Air carrier X had airborne conflict with small transport Y in arsa. Visual separation used.

Attributes
ACN	174515
Time
Date	199104
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : smf
State Reference	CA
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mcc
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	VFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
ASRS Report	174515
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 9000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Intra Facility Coordination Failure other

Narrative:

Air carrier X was northbound on a right downwind for runway 16R at smf. Air carrier X was at 4000' level. In the same area was a VFR small transport Y descending through 4000' southbound for davis airport. Air carrier X came in close proximity to the small transport Y. Air carrier X was issued a TA and instructed to turn away form the small transport Y. Air carrier X reported the small transport Y in sight. Small transport Y also had air carrier X in sight. When the aircraft passed they were approximately 1-1 1/2 mi apart. Both aircraft were under approach control supervision, but on different frequencys.

Original NASA ASRS Text

Title: ACR X HAD AIRBORNE CONFLICT WITH SMT Y IN ARSA. VISUAL SEPARATION USED.

Narrative: ACR X WAS NBND ON A RIGHT DOWNWIND FOR RWY 16R AT SMF. ACR X WAS AT 4000' LEVEL. IN THE SAME AREA WAS A VFR SMT Y DSNDING THROUGH 4000' SBND FOR DAVIS ARPT. ACR X CAME IN CLOSE PROX TO THE SMT Y. ACR X WAS ISSUED A TA AND INSTRUCTED TO TURN AWAY FORM THE SMT Y. ACR X RPTED THE SMT Y IN SIGHT. SMT Y ALSO HAD ACR X IN SIGHT. WHEN THE ACFT PASSED THEY WERE APPROX 1-1 1/2 MI APART. BOTH ACFT WERE UNDER APCH CTL SUPERVISION, BUT ON DIFFERENT FREQS.

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.