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-31/16 Amdt 1 Pitch Trim Switch - Modification 9/77 Applicability: Model PA-31 and PA-31-300 S/Nos. 31-2 to 31-797; PA-31-350 S/Nos. 31-5001 to 31-5004; and PA-31P S/Nos 31P-1 to 31P-109; fitted with Rocker Type switch on pilot's control wheel. Document: 1. Piper SB No. 527; or 2. FAA AD 77-09-10. Compliance: Within 100 hours time in service after 28 February 1977.