COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Gates Learjet 35 and 36 Series Aeroplanes AD/LEARJET 35/16 Maximum Operating Airspeed (VMO) - Reduction and Terminating Modification Applicability: All model 35 series with S/Nos. 35-050 to 35-339 except 35-054 and 35-065. All model 36 series with S/Nos. 36-017 and 36-045. 11/80 Requirement: To prevent the encountering of a possible overload flight condition that could fail the forward engine mount, accomplish the following: 1. Install airspeed warning placards and modify the mach/overspeed switch circuit to effect a reduced maximum operating airspeed (VMO) of 307 KIAS, from sea level to 31,100 feet altitude. 2. Replace or re-age both forward engine mounts in accordance with Gates Learjet Corporation Airplane Modification Kit AMK 80-6. Note: FAA AD 80-17-11, Amdt. 39-3888 refers. Compliance: Para. 1 - Within 75 hours time in service after 8 October 1980. Reduction in VMO to remain until modified in accordance with Para. 2 requirement. Para. 2 - Within 600 hours time in service after 8 October 1980. Background: Exceeding the maximum operating airspeed is suspected as a causal factor in recent overseas accidents involving the subject model aeroplanes.