COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Enstrom F-28 Series Helicopters AD/ENST 28/15 Amdt 2 Tail Rotor Spindle and Drive Shaft - Inspection and Retirement 8/77 Applicability: All models F-28 and 280. Requirement: 1. Remove tail rotor spindles P/N 28-15202 from service and replace with a new spindle P/N 28-15202-13 or a re- worked spindle which may be identified by an 8- character serial number acid etched on the outside of the spindle centre section. 2. Install tail rotor strike tabs in accordance with Enstrom Service Directive Bulletin No. 0037 Revision A or FAA AD 77-04-04 Amendment 39-2839. 3. Inspect the tail rotor spindle in accordance with the above Bulletin or FAA AD. 4. Inspect the tail rotor drive shaft in accordance with Enstrom ServiceDirective Bulletin No. 0039. Compliance: For Para. 1 - Within 10 hours time in service after 17 August 1977. For Para. 2 - Forthwith. For Para. 3 and 4 - Before further flight following any tail rotor strike.