Narrative:

Flight experienced hot microphone on final approach; 12 mi from ZZZ1 VOR. Already had landing clearance; taxied in with no problem. Called maintenance; thought it was the communication box transmit switch. Mechanic told me to use the yoke transmit switch and ZZZ would check again. On the flight to ZZZ; air carrier X experienced hot microphone intermittently throughout the flight causing distraction to the flight crew and ATC. I had center and tower phone numbers and would have called using my cell if necessary. In ZZZ; maintenance said problem was the yoke switch and just not to touch the switch. He said that it would take a long time to get to the wiring to prevent the hot microphone (I had 8 more lndgs to do that day). The mechanic wanted me to just take the aircraft as is; and I was thinking that the chances that I would hit that switch again that day; due to human factors; was very good. I asked if there was a good possibility that the microphone would go hot again and the mechanic said possibly. I explained that it would be very irresponsible of me to knowingly take up an airplane with a stuck or hot microphone problem and possibly cause confusion for all of the users of the airspace; not to mention how angry the ATC controller would be at me. The mechanic decided to troubleshoot again. He took the #2 communication box out and put it in the #1 communication box side and then determined that the problem was in the #1 communication box after all; and not the yoke or the transmit button. Flight to ZZZ2 was canceled when it was determined that there was no other communication box to put in the #2 side. Flight to ZZZ1 was also canceled. When I showed up for flight to ZZZ2; I was again given aircraft X. The mechanic wrote up the communication discrepancy as a side tone problem and then cleared the write-up. I flew to ZZZ2 and at about 60 mi from ZZZ2 VOR; I lost my #2 DME. The aircraft had an MEL from the morning -- #1 DME was inoperative so I had no DME capability at all in the aircraft. I informed center of the problem coordination DME checks with him. Even though I know I'm not supposed to; I recycled the #2 DME circuit breaker. No changes occurred for around 30 seconds; then the led lights on the first officer side popped intermittently. I asked ATC for a DME check and the distances were 4 mi off. We kept up with the ATC DME checks. The #1 DME led lights did eventually come on and the DME started to check with ATC around 20 mi out. After switching to ZZZ2 tower; I began to have the hot microphone problem again. The tower controller confirmed that there was a hot microphone problem. The problem seemed to be the #2 communication side. In ZZZ2 I went to ramp and called the ZZZ radio shop to find out exactly what they did earlier. The technicians were no longer there. I called maintenance control and asked to talk to mr X who had dealt with the aircraft earlier. He assured me that the technicians took both communication boxes up and ran a number of tests; that some parameters were off; they were corrected and the boxes put back in the aircraft. I asked if the original #1 communication box had been put in the #2 side; and mr X informed me that it had. I informed mr X that I would fly the aircraft back to ZZZ; because I knew that it would be stuck in ZZZ2 if I did not; and that I would not take that aircraft up again. I also called chief pilot and informed him of what was going on and that my plan was to use the cell phone if it became necessary. The departure was delayed because a 25 inch piece of the passenger entry door seal fell off the frame. I then called for a mechanic and he fixed it; telling me that it was going to fall off again. He signed off the logbook and we took off for ZZZ. During flight; we experienced the hot microphone problem intermittently and then just consistently again on center and could not communicate. We switched to 121.5 to listen and center very annoyingly asked us to get off the frequency and contact ZZZ. The first officer informed ZZZ approach that we had a microphone problem and received clearance. We landed without additional incident.

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Original NASA ASRS Text

Title: A B737-200 CAPT RPTS FOR 2 DAYS AND 4 FLTS WITH NUMEROUS LNDGS AND 2 CANCELLATIONS THIS ACFT OPERATED WITH A HOT MIKE CAUSING INTERFERENCE WITH ATC COMS.

