Date: 201606
Local time of day: 0601-1200
Location: ATL.Airport, GA
Flight conditions: VMC
Light: Daylight
Aircraft: Regional Jet 200 ER/LR (CRJ200)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B ATL
ATC / advisory: TRACON A80
Aircraft component: VHF
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion; Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: ATL was running an east operation and we were on approach for RWY 10. Were given vectors to turn north for the base leg and 3;000 ft. I had spotted the preceding aircraft; as well as the aircraft on approach for RWY 9R. Approach called us and issued a right turn to a heading of 070. I sensed everything went quiet because usually there is a bit more with that clearance; so I looked at radio and realized that Comm 1 was transmitting. We had a stuck microphone; yet as I scanned all the switches; none were in the X/T position. The FO and I both made the realization almost at the same time and each began checking our switches more thoroughly. The FO was the PF; and as we were converging with traffic from the adjacent runway coupled with a small delay caused by our becoming aware of the malfunction; he elected to disengage the autopilot to expedite the turn back towards our localizer. Additionally; because we had strayed and it appeared the adjacent aircraft had started a descent based on our TCAS he started a shallow descent as well. Once we established a heading back towards our approach course and were no longer in unsafe proximity of the 9R approach course; we leveled off. To make matters worse during this situation we didn't realize for a few moments that he and I couldn't hear one another over the crew intercom; and the FO is hearing impaired. We were both talking thinking the other person could hear; and at one point he asked me to take the controls so he could investigate his headphone jacks but I didn't hear him. Nothing came of that because he was only a moment in doing so; but under a different set of circumstances there could have been very different results. I didn't think there was a procedure in the QRH for our situation and felt that what little time I had to correct this problem without it escalating into an even bigger problem was best spent trying to [troubleshoot] a couple of things I knew of from basic system knowledge. I isolated the Comms by selecting EMERG on both RTUs and it solved the problem. Although the FO could not hear ATC or me; I was able reestablish communication with the approach controller and obtain proper clearances. As we crossed the outer marker; ATC issued a low altitude alert as a result of the descent maneuver we performed earlier. We had leveled off at 2;200ft and ATC advised us that the minimum altitude at the outer marker was 2;700ft. We established the aircraft on the glideslope and continued to a normal landing. The FO's Comms came back somewhere along the approach but went back out during taxi in. We reported to ground control that we were having problems with the radios and we were extra vigilant during taxi in.The biggest threat was losing communication with ATC at a very critical phase of the approach; in very congested and busy airspace. While you must follow ATC clearances; when put in our situation; I felt it more imperative to safeguard our aircraft and go back to 'see and avoid' for the time period we were out of communication with ATC. Secondly; because the nature of this malfunction didn't allow a determination of the full scope of debilitation immediately; it became a huge distraction when coupled with the tight constraints of the operating environment. The idea of flying in such a busy and complex airspace without imperiling one's own aircraft as well as others caused extreme pressure to correct the issue.I did feel a moment of uncertainty as it pertains to lost comm situations. I know the airspace and the typical flow of the traffic pattern in ATL very well; and since it was a clear day I felt it the proper course of action to just land while squawking 7600. There is not much; if any; guidance for lost communication situations in company manuals. I have since been reviewing what the proper course of action is in a busy; complex airspace but I find that most of the rhetoric is generic and not practical. While it is not a common event; I would be very interestedin what a discussion with ATL ATC about what they would like aircraft to do in lost comm situations would reveal.




Synopsis: CRJ-200 Captain reported a loss of communication with his First Officer and ATC while on approach to ATL.