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 28/23 RAJAY Turbocharger and Fuel Nozzle Vent Line - Modification Applicability: Model F-28C and 280C. Requirement: Part 1: For turbocharger S/Nos. less than 70484: 12/79 (a) Remove the turbocharger from the helicopter in accordance with the Enstrom Maintenance Manual. (b) Using a 5/32 Allen wrench, remove the six countersunk cap screws that secure the compressor housing to the bearing housing assembly. If necessary, gently tap the compressor (c) Reinstall the compressor housing by placing the turbocharger on the compressor housing using a new gasket, Rajay P/N TC6-44. Secure with six cap screws and tighten evenly and alternately to 90 + 10 inch- pounds. (d) Reinstall the turbocharger in the helicopter in accordance with the Enstrom Maintenance Manual. Part 2: for turbocharger S/Nos. 70484 and higher: (a) Remove the induction system air inlet filter in accordance with the Enstrom Maintenance Manual. (b) Remove the AN815-6D union which attaches the fuel nozzle air vent installation to the induction system air inlet filter container. Save the AN924- 6D nut which was holding the union in place, for reinstallation, in accordance with step D. (c) Install an AN832-6D union, in place of the AN815-6D union, so that the AN924-6D nut is outside of the filter container. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES (d) Attach the fuel nozzle air vent line to the AN832-6D union. (e) Replace the air filter in accordance with the Enstrom Maintenance Manual. Note: FAA AD 79-02-01 AMDT. 39-3390 refers. Compliance: Within 100 hours time in service after 29 February 1980. Background: This Directive is issued in order to prevent damage to the turbo charger and possible engine power loss.