Narrative:

Numerous aircraft in area. During descent, tower advised us of potential traffic, recommend we remain at or above 7000 MSL. Tower again advised of traffic, 10-11 O'clock position and approximately 7000 MSL (not sure on this altitude). Both pilots located traffic at 10 O'clock maneuvering (we're at 9000-9500 at this point). Pilot (captain) asked me: 'does that look like 7000 ft?' I said it did. I had thought the traffic was climbing, so seeing it maneuvering struck me as odd. Just after the above short discussion, I spotted an small aircraft, 11:30-12 O'clock climbing/slight left bank towards us, distance less than 1/4 mi. Immediately begin rapid descent, hard right turn. Both aircraft around 8500 MSL at this point. Contributing factors: 1) tower attempts to give good TA's and separate traffic, but is usually under high workload. 2) I believe we, as a crew, mistook what was probably 2 separate TA's (2 targets) as one. Spotting 1 aircraft may have given us a false sense of security (extremely short lived). Corrective actions: 1) obviously, as a crew, we must be ever vigilant. 2) this type of situation is very common at prescott. Very high density student training is conducted during daylight hours. It seems a radar approach system is badly needed. Tower controllers are busy enough that advising arrs/departures is hard to do. 3) along with 2) above, a more standardized system of arrival and departure procedures. Military training relies on this approach and I think it would serve prescott well, rather than the current willy-nilly environment.

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Original NASA ASRS Text

Title: COMMUTER FLT HAS NMAC WITH SMA.

Narrative: NUMEROUS ACFT IN AREA. DURING DSCNT, TWR ADVISED US OF POTENTIAL TFC, RECOMMEND WE REMAIN AT OR ABOVE 7000 MSL. TWR AGAIN ADVISED OF TFC, 10-11 O'CLOCK POS AND APPROX 7000 MSL (NOT SURE ON THIS ALT). BOTH PLTS LOCATED TFC AT 10 O'CLOCK MANEUVERING (WE'RE AT 9000-9500 AT THIS POINT). PLT (CAPT) ASKED ME: 'DOES THAT LOOK LIKE 7000 FT?' I SAID IT DID. I HAD THOUGHT THE TFC WAS CLBING, SO SEEING IT MANEUVERING STRUCK ME AS ODD. JUST AFTER THE ABOVE SHORT DISCUSSION, I SPOTTED AN SMA, 11:30-12 O'CLOCK CLBING/SLIGHT L BANK TOWARDS US, DISTANCE LESS THAN 1/4 MI. IMMEDIATELY BEGIN RAPID DSCNT, HARD R TURN. BOTH ACFT AROUND 8500 MSL AT THIS POINT. CONTRIBUTING FACTORS: 1) TWR ATTEMPTS TO GIVE GOOD TA'S AND SEPARATE TFC, BUT IS USUALLY UNDER HIGH WORKLOAD. 2) I BELIEVE WE, AS A CREW, MISTOOK WHAT WAS PROBABLY 2 SEPARATE TA'S (2 TARGETS) AS ONE. SPOTTING 1 ACFT MAY HAVE GIVEN US A FALSE SENSE OF SECURITY (EXTREMELY SHORT LIVED). CORRECTIVE ACTIONS: 1) OBVIOUSLY, AS A CREW, WE MUST BE EVER VIGILANT. 2) THIS TYPE OF SITUATION IS VERY COMMON AT PRESCOTT. VERY HIGH DENSITY STUDENT TRAINING IS CONDUCTED DURING DAYLIGHT HRS. IT SEEMS A RADAR APCH SYS IS BADLY NEEDED. TWR CTLRS ARE BUSY ENOUGH THAT ADVISING ARRS/DEPS IS HARD TO DO. 3) ALONG WITH 2) ABOVE, A MORE STANDARDIZED SYS OF ARR AND DEP PROCS. MIL TRAINING RELIES ON THIS APCH AND I THINK IT WOULD SERVE PRESCOTT WELL, RATHER THAN THE CURRENT WILLY-NILLY ENVIRONMENT.

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.