Flight crew of medium large transport had near midair collision with small transport at 8500' MSL.

Attributes
ACN	135760
Time
Date	199002
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sba
State Reference	CA
Altitude	msl bound lower : 8500 msl bound upper : 8800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Route In Use	arrival other enroute : on vectors enroute airway : sba
Flight Plan	IFR
Aircraft 2
Operator	other
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	climbout : intermediate altitude
Route In Use	departure other
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 250 flight time total : 9800 flight time type : 250
ASRS Report	135760
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : cfi pilot : atp
Experience	flight time last 90 days : 150 flight time type : 150
ASRS Report	135758
Events
Anomaly	conflict : nmac
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 300 vertical : 300
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

Approaching gvo from the northwest, sba approach advised of traffic at 10-11(?) O'clock. After crossing gvo on an assigned heading of 180 degrees, sba again advised of traffic at 1 O'clock at 8000'. We reported no contact and were descending through 8500' with clearance to 6000' at the time. Approach responded with instructions to level at 8500'. The descent was stopped at 8300' with an immediate climb back to 8500'. At that time the captain called the traffic and I looked out his windscreen to see and full left side of a twin pass off to our left and slightly above. The moment I saw the other aircraft, I knew we would miss, as he was in a gentle climbing right turn, and there was good relative motion. Instinctively I initiated a descending right turn. The captain was also instinctively on the controls with the same input and the pitch and roll were noticeable, but not at all violent. The other aircraft passed above and to our left, with approximately 300-500' clearance. Had there been no relative motion at the time of visibility contact, I believe a collision would have been hard to avoid, given the reaction/response time of our aircraft. It appeared to me the other aircraft had seen us first and initiated evasive action. The last radar advisory was misleading as my attention was focused at 1 O'clock low when in reality the traffic appeared at 11:30, slightly high. TCAS would have been a big help. Also, our aircraft was being flown on autoplt in the level change/heading select mode, which allowed me to by paying a lot of attention outside, albeit in the wrong area. The automated cockpit is great when it is programmed properly, as it allows a lot more time outside during climbs and descent, such as the tipp toe/quiet bridge approachs into sfo. In retrospect, I wouldn't have done anything different, but the experience just points out the fact that thorough vigilance, especially in high density VFR cannot be overemphasized.

Original NASA ASRS Text

Title: FLT CREW OF MLG HAD NMAC WITH SMT AT 8500' MSL.

Narrative: APCHING GVO FROM THE NW, SBA APCH ADVISED OF TFC AT 10-11(?) O'CLOCK. AFTER XING GVO ON AN ASSIGNED HDG OF 180 DEGS, SBA AGAIN ADVISED OF TFC AT 1 O'CLOCK AT 8000'. WE RPTED NO CONTACT AND WERE DSNDING THROUGH 8500' WITH CLRNC TO 6000' AT THE TIME. APCH RESPONDED WITH INSTRUCTIONS TO LEVEL AT 8500'. THE DSCNT WAS STOPPED AT 8300' WITH AN IMMEDIATE CLB BACK TO 8500'. AT THAT TIME THE CAPT CALLED THE TFC AND I LOOKED OUT HIS WINDSCREEN TO SEE AND FULL LEFT SIDE OF A TWIN PASS OFF TO OUR LEFT AND SLIGHTLY ABOVE. THE MOMENT I SAW THE OTHER ACFT, I KNEW WE WOULD MISS, AS HE WAS IN A GENTLE CLBING RIGHT TURN, AND THERE WAS GOOD RELATIVE MOTION. INSTINCTIVELY I INITIATED A DSNDING RIGHT TURN. THE CAPT WAS ALSO INSTINCTIVELY ON THE CONTROLS WITH THE SAME INPUT AND THE PITCH AND ROLL WERE NOTICEABLE, BUT NOT AT ALL VIOLENT. THE OTHER ACFT PASSED ABOVE AND TO OUR LEFT, WITH APPROX 300-500' CLRNC. HAD THERE BEEN NO RELATIVE MOTION AT THE TIME OF VIS CONTACT, I BELIEVE A COLLISION WOULD HAVE BEEN HARD TO AVOID, GIVEN THE REACTION/RESPONSE TIME OF OUR ACFT. IT APPEARED TO ME THE OTHER ACFT HAD SEEN US FIRST AND INITIATED EVASIVE ACTION. THE LAST RADAR ADVISORY WAS MISLEADING AS MY ATTN WAS FOCUSED AT 1 O'CLOCK LOW WHEN IN REALITY THE TFC APPEARED AT 11:30, SLIGHTLY HIGH. TCAS WOULD HAVE BEEN A BIG HELP. ALSO, OUR ACFT WAS BEING FLOWN ON AUTOPLT IN THE LEVEL CHANGE/HDG SELECT MODE, WHICH ALLOWED ME TO BY PAYING A LOT OF ATTN OUTSIDE, ALBEIT IN THE WRONG AREA. THE AUTOMATED COCKPIT IS GREAT WHEN IT IS PROGRAMMED PROPERLY, AS IT ALLOWS A LOT MORE TIME OUTSIDE DURING CLBS AND DSCNT, SUCH AS THE TIPP TOE/QUIET BRIDGE APCHS INTO SFO. IN RETROSPECT, I WOULDN'T HAVE DONE ANYTHING DIFFERENT, BUT THE EXPERIENCE JUST POINTS OUT THE FACT THAT THOROUGH VIGILANCE, ESPECIALLY IN HIGH DENSITY VFR CANNOT BE OVEREMPHASIZED.

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.