Date: 201201
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: B717 (Formerly MD-95)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Tower ZZZ
Aircraft component: Air/Ground Communication
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Situational Awareness; Troubleshooting; Workload; Confusion; Communication Breakdown; Time Pressure
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Taxi
Result: Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Upon landing on Runway 27L; I turned off the runway and Tower instructed us to hold short of 27R. The First Officer answered. Tower couldn't hear us and instructed us again to hold short. The First Officer answered again and Tower still didn't hear us. Tower instructed again. First Officer went to radio 2 and Tower still couldn't hear us. Tower started sounding very anxious with our lack of response. At that time we heard the stuck mic side tone (beeping) in our head sets. We could hear Tower broadcasting that someone has a hot mic carrier only....Then we couldn't hear anything at all on radio 1 or 2. We knew it was us. I held short of 27R and tried to contact Tower on radio 3 and I couldn't hear anything on radio 3 neither could the First Officer. We could hear (intermittently) aircraft behind us that were trying to take another route to get across 27R. I was concerned that Tower might think that we couldn't hear them and thought they were concerned we might cross without us acknowledging clearance. So; I squawked 7600 on the transponder briefly; then squawked 7700 on the transponder while pushing the IDENT button to let them know we had radio failure/problems. Also; I flashed my landing light in hope they would understand that I was looking for a tower light signal to cross the runway. I waited and shortly there after I saw Tower flash a green light signal and I crossed 27R and headed to the gate. The First Officer briefly got in contact with ground and explained we had radio failure. Ground cleared us to the gate and they would contact ramp. Then the radios went out again. Upon reaching the gate and deplaning I tried to contact Maintenance on all 3 radios and couldn't. The First Officer tried as well. The radios would briefly intermittently operate. When we could hear Maintenance; they said it sounds like a hot mic; just a carrier; nothing else. At that time; the gate agent came down to the aircraft and said we needed to call Tower and gave me the number. I called Tower and they thanked me for the efforts I did to communicate with them via lights; transponder; etc. But; they said I squawked 7500 briefly; then 7700 and that caught their attention. They knew we had radio problems but they had to confirm that my aircraft was secure because I inadvertently squawked 7500. I confirmed the aircraft was secure and we had radio failure; not a hijacking. So; I am not sure what I did because I was truly saturated. I either went through 7500 on the way to 7600; or I just squawked 7500 then 7700. Nonetheless; Tower thanked me for the professionalism and they said that if the aircraft is secure then it was a non issue. Suggestions; simply; moral of the; take your time! I was truly saturated and was concerned at the tone of the Ground Controller because they couldn't get in contact with us and they wanted us to hold short. I should have been more concerned with my fingers and paid closer attention to the codes I was transmitting. But; we as pilots think we can multitask and I was doing that; flashing lights; holding short; trying different radios; squawking codes; IDENTing; and trying to diagnose the problem; and in the process I transmitted a wrong code.




Synopsis: A B717 communications system was blocked by an internal stuck microphone so the crew used their transponder and landing lights to alert ATC who then gave them a green light to cross the runway to the ramp.