COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES British Aerospace (Scottish Aviation) Twin Pioneer Series Aeroplanes AD/SA-TP/28 Wing Lift Strut Fretting 12/86 Applicability: All models. Requirement: Modify in accordance with Scottish Aviation MNS No 965. Compliance: Prior to the issue of a Certificate of Airworthiness. Background: This modification is to eliminate fretting on the surface of the wing lift strut at the stabilizer strut fitting.