What was found
EWR - FLT 4587 - DURING TAXI OUT, CREW NOTED SMOKE IN CABIN AFTER APU FAIL AND SHUT DOWN. CREW RETURNED TO GATE AND PASENGERS WERE DEPLANED NORMALLY. NO FURTHER INCIDENTS WERE REPORTED. MAINTENANCE WAS SENT FROM LGA. AIRCRAFT WAS INSPECTED AND APU WAS DEFERRED. (M)