What was found
ON APPROACH HEARD A SIZZLING SOUND AND SMOKE SEEPING FROM BEHIND CAPT CHAIR. NO CIRCUIT BREAKERS WERE POPPED. UPON ARRIVAL AT A/C SMELLED NO UNUSUAL ODORS. FOUND NO CIRCUIT BREAKERS IN COCKPIT POPPED. OPENED CIRCUIT BREAKER PANEL BEHIND / CAPTAIN SEAT AND FWD F/A'S SEAT AND INSPECTED AREAS FOR EVIDENCE OF ARCING OR LOOSE CONNECTORS AND FOUND NONE. CHECKED E&E / BAY AND FWD ACCESSORY AND FOUND NO RELATED DEFECTS. RAN AC PACK WITH APU AND ENGINE AND SMELLED NO UNUSUAL ODORS. FOUND / EMPTY COOKIE CONTAINER WEDGED BEHIND CAPTAINS SEAT. COOKIE CONTAINER IS SUSPECTED SOURCE OF SIZZLING / SOU. WORK DONE PER 717 FAULT ISOLATION MANUAL 21-22. CHIEF INSPECTOR NOTIFIED AS REQUIRED. A/C OK FOR SERVICE.