FLC OF AN MD88 CLBED IN RESPONSE TO A TCASII RA. WHEN RPTING IT TO ATC; CTLR ADVISED THAT RPTRS HAD NOT BEEN AT THEIR ASSIGNED ALT.

Narrative

FLT WAS ON THE AIRWAY S OF FLM LEVEL AT FL250. CTR CLRED US TO FL280 AND CAPT READ BACK CLRNC. I CLBED ACFT TO FL280 WITH AUTOPLT ENGAGED AND WE LEVELED AT FL280. CAPT THEN HEARD CTR RESPOND TO ANOTHER ACFT AT OUR SAME FLT LEVEL. HE THEN POINTED OUT TFC ON OUR TCASII AT OUR 12 O'CLOCK POS; SAME ALT AND CLOSING. HE THEN QUERIED ATC TO THAT TFC. ATC RESPONDED BY SAYING THAT WE WERE ASSIGNED FL270. WHILE THE CAPT WAS RESPONDING TO THAT WE RECEIVED A TA FOLLOWED BY AN RA. THE CAPT IMMEDIATELY BEGAN A CLB PER THE RA AND INFORMED ATC. I THEN TOOK CTL OF THE ACFT AND LEVELED AT FL290; WHICH ATC HAD NOW CLRED US TO. THE CAPT INFORMED ATC THAT WE WERE AT FL290 AND THAT WE HAD ORIGINALLY BEEN CLRED TO FL280 AND HAD ACKNOWLEDGED THAT ALT TO ATC. ATC THEN INFORMED US THAT PER REGS HE MUST INFORM US THAT POSSIBLE ALTDEV HAD OCCURRED AND THEN HE TURNED US OVER TO THE NEXT SECTOR. CTLR ERROR CREATED THE PROB. THIS WAS SUBSEQUENTLY VERIFIED BY REVIEW OF THE TAPES; BUT TCASII AND ITS USE ALLOWED US AMPLE TIME TO ANALYZE AND REACT TO WHAT COULD HAVE BEEN A SERIOUS SIT. IT ALLOWED A SEPARATION OF PROBABLY 1000 FT AS OPPOSED TO A FEW HUNDRED OR POSSIBLY LESS.