AN ACR B737 FLC MADE SEVERAL ERRORS USING THE AUTOFLT SYS AND TRIGGER AN RA TO WHICH THEY PROPERLY REACT. AFTER ALL OF THIS THEY WERE ABLE TO COMPLETE THE APCH AND LNDG.

Narrative

I WAS FLYING THE LOC APCH TO RWY 27 AT SAN DIEGO (LINDBERG FIELD). APCH CTL HAD TURNED US BASE LEG AT 4000 FT (180 KTS) THEN GAVE US A HDG OF 240 DEGS MAINTAIN 3800 FT UNTIL ON APCH. CLRED FOR THE LOC APCH RWY 27. I REACHED DOWN AND SWITCHED THE AUTOTUNE TO MANUAL (UNAWARE THE OTHER PLT HAD JUST DONE THAT FOR ME) AND MISTAKENLY INCREASED THE AIRSPD TO 240 KIAS INSTEAD OF THE HEADING BUG. WE WERE CLRED BEHIND ANOTHER B737 WHICH WE HAD IN SIGHT. I IMMEDIATELY DISENGAGED THE AUTOPLT AND AUTOTHROTTLES BECAUSE THE ACFT WAS ACCELERATING AND NOT TURNING TO INTERCEPT FINAL. WHEN I REALIZED MY RADIO WAS NOT TUNED TO THE PROPER FREQ I SAW THAT WE WERE GOING THROUGH FINAL APCH. I MADE AN IMMEDIATE TURN. WE ENDED UP GOING SLIGHTLY THROUGH FINAL. I KEPT THE ACFT I WAS FOLLOWING IN SIGHT AND STARTED A SLOW DSCNT. WE RECEIVED THE RA AND FOLLOWED THE COMMANDS AND ADVISED ATC. WE IMMEDIATELY RE-ESTABLISHED ON THE LOC (AFTER CLR OF CONFLICT) AND THE REST OF THE APCH WAS NORMAL. THE FACTORS FROM MY END WERE THAT I ROTATED THE WRONG KNOB ON THE FMC PANEL (AIRSPD INSTEAD OF HEADING) AND WHEN I THOUGHT I WAS TUNING THE LOC I ACTUALLY PUT THE NAV RADIOS IN AUTOTUNE. EVERYTHING HAPPENED AT THE SAME TIME AND IT TOOK A FEW SECONDS TO ANALYZE WHAT WAS HAPPENING CAUSING ME TO DEVIATE THROUGH THE COURSE AND DSND LOWER THAN THE ASSIGNED 3800 FT.