ZDC controller experienced loss of separation with 2 en route aircraft.

Attributes
ACN	589939
Time
Date	200308
Day	Sat
Local Time Of Day	0601 To 1200
Place
State Reference	VA
Altitude	msl bound lower : 18400 msl bound upper : 19000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc.artcc tower : dfw.tower
Operator	common carrier : air carrier
Make Model Name	B717 (Formerly MD-95)
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zdc.artcc
Operator	general aviation : personal
Make Model Name	PA-46 Malibu
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Experience	controller military : 6 controller radar : 15
ASRS Report	589939
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : radar other controllera
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Consequence	faa : investigated
Miss Distance	horizontal : 21000 vertical : 600
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I issued aircraft #1 a climb to FL230. I realized that aircraft #1 was in conflict with aircraft #2 and amended aircraft #1 altitude to FL180. Aircraft #2 was at FL190. Aircraft #1 did not read back clearance. I inadvertently issued a clearance to aircraft #1 to climb to FL190. I issued traffic to aircraft #1 on aircraft #2 at FL190 and advised when to expect higher altitude. I issued traffic to aircraft #2 on traffic climbing to FL180. I observed aircraft #1 climb through FL180 and advised him that assigned altitude was FL180. Issued immediate turn to aircraft #1 and restated assigned altitude was FL180. Aircraft #2 advised aircraft #1 was in sight. Aircraft #1 reclred to FL180 and was cleared on course.

Original NASA ASRS Text

Title: ZDC CTLR EXPERIENCED LOSS OF SEPARATION WITH 2 ENRTE ACFT.

Narrative: I ISSUED ACFT #1 A CLB TO FL230. I REALIZED THAT ACFT #1 WAS IN CONFLICT WITH ACFT #2 AND AMENDED ACFT #1 ALT TO FL180. ACFT #2 WAS AT FL190. ACFT #1 DID NOT READ BACK CLRNC. I INADVERTENTLY ISSUED A CLRNC TO ACFT #1 TO CLB TO FL190. I ISSUED TFC TO ACFT #1 ON ACFT #2 AT FL190 AND ADVISED WHEN TO EXPECT HIGHER ALT. I ISSUED TFC TO ACFT #2 ON TFC CLBING TO FL180. I OBSERVED ACFT #1 CLB THROUGH FL180 AND ADVISED HIM THAT ASSIGNED ALT WAS FL180. ISSUED IMMEDIATE TURN TO ACFT #1 AND RESTATED ASSIGNED ALT WAS FL180. ACFT #2 ADVISED ACFT #1 WAS IN SIGHT. ACFT #1 RECLRED TO FL180 AND WAS CLRED ON COURSE.

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.