What was found
(CAN) JUST PRIOR TO LDG PILOT SMELLED SOMETHING LIKE PLASTIC OR RATHER BURNING BUT NOT SMOKE. AFTER SHUTTING DOWN, PILOT COULD SEE SMOKE INSIDE TAILBOOM & STRONG SMOKE OF SOMETHING ELECTICAL SMOKING IN MAIN CARGO BAY, PILOT INVESTIGATED FURTHER TO FIND SOURCE & FOUND NOTHING OUT OF ORDINARY. PILOT TRIED START WHEN GUIDE & PASSENGER COULD SEE 3 SPARKS UNDER BELLY OF A/C. FURTHER INVESTIGATION LEAD TO BATTERY BAY. ONE OF WIRE CONNECTORS ON POSITIVE POST OF BATTERY GOT WELDED TO BATTERY CASE. BOTTOM OF BATTERY CASE BURNT&SOURCE TO GROUND TO AIRFRAME. ARE 2 WIRES OR CABLES TO POSITIVE POST OF BATTERY.