COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Ayres Thrush (Snow) Commander Series Aeroplanes AD/AC-SNOW/15 Forward Fuselage Upper Longerons - Inspection and Modification Applicability: All models S2R-R1820 with S/Nos R1820-001 to R1820-031. 6/84 Requirement: 1. Visually inspect the forward fuselage upper longerons for Cracks in accordance with the following: (a) remove the fuselage side skins located between the wing upper surface and the hopper to gain access to the upper longerons between the firewall and the cockpit. (b) check the longerons in the areas shown in Fig 1 of Ayres Corporation SB No SB-AG-16 dated 1 April 1984 as follows: (i) between the upper engine mount and first hopper attachment bracket; (ii) each vertical and diagonal tube intersection at the upper longeron; (iii) each hopper attachment bracket. 2. Incorporate tubular split-sleeve modification P/N CK-AG-19 on both upper longerons in accordance with Ayres Corporation SB No SB-AG-16. Note: FAA Ayres Emergency AD dated 7 May 1984 refers. Compliance: For para 1: Before further flight after 17 May 1984 and thereafter at intervals not exceeding 10 hours' time in service, until modified in accordance with para 2. Note: This inspection may be accomplished by the pilot in command in which case the pilot shall enter and certify for this AD in column 2 part 3 of the maintenance release on each occasion. For para 2: Within 100 hours' time in service after 17 May 1984. Background: Failure of both upper longerons has occurred on aircraft in service overseas. This condition if undetected could result in separation of the engine in flight.