NMAC AFTER ALT BUST.

Narrative

WHILE INBOUND TO MSP WE WERE DSNDING TO FL290 AS DIRECTED BY ZMP. AS THE PF; I OBSERVED THE ALT ALERT SIGNAL; AT WHICH TIME NOTICED OUR ACFT HAD DSNDED 300 FT BELOW OUR ASSIGNED FL290. WE WERE IN A GRADUAL DSCNT AT 1000 FPM. AT THIS TIME WE RECEIVED AN RA COMMAND FROM TCASII TO CLB; WHICH WE DID. WE ALSO NOTICED OUR INTRUDER ACFT VISUALLY AT AN APPROX 10 O'CLOCK POS AND BELOW US. AFTER THE CLB WAS INITIATED WE HEARD A 'CLR OF CONFLICT' FROM THE TCASII. ONCE THE RA WAS ANNOUNCED AND OUR ACFT BEGAN TO CLB WE DSNDED APPROX 100 FT. THE INTRUDER PASSED BELOW AND BEHIND US. AFTER LEVEL AT FL290; ZMP ASKED WHAT OUR ALT WAS. NO MENTION OF THE CONFLICT WAS HEARD BY THE OTHER ACFT. DURING OUR DSCNT TO FL290; OUR LEAD FLT ATTENDANT HAD COME INTO THE COCKPIT TO COUNT HER LIQUOR MONEY COLLECTED DURING THE TRIP. ALTHOUGH HER PRESENCE IN THE COCKPIT WAS NO EXCUSE FOR MISSING LEVELOFF AT FL290 IT WAS; HOWEVER; SOMEWHAT OF A DISTR. SUPPLEMENTAL INFO FROM ACN 292872: I CALLED 1000 FT TO LEVELOFF AND THE CAPT ACKNOWLEDGED. AT ABOUT THAT TIME WE RECEIVED A TA. THE TFC WAS ABOUT 2000 FT BELOW US AND IN OUR 10 O'CLOCK POS. AT THAT TIME BOTH THE CAPT AND I BEGAN OUR SEARCH FOR THE TFC. WE WERE STILL DSNDING TO FL290. ON TCASII IT WAS 1000 FT BELOW US 10 O'CLOCK POS AND LESS THAN 2 MI. AT THIS POINT I THOUGHT WE WERE LEVEL AT FL290 AND I ALSO BELIEVE THE CAPT THOUGHT WE WERE ALSO LEVEL. WE WERE STILL SEARCHING FOR THE TFC AND NOTICED THAT WE HAD LESS THAN 1000 FT APART VERTLY. I THOUGHT THAT THE INTRUDER WAS CLBING TOWARD US. NEXT THE ALT ALERTER WENT OFF AT FL287. THE CAPT ROLLED THE AUTOPLT VERT WHEEL BACK AND BEGAN CLBING; THEN ADVANCED THE THRUST LEVERS AND WE BEGAN TO CLB. I NOTICED ON THE TCASII THAT THE INTRUDER PASSED DIRECTLY BELOW US AT ABOUT 500 FT. DURING THE RECOVERY THE TCASII WENT BLANK. TCASII FAILED MOMENTARILY. THE LEAD FLT ATTENDANT WAS IN THE COCKPIT AT THE TIME; SHE WAS NOT TALKING. I BELIEVE WE BECAME PREOCCUPIED LOOKING FOR THE TFC. THE TCASII WORKED! ALTHOUGH WHILE ON THE APCH INTO MSP WE OBSERVED SEVERAL FALSE IMAGES AND WE WROTE UP THE TCASII UPON LNDG.