Near midair collision, TCASII RA.

Attributes
ACN	282707
Time
Date	199409
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : sfo
State Reference	CA
Altitude	msl bound lower : 8500 msl bound upper : 9000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oak
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent : approach descent other landing other
Route In Use	arrival other enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	general aviation : corporate
Make Model Name	Beechcraft Twin Turboprop Jet Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 12000 flight time type : 220
ASRS Report	282707
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : nmac
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 0 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

VFR conditions. Cleared from over cedes intersection heading 230 degrees descend from 11000 ft to 7000 ft at 170 KTS. Passing 9500 ft received TA on TCASII. Captain flying, first officer looked to right and saw king air below and at time paralleling course. At 9100 ft got RA and first officer looked out to right and king air had turned directly towards us. First officer called for an immediate level off. I disconnected autoplt and leveled aircraft at 9000 ft. King air passed directly below us at 8500 ft. I saw aircraft appear as it came in view from my left window. Had descent continued there would have been a collision. First officer immediately contacted approach control asking about traffic. Approach seemed vague about who it was. The king air must have been monitoring the frequency. He responded to approach's questioning his location and said, 'I had xx in sight.' I don't think he was aware of our immediate action of stopping our 1800-2000 FPM rate of descent to avoid collision. I contacted approach control supervisor upon arrival at sfo. He had already spoken to controller and apparently king air was VFR. Controller was working us and an aircraft directly below us and as king air got close to being between both ourselves and lower altitude aircraft, he blended in on controller's scope. Supervisor apologized and said he had no real answers one becomes confident and trusting when being controled into an airport of the size of sfo. We rely on traffic separation. It is also a time that is very busy for flight crew -- setting up FMS, final approach briefings, checklists, monitoring approach frequencys to hear what other aircraft are doing. Thanks to a diligent and observant first officer and TCASII, this potential collision was avoided. Suggestions: when VFR traffic in arrival area as this, approach should try to contact and advise of descending traffic and/or do not descend arriving traffic through VFR traffic until clear and/or put arrival in the TCA to avoid this type of conflict/or make it an arrival corridor within TCA.

Original NASA ASRS Text

Title: NMAC, TCASII RA.

Narrative: VFR CONDITIONS. CLRED FROM OVER CEDES INTXN HDG 230 DEGS DSND FROM 11000 FT TO 7000 FT AT 170 KTS. PASSING 9500 FT RECEIVED TA ON TCASII. CAPT FLYING, FO LOOKED TO R AND SAW KING AIR BELOW AND AT TIME PARALLELING COURSE. AT 9100 FT GOT RA AND FO LOOKED OUT TO R AND KING AIR HAD TURNED DIRECTLY TOWARDS US. FO CALLED FOR AN IMMEDIATE LEVEL OFF. I DISCONNECTED AUTOPLT AND LEVELED ACFT AT 9000 FT. KING AIR PASSED DIRECTLY BELOW US AT 8500 FT. I SAW ACFT APPEAR AS IT CAME IN VIEW FROM MY L WINDOW. HAD DSCNT CONTINUED THERE WOULD HAVE BEEN A COLLISION. FO IMMEDIATELY CONTACTED APCH CTL ASKING ABOUT TFC. APCH SEEMED VAGUE ABOUT WHO IT WAS. THE KING AIR MUST HAVE BEEN MONITORING THE FREQ. HE RESPONDED TO APCH'S QUESTIONING HIS LOCATION AND SAID, 'I HAD XX IN SIGHT.' I DON'T THINK HE WAS AWARE OF OUR IMMEDIATE ACTION OF STOPPING OUR 1800-2000 FPM RATE OF DSCNT TO AVOID COLLISION. I CONTACTED APCH CTL SUPVR UPON ARR AT SFO. HE HAD ALREADY SPOKEN TO CTLR AND APPARENTLY KING AIR WAS VFR. CTLR WAS WORKING US AND AN ACFT DIRECTLY BELOW US AND AS KING AIR GOT CLOSE TO BEING BTWN BOTH OURSELVES AND LOWER ALT ACFT, HE BLENDED IN ON CTLR'S SCOPE. SUPVR APOLOGIZED AND SAID HE HAD NO REAL ANSWERS ONE BECOMES CONFIDENT AND TRUSTING WHEN BEING CTLED INTO AN ARPT OF THE SIZE OF SFO. WE RELY ON TFC SEPARATION. IT IS ALSO A TIME THAT IS VERY BUSY FOR FLC -- SETTING UP FMS, FINAL APCH BRIEFINGS, CHKLISTS, MONITORING APCH FREQS TO HEAR WHAT OTHER ACFT ARE DOING. THANKS TO A DILIGENT AND OBSERVANT FO AND TCASII, THIS POTENTIAL COLLISION WAS AVOIDED. SUGGESTIONS: WHEN VFR TFC IN ARR AREA AS THIS, APCH SHOULD TRY TO CONTACT AND ADVISE OF DSNDING TFC AND/OR DO NOT DSND ARRIVING TFC THROUGH VFR TFC UNTIL CLR AND/OR PUT ARR IN THE TCA TO AVOID THIS TYPE OF CONFLICT/OR MAKE IT AN ARR CORRIDOR WITHIN TCA.

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.