B767 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Workload
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Unstabilized Approach
Flight Crew Became Reoriented; Flight Crew Executed Go Around / Missed Approach
Human Factors
We were proceeding direct to JADOP at 5000 feet and had been cleared for the ILS 9 approach at CVG.  The Captain asked if I had identified the localizer.  I replied that I was listening for it; but had not yet heard it; and remarked that as we were getting close to the localizer; I should be able to hear it.  I informed Approach Control that we were not receiving the Runway 9 localizer.  Approach Control asked the Tower; and the Tower said that it was up and in the green.  We turned inbound on the final approach course based on FMS RNAV data and I was able to see the runway at that point.  We were descending on the final approach course and configuring for landing.  At this point; the exact sequence becomes very hazy because my task loading was fairly high - listening through the ambient noise (the packs in this aircraft are noisier than most; even in single pack operation) for the Captain's configuration commands and responding to ATC questions about our status.  It eventually reached a point where I had to tell Approach Control to standby; prioritizing the first item of 'aviate; navigate; communicate' over the third.  Approach Control called with a low altitude alert somewhere around 2;400 feet and the Captain called for a go-around.  We had visual contact with the runway throughout this event and were not in IMC at any time prior to the go-around.  After the go-around; the Captain found that the localizer frequency had been changed from 111.9 to 110.9.  I do not know how that could have happened; as I had not been doing anything in that area.  I had changed frequencies on the left comm radio a number of times during the arrival; but I don't remember ever reaching for or turning the wrong knob during that time.  I was able to identify the localizer; so we informed Approach Control that we could take vectors for the approach again.  While being vectored; the Captain had me set up the ILS 9 in the FMS again; and while doing that; I saw in the scratchpad a runway/localizer frequency mismatch message.  I did not see that; an 'FMC Message' EICAS message; or the FMC discrete light at any time before then. We completed the approach and landed normally.Reviewing the event afterward; I don't know why it didn't occur to me to check the localizer frequency on the ILS receiver.  It seems so obvious a thing to check; but I suppose there was a bias toward believing that it was set correctly since it had already been set up and briefed prior to top of descent.  That in combination with being at a point where there was a lot of intra-cockpit communication; aircraft configuration; and the flurry of non-routine ATC communications left me without a lot of brain cycles to do logical troubleshooting of what is a relatively uncommon occurrence.
B767 First Officer reported executing a go-around after TRACON issued a low altitude alert on approach to CVG. The localizer was later found to be mistuned.