BE400 CROSSED RWY AT APC WITHOUT ATC CLRNC.

Narrative

WE WERE RETURNING EMPTY TO THE ARPT. THE WINDS WERE BLOWING TOWARDS THE E; SO RWY 24 WAS ASSIGNED FROM THE TWR. THE LNDG AND ROLLOUT WERE UNEVENTFUL. AFTER LNDG; THE TWR ASSIGNED: 'TURN R AT THE END OF RWY 24 AND CONTACT GND.' I WAS FLYING IN THE L SEAT; SO THE FO ANSWERED THE RADIO AS I STARTED RUNNING THROUGH THE MEMORY ITEMS OF THE AFTER LNDG CHKLIST THAT THE L SEAT PLT SHOULD ACCOMPLISH. AS WE APCHED RWYS 18R/36L; I SPECIFICALLY ASKED THE FO: 'ARE WE CLRED ACROSS RWY 18R?' I WAS TOLD: 'YES; YOU ARE CLRED TO THE RAMP.' IT IS COMMON KNOWLEDGE THAT WHEN RWY 24 IS IN USE; RWY 18R IS USED AS A TXWY; SO THIS WAS A LIKELY RESPONSE AND CLRNC. THE FO HAD DIALED IN THE GND FREQ. AFTER XING RWY 18R; THE GND CTLR (DIFFERENT CTLR) SAID 'PLEASE GIVE ME A QUICK CALL WHEN YOU GET TO THE TERMINAL. IT IS FOR INFO PURPOSES ONLY.' THE FO PHONED THE GND CTLR. WE WERE TOLD THAT EVEN THOUGH RWY 18R WAS A TXWY; IT IS REQUIRED THAT WE CONTACT GND BEFORE XING RWY 18R; AS OUR CLRNC WAS TO 'MAKE A R AND CONTACT GND;' NOT 'MAKE A R AND MONITOR GND.' THE CTLR WAS BEING HELPFUL; AND MADE IT CLR THAT HE WAS NOT GOING TO PURSUE THE MATTER ANY FURTHER THAN OUR PHONE CALL. HE ALSO MADE IT CLR THAT THERE WERE NO OTHER ACFT WITHIN THE CLASS D AIRSPACE BUT US. 3 PROBS CAUSED THE CONFUSION. FIRST BEING TOO FAMILIAR WITH THE ARPT; CAUSING US TO UNWITTINGLY TAKE LIBERTIES BY OUR KNOWLEDGE OF RWY 18R'S STATUS AS A TXWY. SECOND; HEARING WHAT WE WANTED THE CTLR TO SAY; NOT WHAT HE ACTUALLY SAID. LASTLY; MY SOLELY RELYING ON THE FO TO ACCOMPLISH WHAT SHOULD BE A ROUTINE AND SIMPLE TASK. THE CONCERN COULD HAVE BEEN AVOIDED 2 WAYS. FIRST; BY MY TAKING NOTE FROM THE L SEAT ON WHAT THE FO SHOULD BE DOING FROM THE R SEAT. SECOND; BY KEYING THE RADIO MIKE MYSELF TO ASSURE WE WERE CLRED ACROSS RWY 18R RATHER THAN JUST ASKING THE FO.