Less than standard separation between 2 air carrier aircraft. Operational error.

Attributes
ACN	131532
Time
Date	198912
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : mdw
State Reference	IL
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : ord tower : sbn
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 220 flight time total : 12500 flight time type : 9500
ASRS Report	131531
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation other anomaly other
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : took evasive action none taken : insufficient time
Consequence	Other
Miss Distance	horizontal : 2000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Intra Facility Coordination Failure Operational Error

Narrative:

We were being vectored for an ILS approach to runway 4R at mdw. Approach was handling us on 118.4. WX was IMC, and mdw was reporting 25 overcast, 2 1/2 snow. We were on a heading of 270 degrees when I saw medium large transport Y's 3 landing lights directly ahead at about our altitude. I started to take control of our aircraft and turn left when approach directed us to immediately turn left to 180 degrees and descend to 3000'. The traffic passed us left to right, apparently on localizer to 4R. When I asked the controller our distance from traffic, he only gave us instructions to switch to 119.35. The approach controller on 118.4 had apparently forgotten about us and allowed us to fly into airspace normally controled on 119.35.

Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN 2 ACR ACFT. OPERATIONAL ERROR.

Narrative: WE WERE BEING VECTORED FOR AN ILS APCH TO RWY 4R AT MDW. APCH WAS HANDLING US ON 118.4. WX WAS IMC, AND MDW WAS RPTING 25 OVCST, 2 1/2 SNOW. WE WERE ON A HDG OF 270 DEGS WHEN I SAW MLG Y'S 3 LNDG LIGHTS DIRECTLY AHEAD AT ABOUT OUR ALT. I STARTED TO TAKE CONTROL OF OUR ACFT AND TURN LEFT WHEN APCH DIRECTED US TO IMMEDIATELY TURN LEFT TO 180 DEGS AND DSND TO 3000'. THE TFC PASSED US LEFT TO RIGHT, APPARENTLY ON LOC TO 4R. WHEN I ASKED THE CTLR OUR DISTANCE FROM TFC, HE ONLY GAVE US INSTRUCTIONS TO SWITCH TO 119.35. THE APCH CTLR ON 118.4 HAD APPARENTLY FORGOTTEN ABOUT US AND ALLOWED US TO FLY INTO AIRSPACE NORMALLY CTLED ON 119.35.

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.