Narrative:

On climb out from cae, we were initially given FL230. We were then asked to maintain FL210. About 5 mins later we were told to climb to FL280 and that would be a final. I acknowledged all 3 to center and put each altitude in the altitude reminder. The copilot (PF) also put FL280 in the cabin pressurization, as it had been set for our originally filed altitude of FL310. As we passed through FL215 we were told by ZTL to descend and maintain FL210. We did so and I asked where our traffic was. The controller said we had a company jet at 12 O'clock and 3 mi, at FL220. I remarked that we had been cleared to FL280 and he acknowledged with a 'roger.' I told him I had the traffic in sight, and nothing more was said at that time. Approaching atl, I was told by ZTL of a possible altitude conflict and told to call them on the ground. No evasive action was required. This incident, in my opinion, was caused by the failure of the controller to amend our clearance to FL210 after giving the clearance to climb to FL280 when it became apparent there was a traffic conflict. If I was given such a clearance (both of us never heard any modification of clearance to FL280), it was not acknowledged and center made no further attempt to make sure we received it. Both of us are sure, however, no such clearance was given. Closer attention to detail by the controller and all involved is essential.

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Original NASA ASRS Text

Title: LOSS OF SEPARATION BETWEEN 2 ACR ACFT ON CLIMBOUT. OPERATIONAL ERROR INDICATED.

Narrative: ON CLBOUT FROM CAE, WE WERE INITIALLY GIVEN FL230. WE WERE THEN ASKED TO MAINTAIN FL210. ABOUT 5 MINS LATER WE WERE TOLD TO CLB TO FL280 AND THAT WOULD BE A FINAL. I ACKNOWLEDGED ALL 3 TO CENTER AND PUT EACH ALT IN THE ALT REMINDER. THE COPLT (PF) ALSO PUT FL280 IN THE CABIN PRESSURIZATION, AS IT HAD BEEN SET FOR OUR ORIGINALLY FILED ALT OF FL310. AS WE PASSED THROUGH FL215 WE WERE TOLD BY ZTL TO DSND AND MAINTAIN FL210. WE DID SO AND I ASKED WHERE OUR TFC WAS. THE CTLR SAID WE HAD A COMPANY JET AT 12 O'CLOCK AND 3 MI, AT FL220. I REMARKED THAT WE HAD BEEN CLRED TO FL280 AND HE ACKNOWLEDGED WITH A 'ROGER.' I TOLD HIM I HAD THE TFC IN SIGHT, AND NOTHING MORE WAS SAID AT THAT TIME. APCHING ATL, I WAS TOLD BY ZTL OF A POSSIBLE ALT CONFLICT AND TOLD TO CALL THEM ON THE GND. NO EVASIVE ACTION WAS REQUIRED. THIS INCIDENT, IN MY OPINION, WAS CAUSED BY THE FAILURE OF THE CTLR TO AMEND OUR CLRNC TO FL210 AFTER GIVING THE CLRNC TO CLB TO FL280 WHEN IT BECAME APPARENT THERE WAS A TFC CONFLICT. IF I WAS GIVEN SUCH A CLRNC (BOTH OF US NEVER HEARD ANY MODIFICATION OF CLRNC TO FL280), IT WAS NOT ACKNOWLEDGED AND CENTER MADE NO FURTHER ATTEMPT TO MAKE SURE WE RECEIVED IT. BOTH OF US ARE SURE, HOWEVER, NO SUCH CLRNC WAS GIVEN. CLOSER ATTN TO DETAIL BY THE CTLR AND ALL INVOLVED IS ESSENTIAL.

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.