What was found
FLT 654 - CLT-ROA - AFTER AIRCRAFT PULLED AWAY FROM THE JETWAY FOR DEPARTURE, THE APU FAILED. THE CABIN FILLED WITH SMOKE. THE LAVATORY SMOKE DETECTOR SOUNDED, BUT THERE WAS NO APU FIRE INDICATION IN THE COCKPIT. PASSENGERS WERE EVACUATED DOWN THE ENTRY DOOR STAIRS. MAINTENANCE REPLACED THE APU. (M)