COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Fairchild (Swearingen) SA226 and SA227 Series Aeroplanes AD/SWSA226/74 Amdt 3 Landing Gear Stress Corrosion 2/98 Applicability: Models SA226-T, SA226-AT, SA226-TC, SA226-T(B), SA227-AC, SA227-AT, SA227-BC, SA227-TT, SA227-CC, and SA227-DC, all serial numbers, equipped with one or more of the following Ozone Industries Inc: 1. MLG Yoke P/n OAS5453 all dash numbers up to and including -19 or 2. NLG yoke P/n OAS5451 all dash numbers up to and including -17 Requirement: 1. Inspect and protect, in accordance with the following Fairchild SBs as revised 28 September 1995, and as applicable: a. SB 226-32-065, b. SB 227-32-039, or c. SB CC7-32-007. Note: Requirement document Effective pages are as follows: a. 1, 5, and 8 Revised 28 September 1995 b. 2, 3, 4, 6, 7, and 9 Issued 16 August 1995. 2. Replace cracked NLG and MLG yokes. Note 1. Replacement of a yoke assembly with an approved part other than that specified in the Applicability statement terminates the repetitive inspection requirement for that landing gear. Note 2. FAA AD 96-19-05 refers. Compliance: 1. Unless already accomplished, within 75 hours time in service after 29 January 1998, or prior to the installation of a replacement nose or main landing gear; thereafter, at intervals not exceeding 2500 hours time in service or 12 months, whichever occurs first. 2. Prior to further flight. This amendment becomes effective on 29 January 1998. Background: The actions specified in this Directive are intended to prevent MLG or NLG failure caused by stress corrosion cracks in the yokes, which if not detected could cause loss of control of the aircraft during landing operations. Amendment 1 was raised to incorporate the revised procedures of the amended requirement document and the revised FAA AD. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Amendment 2 was raised to remove cracked NLG and MLG yokes from service, due to an inability to determine, or to predict, crack growth on areas where stress corrosion occurs in primary structure with a single load path, (landing gear is considered to be such structure). Amendment 3 is raised to clarify that a MLG yoke or NLG yoke must now be removed from service before further flight if any cracks are detected during inspection. The previous staggered replacement time was intended to be applicable for the initial inspection only. Amendment 2 of this airworthiness directive became effective on 30 October 1995. Amendment 1 of this airworthiness directive became effective on 27 October 1995. The original issue of this airworthiness directive became effective on 25 October 1995.