Narrative: FLT EXPERIENCED HOT MIKE ON FINAL APCH; 12 MI FROM ZZZ1 VOR. ALREADY HAD LNDG CLRNC; TAXIED IN WITH NO PROB. CALLED MAINT; THOUGHT IT WAS THE COM BOX XMIT SWITCH. MECH TOLD ME TO USE THE YOKE XMIT SWITCH AND ZZZ WOULD CHK AGAIN. ON THE FLT TO ZZZ; ACR X EXPERIENCED HOT MIKE INTERMITTENTLY THROUGHOUT THE FLT CAUSING DISTR TO THE FLT CREW AND ATC. I HAD CTR AND TWR PHONE NUMBERS AND WOULD HAVE CALLED USING MY CELL IF NECESSARY. IN ZZZ; MAINT SAID PROB WAS THE YOKE SWITCH AND JUST NOT TO TOUCH THE SWITCH. HE SAID THAT IT WOULD TAKE A LONG TIME TO GET TO THE WIRING TO PREVENT THE HOT MIKE (I HAD 8 MORE LNDGS TO DO THAT DAY). THE MECH WANTED ME TO JUST TAKE THE ACFT AS IS; AND I WAS THINKING THAT THE CHANCES THAT I WOULD HIT THAT SWITCH AGAIN THAT DAY; DUE TO HUMAN FACTORS; WAS VERY GOOD. I ASKED IF THERE WAS A GOOD POSSIBILITY THAT THE MIKE WOULD GO HOT AGAIN AND THE MECH SAID POSSIBLY. I EXPLAINED THAT IT WOULD BE VERY IRRESPONSIBLE OF ME TO KNOWINGLY TAKE UP AN AIRPLANE WITH A STUCK OR HOT MIKE PROB AND POSSIBLY CAUSE CONFUSION FOR ALL OF THE USERS OF THE AIRSPACE; NOT TO MENTION HOW ANGRY THE ATC CTLR WOULD BE AT ME. THE MECH DECIDED TO TROUBLESHOOT AGAIN. HE TOOK THE #2 COM BOX OUT AND PUT IT IN THE #1 COM BOX SIDE AND THEN DETERMINED THAT THE PROB WAS IN THE #1 COM BOX AFTER ALL; AND NOT THE YOKE OR THE XMIT BUTTON. FLT TO ZZZ2 WAS CANCELED WHEN IT WAS DETERMINED THAT THERE WAS NO OTHER COM BOX TO PUT IN THE #2 SIDE. FLT TO ZZZ1 WAS ALSO CANCELED. WHEN I SHOWED UP FOR FLT TO ZZZ2; I WAS AGAIN GIVEN ACFT X. THE MECH WROTE UP THE COM DISCREPANCY AS A SIDE TONE PROB AND THEN CLRED THE WRITE-UP. I FLEW TO ZZZ2 AND AT ABOUT 60 MI FROM ZZZ2 VOR; I LOST MY #2 DME. THE ACFT HAD AN MEL FROM THE MORNING -- #1 DME WAS INOP SO I HAD NO DME CAPABILITY AT ALL IN THE ACFT. I INFORMED CTR OF THE PROB COORD DME CHKS WITH HIM. EVEN THOUGH I KNOW I'M NOT SUPPOSED TO; I RECYCLED THE #2 DME CIRCUIT BREAKER. NO CHANGES OCCURRED FOR AROUND 30 SECONDS; THEN THE LED LIGHTS ON THE FO SIDE POPPED INTERMITTENTLY. I ASKED ATC FOR A DME CHK AND THE DISTANCES WERE 4 MI OFF. WE KEPT UP WITH THE ATC DME CHKS. THE #1 DME LED LIGHTS DID EVENTUALLY COME ON AND THE DME STARTED TO CHK WITH ATC AROUND 20 MI OUT. AFTER SWITCHING TO ZZZ2 TWR; I BEGAN TO HAVE THE HOT MIKE PROB AGAIN. THE TWR CTLR CONFIRMED THAT THERE WAS A HOT MIKE PROB. THE PROB SEEMED TO BE THE #2 COM SIDE. IN ZZZ2 I WENT TO RAMP AND CALLED THE ZZZ RADIO SHOP TO FIND OUT EXACTLY WHAT THEY DID EARLIER. THE TECHNICIANS WERE NO LONGER THERE. I CALLED MAINT CTL AND ASKED TO TALK TO MR X WHO HAD DEALT WITH THE ACFT EARLIER. HE ASSURED ME THAT THE TECHNICIANS TOOK BOTH COM BOXES UP AND RAN A NUMBER OF TESTS; THAT SOME PARAMETERS WERE OFF; THEY WERE CORRECTED AND THE BOXES PUT BACK IN THE ACFT. I ASKED IF THE ORIGINAL #1 COM BOX HAD BEEN PUT IN THE #2 SIDE; AND MR X INFORMED ME THAT IT HAD. I INFORMED MR X THAT I WOULD FLY THE ACFT BACK TO ZZZ; BECAUSE I KNEW THAT IT WOULD BE STUCK IN ZZZ2 IF I DID NOT; AND THAT I WOULD NOT TAKE THAT ACFT UP AGAIN. I ALSO CALLED CHIEF PLT AND INFORMED HIM OF WHAT WAS GOING ON AND THAT MY PLAN WAS TO USE THE CELL PHONE IF IT BECAME NECESSARY. THE DEP WAS DELAYED BECAUSE A 25 INCH PIECE OF THE PAX ENTRY DOOR SEAL FELL OFF THE FRAME. I THEN CALLED FOR A MECH AND HE FIXED IT; TELLING ME THAT IT WAS GOING TO FALL OFF AGAIN. HE SIGNED OFF THE LOGBOOK AND WE TOOK OFF FOR ZZZ. DURING FLT; WE EXPERIENCED THE HOT MIKE PROB INTERMITTENTLY AND THEN JUST CONSISTENTLY AGAIN ON CTR AND COULD NOT COMMUNICATE. WE SWITCHED TO 121.5 TO LISTEN AND CTR VERY ANNOYINGLY ASKED US TO GET OFF THE FREQ AND CONTACT ZZZ. THE FO INFORMED ZZZ APCH THAT WE HAD A MIKE PROB AND RECEIVED CLRNC. WE LANDED WITHOUT ADDITIONAL INCIDENT.

Data retrieved from NASA's ASRS site as of January 2009 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.