COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Agusta A109 Series Helicopters AD/A109/23 Tail Boom and Vertical Fin Modification 8/94 Applicability: All models A109A, A109AII and A109C with serial numbers up to and including 7670, except for serial numbers 7630, 7633, 7645, 7651, 7654, 7663, and 7665 to 7669. Requirement: Action in accordance with Agusta Bollettino Technico 109-96. Note: RAI AD 94-098 refers. Compliance: Part I - Within 100 hours time in service after 21 July 1994 or prior to 30 June 1995, whichever occurs first. Part II - At each 300 hour inspection after accomplishment of Part I. Background: Some cracking of structural parts has been found in the vertical fin attachment area of the tail boom. This Directive provides for ready access to the area, and the inspection requirements.