FAILURE OF THE PILOT TO FOLLOW PROCEDURES CONCERNING USE OF THE ENGINE INLET ANTI-ICE SYSTEM AND/OR CONTINUOUS IGNITION WHILE OPERATING IN ICING CONDITIONS, WHICH RESULTED IN PROBABLE ICE INGESTION AND LOSS OF ENGINE POWER; AND THE PILOT'S FAILURE TO MAINTAIN SUFFICIENT AIRSPEED WHILE COPING WITH THE ENGINE PROBLEM, WHICH RESULTED IN A STALL. FACTORS RELATED TO THE ACCIDENT WERE: DARKNESS, ICING CONDITIONS, AND ENGINE INLET (NACELLE) ICE.