Ont tower controller experienced possible loss of separation between 2 arrs.

Attributes
ACN	599187
Time
Date	200311
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ont.airport
State Reference	CA
Altitude	msl single value : 2700
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sct.tracon tower : ont.tower
Operator	common carrier : air carrier
Make Model Name	Brasilia EMB-120 All Series
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : ont.tower
Operator	general aviation : personal
Make Model Name	Cessna 210 Centurion / Turbo Centurion 210C, 210D
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : traffic pattern
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : local
Qualification	controller : radar
Experience	controller limited radar : 2 controller non radar : 7 controller time certified in position1 : 2 flight time total : 200
ASRS Report	599187
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : airborne less severe non adherence : clearance non adherence : required legal separation non adherence : published procedure
Independent Detector	other controllera
Resolutory Action	controller : issued advisory
Miss Distance	horizontal : 6000 vertical : 200
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X on visual approach to runway 26R, flew in front of aircraft Y on a 4 mi final for runway 26L (ILS approach). Once on the ground air carrier X apologized for the abrupt turn into final. Claimed approach control could not get the C210 to report air carrier X in sight.

Original NASA ASRS Text

Title: ONT TWR CTLR EXPERIENCED POSSIBLE LOSS OF SEPARATION BTWN 2 ARRS.

Narrative: ACR X ON VISUAL APCH TO RWY 26R, FLEW IN FRONT OF ACFT Y ON A 4 MI FINAL FOR RWY 26L (ILS APCH). ONCE ON THE GND ACR X APOLOGIZED FOR THE ABRUPT TURN INTO FINAL. CLAIMED APCH CTL COULD NOT GET THE C210 TO RPT ACR X IN SIGHT.

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.