Conflict with VFR aircraft in marginal VFR conditions.

Attributes
ACN	255801
Time
Date	199310
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : pdz airport : ont
State Reference	CA
Altitude	msl bound lower : 5000 msl bound upper : 5500
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Route In Use	departure sid : sid enroute airway : ont
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 22000 flight time type : 8000
ASRS Report	255801
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : airborne less severe
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action other
Consequence	Other
Miss Distance	horizontal : 1200 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Ont reporting thin obscuration, 3 mi haze and smoke. Departed via prado departure -- thermal transition. At pdz 130 degrees/7 DME, I was issued climb from 4000 to 7000. Departure control issued VFR traffic 9500 ft. Many targets on TA/vsi indicator approximately 5000 climbing. We had just climbed above haze and smoke. TCASII issued 'traffic -- descend.' pushed over, reduced power to idle, had a short sighting of other aircraft, resumed departure and climb. Other aircraft light twin -- departure control said he never saw other traffic. Other aircraft took possible evasive action of right turn. TCASII indicated his altitude as plus 500 ft (about 5500 MSL), range about 1 mi. Until TA and RA this traffic covered by other targets closer in range. TCASII probably prevented midair. 3 mi visibility not enough for VMC operations of high performance aircraft. I find it difficult to interpret TCASII information while scanning instruments in VMC and complying with departures. I believe that our operations (not using FMS to fly aircraft) allows more coordination of pilots and aircraft.

Original NASA ASRS Text

Title: CONFLICT WITH VFR ACFT IN MARGINAL VFR CONDITIONS.

Narrative: ONT RPTING THIN OBSCURATION, 3 MI HAZE AND SMOKE. DEPARTED VIA PRADO DEP -- THERMAL TRANSITION. AT PDZ 130 DEGS/7 DME, I WAS ISSUED CLB FROM 4000 TO 7000. DEP CTL ISSUED VFR TFC 9500 FT. MANY TARGETS ON TA/VSI INDICATOR APPROX 5000 CLBING. WE HAD JUST CLBED ABOVE HAZE AND SMOKE. TCASII ISSUED 'TFC -- DSND.' PUSHED OVER, REDUCED PWR TO IDLE, HAD A SHORT SIGHTING OF OTHER ACFT, RESUMED DEP AND CLB. OTHER ACFT LIGHT TWIN -- DEP CTL SAID HE NEVER SAW OTHER TFC. OTHER ACFT TOOK POSSIBLE EVASIVE ACTION OF R TURN. TCASII INDICATED HIS ALT AS PLUS 500 FT (ABOUT 5500 MSL), RANGE ABOUT 1 MI. UNTIL TA AND RA THIS TFC COVERED BY OTHER TARGETS CLOSER IN RANGE. TCASII PROBABLY PREVENTED MIDAIR. 3 MI VISIBILITY NOT ENOUGH FOR VMC OPS OF HIGH PERFORMANCE ACFT. I FIND IT DIFFICULT TO INTERPRET TCASII INFO WHILE SCANNING INSTS IN VMC AND COMPLYING WITH DEPS. I BELIEVE THAT OUR OPS (NOT USING FMS TO FLY ACFT) ALLOWS MORE COORD OF PLTS AND ACFT.

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.