COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 177 Series Aeroplanes AD/CESSNA 177/16 Oil Pressure Gauge Line 3/74 Applicability: Model 177 with S/Nos. 17700001 to 17701160. Requirement: 1. Inspect the oil pressure gauge line along the entire length from firewall to instrument panel, paying particular attention to the following areas: (a) in the vicinity of the flap control switch; (b) adjacent to the blast cooling nozzle of those aircraft fitted with radio cooling equipment. 2. Adjust the line as required to prevent chafing. Compliance: Within 100 hours time in service after 29 March 1974.