FA50 EXPEDITES DSCNT AND TURNS DURING VISUAL APCH TO PVD AND LOSSES SIGHT OF ARPT.

Narrative

THE CAPT WAS FLYING AT THE END OF A LONG DAY. WE SPOTTED PVD ARPT AND WERE CLRED FOR A VISUAL APCH. THE CAPT ENTERED A R DOWNWIND FOR RWY 23. TWR CLRED US TO LAND ON RWY 23. THE CAPT NOTED A 20 KT XWIND AT PATTERN ALT SO HE CORRECTED TO GIVE US ENOUGH ROOM FOR OUR BASE TURN. AS THE CAPT TURNED BASE HE TURNED SOMEWHAT STEEPER THAN NORMAL AND BEGAN TO DSND RAPIDLY. I CALLED THIS TO HIS ATTN AS WE PASSED THROUGH ABOUT 800 FT AGL. WE HAD THE ARPT AND BEACON IN SIGHT; BUT WERE NOW HAVING A HARD TIME MAKING OUT THE RWY LIGHTS FOR RWY 23; DUE TO OUR LOW ALT. WE WERE NOW HEADED FOR THE ARPT BUT WELL W OF RWY 23. THE TWR CAME ON THE RADIO AND ASKED IF WE 'HAD RWY 23 IN SIGHT?' I COULD NOW SEE THE LIGHTS AND REPLIED 'YES.' I THEN ALERTED THE CAPT THAT WE WERE AT 500 FT AGL AND TOLD HIM TO TURN L 90 DEGS TO LINE UP WITH THE RWY OFF TO OUR L. THE CAPT MADE A TIGHT R BASE TURN TO FINAL AND LANDED UNEVENTFULLY. THE TWR SAID NOTHING ELSE ABOUT OUR STRANGE APCH AND LOW ALT OVER THE CITY WHILE WE WERE TRYING TO MAKE OUT THE RWY. FATIGUE DEFINITELY CONTRIBUTED TO THIS BAD APCH. WE HAD BEEN FLYING MOST OF THE DAY. ALSO WE WERE AT A STRANGE ARPT AND AT NIGHT. WE HAD THE ILS TUNED; BUT THE CAPT DID NOT USE IT FOR HIS BASE AND TURN TO FINAL. HE USED THE GS; BUT WELL BEFORE HE INTERCEPTED THE LOC. THIS RESULTED IN OUR PREMATURE DSCNT TO A LOW ALT.