COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Electrical Equipment
AD/ELECT/23 Nickel Cadmium Batteries with Polystyrene
Cell Cases - Inspection and Replacement
1/72
Applicability: Any nickel cadmium battery, containing polystyrene cell cases, that is capable of being used to start an aircraft engine or A.P.U., except those installed in aircraft which have the battery charging automatically controlled as a function of battery temperature.
Requirement: 1. Visually inspect each battery including the cell links and cell tops for evidence of heat damage.
2. (a) Replace each cell having a polystyrene case with an equivalent cell having a nylon case; OR
2. (b) Replace any battery containing any polystyrene cell cases with a battery which is approved for aircraft use containing all nylon cells.
Compliance: For Para. 1 - Within 30 hours time in service after 28 January 1972 and thereafter at intervals not exceeding 7 days for a battery that is used for an engine or A.P.U. start, or attempted start, until replacement of the battery in accordance with para. 2.
For Para. 2 - Any battery found to have evidence of heat damage - before further flight, and for any other battery before 1 August 1972.
Note 1: Polystyrene cell cases can be identified by their clear or slight yellow plastic appearance. Marathon (Sonotone) batteries manufactured prior to 1969 (Type CA20, CA20H and CA21H) contained polystyrene cell cases. Marathon batteries manufactured in 1969 or later and those manufactured by others contain nylon cells which can be identified by their milky white or bluish appearance.
Note 2: Any battery rebuilt since new may contain a mixture of polystyrene and nylon cells.