Narrative:

I was working the ZHU (houston center) izd (woodville) sector. This sector provides high altitude (above FL240) sequencing for the houston terminal area traffic. At the time of the event; there were approximately 8 aircraft on frequency. 2 were overflts along with 3 on vectors for the sequence and 3 more established inbound for houston and descending. It was in this situation that the stuck microphone occurred on board air carrier X. First; I have to see if I can still communicate with the other aircraft on frequency. As it turned out I was able to continue 2-WAY communication with the other aircraft on frequency as we were able to cut through the open microphone on board air carrier X albeit with some difficulty. Second; I have to resolve any conflicts which may potentially occur. Third; I have to try and determine who has the stuck microphone. Notable situation #1 -- as I was attempting to find the culprit; 2 things happened which delayed the identing of the guilty aircraft: 1) when I broadcast to air carrier X asking him to increase his descent rate I got a readback from a different aircraft and mistakenly thought it was the crew of air carrier X due to all of the backgnd noise on frequency. 2) an air carrier Y overflt had left the frequency without my knowledge so as I attempted to make contact with this aircraft I received no reply. This led to my determination that air carrier Y was my stuck microphone. At this point; I have another aircraft try him on 121.5 to see if he's listening and the supervisor is about to call air carrier Y operations in an effort to get the crew to close their microphone. Shortly thereafter; the controller who had previously worked air carrier Y informed me that air carrier Y was not my stuck microphone as he had returned to the previous frequency to report the event. As a result I had to retry and find my culprit aircraft. Once all remaining aircraft were finally switched to other frequencys I was left with air carrier X and a stuck microphone. Notable situation #2 -- when air carrier X finally unstuck his microphone; I informed the crew of the situation which had lasted for quite a few mins. The crew was rather adamant about how unlikely that the stuck microphone could be attributable to them. The aircraft was then switched to the low altitude controller. The low altitude controller issued air carrier X his crossing restr which air carrier X read back and immediately the open microphone scenario repeated itself except it was now on the low altitude sector. Once again air carrier X had a stuck microphone. When the low altitude controller finally regained communications with air carrier X and informed them of their microphone issue; the crew then took measures to avoid another incident. Regarding notable situation #1; the crew of the air carrier Y aircraft no doubt took appropriate action trying to re-establish communications with ATC; however; in this scenario efforts to remedy the situation were delayed due to my false impression that the air carrier Y aircraft was my stuck microphone for the reasons previously noted. In notable situation #2; the crew of air carrier X's failure to heed my warnings resulted in another stuck microphone situation on yet another frequency. Although rare; stuck mikes do occur often enough to warrant attention; in my opinion. I would like to see some sort of warning device in the cockpit which would alert the flight deck crew of an open microphone (ie; a small light on the dash of the aircraft or perhaps circuitry within the transmitter which might give audible cues when 'dead air' is detected after a short period of time). As mentioned before; the crew of the air carrier Y flight certainly made a good choice by going back to their previous frequency and seeking guidance. However; in my estimation; their departure from my frequency could be viewed as having been made a little too hastily since I did have 2-WAY communication with all other aircraft on frequency and very likely might have had success communicating with air carrier Y as well. Maybe; had I not initially decided that air carrier Y was my culprit; I may have been able to go backwards and have found the real stuck microphone a little sooner than I actually did -- maybe. I supposed I'm looking for a little more patience from the flight crews in a scenario like mine; but it is difficult to argue against the decision to seek a clear frequency as other scenarios could have imminent situations which would require immediate control instructions from ATC.

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Original NASA ASRS Text

Title: ZHU CTLR DESCRIBED STUCK MIKE EVENT DETAILING POTENTIAL CONSEQUENCES OF THESE TYPES OF EVENTS.

