Narrative:

After acknowledging clearance to cross freal intersection at/above 5000 ft for the ILS approach runway 26R, the first officer's yoke switch stuck in transmit. We did not catch this problem, causing the approach frequency to become jammed by our stuck microphone. TRACON was forced to break off the approachs of some other aircraft. With simultaneous approachs in progress, and without communication ability, atl TRACON had to wait until we cleared the frequency by switching to tower before approachs could resume. Communication with tower was normal, including instructions to 'hold short of runway 26L at the west end.' it wasn't until we held there for a bit and I noticed I wasn't hearing any more communication from tower, such as aircraft being cleared for takeoff, etc, that we discovered the stuck microphone. The first officer had noted en route that his yoke switch would stick in transmit. Knowing this, we should have been more alert to the potential of causing a stuck microphone problem. I should have instructed the first officer to use his hand microphone. I use mine routinely en route. But in today's world of headsets/boom mikes, most pilots never use the hand microphone. Also, all I can figure is that we got busy looking for the airport in the haze, looking for the aircraft we were following, running landing checklist, etc, such that we simply failed to notice our stuck microphone. But this is no excuse. We should have noticed the approach frequency was unusually quiet. In fact, it was this unusual quietness I noticed while holding short of runway 26L after landing and awaiting crossing clearance that made me query the first officer about the possibility of his yoke switch being stuck. (By the way, even after discovering we'd been communication jamming ATC, the first officer still wanted to use his yoke switch/boom microphone. I had to direct him to stop and use his hand microphone for taxi into the gate.

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Original NASA ASRS Text

Title: AN MD88 ON APCH HAS THE FO'S YOKE SWITCH FAIL IN THE XMIT POS CAUSING TRACON TROUBLES. ON GND HOLDING SHORT MIKE STUCK AGAIN CAUSING TWR PROBS.

Narrative: AFTER ACKNOWLEDGING CLRNC TO CROSS FREAL INTXN AT/ABOVE 5000 FT FOR THE ILS APCH RWY 26R, THE FO'S YOKE SWITCH STUCK IN XMIT. WE DID NOT CATCH THIS PROB, CAUSING THE APCH FREQ TO BECOME JAMMED BY OUR STUCK MIKE. TRACON WAS FORCED TO BREAK OFF THE APCHS OF SOME OTHER ACFT. WITH SIMULTANEOUS APCHS IN PROGRESS, AND WITHOUT COM ABILITY, ATL TRACON HAD TO WAIT UNTIL WE CLRED THE FREQ BY SWITCHING TO TWR BEFORE APCHS COULD RESUME. COM WITH TWR WAS NORMAL, INCLUDING INSTRUCTIONS TO 'HOLD SHORT OF RWY 26L AT THE W END.' IT WASN'T UNTIL WE HELD THERE FOR A BIT AND I NOTICED I WASN'T HEARING ANY MORE COM FROM TWR, SUCH AS ACFT BEING CLRED FOR TKOF, ETC, THAT WE DISCOVERED THE STUCK MIKE. THE FO HAD NOTED ENRTE THAT HIS YOKE SWITCH WOULD STICK IN XMIT. KNOWING THIS, WE SHOULD HAVE BEEN MORE ALERT TO THE POTENTIAL OF CAUSING A STUCK MIKE PROB. I SHOULD HAVE INSTRUCTED THE FO TO USE HIS HAND MIKE. I USE MINE ROUTINELY ENRTE. BUT IN TODAY'S WORLD OF HEADSETS/BOOM MIKES, MOST PLTS NEVER USE THE HAND MIKE. ALSO, ALL I CAN FIGURE IS THAT WE GOT BUSY LOOKING FOR THE ARPT IN THE HAZE, LOOKING FOR THE ACFT WE WERE FOLLOWING, RUNNING LNDG CHKLIST, ETC, SUCH THAT WE SIMPLY FAILED TO NOTICE OUR STUCK MIKE. BUT THIS IS NO EXCUSE. WE SHOULD HAVE NOTICED THE APCH FREQ WAS UNUSUALLY QUIET. IN FACT, IT WAS THIS UNUSUAL QUIETNESS I NOTICED WHILE HOLDING SHORT OF RWY 26L AFTER LNDG AND AWAITING XING CLRNC THAT MADE ME QUERY THE FO ABOUT THE POSSIBILITY OF HIS YOKE SWITCH BEING STUCK. (BY THE WAY, EVEN AFTER DISCOVERING WE'D BEEN COM JAMMING ATC, THE FO STILL WANTED TO USE HIS YOKE SWITCH/BOOM MIKE. I HAD TO DIRECT HIM TO STOP AND USE HIS HAND MIKE FOR TAXI INTO THE GATE.

Data retrieved from NASA's ASRS site as of July 2007 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.