Narrative:

On approach to runway 28L at san francisco international airport our navigation receivers (2) were tuned to the localizer frequency of 109.55. The aircraft had off flags on both the localizer and GS, although it was receiving an identify. The approach was completed in visual conditions. Upon investigation we found that although we had 40 channel control heads installed in our aircraft we only had 20 channel navigation receivers. We have been told that other operators have experienced the same problem.

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Original NASA ASRS Text

Title: CORP ACFT HAS RADIO CHANNEL PROBLEMS ON ILS APCH.

Narrative: ON APCH TO RWY 28L AT SAN FRANCISCO INTL ARPT OUR NAV RECEIVERS (2) WERE TUNED TO THE LOC FREQ OF 109.55. THE ACFT HAD OFF FLAGS ON BOTH THE LOC AND GS, ALTHOUGH IT WAS RECEIVING AN IDENT. THE APCH WAS COMPLETED IN VISUAL CONDITIONS. UPON INVESTIGATION WE FOUND THAT ALTHOUGH WE HAD 40 CHANNEL CTL HEADS INSTALLED IN OUR ACFT WE ONLY HAD 20 CHANNEL NAV RECEIVERS. WE HAVE BEEN TOLD THAT OTHER OPERATORS HAVE EXPERIENCED THE SAME PROBLEM.

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.