Carj and small aircraft have near midair collision near smf.

Attributes
ACN	739179
Time
Date	200705
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : smf.airport
State Reference	CA
Altitude	msl single value : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : nct.tracon tracon : ggg.tracon
Operator	common carrier : air carrier
Make Model Name	Regional Jet 200 ER&LR
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival star : flunk
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : nct.tracon
Operator	general aviation : personal
Make Model Name	Helicopter
Operating Under FAR Part	Part 91
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : cfi pilot : multi engine
Experience	flight time last 90 days : 110 flight time total : 2000 flight time type : 660
ASRS Report	739179
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : nmac
Independent Detector	aircraft equipment : tcas other controllera other flight crewb
Resolutory Action	controller : issued advisory flight crew : took evasive action
Miss Distance	horizontal : 0 vertical : 400
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance Airspace Structure
Primary Problem	Ambiguous

Narrative:

During descent on the arrival into smf; we received a traffic call from norcal approach concerning traffic at our 12 O'clock position; type and altitude unknown. The captain was flying the aircraft with the autoplt engaged during the descent. We were cleared to 4000 ft in the descent. I visually acquired the aircraft at around 4600 ft; and advised the captain that the target had no relative motion. TCAS sounded at about this time with a TA. We leveled at 4000 ft and I told the captain we needed to descend now because of the collision hazard. The captain finally saw the aircraft in our windscreen; disconnected the autoplt and dove under the other aircraft. It was a eurocoupe private aircraft and we were overtaking on approximately the same heading. We were 236 degree heading; the eurocoupe was approximately a 250 degree heading. We did not get an RA; most likely because the aircraft was using a mode a transponder. Miss was close to 400 ft vertically.

Original NASA ASRS Text

Title: CARJ AND SMA HAVE NMAC NEAR SMF.

Narrative: DURING DSCNT ON THE ARR INTO SMF; WE RECEIVED A TFC CALL FROM NORCAL APCH CONCERNING TFC AT OUR 12 O'CLOCK POS; TYPE AND ALT UNKNOWN. THE CAPT WAS FLYING THE ACFT WITH THE AUTOPLT ENGAGED DURING THE DSCNT. WE WERE CLRED TO 4000 FT IN THE DSCNT. I VISUALLY ACQUIRED THE ACFT AT AROUND 4600 FT; AND ADVISED THE CAPT THAT THE TARGET HAD NO RELATIVE MOTION. TCAS SOUNDED AT ABOUT THIS TIME WITH A TA. WE LEVELED AT 4000 FT AND I TOLD THE CAPT WE NEEDED TO DSND NOW BECAUSE OF THE COLLISION HAZARD. THE CAPT FINALLY SAW THE ACFT IN OUR WINDSCREEN; DISCONNECTED THE AUTOPLT AND DOVE UNDER THE OTHER ACFT. IT WAS A EUROCOUPE PVT ACFT AND WE WERE OVERTAKING ON APPROX THE SAME HDG. WE WERE 236 DEG HDG; THE EUROCOUPE WAS APPROX A 250 DEG HDG. WE DID NOT GET AN RA; MOST LIKELY BECAUSE THE ACFT WAS USING A MODE A XPONDER. MISS WAS CLOSE TO 400 FT VERTICALLY.

Data retrieved from NASA's ASRS site as of January 2009 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.