Narrative:

While being vectored to intercept localizer for ILS 35R approach at den, approach controller issued instructions to change runway to 36, and then issued localizer frequency as 111.3--all with very short notice. As soon as it was put into navigation, dci showed us going through localizer, so I made appropriate inputs to re-intercept--and once intercepted got G/south indications and began following it down. Had descended from 8000' down to approximately 7200' when controller told us to 'climb immediately to 8000' and turn left heading 320 degrees--show you well below altitude and right of course.' I complied. He then said, '...gave you wrong localizer frequency; it is 111.9 for 36.' completed approach 36 den west/O further incident. Contributing factors: WX was low IFR, controller was very busy. We as a crew were quite busy trying to organize ourselves with last minute runway/approach change. On time to properly brief approach. Long afternoon of IFR flying. Also, localizer frequencys for 35R (109.3), 36 (111.9), and runway 35R apa approximately 13 south of den (111.3). I was following apa 35R localizer. Unknowingly, approach also following false G/south indications. Perceptions: the last minute runway/approach change didn't allow for proper approach brief. We failed to identify the localizer. I will do it or make certain captain does it in the future. Controller either looked at apa 35R frequency, or transposed some #'south between 35R and 36 frequencys at den to come up with 111.3. Why do they issue localizer frequencys anyway?

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Original NASA ASRS Text

Title: COMMUTER LTT DOES A SERIES OF GYRATIONS ON A VECTORED ILS APCH AS APCH CTLR CHANGES RWY ILS ASSIGNMENT. FLT CREW DIALS IN ILS FREQ AS GIVEN BY CTLR. WRONG ILS. WRONG ARPT.

Narrative: WHILE BEING VECTORED TO INTERCEPT LOC FOR ILS 35R APCH AT DEN, APCH CTLR ISSUED INSTRUCTIONS TO CHANGE RWY TO 36, AND THEN ISSUED LOC FREQ AS 111.3--ALL WITH VERY SHORT NOTICE. AS SOON AS IT WAS PUT INTO NAV, DCI SHOWED US GOING THROUGH LOC, SO I MADE APPROPRIATE INPUTS TO RE-INTERCEPT--AND ONCE INTERCEPTED GOT G/S INDICATIONS AND BEGAN FOLLOWING IT DOWN. HAD DSNDED FROM 8000' DOWN TO APPROX 7200' WHEN CTLR TOLD US TO 'CLB IMMEDIATELY TO 8000' AND TURN LEFT HDG 320 DEGS--SHOW YOU WELL BELOW ALT AND RIGHT OF COURSE.' I COMPLIED. HE THEN SAID, '...GAVE YOU WRONG LOC FREQ; IT IS 111.9 FOR 36.' COMPLETED APCH 36 DEN W/O FURTHER INCIDENT. CONTRIBUTING FACTORS: WX WAS LOW IFR, CTLR WAS VERY BUSY. WE AS A CREW WERE QUITE BUSY TRYING TO ORGANIZE OURSELVES WITH LAST MINUTE RWY/APCH CHANGE. ON TIME TO PROPERLY BRIEF APCH. LONG AFTERNOON OF IFR FLYING. ALSO, LOC FREQS FOR 35R (109.3), 36 (111.9), AND RWY 35R APA APPROX 13 S OF DEN (111.3). I WAS FOLLOWING APA 35R LOC. UNKNOWINGLY, APCH ALSO FOLLOWING FALSE G/S INDICATIONS. PERCEPTIONS: THE LAST MINUTE RWY/APCH CHANGE DIDN'T ALLOW FOR PROPER APCH BRIEF. WE FAILED TO IDENT THE LOC. I WILL DO IT OR MAKE CERTAIN CAPT DOES IT IN THE FUTURE. CTLR EITHER LOOKED AT APA 35R FREQ, OR TRANSPOSED SOME #'S BTWN 35R AND 36 FREQS AT DEN TO COME UP WITH 111.3. WHY DO THEY ISSUE LOC FREQS ANYWAY?

Data retrieved from NASA's ASRS site as of August 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.