COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Piper PA-31 Series Aeroplanes AD/PA-31/4 Amdt 1 Elevator Torque Tube - Inspection 12/68 Applicability: All models not modified in accordance with Section 11 of Piper SB No. 284. Requirement: Remove the elevator torque tube assembly from the aircraft and dismantle the horn assembly P/N 40006-00 and brackets P/N 40066-00 from the tube. Remove the finish from the tube and inspect for cracking using dye penetrant or magnetic particle methods. Compliance: At intervals not exceeding 100 hours time in service.