Narrative:

From start to finish of flight including taxi out; ATC complained of a stuck microphone. It took us three to four frequency changes for us to realize that it was our aircraft. We investigated the possibility of it being us with stuck microphone every time a controller said something about it and received successful radio checks each time. We ended up figuring out it was the first officer's yoke switch and ended up disconnecting all his mics and going to alternate mode on the first officer's side and still had reports of hot microphone on our previous frequency that we had in radio number two; while we used radio number one. We advised ATC of our issue and landed uneventfully. When debriefing with maintenance control and his investigation into malfunction; it appears that a new yoke microphone switch (first officer's side) was installed incorrectly the night prior; which led to a hot microphone connection without any activation of the switch. Basically the aircraft microphone was hardwired hot from the time power was applied to it. While we trouble shot it every time; ATC issued a warning we did not think it was us until we realized the issue was following us through our frequencies. Chief pilot was contacted and debriefed accordingly; we also advised maintenance and dispatch to report the issue. [Recommend] re-evaluate maintenance control's evaluation procedures as related to communication equipment repair and operation's check. ATC in all phases of flight putting out that someone had a stuck microphone.

Google
 

Original NASA ASRS Text

Title: Pilot reports that from start to finish of flight including taxi out; ATC complained of a stuck MIC. A new MIC switch was installed incorrectly on the First Officer's yoke the night prior; which led to a hot MIC connection without any activation of the switch on their B737 aircraft.

Narrative: From start to finish of flight including taxi out; ATC complained of a stuck MIC. It took us three to four frequency changes for us to realize that it was our aircraft. We investigated the possibility of it being us with stuck MIC every time a Controller said something about it and received successful radio checks each time. We ended up figuring out it was the FO's yoke switch and ended up disconnecting all his MICs and going to alternate mode on the FO's side and still had reports of hot MIC on our previous frequency that we had in radio number two; while we used radio number one. We advised ATC of our issue and landed uneventfully. When debriefing with Maintenance Control and his investigation into malfunction; it appears that a new yoke MIC switch (FO's side) was installed incorrectly the night prior; which led to a hot MIC connection without any activation of the switch. Basically the aircraft MIC was hardwired hot from the time power was applied to it. While we trouble shot it every time; ATC issued a warning we did not think it was us until we realized the issue was following us through our frequencies. Chief Pilot was contacted and debriefed accordingly; we also advised Maintenance and Dispatch to report the issue. [Recommend] Re-evaluate Maintenance Control's evaluation procedures as related to communication equipment repair and operation's check. ATC in all phases of flight putting out that someone had a stuck MIC.

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.