Narrative:

We were being vectored for 23R ILS. First officer was fling. We did approach check and verified that 23R localizer was idented. Then I was off radio for a minute to brief the passenger that we were about to land. I looked up and realized my first officer was flying through the localizer. For some reason he had changed the frequency I had put in to the frequency for the parallel runway 23L. I immediately recognized the situation, but he had already flown through the localizer 23R. He turned back to the left and intercepted the localizer. His explanation was, 'I thought the 23R localizer was 108.5, so I put it in.' never mind the fact that it's 111.7 and that it had already been tuned and idented! I learned to do the passenger briefings prior to the approach checklist, and my first officer hopefully learned not to try to memorize localizer frequencys.

Related reports:

Google
 

Original NASA ASRS Text

Title: COMMUTER FLT CREW FLIES THROUGH LOC COURSE. WRONG FREQ.

Narrative: WE WERE BEING VECTORED FOR 23R ILS. F/O WAS FLING. WE DID APCH CHK AND VERIFIED THAT 23R LOC WAS IDENTED. THEN I WAS OFF RADIO FOR A MINUTE TO BRIEF THE PAX THAT WE WERE ABOUT TO LAND. I LOOKED UP AND REALIZED MY F/O WAS FLYING THROUGH THE LOC. FOR SOME REASON HE HAD CHANGED THE FREQ I HAD PUT IN TO THE FREQ FOR THE PARALLEL RWY 23L. I IMMEDIATELY RECOGNIZED THE SITUATION, BUT HE HAD ALREADY FLOWN THROUGH THE LOC 23R. HE TURNED BACK TO THE LEFT AND INTERCEPTED THE LOC. HIS EXPLANATION WAS, 'I THOUGHT THE 23R LOC WAS 108.5, SO I PUT IT IN.' NEVER MIND THE FACT THAT IT'S 111.7 AND THAT IT HAD ALREADY BEEN TUNED AND IDENTED! I LEARNED TO DO THE PAX BRIEFINGS PRIOR TO THE APCH CHKLIST, AND MY F/O HOPEFULLY LEARNED NOT TO TRY TO MEMORIZE LOC FREQS.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.