A PA28-140 PLT LANDED ON AN ABANDONED RWY AT PIR. ERROR ADMITTED.

Narrative

I WAS PRACTICING A VOR 25 APCH UNDER THE HOOD WITH A QUALIFIED SAFETY PLT. IT HAD SNOWED MORE THAN 6 INCHES OVER THE PAST SEVERAL DAYS; BUT BOTH RWY 25 AND RWY 31 WERE OPEN. I HAD TAKEN OFF ON RWY 31 WHICH WAS CLR IN THE MIDDLE AND HAD A LIGHT DUSTING OF SNOW ON THE EDGES. I HAD DSNDED TO MINIMUMS; LIFTED THE HOOD AND DECIDED TO LAND OUT OF THE APCH. THE RWY LOOKED CLR OF SNOW ON THE L SIDE AND PROVIDED EASILY ENOUGH CLR LENGTH FOR A TOUCH- AND-GO. WE UNEVENTFULLY TOUCHED DOWN AND TOOK OFF AGAIN. WE WERE QUITE SURPRISED WHEN WE SAW SOME X'S ON THE RWY ABOUT MIDFIELD. THEN WE REALIZED WE HAD LANDED ON AN ABANDONED RWY ABOUT 100 YARDS FROM THE ACTIVE RWY 25. THE ABANDONED RWY WAS USED BY THE HWY PATROL FOR EMER DRIVER TRAINING. NO ONE WAS THERE THAT DAY. WE THEN LOOKED OVER AT THE 'REAL' RWY 25 AND SAW THAT IT WAS HARDLY VISIBLE AS IT WAS COVERED WITH A LIGHT DUSTING OF SNOW. WE RPTED THE SIT TO FSS SO THEY COULD WARN OTHERS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR IS BASED AT PIR. THE ABANDONED RWY IS COMMON KNOWLEDGE AMONG THE LCL PLTS. THE X'S EXTEND THE FULL LENGTH OF THE ABANDONED RWY WHEN NOT COVERED BY SNOW. THE FSS SAID THAT IT WOULD PASS THIS INFO ON. THE FAA HAS NOT CONTACTED THE RPTR ON THIS. THE RPTR BELIEVES THAT A WARNING ON THE INST APCH AND ARPT PAGES WOULD BE A GOOD REMINDER; ESPECIALLY FOR TRANSIENT PLTS.