Narrative:

Climbing northeast out of atl, I believe we were cleared to an intermediate altitude of FL230. The first officer obviously thought we were cleared to FL230 as he had set 230 in the mode control panel (I was flying). As we climbed through 20300', the controller asked our altitude and told us we were assigned FL190 due to traffic, and to turn right immediately to a heading of 170 degrees. As I initiated the turn I also took action to return the airplane to FL190. I then saw our traffic (small aircraft Y) pass from right to left in my side window. I estimate we had been as high as 20500', were now descending into the traffic. Apparently if we had been cleared to a FL190 hold down altitude for traffic, I missed hearing the clearance. If the first officer had heard and responded (another flight could have responded to our flight), he missed resetting the mode control panel altitude selector. We also had an auxiliary crew member on the jumpseat who thought we were cleared to FL230. Obviously someone made a mistake! Compounding that mistake, my reaction was to head for the altitude the controller said we were clrd to (FL190), when in fact we were already 500' above the traffic. Unless the lag in altitude reporting creates substantial doubt to the controller, perhaps it would be helpful in his rapid decision making for the evasive clearance to include a new altitude assignment. Callback conversation with reporter revealed the following: reporter (air carrier PIC) has had no further word and no request for statement from FAA. Could add no details, but says that if controller meant to restrict their climb to FL190, they did not get that restriction and did not acknowledge for it. In retrospect he says he should not have started back down without asking controller if that is what he wanted. Supplemental information from acn 94740: next the controller called out traffic to us at 2:30 position at FL200. I acknowledged the traffic. We continued our climb. We were approximately 20500' and climbing when the controller in a hurried voice asked us if we were still climbing. I acknowledged affirmative. He said we were only cleared to FL190 and to turn immediately to a heading of 170 degrees.

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Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN ACR AND SMALL TURBOPROP ACFT AT FL200.

Narrative: CLBING NE OUT OF ATL, I BELIEVE WE WERE CLRED TO AN INTERMEDIATE ALT OF FL230. THE F/O OBVIOUSLY THOUGHT WE WERE CLRED TO FL230 AS HE HAD SET 230 IN THE MODE CONTROL PANEL (I WAS FLYING). AS WE CLBED THROUGH 20300', THE CTLR ASKED OUR ALT AND TOLD US WE WERE ASSIGNED FL190 DUE TO TFC, AND TO TURN RIGHT IMMEDIATELY TO A HDG OF 170 DEGS. AS I INITIATED THE TURN I ALSO TOOK ACTION TO RETURN THE AIRPLANE TO FL190. I THEN SAW OUR TFC (SMA Y) PASS FROM RIGHT TO LEFT IN MY SIDE WINDOW. I ESTIMATE WE HAD BEEN AS HIGH AS 20500', WERE NOW DSNDING INTO THE TFC. APPARENTLY IF WE HAD BEEN CLRED TO A FL190 HOLD DOWN ALT FOR TFC, I MISSED HEARING THE CLRNC. IF THE F/O HAD HEARD AND RESPONDED (ANOTHER FLT COULD HAVE RESPONDED TO OUR FLT), HE MISSED RESETTING THE MODE CONTROL PANEL ALT SELECTOR. WE ALSO HAD AN AUX CREW MEMBER ON THE JUMPSEAT WHO THOUGHT WE WERE CLRED TO FL230. OBVIOUSLY SOMEONE MADE A MISTAKE! COMPOUNDING THAT MISTAKE, MY REACTION WAS TO HEAD FOR THE ALT THE CTLR SAID WE WERE CLRD TO (FL190), WHEN IN FACT WE WERE ALREADY 500' ABOVE THE TFC. UNLESS THE LAG IN ALT RPTING CREATES SUBSTANTIAL DOUBT TO THE CTLR, PERHAPS IT WOULD BE HELPFUL IN HIS RAPID DECISION MAKING FOR THE EVASIVE CLRNC TO INCLUDE A NEW ALT ASSIGNMENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR (ACR PIC) HAS HAD NO FURTHER WORD AND NO REQUEST FOR STATEMENT FROM FAA. COULD ADD NO DETAILS, BUT SAYS THAT IF CTLR MEANT TO RESTRICT THEIR CLB TO FL190, THEY DID NOT GET THAT RESTRICTION AND DID NOT ACKNOWLEDGE FOR IT. IN RETROSPECT HE SAYS HE SHOULD NOT HAVE STARTED BACK DOWN WITHOUT ASKING CTLR IF THAT IS WHAT HE WANTED. SUPPLEMENTAL INFO FROM ACN 94740: NEXT THE CTLR CALLED OUT TFC TO US AT 2:30 POS AT FL200. I ACKNOWLEDGED THE TFC. WE CONTINUED OUR CLB. WE WERE APPROX 20500' AND CLBING WHEN THE CTLR IN A HURRIED VOICE ASKED US IF WE WERE STILL CLBING. I ACKNOWLEDGED AFFIRMATIVE. HE SAID WE WERE ONLY CLRED TO FL190 AND TO TURN IMMEDIATELY TO A HDG OF 170 DEGS.

Data retrieved from NASA's ASRS site as of August 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.