Narrative:

Aircraft X; A320; departed phl; sbound routing over sby. Aircraft checked onto my frequency climbing to FL280. This was confirmed by analyzing ARTCC voice tape. Aircraft Y; CRJ1; was northbound; level at FL290; also routed over sby. Aircraft X was only cleared to FL280 because aircraft Y was conflicting traffic; opposite direction. Aircraft X pilot advised me that he was requesting FL300 if the 'rides' were smooth. I acknowledged his request and stated that we would work on getting him the requested altitude after sby; which is when aircraft X and aircraft Y would be clear of each other. While performing other duties in a busy; combined sector; an aircraft called requesting confirmation of assigned altitude. As the call sign was scrambled; I asked for a repeat. Aircraft X asked to confirm that he was cleared to FL300. At this point; aircraft X was showing a reported altitude of FL280. Aircraft Y was level at FL290; head-on and 5 mi or less from each other. I cleared aircraft X to maintain FL280 and turned aircraft to a 180 degree heading; a turn of approximately 40 degrees. I then cleared aircraft Y to turn left to a 330 degree heading; a turn of approximately 55 degrees. Aircraft Y replied that he was turning '30 degrees left' and was descending in response to a TCAS RA. A moment later; aircraft X replied they were responding to a TCAS RA. Once aircraft were clear of each other; I reclred both aircraft back onto their rtes and reassigned altitudes. Aircraft Y replied 'that was close' and aircraft X replied they were going to file an near midair collision report. ZDC quality assurance office analysis of the event showed that aircraft X was only cleared to FL280 and the pilot deviated from his assigned altitude; causing the event. Supplemental information from acn 735599: we were cruising at FL280 and got clearance to FL300. We got a TA followed by an RA and center asking us to turn left to 180 degrees. The other aircraft got a clearance to turn left to 270 degrees. He was at FL290. We followed RA to 'clear of conflict.' then climbed back up to FL280 and on course.

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Original NASA ASRS Text

Title: ZDC CTLR ISSUES CORRECTIVE TURNS WHEN A320 OVERSHOOTS ALT ASSIGNMENT BUT SEPARATION IS LOST WITH A CRJ.

Narrative: ACFT X; A320; DEPARTED PHL; SBOUND ROUTING OVER SBY. ACFT CHKED ONTO MY FREQ CLBING TO FL280. THIS WAS CONFIRMED BY ANALYZING ARTCC VOICE TAPE. ACFT Y; CRJ1; WAS NBOUND; LEVEL AT FL290; ALSO ROUTED OVER SBY. ACFT X WAS ONLY CLRED TO FL280 BECAUSE ACFT Y WAS CONFLICTING TFC; OPPOSITE DIRECTION. ACFT X PLT ADVISED ME THAT HE WAS REQUESTING FL300 IF THE 'RIDES' WERE SMOOTH. I ACKNOWLEDGED HIS REQUEST AND STATED THAT WE WOULD WORK ON GETTING HIM THE REQUESTED ALT AFTER SBY; WHICH IS WHEN ACFT X AND ACFT Y WOULD BE CLR OF EACH OTHER. WHILE PERFORMING OTHER DUTIES IN A BUSY; COMBINED SECTOR; AN ACFT CALLED REQUESTING CONFIRMATION OF ASSIGNED ALT. AS THE CALL SIGN WAS SCRAMBLED; I ASKED FOR A REPEAT. ACFT X ASKED TO CONFIRM THAT HE WAS CLRED TO FL300. AT THIS POINT; ACFT X WAS SHOWING A RPTED ALT OF FL280. ACFT Y WAS LEVEL AT FL290; HEAD-ON AND 5 MI OR LESS FROM EACH OTHER. I CLRED ACFT X TO MAINTAIN FL280 AND TURNED ACFT TO A 180 DEG HDG; A TURN OF APPROX 40 DEGS. I THEN CLRED ACFT Y TO TURN L TO A 330 DEG HDG; A TURN OF APPROX 55 DEGS. ACFT Y REPLIED THAT HE WAS TURNING '30 DEGS L' AND WAS DSNDING IN RESPONSE TO A TCAS RA. A MOMENT LATER; ACFT X REPLIED THEY WERE RESPONDING TO A TCAS RA. ONCE ACFT WERE CLR OF EACH OTHER; I RECLRED BOTH ACFT BACK ONTO THEIR RTES AND REASSIGNED ALTS. ACFT Y REPLIED 'THAT WAS CLOSE' AND ACFT X REPLIED THEY WERE GOING TO FILE AN NMAC RPT. ZDC QUALITY ASSURANCE OFFICE ANALYSIS OF THE EVENT SHOWED THAT ACFT X WAS ONLY CLRED TO FL280 AND THE PLT DEVIATED FROM HIS ASSIGNED ALT; CAUSING THE EVENT. SUPPLEMENTAL INFO FROM ACN 735599: WE WERE CRUISING AT FL280 AND GOT CLRNC TO FL300. WE GOT A TA FOLLOWED BY AN RA AND CTR ASKING US TO TURN L TO 180 DEGS. THE OTHER ACFT GOT A CLRNC TO TURN L TO 270 DEGS. HE WAS AT FL290. WE FOLLOWED RA TO 'CLR OF CONFLICT.' THEN CLBED BACK UP TO FL280 AND ON COURSE.

Data retrieved from NASA's ASRS site as of January 2009 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.