What was found
A BATTERY TEMP LIGHT ILLUMINATED DURING FLIGHT. EMERGENCY PROCEDURES INITIATED. FOUND ACFT BATTERY SHORTED. A SECONDARY LEAD IS ATTACHED TO ACFT BATTERY USING A METAL TAB LUG WHICH IS CONNECTED TO THE WIRE END CONNECTOR USING A NUT AND BOLT WHICH IS PROTECTED BY HEAT SHRINK INSULATOR. THIS NUT AND BOLT CONNECTING THE WIRE END CONNECTOR AND TAB LUG WEARS THROUGH THE INSULATION AND CONTACTS THE NICAD BATTERY'S CASE SHORTING THE BATTERY AND OVERHEATING IT. REPLACED THE WIRE TERMINAL CONNECTOR AND TAB LUG WITH A SINGLE APPROPRIATE SIZE WIRE AND TERMINAL. REPAIRED 2 OTHER ACFT WITH SAME PROBLEM.