COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Pilatus Porter PC-6 Series Aeroplanes AD/PC-6/42 Collector Tank Venting 2/96 Applicability: All PC-6 aircraft up to and including aircraft S/N 915 fitted with a turboprop engine excepting aircraft S/N 902 which has previously been modified by Pilatus. Requirement: Unless previously carried out action in accordance with Pilatus Service Bulletin No 171. Requirements of Pilatus SB 118, issued December 1972, must be incorporated prior to compliance with this Directive. Compliance: Prior to 30 April 1996. Background: The manufacturer has advised that due to the collector tank not completely refilling fuel starvation may occur when an aircraft is used for parachute dropping or sky- diving missions.