Narrative:

We were on runway 17L localizer and GS and cleared for a visual approach with cos TRACON. ATC advised us of a cessna skymaster at a 10 O'clock position traffic which would be vectored behind us to runway 17R and advised us to contact tower. We were now approaching about 9000 ft MSL and 200 KIAS with flaps and gear up as I recall. We were both looking for the traffic, I switched to the tower frequency, but didn't call because we were both alerted by a TCASII TA. We had seen the traffic on the TCASII before, but now, it was inside of 2.5 mi and 100-300 ft below us. We received a TCASII RA just a moment after the initial TA to climb. The captain added a lot of power and aggressively initiated a pitch-up into a steep climb. Neither of us had gotten the skymaster in sight. When we initiated the RA maneuver, the traffic was at our altitude and less than a mi as on the TCASII display. Captain said he now sighted the plane in a left bank pointed toward us at our 10 O'clock position, 1/8 mi, and 200 ft below us as well as on the TCASII. I contacted tower and advised we had executed a TCASII RA. Tower said the other aircraft had us in visual contact, we doubt it. A passenger on the ground asked if the tower told us about the other plane. This was an entirely unacceptable loss of separation, it seemed to me the cessna wasn't given a vector (heading) as we had been told because if so that would've been an ATC bust. If he actually had visual contact with us, he was still way too close.

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Original NASA ASRS Text

Title: DO328 LNDG COS HAS TCASII TA AND TCASII RA WITH C337 ON APCH.

Narrative: WE WERE ON RWY 17L LOC AND GS AND CLRED FOR A VISUAL APCH WITH COS TRACON. ATC ADVISED US OF A CESSNA SKYMASTER AT A 10 O'CLOCK POS TFC WHICH WOULD BE VECTORED BEHIND US TO RWY 17R AND ADVISED US TO CONTACT TWR. WE WERE NOW APCHING ABOUT 9000 FT MSL AND 200 KIAS WITH FLAPS AND GEAR UP AS I RECALL. WE WERE BOTH LOOKING FOR THE TFC, I SWITCHED TO THE TWR FREQ, BUT DIDN'T CALL BECAUSE WE WERE BOTH ALERTED BY A TCASII TA. WE HAD SEEN THE TFC ON THE TCASII BEFORE, BUT NOW, IT WAS INSIDE OF 2.5 MI AND 100-300 FT BELOW US. WE RECEIVED A TCASII RA JUST A MOMENT AFTER THE INITIAL TA TO CLB. THE CAPT ADDED A LOT OF PWR AND AGGRESSIVELY INITIATED A PITCH-UP INTO A STEEP CLB. NEITHER OF US HAD GOTTEN THE SKYMASTER IN SIGHT. WHEN WE INITIATED THE RA MANEUVER, THE TFC WAS AT OUR ALT AND LESS THAN A MI AS ON THE TCASII DISPLAY. CAPT SAID HE NOW SIGHTED THE PLANE IN A L BANK POINTED TOWARD US AT OUR 10 O'CLOCK POS, 1/8 MI, AND 200 FT BELOW US AS WELL AS ON THE TCASII. I CONTACTED TWR AND ADVISED WE HAD EXECUTED A TCASII RA. TWR SAID THE OTHER ACFT HAD US IN VISUAL CONTACT, WE DOUBT IT. A PAX ON THE GND ASKED IF THE TWR TOLD US ABOUT THE OTHER PLANE. THIS WAS AN ENTIRELY UNACCEPTABLE LOSS OF SEPARATION, IT SEEMED TO ME THE CESSNA WASN'T GIVEN A VECTOR (HEADING) AS WE HAD BEEN TOLD BECAUSE IF SO THAT WOULD'VE BEEN AN ATC BUST. IF HE ACTUALLY HAD VISUAL CONTACT WITH US, HE WAS STILL WAY TOO CLOSE.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.