Near midair collision between air carrier medium large transport and small aircraft Y vicinity of or...

Attributes
ACN	144367
Time
Date	199004
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : jvl airport : ord
State Reference	WI
Altitude	msl bound lower : 11000 msl bound upper : 11500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival star : star
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 180 flight time total : 5000 flight time type : 2000
ASRS Report	144367
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : nmac
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On descent to ord, 15 mi west of janesville VOR, (ATC cleared us to cross 10 mi west of VOR at 11000') we were passing through 11300' when approach issued a traffic advisory for traffic at 12 O'clock 3 mi, 11000' unverified. Approach also said we may want to stop our descent a that time, until traffic clears. I stopped the descent, and initiated a climb back to 11500' (I chose 11500', just to give us some extra clearance) and informed ATC of our actions. Approximately 10 seconds later, I saw our traffic, small aircraft Y pass below us at approximately 11000'. I called out traffic to approach and verified we were still cleared to 11000'. Continued descent to 11000' and remainder of approach with no further problems. It should be noted that during this avoidance, the captain (PNF) was communicating with company maintenance, and was not aware of the communication between ATC and myself. If ord approach had not called out that traffic, we would have had a very close 'near miss'.

Original NASA ASRS Text

Title: NMAC BETWEEN ACR MLG AND SMA Y VICINITY OF ORD.

Narrative: ON DSNT TO ORD, 15 MI W OF JANESVILLE VOR, (ATC CLRED US TO CROSS 10 MI W OF VOR AT 11000') WE WERE PASSING THROUGH 11300' WHEN APCH ISSUED A TFC ADVISORY FOR TFC AT 12 O'CLOCK 3 MI, 11000' UNVERIFIED. APCH ALSO SAID WE MAY WANT TO STOP OUR DSNT A THAT TIME, UNTIL TFC CLRS. I STOPPED THE DSNT, AND INITIATED A CLB BACK TO 11500' (I CHOSE 11500', JUST TO GIVE US SOME EXTRA CLRNC) AND INFORMED ATC OF OUR ACTIONS. APPROX 10 SECS LATER, I SAW OUR TFC, SMA Y PASS BELOW US AT APPROX 11000'. I CALLED OUT TFC TO APCH AND VERIFIED WE WERE STILL CLRED TO 11000'. CONTINUED DSNT TO 11000' AND REMAINDER OF APCH WITH NO FURTHER PROBS. IT SHOULD BE NOTED THAT DURING THIS AVOIDANCE, THE CAPT (PNF) WAS COMMUNICATING WITH COMPANY MAINT, AND WAS NOT AWARE OF THE COM BTWN ATC AND MYSELF. IF ORD APCH HAD NOT CALLED OUT THAT TFC, WE WOULD HAVE HAD A VERY CLOSE 'NEAR MISS'.

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.

Near midair collision between air carrier medium large transport and small aircraft Y vicinity of ord.