B757 FLC EXECUTED A TCASII RA CLB WHEN; APPARENTLY; AN MD88 DSNDS 500 FT BELOW ASSIGNED ALT. ARTCC CTLR ACTIONS COULD NOT STOP LOSS OF SEPARATION.

Narrative

WHILE IN CRUISE HEADING E (090 DEGS) ON THE J-8 AIRWAY; WE HAD A TFC CONFLICT (TCASII RA): HAD AN AURAL TA. LOOKED DOWN AT SCOPE AND SAW TFC AT SAME ALT APPROX 12 O'CLOCK POS EITHER 10 OR 20 MI. ATC GAVE US A TURN R TO 160 DEGS. HE DID NOT SAY IMMEDIATELY OR SOUND STRESSFUL IN HIS VOICE. WE TURNED R IMMEDIATELY USING AUTOPLT. RIGHT AFTER STARTING TURN WE RECEIVED A TCASII RA COMMANDING A CLB. TURNED OFF AUTOPLT AND CLBED APPROX 250-300 FT. WHEN WE STARTED OUR TURN WE BOTH (AND JUMP SEATER) SAW THE TFC. WE HAD THE ACFT IN SIGHT WHILE WE WERE CLBING AND TURNING. THE 3 OF US ESTIMATED HORIZ DISTANCE OF 1-2 MI. THE OTHER ACFT TOLD ATC THAT THEY HAD DSNDED 400-500 FT; SO OUR VERT MISS WAS ABOUT 750 FT. WHEN TFC HAD PASSED AND TCASII COMMANDED 'CLR'; WE WENT BACK TO FL290. WE TOLD ATC OF CONFLICT AND THAT WE CLBED AND ASKED WHAT HAPPENED. HE NEVER GAVE US A CLR ANSWER AND CLRED US BACK ON COURSE. SUPPLEMENTAL INFO FROM ACN 405913: WE CLBED APPROX 250 FT IN A R CLBING TURN. ACR Y RPTED HE DSNDED 500 FT BUT I DON'T THINK HE INITIATED A TURN. BOTH OF US WERE AT FL290.