ALTDEV ALT EXCURSION DURING FLC RESPONSE TO TCASII RA. EVASIVE ACTION CLB.

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WE CROSSED DAWNA AT 12000 AS ASSIGNED ON A HDG VECTOR. WE WERE SOON CLRED 'EXPEDITE' TO 10000. OUT OF 10800; WE WERE INFORMED THAT THERE WAS TFC AT 10500 THAT WE NEEDED TO GET BELOW. SHORTLY THEREAFTER; TRACON POINTED OUT ADDITIONAL TFC AT 9500; 12 O'CLOCK. WE WERE NOT VISUAL ON ANY OF THIS TFC; BUT MY IMPRESSION WAS THAT WE WOULD BE 'STACKED.' WITHIN SECONDS AFTER REACHING 10000; WE GOT A TCASII COMMAND (RA) 'CLB!; CLB!' AT THIS POINT WE HAD 2 TARGETS ON THE HSI: 12 O'CLOCK TFC AT VERY CLOSE RANGE (RED) AND 1130 O'CLOCK TFC (YELLOW) WITH SOME SEPARATION. COPLT WAS FLYING AND HE RESPONDED TO RA WITH GRADUAL PULL UP. AT ABOUT 10150; TCASII STOPPED ANNUNCIATING; AND REVERTED TO 'MONITOR VERT SPD' AS HE SLOWLY LET IT SETTLE BACK TOWARD 10000. AT ABOUT 10050 WE GOT ANOTHER RA. þCLB!' AT THIS POINT; THERE WERE 3 TARGETS: 2 RED TARGETS; VERY CLOSE RANGE AT 12 O'CLOCK -- THEY WERE SO CLOSE TO EACH OTHER AS TO BE ALMOST TOUCHING -- AND STILL THE TFC AT 10500 WAS 1130 O'CLOCK; YELLOW; AND NOT ON AN APPARENT COLLISION COURSE. THE COPLT HESITATED; SO I PULLED IT UP MYSELF; ADDED PWR; AND HE AGAIN RESUMED CLB TRYING TO SATISFY THE TCASII WHILE NOT CLBING ANY FASTER OR HIGHER THAN SEEMED NECESSARY. SHORTLY; THE CTLR DEMANDED THAT WE DSND; INFORMED US THAT SEPARATION HAD BEEN VIOLATED. AT ABOUT THIS TIME; THE COPLT SAW AN SMA FLY UNDER THE NOSE. OBSERVATIONS: OUR INITIAL PULL-UP AT 10100 TO 10150 PROBABLY DID NOT PROMPT THE SEPARATION ALERT. FOR THE SECOND RA THERE WERE 2 RED TARGETS; VERY CLOSE RANGE; AT 12 O'CLOCK. I DID NOT HAVE OR TAKE THE TIME TO ANALYZE THEIR RELATIVE ALTS OR TRENDS. I KNEW THAT APCH WAS CTLING 1 OF THESE; BUT WHAT ABOUT THE OTHER? WITH THE PRESENCE OF THE SECOND TARGET; I PULLED UP MORE AGGRESSIVELY. THE 10500 TFC WAS STILL YELLOW; STILL AT 1130 O'CLOCK AND STILL NOT ON AN APPARENT COLLISION COURSE. THE 2 TARGETS AT 12 O'CLOCK; CLOSE RANGE; WERE GENERATING 'PULL UP' AND EITHER OR BOTH OF THESE TARGETS MAY WELL HAVE BEEN OUT OF OUR VISUAL RANGE; BELOW THE NOSE. THE 1130 O'CLOCK TFC WAS ABOVE US; AND THOUGH WE DIDN'T SEE IT; IT WOULD AT LEAST BE IN A POS WHERE WE COULD SEE IT. WE DID NOT GET AN ALT ALERT; SO WE DID NOT GET TO 10300. AS THIS SIT DEVELOPED; IT BECAME CLR TO ME THAT APCH MIGHT HAVE BEEN CTLING US INTO TROUBLE. NONE OF THIS TFC WAS IN SIGHT; BUT IT SOUNDED LIKE HE MAY HAVE BEEN 'STACKING' US. IT OCCURRED TO ME THAT TCASII MAY WELL NOT LIKE THIS SIT. I REALIZE THAT ATC'S SEPARATION GUIDELINES ALLOW 500 FT. BUT THEY MUST REALIZE THAT; IF THEY VECTOR US INTO A STACK WITH ONLY 500 FT VERT AND NO LATERAL SEPARATION; WE WILL GET A TCASII ALERT AND IT WILL CAUSE EXACTLY THIS KIND OF TROUBLE.