COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Grumman G21 (Goose) Series Aeroplanes AD/G21/2 Horizontal Stabiliser Lower Strut Fittings - Inspection and Life Limitation Applicability: All model G21A. 10/77 Requirement: 1 Inspect the threaded portion of the strut lower adjustable end fitting P/N 12561-3 for cracks using a magnetic particle inspection technique. 2. Retire from service strut lower adjustable end fittings P/N 12561-3. Note: Grumman Customer Bulletin G21A No. 3 and FAA AD 53-31-2 refer. Compliance: 1. Initially, before issue of Certificate of Airworthiness and thereafter at intervals not exceeding 1000 hours time in service. 2. Before exceeding 3200 hours time in service.