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 28/16 Tail Rotor Pitch Link Retainer and Guide Bolt - Replacement 10/77 Applicability: Models F-28C and 280C fitted with the Wide Cord tail rotors and S/Nos. as listed in the requirement document. Requirement: 1. Inspect the P/N 28-16320 pitch link retainer in accordance with Enstrom Service Directive Bulletin No. 0040. 2. Replace the P/N 28-16320 pitch link retainer and guide bolts in accordance with Enstrom Service Directive Bulletin No. 0040 and 0043. FAA AD 77-15-04 refers. Compliance: 1. For Part 1 of the requirement document - before each flight, until part 2 is complied with. 2. For Part 2 of the requirement document - within 100 hours time in service after 30 November 1977.