Air carrier Y issued visual approach clearance to follow wrong aircraft had less than standard separ...

Attributes
ACN	199007
Time
Date	199201
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ord
State Reference	IL
Altitude	msl bound lower : 3500 msl bound upper : 3500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 4 Turbojet Eng
Navigation In Use	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 : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
ASRS Report	199007
Person 2
Affiliation	government : faa
Function	other personnel other
Qualification	controller : radar
ASRS Report	199105
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
Consequence	Other
Miss Distance	horizontal : 15000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error
Situations
Navigational Aid	Unspecified

Narrative:

I was working approach at the O'hare TRACON, runway 27R, simultaneous visuals. There was a lot of coasting and target loss occurring, both primary and secondary target loss. Air carrier X was one of those coasting and loss of target problems. I had already cleared him for the visual approach and was working with moderate to heavy traffic. Air carrier Y was told he would follow air carrier X. As I was working with other aircraft to set them up for the approach, air carrier X had completely dropped off, both data and target. When I did turn air carrier Y on base, there was only air carrier medium large transport, the previous aircraft as a reference point. So I turned to follow him, not realizing air carrier X was still there. After working with other duties, air carrier Y asked me if he was really following air carrier X. I did not see any target at that time until the second or third sweep. When I did see and remember air carrier X, it was a very small primary target just inside the marker. Air carrier Y was approximately 2 1/2-3 mi behind him. I then pulled air carrier Y off of the approach for another sequence. In my opinion, this situation occurred because of equipment problems. How can I work when I do not see targets. How about updating equipment at the busiest and most complex airport. I have taken my own actions or techniques to help prevent this from happening or going this far again. Supplemental information from acn 199105. Parallel visuals in use. Radar beacon system was continuously coasting. When the supervisor switched beacon channels, air carrier X did not hold his tag. Thus, the arrival controller turned air carrier Y into the same gap. Altitude and visual separation were applied after the second aircraft questioned the operation. Ultimately air carrier Y was taken out and resequenced.

Original NASA ASRS Text

Title: ACR Y ISSUED VISUAL APCH CLRNC TO FOLLOW WRONG ACFT HAD LTSS FROM ACR X WDB. LESS THAN HVY JET SEPARATION FOR WAKE TURB. SITUATION: ATC EQUIP PROBLEM RADAR NON DETECTION OF ACFT BY TRACON RADAR TRACKING COASTING.

Narrative: I WAS WORKING APCH AT THE O'HARE TRACON, RWY 27R, SIMULTANEOUS VISUALS. THERE WAS A LOT OF COASTING AND TARGET LOSS OCCURRING, BOTH PRIMARY AND SECONDARY TARGET LOSS. ACR X WAS ONE OF THOSE COASTING AND LOSS OF TARGET PROBLEMS. I HAD ALREADY CLRED HIM FOR THE VISUAL APCH AND WAS WORKING WITH MODERATE TO HVY TFC. ACR Y WAS TOLD HE WOULD FOLLOW ACR X. AS I WAS WORKING WITH OTHER ACFT TO SET THEM UP FOR THE APCH, ACR X HAD COMPLETELY DROPPED OFF, BOTH DATA AND TARGET. WHEN I DID TURN ACR Y ON BASE, THERE WAS ONLY ACR MLG, THE PREVIOUS ACFT AS A REF POINT. SO I TURNED TO FOLLOW HIM, NOT REALIZING ACR X WAS STILL THERE. AFTER WORKING WITH OTHER DUTIES, ACR Y ASKED ME IF HE WAS REALLY FOLLOWING ACR X. I DID NOT SEE ANY TARGET AT THAT TIME UNTIL THE SECOND OR THIRD SWEEP. WHEN I DID SEE AND REMEMBER ACR X, IT WAS A VERY SMALL PRIMARY TARGET JUST INSIDE THE MARKER. ACR Y WAS APPROX 2 1/2-3 MI BEHIND HIM. I THEN PULLED ACR Y OFF OF THE APCH FOR ANOTHER SEQUENCE. IN MY OPINION, THIS SITUATION OCCURRED BECAUSE OF EQUIP PROBLEMS. HOW CAN I WORK WHEN I DO NOT SEE TARGETS. HOW ABOUT UPDATING EQUIP AT THE BUSIEST AND MOST COMPLEX ARPT. I HAVE TAKEN MY OWN ACTIONS OR TECHNIQUES TO HELP PREVENT THIS FROM HAPPENING OR GOING THIS FAR AGAIN. SUPPLEMENTAL INFO FROM ACN 199105. PARALLEL VISUALS IN USE. RADAR BEACON SYS WAS CONTINUOUSLY COASTING. WHEN THE SUPVR SWITCHED BEACON CHANNELS, ACR X DID NOT HOLD HIS TAG. THUS, THE ARR CTLR TURNED ACR Y INTO THE SAME GAP. ALT AND VISUAL SEPARATION WERE APPLIED AFTER THE SECOND ACFT QUESTIONED THE OP. ULTIMATELY ACR Y WAS TAKEN OUT AND RESEQUENCED.

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.

Air carrier Y issued visual approach clearance to follow wrong aircraft had less than standard separation from air carrier X widebody transport. Less than heavy jet separation for wake turbulence. Situation: ATC equipment problem radar non detection of aircraft by TRACON radar tracking coasting.