What was found
DURING ANNUAL INSPECTION, BATTERY ACID WAS FOUND TO HAVE LEAKED INTO COCKPIT ONTO LEFT RUDDER PEDAL, ATTACHING TUBING, AND GENERAL AREA BELOW PEDAL. ACID HAD FLOWED THROUGH CORRODED RIVET HOLE ONTO SEAT FOR CABIN HEAT AND DRIPPED INTO FLOOR AREA. SUBMITTER BELIEVED THE BATTERY WAS TOO FULL OF ACID AND GASSED DURING CHARGING ALLOWING LIQUID INTO BATTERY BOX, AND, SUGGESTED CLOSE INSPECTION OF BATTERY BOXES DURING ALL MAINTENANCE.