A PLT APCHING BWI REPORTS MISSING AN ALT RESTRICTION BECAUSE OF CONFUSION ABOUT WHY THE RADIAL OUT OF CSN TO OTT ON THE RAVNN ONE RNAV AND THE NOTTINGHAM SIX ARR ARE DIFFERENT EVEN THOUGH BOTH GO TO SAME FIX.

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WE WERE CLEARED THE RAVNN ONE ARRIVAL INTO BWI. DURING THE DESCENT I REMARKED TO THE FO (PNF) THAT THE RADIAL OUT OF CSN (096) SHOWED WE WERE NORTH OF THE COURSE DEPICTED ON THE AIRCRAFT DISPLAY. TO ME THIS WAS UNUSUAL BECAUSE THE VOR IS USUALLY EXACTLY IN AGREEMENT WITH THE NAVIGATION DISPLAY. THE FO LOOKED AT THIS FOR A BIT AND THEN REMARKED THAT THE NOTTINGHAM SIX ARRIVAL SHOWED THE OUTBOUND RADIAL FROM CSN TO SACCO TO BE THE 091 RADIAL. I MISINTERPRETED THIS COMMENT TO MEAN WE WERE PERHAPS FLYING THE WRONG ARRIVAL. WE QUICKLY CLEARED UP THIS MISCOMMUNICATION AND DETERMINED WE WERE ON THE PROPER ARRIVAL. DURING THIS INTERVAL WE GOT HIGH ON ARRIVAL AND CROSSED THE FIX UDUDE SEVERAL HUNDRED FEET HIGH. ATC MADE NO COMMENT AND THERE WAS NO CONFLICT WITH ANY OTHER AIRCRAFT. I FEEL THE OUTBOUND RADIAL FROM CSN TO SACCO NEEDS TO BE CORRECTED. ON THE RAVNN ONE ARRIVAL IT IS SHOWN AS THE 096 RADIAL AND THE NOTTINGHAM SIX ARRIVAL SHOWS IT AS THE 091 RADIAL. THESE ARE TWO DIFFERENT RADIALS BETWEEN THE SAME POINT; SO ONE IS APPARENTLY WRONG. INCORRECT RADIAL ON RAVNN ONE ARR BETWEEN CSN AND UDUDE.