Airborne conflict between air carrier aircraft and small transport conducting VFR test flight.

Attributes
ACN	132423
Time
Date	198912
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : pdz airport : cno
State Reference	CA
Altitude	msl bound lower : 8200 msl bound upper : 8200
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tower : ord
Operator	general aviation : personal
Make Model Name	Small Transport
Flight Phase	cruise other
Flight Plan	None
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial
Experience	flight time last 90 days : 25 flight time total : 2800 flight time type : 300
ASRS Report	132423
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe inflight encounter : weather inflight encounter : vfr in imc non adherence : far
Independent Detector	other controllera other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Miss Distance	horizontal : 300
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

Flight was a maintenance check flight. Small transport departed chino airport to lake matthews. Climbed to 10000'. Several layers of broken clouds, visibility 50 mi. Observed several airlines south of lake matthews and opted to stay on north shore. While maneuvering clear of clouds southeast of pdz VOR, I was checking the carburetor air temperature gauge. When I looked up I saw an airliner approximately 1/2 mi in front of me. He was not visible before due to the cloud between us. Upon sighting the airliner I rolled to the left and descended below the cloud layer and departed to the northeast. The airliner never changed his w-erly heading or made any evasive move. Remainder of flight was uneventful. Control tower advised that ontario approach said that we flew in front of an airliner, which was not true, unless another airliner was at my position in clouds. West were not on any arwys when we encountered the airliner. The center of lake matthews is in uncontrolled airspace. Because of that we were relatively sure we would not encounter any airline traffic. However it appears that airliners are vectored across the lake to orange county airport. This presents a potential hazard due to the uncontrolled airspace that they cross below 10000'. No flight plan was filed by small transport, nor were we in contact with ont approach.

Original NASA ASRS Text

Title: AIRBORNE CONFLICT BETWEEN ACR ACFT AND SMT CONDUCTING VFR TEST FLT.

Narrative: FLT WAS A MAINT CHK FLT. SMT DEPARTED CHINO ARPT TO LAKE MATTHEWS. CLBED TO 10000'. SEVERAL LAYERS OF BROKEN CLOUDS, VISIBILITY 50 MI. OBSERVED SEVERAL AIRLINES S OF LAKE MATTHEWS AND OPTED TO STAY ON N SHORE. WHILE MANEUVERING CLR OF CLOUDS SE OF PDZ VOR, I WAS CHKING THE CARB AIR TEMP GAUGE. WHEN I LOOKED UP I SAW AN AIRLINER APPROX 1/2 MI IN FRONT OF ME. HE WAS NOT VISIBLE BEFORE DUE TO THE CLOUD BTWN US. UPON SIGHTING THE AIRLINER I ROLLED TO THE LEFT AND DSNDED BELOW THE CLOUD LAYER AND DEPARTED TO THE NE. THE AIRLINER NEVER CHANGED HIS W-ERLY HDG OR MADE ANY EVASIVE MOVE. REMAINDER OF FLT WAS UNEVENTFUL. CTL TWR ADVISED THAT ONTARIO APCH SAID THAT WE FLEW IN FRONT OF AN AIRLINER, WHICH WAS NOT TRUE, UNLESS ANOTHER AIRLINER WAS AT MY POS IN CLOUDS. W WERE NOT ON ANY ARWYS WHEN WE ENCOUNTERED THE AIRLINER. THE CENTER OF LAKE MATTHEWS IS IN UNCONTROLLED AIRSPACE. BECAUSE OF THAT WE WERE RELATIVELY SURE WE WOULD NOT ENCOUNTER ANY AIRLINE TFC. HOWEVER IT APPEARS THAT AIRLINERS ARE VECTORED ACROSS THE LAKE TO ORANGE COUNTY ARPT. THIS PRESENTS A POTENTIAL HAZARD DUE TO THE UNCONTROLLED AIRSPACE THAT THEY CROSS BELOW 10000'. NO FLT PLAN WAS FILED BY SMT, NOR WERE WE IN CONTACT WITH ONT APCH.

Data retrieved from NASA's ASRS site as of August 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.