COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Hot Air Balloons AD/BAL/8 Amdt 1 Instruments in Hot Air Balloons 9/90 Applicability: All balloons for which a system of maintenance has not been approved pursuant to CAR 38(3). Requirement: Carry out a calibration check of all instruments in accordance with manufacturer's instructions/specifications. Compliance: At intervals not exceeding three years. Background: Whilst CAR 2 definition of "aircraft" covers balloons, these aircraft do not have a major inspection requirement nor are ambient or envelope temperature indicators currently addressed.