COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Electrical Equipment AD/ELECT/54 Sealed Lead Acid Aircraft Batteries 7/90 Applicability: All installed Gates Varley/Tungstone Energy Products/Hawker Energy Products sealed lead acid batteries listed below: 18 AH batteries with the following product numbers: 25 AH batteries with the following product numbers: 9750-0730, 9750-0734, 9750-0738, 9750-0640, 9750-0650, 9750-0740, 9750-0742, 9750-0744, 9750-0658, 9750-0660 9750-0772. 9750-0750, 9750-0781. Note 1. Aircraft known to have batteries of this type fitted include but are not limited to BAe 125 Series; Shorts Skyvan Series; and BAe. Jetstream series. Note 2. Gates Varley SB M1-89 Issue 2 (made mandatory by CAA (UK) also refers. Requirement: Remove from the aircraft and carry out a capacity test in accordance with the aircraft maintenance manual or other approved procedure. Compliance: 1. 18 AH batteries in the serial number range A1810 to A7637, and 25 AH batteries in the serial number range B0095 to CO 575 - initially 6 months after initial installation in an aircraft, and thereafter at intervals not exceeding 3 months. 2. 18 AH batteries with serial numbers below A1810 and above A7637, and 25 AH batteries with serial numbers below B0095 and above CO 575 - initially 6 months after initial installation, then after a further 6 months, and thereafter at intervals not exceeding 3 months. Background: Affected batteries have been found to exhibit an unexpected loss of capacity which reduces the time for which the battery can power emergency services in the event of a power failure.