FATIGUED CREW OF DC9 ALTDEV ON APCH.

Narrative

I WAS PF. WE WERE ISSUED CLRNC TO DSND AND MAINTAIN 9000 FT MSL. AFTER THIS CLRNC WAS RECEIVED; WE WERE ISSUED CLRNC TO TURN R 230 DEG HDG TO INTERCEPT LOC RWY 19R AT IAD. OUR POS AT THE TIME OF RECEIVING THIS HEADING CLRNC WAS SLIGHTLY R OF LOC (BECAUSE; AS I WAS TURNING TOWARD HEADING 230 DEGS AND DIALING IN LOC FREQ; I OBSERVED LOC COURSE DEV INDICATOR 1/3 SCALE L). THIS HEADING CONTINUED TO TAKE US FARTHER R OF COURSE. WHILE PERPLEXED AND CONFIRMING LOC FREQ TO BE CORRECTLY DIALED IN; I FAILED TO ADEQUATELY MONITOR MY ALT. AT THE TIME; APCH CTLR ALSO MADE A COMMENT STATING WE HAD FLOWN THROUGH LOC. I THEN RESPONDED ON THE RADIO; STATING OUR POS AT INITIAL RECEIPT OF 230 DEG HDG CLRNC. MY TALKING ON THE RADIO; AS PF; FURTHER CONTRIBUTED TO MY LACK OF AWARENESS OF MY ALT PROGRESSION FROM 9000 FT MSL TO 8500 FT MSL. APCH CTLR; NOTICING OUR ALT; ISSUED FURTHER CLRNC TO 8000 FT MSL. WE APOLOGIZED TO CTLR. SHE RESPONDED 'NO PROB.' FACTORS: 1) I WAS VERY TIRED; 2) I WAS ANGRY AT MY FLT ATTENDANT CREW; 3) I WAS QUERYING CTLR WHY SHE ISSUED 230 DEG HDG; WHEN ONLY FO SHOULD HAVE BEEN TALKING. I SHOULD HAVE BEEN 'FLYING THE PLANE;' AND 4) I WAS SIMPLY INVOLVED IN TOO MANY TASKS AT ONE TIME.