Air carrier X overtook air carrier Y. Less than standard separation. System error.

Attributes
ACN	119809
Time
Date	198907
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : bsv
State Reference	OH
Altitude	msl bound lower : 23000 msl bound upper : 23000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zob
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise 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	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
ASRS Report	119809
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated
Miss Distance	horizontal : 25500 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

2 departure aircraft off pittsburgh flying northeast bound over bsv VOR. 2 similar type aircraft (air carrier X, air carrier Y) with one ending up 60 KTS faster than the other. I was awaiting higher altitude from next sector, data became overlapped thus I was not aware of speed differential. There was another situation happening in my sector that demanded my attention. When got back to the 2 departures and separated the data blocks, I immediately recognized the problem and turned the second aircraft. Separation was lost with 4.25 mi. No evasive action was required.

Original NASA ASRS Text

Title: ACR X OVERTOOK ACR Y. LESS THAN STANDARD SEPARATION. SYSTEM ERROR.

Narrative: 2 DEP ACFT OFF PITTSBURGH FLYING NE BOUND OVER BSV VOR. 2 SIMILAR TYPE ACFT (ACR X, ACR Y) WITH ONE ENDING UP 60 KTS FASTER THAN THE OTHER. I WAS AWAITING HIGHER ALT FROM NEXT SECTOR, DATA BECAME OVERLAPPED THUS I WAS NOT AWARE OF SPEED DIFFERENTIAL. THERE WAS ANOTHER SITUATION HAPPENING IN MY SECTOR THAT DEMANDED MY ATTN. WHEN GOT BACK TO THE 2 DEPS AND SEPARATED THE DATA BLOCKS, I IMMEDIATELY RECOGNIZED THE PROBLEM AND TURNED THE SECOND ACFT. SEPARATION WAS LOST WITH 4.25 MI. NO EVASIVE ACTION WAS REQUIRED.

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.