For aircraft with 5,000 hours time in service or more; at the initial and repetitive times specified in the Compliance section. B. Model 502A aircraft. 1. For engine mounts without gussets installed, inspect the engine mount in accordance with Snow Engineering Co. SL No. 253 Revision C, dated a. For aircraft with less than 5,000 hours time in service; at the initial and repetitive times specified in the Compliance section. |
| b. For aircraft with 5,000 hours time in service or more; at the initial and repetitive times specified in the Compliance section. 2. For engine mounts with gussets installed, inspect the engine mount in accordance with Snow Engineering Co. SL No. 253 Revision C, dated a. For aircraft with less than 5,000 hours time in service; at the initial and repetitive times specified in the Compliance section. b. For aircraft with 5,000 hours time in service or more; at the initial and repetitive times specified in the Compliance section. If crack damage is detected during any inspection, replace with a new engine mount or repair the engine mount. If choosing repair, contact Air Tractor, Inc. for repair instructions. Note: FAA AD 2009-11-05 Amdt 39-15915. | |
Compliance: | A. Model AT-400, AT-400A, AT-402, AT-402A, AT-402B, AT-502, AT-502B, and AT-503A aircraft. 1.a. Initially, within the next 12 months after 3 July 2008. Repetitively thereafter at intervals not to exceed 12 months, until accumulating 5,000 hours time in service. 1.b. Initially, upon accumulating 5,000 hours time in service or within the next 10 hours time in service after 30 July 2009, or within the next 100 hours time in service from the last inspection performed, whichever occurs later. Repetitively thereafter at intervals no to exceed 100 hours time in service. 2.a. Initially, within the next 12 months after 30 July 2009. Repetitively thereafter at intervals not to exceed 12 months, until accumulating 5,000 hours time in service. 2.b. Initially, upon accumulating 5,000 hours time in service or within the next 10 hours time in service after 30 July 2009, or within the next 100 hours time in service from the last inspection performed, whichever occurs later. Repetitively thereafter at intervals no to exceed 100 hours time in service. B. Model 502A aircraft. 1.a. Initially, upon accumulating 1,300 hours time in service or within the next 100 hours time in service after 3 July 2008, whichever occurs later. Repetitively thereafter at intervals not to exceed 300 hours time in service. |
| 1.b. Initially, upon accumulating 5,000 hours time in service or within the next 10 hours time in service after 30 July 2009, or within the next 100 hours time in service from the last inspection performed, whichever occurs later. Repetitively thereafter at intervals no to exceed 100 hours time in service. 2.a. Initially, upon accumulating 1,300 hours time in service or within the next 100 hours time in service after 30 July 2009, whichever occurs later. Repetitively thereafter at intervals not to exceed 300 hours time in service. 2.b. Initially, upon accumulating 5,000 hours time in service or within the next 10 hours time in service after 30 July 2009, or within the next 100 hours time in service from the last inspection performed, whichever occurs later. Repetitively thereafter at intervals no to exceed 100 hours time in service. | |
| This Amendment becomes effective on 30 July 2009. | |
Background: | Since the issue of FAA AD 2007-13-17, which affected Models AT-602, AT-802, and AT-802A aircraft, Air Tractor received a report of a Model AT-502B aircraft with a crack located where the lower engine mount tube is welded to the engine mount ring. In addition, Air Tractor developed gussets that, when installed in accordance with certain service letters, terminates the repetitive inspection requirement. Consequently, new FAA AD 2008-10-12 establishes new inspection actions for the AT-400 and AT-500 series aircraft and incorporates a mandatory terminating action for the repetitive inspections. The actions required by this Directive are intended to detect and correct cracks in the engine mount, which could result in failure of the engine mount and possible separation of the engine from the aircraft. Amendment 1 is issued in response to a new FAA AD, which was prompted by a report of a Model AT-602 aircraft with a crack completely through the gusset that was installed as required in FAA AD 2008-10-12. Consequently, this Directive requires repetitive inspections of engine mounts of all previously affected aircraft with or without gussets installed. |
David Villiers
Delegate of the Civil Aviation Safety Authority
18 June 2009
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