Narrative:

I was working an arrival and a departure sector (yng). The sector does both. I was working an arrival push as well as a departure rush at the same time. There were 4 overflts passing through the sector during this time. I have worked this sector for 10 yrs and can say that this was probably the busiest I have been. There was a radar associate helping and another person stuffing strips. A supervisor was also watching from behind. While spacing the 2 turboprops and descending a jet (Z) on top of them, I was distraction by the departures. Cle approach is required to give us 5 mi in trail (constant or increasing). My attention was taken away from spacing the arrs to try to maintain separation of the departures. Aircraft #1 was first in arrival sequence. Aircraft #2 was being vectored for spacing and then cleared direct to NAVAID when spacing was achieved. A jet (Z) was being stepped down on top. Aircraft #1 (at 9000 ft) aircraft #2 (descending to 9000 ft) was approximately 6-7 mi in trail. Aircraft #3 (jet being stepped down) was on top of #2 and #1. Jet aircraft (Z) automatic handed off to cle approach with data block not showing what aircraft was doing (150T 125). Conflict alert activated with all 3 data blocks flashing. Common occurrence with jet descending through what computer thought was assigned altitude. I attributed the flashing at first to just this. I was distraction to departures coming out and trying to separate or understand what was happening with them. An embraer jet was in front of a B737 with 5 and 6 mi separation and decreasing. Embraer jet checked on frequency departing 11400 ft for 12000 ft. B737 was already level at 12000 ft behind without communication xfer. When I attempted to suppress conflict alert with aircraft on arrival, I noticed that not only the jet being stepped down on top of aircraft #1 and #2 were flashing, but also aircraft #1 and #2 were in conflict. I immediately issued a turn to aircraft #2, but due to frequency congestion, it took another transmission before aircraft involved were turned and separation was lost. It took another 5-10 mins before I could relinquish control to relieving controller. There were between 19-23 data blocks on scope at that time. Additional departure in trail spacing could have helped prevent operational error in my opinion.

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Original NASA ASRS Text

Title: ZOB CTLR INVOLVED IN OPERROR IN COMPLEX ARR DEP TFC SIT.

Narrative: I WAS WORKING AN ARR AND A DEP SECTOR (YNG). THE SECTOR DOES BOTH. I WAS WORKING AN ARR PUSH AS WELL AS A DEP RUSH AT THE SAME TIME. THERE WERE 4 OVERFLTS PASSING THROUGH THE SECTOR DURING THIS TIME. I HAVE WORKED THIS SECTOR FOR 10 YRS AND CAN SAY THAT THIS WAS PROBABLY THE BUSIEST I HAVE BEEN. THERE WAS A RADAR ASSOCIATE HELPING AND ANOTHER PERSON STUFFING STRIPS. A SUPVR WAS ALSO WATCHING FROM BEHIND. WHILE SPACING THE 2 TURBOPROPS AND DSNDING A JET (Z) ON TOP OF THEM, I WAS DISTR BY THE DEPS. CLE APCH IS REQUIRED TO GIVE US 5 MI IN TRAIL (CONSTANT OR INCREASING). MY ATTN WAS TAKEN AWAY FROM SPACING THE ARRS TO TRY TO MAINTAIN SEPARATION OF THE DEPS. ACFT #1 WAS FIRST IN ARR SEQUENCE. ACFT #2 WAS BEING VECTORED FOR SPACING AND THEN CLRED DIRECT TO NAVAID WHEN SPACING WAS ACHIEVED. A JET (Z) WAS BEING STEPPED DOWN ON TOP. ACFT #1 (AT 9000 FT) ACFT #2 (DSNDING TO 9000 FT) WAS APPROX 6-7 MI IN TRAIL. ACFT #3 (JET BEING STEPPED DOWN) WAS ON TOP OF #2 AND #1. JET ACFT (Z) AUTO HANDED OFF TO CLE APCH WITH DATA BLOCK NOT SHOWING WHAT ACFT WAS DOING (150T 125). CONFLICT ALERT ACTIVATED WITH ALL 3 DATA BLOCKS FLASHING. COMMON OCCURRENCE WITH JET DSNDING THROUGH WHAT COMPUTER THOUGHT WAS ASSIGNED ALT. I ATTRIBUTED THE FLASHING AT FIRST TO JUST THIS. I WAS DISTR TO DEPS COMING OUT AND TRYING TO SEPARATE OR UNDERSTAND WHAT WAS HAPPENING WITH THEM. AN EMBRAER JET WAS IN FRONT OF A B737 WITH 5 AND 6 MI SEPARATION AND DECREASING. EMBRAER JET CHKED ON FREQ DEPARTING 11400 FT FOR 12000 FT. B737 WAS ALREADY LEVEL AT 12000 FT BEHIND WITHOUT COM XFER. WHEN I ATTEMPTED TO SUPPRESS CONFLICT ALERT WITH ACFT ON ARR, I NOTICED THAT NOT ONLY THE JET BEING STEPPED DOWN ON TOP OF ACFT #1 AND #2 WERE FLASHING, BUT ALSO ACFT #1 AND #2 WERE IN CONFLICT. I IMMEDIATELY ISSUED A TURN TO ACFT #2, BUT DUE TO FREQ CONGESTION, IT TOOK ANOTHER XMISSION BEFORE ACFT INVOLVED WERE TURNED AND SEPARATION WAS LOST. IT TOOK ANOTHER 5-10 MINS BEFORE I COULD RELINQUISH CTL TO RELIEVING CTLR. THERE WERE BTWN 19-23 DATA BLOCKS ON SCOPE AT THAT TIME. ADDITIONAL DEP IN TRAIL SPACING COULD HAVE HELPED PREVENT OPERROR IN MY OPINION.

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.