A B737 AND B757 APCHING HEAD-ON CAME VERY CLOSE WHEN CTLR CLRED THE HIGHER OF THE 2 TO DSND VISUALLY FROM 1000 FT ABOVE TO 1000 FT BELOW THE OTHER. BOTH ACFT RECEIVED TCASII RA'S BUT INCLUDED A ROLL AWAY IN THEIR AVOIDANCE MANEUVER.

Narrative

WHILE CRUISING AT 17000 FT; ATC ADVISED ME OF TFC AT 12 O'CLOCK AT 16000 FT ABOUT 25 MI. WE CALLED THE TFC IN SIGHT AND ATC CLRED US DOWN TO 15000 FT AND TO MAINTAIN A VISUAL ON THE TFC. AFTER I STARTED MY DSCNT; MY TCASII INDICATED I NEEDED TO INCREASE MY DSCNT RATE; SO I INCREASED MY DSCNT RATE SO AS TO HAVE A 1000 FT SEPARATION AS WE PASSED. I ALSO TURNED ABOUT 20 DEGS R TO PROVIDE SOME LATERAL SEPARATION AS WELL. I DID NOT START MY LEVELOFF UNTIL I REACHED 15000 FT; WHICH RESULTED IN MY STOPPING DSCNT AT 14500 FT; AT WHICH POINT MY TCASII INDICATED WE WERE CLR OF CONFLICT AND WE IMMEDIATELY CLBED BACK TO 15000 FT. AS WE DSNDED THROUGH 15000 FT; WE ADVISED ATC THAT WE WERE RESPONDING TO OUR TCASII EVEN THOUGH WE HAD THE TFC VISUALLY. ALTHOUGH WE EACH HAD THE OTHER IN SIGHT WITH OUR LNDG LIGHTS ON; I NOW REALIZE THAT DISTANCE PERCEPTION AT NIGHT IS VERY DECEPTIVE; AND IN THE FUTURE WOULD NOT ACCEPT SUCH A CLRNC. SUPPLEMENTAL INFO FROM ACN 444103: WE WERE FERRYING FROM NEW YORK TO NAVY NORFOLK TO BEGIN A MIL CHARTER. I WAS CRUISING AT 16000 FT. IT WAS A CLR NIGHT. ZDC CALLED AND ADVISED US OF OPPOSITE DIRECTION TFC; AN ACR FLT AT 17000 FT. THEY HAD THEIR LNDG LIGHTS ON. I FLASHED MY LNDG LIGHTS AND TOLD CTR THEY WERE IN SIGHT. A SHORT TIME LATER CTR ASKED ACR IF THEY HAD US IN SIGHT. (I THINK THIS WAS THE SECOND TIME HE ASKED THEM). THEY SAID THEY HAD US IN SIGHT. THE CTLR CLRED ACR TO MAKE A VISUAL DSCNT TO 15000 FT. I TURNED MY LNDG LIGHTS ON AND LEFT THEM ON. I LOOKED AT THEM OUT THE WINDOW AND THEY APPEARED TO BE BEGINNING THEIR DSCNT. MY FO WAS LOOKING AT HIS TCASII DISPLAY AND SAID 'YOU'RE GOING TO HAVE TO GET OUT OF HERE.' THEY WERE CLOSING VERY FAST. THE TCASII AMBER ADVISORY AND AURAL WARNING WENT OFF. IT WAS CLR TO OUR R. I DISCONNECTED THE AUTOPLT AND RAPIDLY ROLLED INTO A R BANK. AT THIS TIME WE GOT A RED RA OF 'DON'T CLB' FOLLOWED QUICKLY BY A 'DSND' COMMAND. I PUSHED THE NOSE OVER PRETTY HARD AND CONTINUED MY TURN. I ROLLED LEVEL AS THEY PASSED OFF OUR L ABOUT 500-1000 FT AND AT OUR ALT. EVEN THOUGH THEY ROGERED THE VISUAL DSCNT CLRNC; IT SEEMS AS IF THEY STILL THOUGHT THEY HAD RADAR SEPARATION. SINCE MY TCASII WAS COMMANDING A DSCNT; SHOULDN'T THEIRS HAVE GIVEN THEM A CLB?