ZDC controller unable to establish legal separation between a descending B737 and an en route A320.

Attributes
ACN	526983
Time
Date	200110
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	intersection : boton
State Reference	NJ
Altitude	msl bound lower : 34000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc.artcc
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zdc.artcc
Operator	common carrier : air carrier
Make Model Name	B737-200
Operating Under FAR Part	Part 121
Flight Phase	cruise : enroute altitude change
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 15 controller time certified in position2 : 1
ASRS Report	526983
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : published procedure
Independent Detector	atc equipment : conflict alert
Resolutory Action	none taken : detected after the fact
Consequence	faa : investigated
Miss Distance	horizontal : 19200 vertical : 1000
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I gave clearance to aircraft #1 for descent. Aircraft #2 was on converging course. Less than minimum separation occurred.

Original NASA ASRS Text

Title: ZDC CTLR UNABLE TO ESTABLISH LEGAL SEPARATION BTWN A DSNDING B737 AND AN ENRTE A320.

Narrative: I GAVE CLRNC TO ACFT #1 FOR DSCNT. ACFT #2 WAS ON CONVERGING COURSE. LESS THAN MINIMUM SEPARATION OCCURRED.

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.