Pct controller described a loss of separation event resulting from issuing one altitude but thinking...

Narrative:

Giving instruction during the main arrival bank of the day. ZDC was late on getting aircraft down and switching to my position and was the initial reason our aircraft were being vectored abnormally high into our sector for sequence on the arrival. The complexity of the sector was increasing so I took over from the developmental; and gave an altitude of 9000 to a south bound air carrier Y; when I meant to restate 8000; because of traffic opposite direction at 7000. Air carrier X was opposite direction to air carrier Y as well and some 10 miles away. I thought I had lateral and vertical; but when I noticed the situation; I turned air carrier Y right to a 270 heading. No response from air carrier Y. I turned air carrier X east to 090 with no response. I again did this to each aircraft with no response from either one. Finally after issuing a traffic alert to air carrier X; who acknowledged turning east to 090. It was a case of meaning one thing and saying another. Recommendation; should have put ZDC into a hold earlier than I did. Should have re-scanned my altitude assignments again; especially during high complex situations. Focusing more on all prospective situations. Make sure I say what I mean and mean what I say.

Original NASA ASRS Text

Title: PCT Controller described a loss of separation event resulting from issuing one altitude but thinking another; the reporter adding that ZDC should have been placed into holding much sooner.

Narrative: Giving Instruction during the main arrival bank of the day. ZDC was late on getting aircraft down and switching to my position and was the initial reason our aircraft were being vectored abnormally high into our sector for sequence on the arrival. The complexity of the sector was increasing so I took over from the developmental; and gave an altitude of 9000 to a south bound ACR Y; when I meant to restate 8000; because of traffic opposite direction at 7000. ACR X was opposite direction to ACR Y as well and some 10 miles away. I thought I had lateral and vertical; but when I noticed the situation; I turned ACR Y right to a 270 heading. No response from ACR Y. I turned ACR X East to 090 with no response. I again did this to each aircraft with no response from either one. Finally after issuing a Traffic Alert to ACR X; who acknowledged turning East to 090. It was a case of meaning one thing and saying another. Recommendation; should have put ZDC into a hold earlier than I did. Should have re-scanned my altitude assignments again; especially during high complex situations. Focusing more on all prospective situations. Make sure I say what I mean and mean what I say.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	953531
Time
Date	201106
Local Time Of Day	1801-2400
Place
Locale Reference	PCT.TRACON
State Reference	VA
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Approach
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Published Material / Policy

Pct controller described a loss of separation event resulting from issuing one altitude but thinking another; the reporter adding that ZDC should have been placed into holding much sooner.