A C182 PLT SWITCHED THE MAIN RADIO OFF TO ANSWER A PAX'S QUESTION AND FORGOT TO SWITCH IT ON IN A TIMELY MANNER.

Narrative

WHILE CONDUCTING A CAP CADET ORIENTATION FLT WITH A LEARNING IMPAIRED CADET; I WAS CLRED FOR VISUAL APCH TO RWY 33 AND TO RPT A 1 MI FINAL. AT 3 MI OUT; THE CADET BEGAN TO ASK SEVERAL QUESTIONS; BUT WAS DROWNED OUT BY TWR RADIO TFC. I SWITCHED THE RADIO TO COM #2 (OFF) INTENDING TO RETURN TO COM #1 AFTER ANSWERING THE QUESTIONS. AT 1 MI FINAL; I CALLED TWR WITHOUT RESPONSE AND CONTINUED UNTIL OVER THE NUMBERS WHERE I DISCOVERED MY ERROR; SWITCHED TO COM #1; AND ESTABLISHED CONTACT WITH THE TWR AS I BEGAN A GAR. I WAS CLRED FOR R DOWNWIND RWY 20 AND LANDED UNEVENTFULLY. TWR SAID THEY HAD TRIED TO CALL ME AND HAD GIVEN ME A GREEN LIGHT AS WELL; BUT I HAD BEEN SO PREOCCUPIED WITH ESTABLISHING RADIO CONTACT AND TROUBLESHOOTING THE RADIOS I FAILED TO SEE THE LIGHT GUN SIGNAL. FORTUNATELY NO TFC CONFLICTS OCCURRED. IN HINDSIGHT; I SHOULD NOT HAVE LET MY EXTRA CONCERN FOR AN IMPAIRED CADET OVERRIDE GOOD STERILE COCKPIT PROCS AND CAUSE ME TO BE DISTR FROM MY PRIMARY JOB; WHICH IS THE SAFE OP OF THE ACFT. I KNOW BETTER; BUT I FAILED TO FOLLOW MY TRAINING AND EXPERIENCE IN THIS INSTANCE.