Falcon 900 flight crew has near midair collision during approach to sjc.

Attributes
ACN	698318
Time
Date	200605
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : nct.tracon
State Reference	CA
Altitude	msl single value : 6000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : nct.tracon
Operator	general aviation : corporate
Make Model Name	Falcon 900
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	arrival : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Texan T6 Harvard
Flight Phase	cruise : enroute altitude change
Person 1
Affiliation	company : corporate
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 70 flight time total : 7100 flight time type : 450
ASRS Report	698318
Person 2
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : nmac
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : returned to original clearance flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 100 vertical : 200
Supplementary
Problem Areas	Flight Crew Human Performance Airspace Structure ATC Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

I was the PF for a falcon 900 on an IFR flight plan talking with norcal approach. We were a few mi southwest of watsonville airport in california. We were at 6000 ft MSL direct to gilro intersection for a final destination at san jose airport. On this heading and altitude we saw a T-6 aircraft at our altitude and at our 12 O'clock position. The T-6 was in a right turn at approximately 90 degree bank. I made a left; descending turn to miss the T-6. Our TCAS did not show any aircraft in the vicinity. I descended to approximately 5400 ft MSL and then climbed back up to 6000 ft MSL direct gilro intersection. We advised approach control of our evasive action and they stated they had a target but no altitude on the T-6. This near miss occurred because the T-6 was not receiving radar advisories and flying with either an inoperative or no transponder.

Original NASA ASRS Text

Title: FALCON 900 FLT CREW HAS NMAC DURING APCH TO SJC.

Narrative: I WAS THE PF FOR A FALCON 900 ON AN IFR FLT PLAN TALKING WITH NORCAL APCH. WE WERE A FEW MI SW OF WATSONVILLE ARPT IN CALIFORNIA. WE WERE AT 6000 FT MSL DIRECT TO GILRO INTXN FOR A FINAL DEST AT SAN JOSE ARPT. ON THIS HDG AND ALT WE SAW A T-6 ACFT AT OUR ALT AND AT OUR 12 O'CLOCK POS. THE T-6 WAS IN A R TURN AT APPROX 90 DEG BANK. I MADE A L; DSNDING TURN TO MISS THE T-6. OUR TCAS DID NOT SHOW ANY ACFT IN THE VICINITY. I DSNDED TO APPROX 5400 FT MSL AND THEN CLBED BACK UP TO 6000 FT MSL DIRECT GILRO INTXN. WE ADVISED APCH CTL OF OUR EVASIVE ACTION AND THEY STATED THEY HAD A TARGET BUT NO ALT ON THE T-6. THIS NEAR MISS OCCURRED BECAUSE THE T-6 WAS NOT RECEIVING RADAR ADVISORIES AND FLYING WITH EITHER AN INOP OR NO XPONDER.

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.