A CHARTERED JET PIC DOES NOT FOLLOW HDG AND ALT ASSIGNMENTS AS ASSIGNED BY DEP CTL AT LAS; NV.

Narrative

DEPARTED LAS WITH 1 PAX; WX WAS LIGHT RAIN; FAIR VISIBILITY. PAX ARRIVED EARLY TO ARPT; MAKING FOR A SLIGHT RUSH IN DEP. CAPT WAS PF. ATC ISSUED A TURN FOR TFC IN THE CLB. SHORTLY AFTER; THEY ISSUED A NEW HDG TO REINTERCEPT THE SID; THEN ON COURSE. THE CAPT TURNED TO THE HDG AND ALMOST IMMEDIATELY BEGAN TURNING BACK TO THE SID COURSE; BEFORE I COULD REPROGRAM THE FMS FOR THE INTERCEPT. I ADVISED HIM OF THIS AND HIS RESPONSE WAS 'THAT'S WHAT THEY WANTED.' BEFORE I COULD QUESTION ATC THEY CALLED AND ADVISED US TO RETURN TO THE ASSIGNED HDG TO INTERCEPT. AS PNF; I BUGGED THE NEW HDG AND BEGAN REPROGRAMMING THE FMS TO ASSURE COURSE INTERCEPT. ATC ISSUED A FURTHER R TURN TO CORRECT FOR THE INITIAL ERROR. MOMENTS LATER; ATC QUESTIONED OUR ALT. I RESPONDED WITH OUR ASSIGNED ALT; WITHOUT FIRST CHKING THE ALTIMETER; BECAUSE I WAS STILL BUSY REPROGRAMMING THE FMS. ATC QUESTIONED THE ALT AGAIN SO I SWITCHED XPONDERS; THINKING IT WAS AN ENCODER PROB. AFTER ALL THIS (WHICH TOOK MAYBE 20 SECONDS TOTAL) I FINALLY LOOKED UP AT THE ALTIMETER AND REALIZED THE CAPT HAD FLOWN (CLBED) THROUGH THE ASSIGNED ALT BY AT LEAST 500 FT. HE HAD NEVER SAID ANYTHING TO ME ABOUT THE BUST; BUT INSTEAD LET ME 'COVER HIM' WITHOUT EVEN KNOWING IT. I WON'T BE DOING THAT AGAIN! I COULD HAVE PREVENTED MY EMBARRASSMENT BY LOOKING AT THE ALTIMETER BEFORE RESPONDING OR DOING ANYTHING ELSE. I BELIEVE THE CAPT DID NOT SAY ANYTHING BECAUSE HE HAD ALREADY MADE ONE ERROR AND DID NOT WANT TO ADMIT TO ANOTHER. THE AUTOMATION WAS NOT AT FAULT. I FAILED TO READ THE INSTS AND THE CAPT FAILED TO FOLLOW ATC INSTRUCTIONS. BOTH PLTS HAD RAW DATA DISPLAYED AND AVAILABLE; AS WELL AS THE FMS MAP MODE SHOWING. HAD THE CAPT (PF) PAID ATTN TO THESE; AS WELL AS THE ALT ALERTER; THE PROB WOULD NOT HAVE OCCURRED. IN THE FUTURE I WILL LOOK BEFORE ANSWERING AND PAY MORE ATTN TO THE PF (ESPECIALLY THIS ONE).