Narrative:

We were in IMC conditions on a heading to intercept the localizer for the ILS 27R into ord. During this time; the first officer noticed that the number 1 radio tuning unit was not displaying normally. The rtu was only displaying the active frequency and not showing the standby frequency or the active and standby navigation frequencies. We had already deferred rtu number two prior to departure; leaving us the backup tuning unit as our primary means of backup communication. As we approached the localizer; we still had not received a final clearance from ATC. Positive course guidance was received; in which we interpreted that we were going to overshoot the localizer. As we flew past the course; I decided to make a turn back toward the localizer and instructed my first officer to change our squawk code to 7600. I chose to turn the aircraft back without a clearance due to the possibility of flying in close proximity of other traffic on intersecting runways. I also chose to continue flying the aircraft on the approach and delegated my first officer the task of troubleshooting the issue. She switched to the approach frequency on the chart on the back up tuning unit; and we were able to confirm a landing clearance from ATC to land on [runway] 27R. The failure of the rtu 2 had a significant effect on our ability to properly communicate with air traffic control. Rtu 1 not showing all of the frequencies contributed to this event as well.I personally would like to practice different scenarios of communication failures to be able to better handle the situation in a timely fashion. Due to the timing of this event in a critical phase of flight; I still should have given better instructions to my first officer on what actions we could have taken to better handle the situation. I commend her for ability to quickly solve the issue while I maintained positive aircraft control which was primary.

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Original NASA ASRS Text

Title: CRJ-700 Captain reported communication difficulties related to deferred radio tuning units resulted in a track deviation.

Narrative: We were in IMC conditions on a heading to intercept the localizer for the ILS 27R into ORD. During this time; the First Officer noticed that the number 1 Radio Tuning Unit was not displaying normally. The RTU was only displaying the active frequency and not showing the standby frequency or the active and standby navigation frequencies. We had already deferred RTU number two prior to departure; leaving us the Backup Tuning Unit as our primary means of backup communication. As we approached the localizer; we still had not received a final clearance from ATC. Positive course guidance was received; in which we interpreted that we were going to overshoot the localizer. As we flew past the course; I decided to make a turn back toward the localizer and instructed my First Officer to change our squawk code to 7600. I chose to turn the aircraft back without a clearance due to the possibility of flying in close proximity of other traffic on intersecting runways. I also chose to continue flying the aircraft on the approach and delegated my First Officer the task of troubleshooting the issue. She switched to the approach frequency on the chart on the back up tuning unit; and we were able to confirm a landing clearance from ATC to land on [Runway] 27R. The failure of the RTU 2 had a significant effect on our ability to properly communicate with Air Traffic Control. RTU 1 not showing all of the frequencies contributed to this event as well.I personally would like to practice different scenarios of communication failures to be able to better handle the situation in a timely fashion. Due to the timing of this event in a critical phase of flight; I still should have given better instructions to my First Officer on what actions we could have taken to better handle the situation. I commend her for ability to quickly solve the issue while I maintained positive aircraft control which was primary.

Data retrieved from NASA's ASRS site 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.