MLG FLC DISAGREES OVER RESPONSE TO TCASII RA.

Narrative

WE WERE CLRED FOR TKOF OUT OF ONTARIO; CA; BEHIND ANOTHER ACFT; WHICH I BELIEVE WAS A TWIN ENG CESSNA. AT 5850 FT WE RECEIVED A TCASII WARNING AND RA. THE TFC WAS AT 6000 FT; ABOUT 3 MI AHEAD AND CLBING. WE RECEIVED AN ORAL WARNING; TFC TFC DSND DSND; AS WELL AS A PITCH GUIDANCE PRESENTATION TO DSND. I FOLLOWED THE PITCH GUIDANCE PRESENTATION AND DSNDED TO 5700 FT. THE CAPT WAS WATCHING TFC OFF THE R; OR S OF US; BUT THAT WAS NOT THE PROB. HE WANTED ME TO KEEP THE ACFT CLBING; BUT I FOLLOWED THE ADVISORY AGAINST HIS WISHES. AS I LEVELED OFF AT 5700 FT; THE TFC ON THE SCOPE WAS NOW AT 6100 FT. THE CAPT TOOK OVER CTL OF THE ACFT AND BEGIN CLBING NEVER SEEING THE TFC AHEAD; ONLY REACTING TO THE TFC OFF TO THE R; WHICH WAS NOT THE IMMEDIATE PROB. BY THE TIME THE CAPT PULLED THE ACFT UP; WE WERE CLRING THE TFC AHEAD. I FEEL PART OF THE PROB WAS THE HORIZ SIT INDICATOR ON THE CAPT'S SIDE WAS NOT SET ON A CLOSE RANGE; MAKING IT IMPOSSIBLE TO TELL WHICH ACFT WAS THE THREAT. I DID HAVE MY SIDE SET ON THE 10 MI RANGE; MAKING THE TFC EASY TO PICK OUT. I THINK IT WOULD BE ADVISABLE TO SET IT ON A 10; OR 20 MI RANGE UNTIL YOU ARE OUT OF THE LOWER ALTS.