FLC OF AN EMBRAER 145; EVACED THE PAX ON THE ARPT AFTER LNDG DUE TO SMOKE IN THE CABIN CAUSED BY THE ACFT'S AUX PWR UNIT.

Narrative

AFTER LNDG EWR; RWY 4R WITH 48 SOULS ONBOARD; AND CLR OF ALL RWYS; THE AFTER LNDG CHKLIST WAS ACCOMPLISHED. APPROX 60-90 SECONDS LATER; WITH THE APU SUPPLYING THE AIR-CONDITIONING PACKS; THE ENG INDICATING/CREW ALERTING SYS (EICAS) PROVIDED A 'LAVATORY SMOKE' WARNING. THE WARNING SOUNDED IN THE COCKPIT AS WELL AS ON THE FLT ATTENDANT'S PANEL IN THE GALLEY. AFTER IDENTING THE MESSAGE AND SILENCING THE WARNING; THE CREW WAS CONTACTED BY THE FLT ATTENDANT. CAPT DIRECTED HER TO SILENCE THE HORN AND INVESTIGATE THE LAVATORY STATUS. WHILE NO SMOKE WAS INITIALLY VISIBLE; THE SMELL OF SMOKE WAS READILY APPARENT IN THE CABIN ACCORDING TO THE FLT ATTENDANT. MEANWHILE THE FO TOLD GND THAT WE WOULD NEED TO REMAIN STATIONARY FOR A MINUTE OR TWO. WE WERE; AT THE TIME; CLR OF THE RWY; AND ADJACENT OF THE CFR BUILDING. IN THE SHORT PERIOD OF TIME THAT IT TOOK THE FLT ATTENDANT TO GO BACK AND CHK THE LAVATORY; SMOKE SLOWLY BEGAN TO ENTER THE CABIN. NOT FROM ANY ONE APPARENT SOURCE; BUT PROBABLY FROM THE AIR-CONDITIONING SYS. (IT WASN'T HVY SMOKE; BUT IT WAS VISIBLE; ACCORDING TO THE FLT ATTENDANT.) THE FLT ATTENDANT IMMEDIATELY CALLED THE COCKPIT WITH THIS INFO ABOUT SMOKE. SHE MADE IT CLR THAT WE NEEDED TO EVAC. CAPT IMMEDIATELY COMMANDED 'EVAC L SIDE.' FO MEANWHILE; DECLARED AN EMER AND CALLED FOR THE FIRE TRUCKS. GIVEN OUR CONVENIENT POS IN FRONT OF THE FIREHOUSE; TRUCKS WERE ON SCENE IN SECONDS. EMER PERSONNEL ASSISTED WITH WHAT WAS A VERY ORDERLY AND CTLED EVAC THROUGH THE MAIN CABIN DOOR. ALL PAX WERE SAFELY CORRALLED ON GRASS ADJACENT THE ACFT AND SURROUNDED BY POLICE AND EMER PERSONNEL. APPROPRIATE QRH CHKLISTS WERE COMPLETED WITH ALL PAX OFF; EMER PERSONNEL QUICKLY DETERMINED NO FIRE; NO MORE SMOKE; NO DANGER. FLT ATTENDANT WENT ON SHUTTLE BUS WITH PAX TO TERMINAL. COCKPIT CREW STAYED WITH ACFT TO ASSIST WITH TOW BACK TO GATE AREA. MAINT HAD INSISTED ON STARTING ENG TO TAXI BACK. CAPT REFUSED. ACFT WAS TOWED TO RAMP AREA. AT FINAL PARKING SPOT; PARKING AND TERMINATING CHKS WERE COMPLETED. A POSTFLT INSPECTION REVEALED NO ABNORMALITIES. ACFT WAS LEFT IN THE SECURE HANDS OF ARPT POLICE. MAINT LATER DETERMINED THAT THE APU WAS BAD; BURNING OIL; AND HAD PROBABLY CAUSED THE SMOKE.