Air carrier has near midair collision with small aircraft at 10000 ft.

Attributes
ACN	246534
Time
Date	199307
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ord
State Reference	IL
Altitude	msl bound lower : 10000 msl bound upper : 10400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute airway : zau
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	descent 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 : 225 flight time total : 17000 flight time type : 10000
ASRS Report	246534
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	conflict : nmac other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew Other
Miss Distance	horizontal : 200 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

Received warning from ATC that a pop-up VFR target was at our 1 O'clock position, 5 mi and closing at 10500 ft. Target then appeared on TCASII at 10500 ft. As the target aircraft closed, it descended to 10400 ft, then 10300 ft. A TCASII resolution followed. I disengaged the autoplt and descended, turning slightly left. An small transport, green and orange, passed within 200 ft of our aircraft. ATC was notified, further descent was given and we landed uneventfully at ord. Sincerely ATC and TCASII saved the day! It was close.

Original NASA ASRS Text

Title: ACR HAS NMAC WITH SMA AT 10000 FT.

Narrative: RECEIVED WARNING FROM ATC THAT A POP-UP VFR TARGET WAS AT OUR 1 O'CLOCK POS, 5 MI AND CLOSING AT 10500 FT. TARGET THEN APPEARED ON TCASII AT 10500 FT. AS THE TARGET ACFT CLOSED, IT DSNDED TO 10400 FT, THEN 10300 FT. A TCASII RESOLUTION FOLLOWED. I DISENGAGED THE AUTOPLT AND DSNDED, TURNING SLIGHTLY L. AN SMT, GREEN AND ORANGE, PASSED WITHIN 200 FT OF OUR ACFT. ATC WAS NOTIFIED, FURTHER DSCNT WAS GIVEN AND WE LANDED UNEVENTFULLY AT ORD. SINCERELY ATC AND TCASII SAVED THE DAY! IT WAS CLOSE.

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.