COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES SAAB SF340 Series Aeroplanes AD/SF340/31 Stabilizer De-Icing 3/92 Applicability: Model 340B Serial Number 240 through 299 inclusive. Requirement: Action in accordance with the Technical Requirements of LFV (Sweden) AD No 1- 051. Note: SAAB SB SAAB 340-30-039 refers. Compliance: Prior to issue of a Certificate of Airworthiness. Background: Freezing of the control valve and the pressure switch located in the dorsal fin may result in continuously inflated or deflated de-ice boots.