COMMUTER LTT CLBS ABOVE ASSIGNED ALT.

Narrative

WE DEPARTED ROW ON AN IFR FLT PLAN TO ABQ. THE INITIAL CLRNC CLRED US TO 10000 FT AND TO EXPECT 20000 FT 5 OR 10 MINS AFTER DEP. BUT THE CAPT DECIDED TO REQUEST 12000 FT AS A FINAL BECAUSE OF THE WINDS. THE CTLR WAS ZAB. WHEN WE CHKED IN WITH ATC; WE REQUESTED 12000 FT AS A FINAL ALT. ATC TOLD US TO MAINTAIN 10000 FT FOR TFC. WE MADE VISUAL CONTACT WITH THE TFC AND ACKNOWLEDGED IT TO ATC. WITH THE TFC IN SIGHT AND NO FACTOR; I PROCEEDED TO FINISH OUR 10000 FT CHKLIST ITEMS AND TO DOCUMENT OUR OUT AND OFF TIMES. WHILE I WAS DOING THIS THE CAPT STARTED A CLB TO 12000 FT. THE ALT ALERT WENT OFF BECAUSE 10000 FT WAS SET IN THE ALT BOX. THE CAPT SAID TO DISREGARD THE ALERT BECAUSE ATC TOLD US TO CLB AND MAINTAIN 12000 FT AND THE CAPT THEN SET 12000 FT IN THE ALT BOX. I DID NOT HEAR THE ATC RESPONSE. ONCE AT 12000 FT; WE WERE IN RADAR CONTACT AND WE WERE ASKED TO VERIFY OUR ALT. WE REPLIED 12000 FT AND ATC SAID WE WERE ONLY CLRED TO 10000 FT. DURING THIS SHIFT; WHICH STARTED AT EARLY AM; NOW LATE PM; WE DID EXPERIENCE INTERMITTENT PROBS WITH OUR RADIOS; WHERE SOMETIMES ATC WOULD SOUND VERY SOFT AND HARD TO READ; AND OTHER TIMES WOULD BE LOUD AND CLR. CONTRIBUTING FACTORS; FAULTY EQUIP AND PLT FATIGUE.