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

Attributes
ACN	164672
Time
Date	199012
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : eri
State Reference	PA
Altitude	msl bound lower : 19000 msl bound upper : 19400
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 3
ASRS Report	164672
Person 2
Affiliation	government : faa
Function	controller : non radar
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified
Resolutory Action	controller : issued new clearance none taken : insufficient time
Consequence	faa : investigated
Miss Distance	vertical : 400
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Intra Facility Coordination Failure Operational Error

Narrative:

Air carrier X was inbound to cle via jhw and cxr VOR's. Air carrier Y was inbound to pit via direct yng from the northeast. Several data blocks were overlapped on my pvd. In order to separate the data blocks I expanded my radar range. I offset the data block on Y to the east and X to the northwest. I returned my pvd to the normal range. I took the handoff on X. At some point I also accepted the handoff of Y, however I don't recall doing it. With the range returned to normal Y's data block was not in view. Prior to the above events, my manual controller coordinated lower altitudes on several aircraft with the adjacent sector as the aircraft were still in their airspace. In reviewing the incident, the manual controller was given control for descent on air carrier X with respect to Y. Unfortunately this was not communicated to me. When X checked on I descended him to start sequencing for cle. I thought I had control for descent, didn't see the data block on Y and sep was lost. The conflict activated as X descended through FL194. Y was at FL190. When the C/a activated I turned X and expedited his descent.

Original NASA ASRS Text

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

Narrative: ACR X WAS INBND TO CLE VIA JHW AND CXR VOR'S. ACR Y WAS INBND TO PIT VIA DIRECT YNG FROM THE NE. SEVERAL DATA BLOCKS WERE OVERLAPPED ON MY PVD. IN ORDER TO SEPARATE THE DATA BLOCKS I EXPANDED MY RADAR RANGE. I OFFSET THE DATA BLOCK ON Y TO THE E AND X TO THE NW. I RETURNED MY PVD TO THE NORMAL RANGE. I TOOK THE HDOF ON X. AT SOME POINT I ALSO ACCEPTED THE HDOF OF Y, HOWEVER I DON'T RECALL DOING IT. WITH THE RANGE RETURNED TO NORMAL Y'S DATA BLOCK WAS NOT IN VIEW. PRIOR TO THE ABOVE EVENTS, MY MANUAL CTLR COORDINATED LOWER ALTS ON SEVERAL ACFT WITH THE ADJACENT SECTOR AS THE ACFT WERE STILL IN THEIR AIRSPACE. IN REVIEWING THE INCIDENT, THE MANUAL CTLR WAS GIVEN CTL FOR DSNT ON ACR X WITH RESPECT TO Y. UNFORTUNATELY THIS WAS NOT COMMUNICATED TO ME. WHEN X CHKED ON I DSNDED HIM TO START SEQUENCING FOR CLE. I THOUGHT I HAD CTL FOR DSNT, DIDN'T SEE THE DATA BLOCK ON Y AND SEP WAS LOST. THE CONFLICT ACTIVATED AS X DSNDED THROUGH FL194. Y WAS AT FL190. WHEN THE C/A ACTIVATED I TURNED X AND EXPEDITED HIS DSNT.

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.