What was found
AFTER ARRIVAL AT THE GATE, WITH ONLY THE APU POWERING THE AIRCRAFT, SPARKS AND FLASHING LIGHTS WERE REPORTED IN THE FIRST CLASS OVERHEAD CEILING AREA. THE PASSENGER OXYGEN MASKS DEPLOYED AND SMOKE WAS DETECTED IN THE FLIGHT DECK. SEVERAL FLIGHT DECK CIRCUIT BREAKERS TRIPPED. WIRES WERE FOUND CHAFED AND SHORTED IN THE CABIN OVERHEAD CEILING. THE WIRES WERE IDENTIFIED, ISOLATED, AND REPAIRED.