COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Beechcraft 55, 58 and 95-55 (Baron) Series Aeroplanes AD/BEECH 55/78 Fuel Crossfeed Check Valves 5/93 Applicability: All model 58 and 58A aircraft with serial numbers TH-1488, TH-1600, TH-1613 thru TH-1635 and TH-1638 thru TH-1662. Requirement: Action in accordance with Beech mandatory SB No 2454. Note: FAA AD 93-01-23 Amdt 39-8477 refers. Compliance: As specified in the requirement document with a revised effective date of 16 April 1993. Background: Due to possible fuel pressure build up in the cross feed valves, caused by increased temperature, several operators have reported that excessive force was required to operate the fuel selector valve.