A B752 crew on approach to smf took evasive action to avoid a light aircraft.

Attributes
ACN	516983
Time
Date	200107
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : smf.airport
State Reference	CA
Altitude	msl bound lower : 3000 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mcc.tracon
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : mcc.tracon
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 14000 flight time type : 5000
ASRS Report	516983
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer pilot : commercial pilot : cfi
Experience	flight time last 90 days : 290 flight time total : 6000 flight time type : 400
ASRS Report	516974
Events
Anomaly	conflict : nmac non adherence : far other anomaly other
Independent Detector	aircraft equipment : tcas other flight crewa
Resolutory Action	controller : issued alert flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 2000 vertical : 400
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	ATC Human Performance

Narrative:

On a 250 degree heading, vectors for visual runway 16L smf, descending from 5000 ft to 2000 ft. ATC called traffic 'traffic 2 O'clock position, type/altitude unknown.' we were approximately 3000-3500 ft. Nothing on TCASII. We both looked (into sun). First officer pointed left and stated, 'skipper, we have to turn left now.' I disconnected the autoplt and turned left, still descending. Glancing at TCASII, I saw nothing. Now, right wing high, I could see the traffic out the copilot's window. I concluded the turn alone would not clear the conflict. I disconnected the autothrottles and started a 2000 FPM climb. Approximately 2-3 seconds later, we got a pop-up RA to climb. Green arc at 2500 FPM, I flew to it. TCASII showed an aircraft 400 ft directly below us. We leveled at 4000 ft MSL. Continued for a perfect and uneventful landing. ATC stated they were talking to the aircraft on another frequency. They just gave him a squawk, but had not radar idented him yet. I believe he/she was heads down putting in the squawk and noticed their transponder was not on. This would explain the last second pop-up RA. Aircraft seemed very close in to not be in radar contact. For some reason on the runway 16L final approach.

Original NASA ASRS Text

Title: A B752 CREW ON APCH TO SMF TOOK EVASIVE ACTION TO AVOID A LIGHT ACFT.

Narrative: ON A 250 DEG HDG, VECTORS FOR VISUAL RWY 16L SMF, DSNDING FROM 5000 FT TO 2000 FT. ATC CALLED TFC 'TFC 2 O'CLOCK POS, TYPE/ALT UNKNOWN.' WE WERE APPROX 3000-3500 FT. NOTHING ON TCASII. WE BOTH LOOKED (INTO SUN). FO POINTED L AND STATED, 'SKIPPER, WE HAVE TO TURN L NOW.' I DISCONNECTED THE AUTOPLT AND TURNED L, STILL DSNDING. GLANCING AT TCASII, I SAW NOTHING. NOW, R WING HIGH, I COULD SEE THE TFC OUT THE COPLT'S WINDOW. I CONCLUDED THE TURN ALONE WOULD NOT CLR THE CONFLICT. I DISCONNECTED THE AUTOTHROTTLES AND STARTED A 2000 FPM CLB. APPROX 2-3 SECONDS LATER, WE GOT A POP-UP RA TO CLB. GREEN ARC AT 2500 FPM, I FLEW TO IT. TCASII SHOWED AN ACFT 400 FT DIRECTLY BELOW US. WE LEVELED AT 4000 FT MSL. CONTINUED FOR A PERFECT AND UNEVENTFUL LNDG. ATC STATED THEY WERE TALKING TO THE ACFT ON ANOTHER FREQ. THEY JUST GAVE HIM A SQUAWK, BUT HAD NOT RADAR IDENTED HIM YET. I BELIEVE HE/SHE WAS HEADS DOWN PUTTING IN THE SQUAWK AND NOTICED THEIR XPONDER WAS NOT ON. THIS WOULD EXPLAIN THE LAST SECOND POP-UP RA. ACFT SEEMED VERY CLOSE IN TO NOT BE IN RADAR CONTACT. FOR SOME REASON ON THE RWY 16L FINAL APCH.

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.