Close proximity air carrier-large transport GA-small aircraft southeast of den.

Attributes
ACN	96891
Time
Date	198810
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : den
State Reference	CO
Altitude	msl bound lower : 11800 msl bound upper : 12000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : den
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other descent other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	climbout : intermediate altitude
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : cfi pilot : commercial pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 160 flight time total : 14000 flight time type : 13000
ASRS Report	96891
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	conflict : airborne less severe
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 2000 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Flight atl to den ATC reported 'no radio contact traffic 10 to 11 O'clock, 4 mi, transponder indicates 11500', climbing.' we visually acquired traffic in approximately that position (direction unknown), leveled at 12000, (had been cleared to 11000), slowed to 220 KTS. Blue small aircraft passed heading southeast (opposite direction) off left side about 200' below, 2000' abeam, climbing. We did not see this one coming, even though we looked, as usual, for all possible traffic conflicts! Additional radar vectors may have helped. Collision avoidance warning system highly desired!

Original NASA ASRS Text

Title: CLOSE PROX ACR-LGT GA-SMA SOUTHEAST OF DEN.

Narrative: FLT ATL TO DEN ATC RPTED 'NO RADIO CONTACT TFC 10 TO 11 O'CLOCK, 4 MI, TRANSPONDER INDICATES 11500', CLBING.' WE VISUALLY ACQUIRED TFC IN APPROX THAT POS (DIRECTION UNKNOWN), LEVELED AT 12000, (HAD BEEN CLRED TO 11000), SLOWED TO 220 KTS. BLUE SMA PASSED HDG SE (OPPOSITE DIRECTION) OFF L SIDE ABOUT 200' BELOW, 2000' ABEAM, CLBING. WE DID NOT SEE THIS ONE COMING, EVEN THOUGH WE LOOKED, AS USUAL, FOR ALL POSSIBLE TFC CONFLICTS! ADDITIONAL RADAR VECTORS MAY HAVE HELPED. COLLISION AVOIDANCE WARNING SYSTEM HIGHLY DESIRED!

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.