ALTDEV EXCURSION IN FLC RESPONSE TO TCASII RA.

Narrative

AFTER DEPARTING RWY 36R FROM DFW TWR HANDED US OVER TO DEP. DEP GAVE US A HDG OF 240 DEGS AND CLB TO 3000 FT. AT 2300 FT WE RECEIVED AN RA FROM OUR TCASII. THE RATE OF DSCNT REQUIRED BY THE TCASII RA WAS 2200 FPM. THE TCASII SCREEN SHOWED A TARGET R ON TOP OF US AT OUR ALT. A DSCNT WAS IMMEDIATELY BEGUN (I; THE FO FLYING) AS INSTRUCTED BY THE TCASII. THE CAPT IMMEDIATELY INFORMED DEP WE WERE DSNDING IN RESPONSE TO AN RA. THE CTLR TOLD US THERE WAS NOTHING OUT THERE.' AS WE DSNDED THE TFC CONTINUED TO MATCH OUR ALT AND THE RA CONTINUED. AS WE APCHED 1500 FT MSL THE CTLR TOLD US TO IMMEDIATELY CLB AS HE WAS RECEIVING AN ALT ALERT ON US. AGAIN WE REPLIED NO BECAUSE WE WERE STILL FOLLOWING OUR RA WE WERE VMC; SO THERE WAS NEVER A DANGER OF INADVERTENTLY FLYING INTO THE GND. THE CTLR INSISTED WE CLB. WE DECIDED AT THIS POINT; SINCE WE HAVE YET TO SEE THE INTRUDER AND EVEN WITH OUR 2200 FPM RATE OF DSCNT 'HE' HAD CONTINUED TO STAY AT OUR ALT; THAT IT MUST BE A FALSE TARGET. WE THEN INITIATED A CLB. THE 'INTRUDER' FOLLOWED US UP MATCHING OUR ALT. WE TURNED THE TCASII TO TA ONLY AND CLBED TO 3000 FT. UPON REACHING 3000 FT; THE TARGET DISAPPEARED. WE BOTH BELIEVE THE TARGET ISSUED ON THE TCASII WAS IN FACT OURSELVES. SUPPLEMENTAL INFO FROM ACN 284954: THE CREW BELIEVES THIS EVENT TO BE FALSE BUT WHEN YOU GET AN RA YOU DON'T KNOW IF IT IS REAL OR NOT YOU JUST FOLLOW IT. I STILL BELIEVE TCASII TO BE INVALUABLE.