Narrative:

I was captain on flight on mar/93 from mco-phl. At about 42 mi south of sie VOR, we were cleared to descend from FL280(?) to cross 25 mi south of sie VOR at 15000. This, of course, regained a very high rate of descent. We complied with the clearance. At 25 mi south of sie VOR, we were changed to frequency 127.7. When we checked in, the controller cleared us to descend to 13000 ft. I repeated the clearance and the first officer who was flying the aircraft started down. The controller then told us to maintain 15000 ft. I told him we were already at 14300 ft. The controller then told another aircraft to increase his rate of descent. He then told my flight to fly an easterly heading. I repeated the heading clearance and told him we were at 14000 ft (the altitude I had told the first officer to maintain until I understood for sure what the controller wanted). We were cleared to 15000 ft which we complied with. I then asked the controller if there had been a conflict. He said that there had been, that he had mistakenly cleared us to 13000 ft and tried to cancel the clearance but we had not heard it. I can only suggest that when there is a traffic conflict, the controller should use language such as: XXX, climb or descend immediately, so there can be no doubt as to what is wanted.

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Original NASA ASRS Text

Title: POTENTIAL CONFLICT LTSS.

Narrative: I WAS CAPT ON FLT ON MAR/93 FROM MCO-PHL. AT ABOUT 42 MI S OF SIE VOR, WE WERE CLRED TO DSND FROM FL280(?) TO CROSS 25 MI S OF SIE VOR AT 15000. THIS, OF COURSE, REGAINED A VERY HIGH RATE OF DSCNT. WE COMPLIED WITH THE CLRNC. AT 25 MI S OF SIE VOR, WE WERE CHANGED TO FREQ 127.7. WHEN WE CHKED IN, THE CTLR CLRED US TO DSND TO 13000 FT. I REPEATED THE CLRNC AND THE FO WHO WAS FLYING THE ACFT STARTED DOWN. THE CTLR THEN TOLD US TO MAINTAIN 15000 FT. I TOLD HIM WE WERE ALREADY AT 14300 FT. THE CTLR THEN TOLD ANOTHER ACFT TO INCREASE HIS RATE OF DSCNT. HE THEN TOLD MY FLT TO FLY AN EASTERLY HDG. I REPEATED THE HDG CLRNC AND TOLD HIM WE WERE AT 14000 FT (THE ALT I HAD TOLD THE FO TO MAINTAIN UNTIL I UNDERSTOOD FOR SURE WHAT THE CTLR WANTED). WE WERE CLRED TO 15000 FT WHICH WE COMPLIED WITH. I THEN ASKED THE CTLR IF THERE HAD BEEN A CONFLICT. HE SAID THAT THERE HAD BEEN, THAT HE HAD MISTAKENLY CLRED US TO 13000 FT AND TRIED TO CANCEL THE CLRNC BUT WE HAD NOT HEARD IT. I CAN ONLY SUGGEST THAT WHEN THERE IS A TFC CONFLICT, THE CTLR SHOULD USE LANGUAGE SUCH AS: XXX, CLB OR DSND IMMEDIATELY, SO THERE CAN BE NO DOUBT AS TO WHAT IS WANTED.

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.