MULTIPLE RWY OP INTERSECTING RWYS. X LNDG RWY 15 HAD LTSS FROM ACR Y TKOF RWY 18. SYS ERROR. EVASIVE ACTION TAKEN.

Narrative

WASHINGTON APCH ADVISED OF TFC AT 12 O'CLOCK AND; AFTER WE RPTED SPOTTING THE TFC; CLRED US FOR A RIVER VISUAL APCH TO DCA. AFTER CHKING IN WITH THE TWR; WE WERE INFORMED TO EXPECT RWY 15. THE DCA TWR CLRED US TO LAND ON RWY 15. WE TOUCHED DOWN PAST THE THRESHOLD AND WERE ROLLING OUT WHEN I NOTICED THAT ACR Y THAT HAD JUST TAXIED ON TO RWY 18 BEGAN ROLLING FORWARD. ALL I HAD TIME TO DO WAS APPLY MAX BRAKING AND FULL PROP REVERSE. WHEN WE GOT TO THE INTXN. ACR Y HAD JUST FOLLOWED THROUGH IT WITH TKOF THRUST. IT SEEMED LIKE WE PASSED NO MORE THAN 200 TO 300 FT BEHIND THE DEPARTING JET. WHEN NOTHING WAS SAID BY THE TWR; THE DEPARTING AIRLINER; OR MY COPLT; I YELLED ON THE FREQ; 'WHAT HAPPENED HERE?!?' NO RESPONSE. FINALLY -- 'X CROSS RWY 18 (WE HAD CLRED RWY 15 AT M); CONTACT GND CTL AFTER XING. YOU CAN CALL THE TWR WHEN YOU GET IN.' I CALLED THE DCA TWR AND ASKED FOR THE WATCH SUPVR. WHEN I EXPLAINED WHAT HAD JUST HAPPENED A FEW MINS EARLIER; HE EXPRESSED SURPRISE; AND SAID THAT HE HAD NOT BEEN TOLD. THE SUPVR ASKED ME TO RELATE WHAT HAD HAPPENED FROM MY PERSPECTIVE. AFTER DOING SO; I ASKED FOR THE SEQUENCE OF EVENTS FROM THE CTLR'S PERSPECTIVE. HE SAID THAT WAS 'STILL BEING INVESTIGATED' BUT THAT IT WAS 'BASICALLY A FACILITY SCREW-UP; I'LL GRANT YOU THAT.' I THEN ASKED HIM IF HE HAD REVIEWED THE TAPE FOR THAT TIME PERIOD. HE SAID THAT HE HAD AND IT VERIFIED THAT WE DID RECEIVE A CLRNC TO LAND AND OUR ACKNOWLEDGEMENT WAS ON THE TAPE. HE ALSO SAID THAT THE TAPE REVEALED THAT THE AIRLINER WAS CLRED TO TKOF ON RWY 18 AFTER WE WERE CLRED TO LAND ON RWY 15. HOW MUCH AFTER; HE SAID; HE WAS UNABLE TO RECALL AT THAT TIME.