COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Beechcraft 50 (Twin Bonanza) Series Aeroplanes AD/BEECH 50/12 Elevator Control Surfaces NK Applicability: All models prior to S/Nos. DH-170 and FH-89 except H-1 to H-11. Requirement: Action in accordance with Beechcraft SB B50 - No. 35; C50 - No. 26; D50 - No. 20; E50 - No. 11; F50 - No. 4. Compliance: At intervals not exceeding 100 hours' time in service.