Air carrier Y had less than standard separation from air carrier X. System error.

Attributes
ACN	193098
Time
Date	199110
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ord
State Reference	IL
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	IMC
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 : approach
Flight Plan	IFR
Aircraft 2
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	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	controller : approach
Qualification	controller : radar
ASRS Report	193098
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : developmental
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : published procedure
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Training in progress on approach control. Air carrier X is cleared for an ILS approach to 22R at 4000 ft. Air carrier Y is on a north heading passing east of ord. Air carrier Y is slowed and descended to 4000 ft. Trainee neglects to turn air carrier Y to downwind. When brought to his attention he does turn air carrier Y to the standard downwind heading but by this time, a more easterly heading is required. I instruct trainee to turn air carrier Y out and level him off. Trainee does then turn to a 070 degree but does not issue any altitude. By this time evasive action is required and I take the frequency. I turn air carrier Y to an immediate right to 090 degree and level, and descend air carrier X to 3000 ft. Both continued on the approach.

Original NASA ASRS Text

Title: ACR Y HAD LTSS FROM ACR X. SYS ERROR.

Narrative: TRAINING IN PROGRESS ON APCH CTL. ACR X IS CLRED FOR AN ILS APCH TO 22R AT 4000 FT. ACR Y IS ON A N HDG PASSING E OF ORD. ACR Y IS SLOWED AND DSNDED TO 4000 FT. TRAINEE NEGLECTS TO TURN ACR Y TO DOWNWIND. WHEN BROUGHT TO HIS ATTN HE DOES TURN ACR Y TO THE STANDARD DOWNWIND HDG BUT BY THIS TIME, A MORE EASTERLY HDG IS REQUIRED. I INSTRUCT TRAINEE TO TURN ACR Y OUT AND LEVEL HIM OFF. TRAINEE DOES THEN TURN TO A 070 DEG BUT DOES NOT ISSUE ANY ALT. BY THIS TIME EVASIVE ACTION IS REQUIRED AND I TAKE THE FREQ. I TURN ACR Y TO AN IMMEDIATE R TO 090 DEG AND LEVEL, AND DSND ACR X TO 3000 FT. BOTH CONTINUED ON THE APCH.

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.