While descending IFR in VMC aircraft had an near midair collision with an unidentified but reported ...

Attributes
ACN	109149
Time
Date	198904
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : hdf airport : ont
State Reference	CA
Altitude	msl bound lower : 9500 msl bound upper : 9500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star enroute airway : ont
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other cruise other
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 200 flight time total : 8000 flight time type : 200
ASRS Report	109149
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	conflict : nmac
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 0 vertical : 100
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

We were descending from 12000 to 8000'. Passing approximately 9500', approach control gave us traffic at 1-2 O'clock, altitude unknown. I looked over at the copilot when he didn't acknowledge the call and realized he hadn't heard it. He was identing the localizer at the time. I picked up the microphone and asked ATC to reference the traffic again. They gave us 12-1 O'clock, 1 mi, altitude unknown. Just then the copilot saw the traffic approximately 1/4 mi, right to left, just a few hundred ft below us. I had to take positive action to reduce our descent rate and we passed directly over him, about 100' miss distance. The other plane was a yellow and white high wing small aircraft. I told approach control we had the traffic just below us. No other reference was made on the radio by us nor ATC re: the situation. The other plane took no apparent action--he may never have seen us at all. This occurrence yet again points out the importance in not letting cockpit duties interfere with constant vigilance for traffic and the hazards involved with mixing IFR and VFR non-mode C equipped aircraft.

Original NASA ASRS Text

Title: WHILE DESCENDING IFR IN VMC ACFT HAD AN NMAC WITH AN UNIDENTIFIED BUT REPORTED SMA.

Narrative: WE WERE DSNDING FROM 12000 TO 8000'. PASSING APPROX 9500', APCH CTL GAVE US TFC AT 1-2 O'CLOCK, ALT UNKNOWN. I LOOKED OVER AT THE COPLT WHEN HE DIDN'T ACKNOWLEDGE THE CALL AND REALIZED HE HADN'T HEARD IT. HE WAS IDENTING THE LOC AT THE TIME. I PICKED UP THE MIC AND ASKED ATC TO REF THE TFC AGAIN. THEY GAVE US 12-1 O'CLOCK, 1 MI, ALT UNKNOWN. JUST THEN THE COPLT SAW THE TFC APPROX 1/4 MI, RIGHT TO LEFT, JUST A FEW HUNDRED FT BELOW US. I HAD TO TAKE POSITIVE ACTION TO REDUCE OUR DSCNT RATE AND WE PASSED DIRECTLY OVER HIM, ABOUT 100' MISS DISTANCE. THE OTHER PLANE WAS A YELLOW AND WHITE HIGH WING SMA. I TOLD APCH CTL WE HAD THE TFC JUST BELOW US. NO OTHER REF WAS MADE ON THE RADIO BY US NOR ATC RE: THE SITUATION. THE OTHER PLANE TOOK NO APPARENT ACTION--HE MAY NEVER HAVE SEEN US AT ALL. THIS OCCURRENCE YET AGAIN POINTS OUT THE IMPORTANCE IN NOT LETTING COCKPIT DUTIES INTERFERE WITH CONSTANT VIGILANCE FOR TFC AND THE HAZARDS INVOLVED WITH MIXING IFR AND VFR NON-MODE C EQUIPPED ACFT.

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.

While descending IFR in VMC aircraft had an near midair collision with an unidentified but reported small aircraft.