COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Allison Turbine Engines - 250 Series AD/AL 250/79 Fuel Control Bellows Replacement 4/99 Applicability: All Allison Model 250-C18, C20, C28, C30, C20R, B15, B17, B17F series engines fitted with a main fuel control incorporating a beryllium copper Pc bellows. Requirement: Replace the beryllium copper bellows assembly with an inconel 718 stainless steel bellows assembly as per AlliedSignal Aerospace Equipment Systems Service Bulletin GT-242 Revision 2. Note: FAA Airworthiness Directive 98-24-28 refers. Compliance: At the next main fuel control visit to an AlliedSignal Aerospace Equipment Systems authorised repair facility, regardless of the purpose of the visit, but no later than 31 October 1999. This Airworthiness Directive becomes effective on 22 April 1999. Background: This directive has been issued to require the replacement of beryllium copper fuel control Pc bellows. The requirement follows reports of leaking bellows resulting in uncommanded minimum fuel flow conditions, loss of fuel flow control and subsequent forced landings.