Narrative: I WAS WORKING THE ZHU (HOUSTON CTR) IZD (WOODVILLE) SECTOR. THIS SECTOR PROVIDES HIGH ALT (ABOVE FL240) SEQUENCING FOR THE HOUSTON TERMINAL AREA TFC. AT THE TIME OF THE EVENT; THERE WERE APPROX 8 ACFT ON FREQ. 2 WERE OVERFLTS ALONG WITH 3 ON VECTORS FOR THE SEQUENCE AND 3 MORE ESTABLISHED INBOUND FOR HOUSTON AND DSNDING. IT WAS IN THIS SITUATION THAT THE STUCK MIKE OCCURRED ON BOARD ACR X. FIRST; I HAVE TO SEE IF I CAN STILL COMMUNICATE WITH THE OTHER ACFT ON FREQ. AS IT TURNED OUT I WAS ABLE TO CONTINUE 2-WAY COM WITH THE OTHER ACFT ON FREQ AS WE WERE ABLE TO CUT THROUGH THE OPEN MIKE ON BOARD ACR X ALBEIT WITH SOME DIFFICULTY. SECOND; I HAVE TO RESOLVE ANY CONFLICTS WHICH MAY POTENTIALLY OCCUR. THIRD; I HAVE TO TRY AND DETERMINE WHO HAS THE STUCK MIKE. NOTABLE SITUATION #1 -- AS I WAS ATTEMPTING TO FIND THE CULPRIT; 2 THINGS HAPPENED WHICH DELAYED THE IDENTING OF THE GUILTY ACFT: 1) WHEN I BROADCAST TO ACR X ASKING HIM TO INCREASE HIS DSCNT RATE I GOT A READBACK FROM A DIFFERENT ACFT AND MISTAKENLY THOUGHT IT WAS THE CREW OF ACR X DUE TO ALL OF THE BACKGND NOISE ON FREQ. 2) AN ACR Y OVERFLT HAD LEFT THE FREQ WITHOUT MY KNOWLEDGE SO AS I ATTEMPTED TO MAKE CONTACT WITH THIS ACFT I RECEIVED NO REPLY. THIS LED TO MY DETERMINATION THAT ACR Y WAS MY STUCK MIKE. AT THIS POINT; I HAVE ANOTHER ACFT TRY HIM ON 121.5 TO SEE IF HE'S LISTENING AND THE SUPVR IS ABOUT TO CALL ACR Y OPS IN AN EFFORT TO GET THE CREW TO CLOSE THEIR MIKE. SHORTLY THEREAFTER; THE CTLR WHO HAD PREVIOUSLY WORKED ACR Y INFORMED ME THAT ACR Y WAS NOT MY STUCK MIKE AS HE HAD RETURNED TO THE PREVIOUS FREQ TO RPT THE EVENT. AS A RESULT I HAD TO RETRY AND FIND MY CULPRIT ACFT. ONCE ALL REMAINING ACFT WERE FINALLY SWITCHED TO OTHER FREQS I WAS LEFT WITH ACR X AND A STUCK MIKE. NOTABLE SITUATION #2 -- WHEN ACR X FINALLY UNSTUCK HIS MIKE; I INFORMED THE CREW OF THE SITUATION WHICH HAD LASTED FOR QUITE A FEW MINS. THE CREW WAS RATHER ADAMANT ABOUT HOW UNLIKELY THAT THE STUCK MIKE COULD BE ATTRIBUTABLE TO THEM. THE ACFT WAS THEN SWITCHED TO THE LOW ALT CTLR. THE LOW ALT CTLR ISSUED ACR X HIS XING RESTR WHICH ACR X READ BACK AND IMMEDIATELY THE OPEN MIKE SCENARIO REPEATED ITSELF EXCEPT IT WAS NOW ON THE LOW ALT SECTOR. ONCE AGAIN ACR X HAD A STUCK MIKE. WHEN THE LOW ALT CTLR FINALLY REGAINED COMS WITH ACR X AND INFORMED THEM OF THEIR MIKE ISSUE; THE CREW THEN TOOK MEASURES TO AVOID ANOTHER INCIDENT. REGARDING NOTABLE SITUATION #1; THE CREW OF THE ACR Y ACFT NO DOUBT TOOK APPROPRIATE ACTION TRYING TO RE-ESTABLISH COMS WITH ATC; HOWEVER; IN THIS SCENARIO EFFORTS TO REMEDY THE SITUATION WERE DELAYED DUE TO MY FALSE IMPRESSION THAT THE ACR Y ACFT WAS MY STUCK MIKE FOR THE REASONS PREVIOUSLY NOTED. IN NOTABLE SITUATION #2; THE CREW OF ACR X'S FAILURE TO HEED MY WARNINGS RESULTED IN ANOTHER STUCK MIKE SITUATION ON YET ANOTHER FREQ. ALTHOUGH RARE; STUCK MIKES DO OCCUR OFTEN ENOUGH TO WARRANT ATTN; IN MY OPINION. I WOULD LIKE TO SEE SOME SORT OF WARNING DEVICE IN THE COCKPIT WHICH WOULD ALERT THE FLT DECK CREW OF AN OPEN MIKE (IE; A SMALL LIGHT ON THE DASH OF THE ACFT OR PERHAPS CIRCUITRY WITHIN THE XMITTER WHICH MIGHT GIVE AUDIBLE CUES WHEN 'DEAD AIR' IS DETECTED AFTER A SHORT PERIOD OF TIME). AS MENTIONED BEFORE; THE CREW OF THE ACR Y FLT CERTAINLY MADE A GOOD CHOICE BY GOING BACK TO THEIR PREVIOUS FREQ AND SEEKING GUIDANCE. HOWEVER; IN MY ESTIMATION; THEIR DEP FROM MY FREQ COULD BE VIEWED AS HAVING BEEN MADE A LITTLE TOO HASTILY SINCE I DID HAVE 2-WAY COM WITH ALL OTHER ACFT ON FREQ AND VERY LIKELY MIGHT HAVE HAD SUCCESS COMMUNICATING WITH ACR Y AS WELL. MAYBE; HAD I NOT INITIALLY DECIDED THAT ACR Y WAS MY CULPRIT; I MAY HAVE BEEN ABLE TO GO BACKWARDS AND HAVE FOUND THE REAL STUCK MIKE A LITTLE SOONER THAN I ACTUALLY DID -- MAYBE. I SUPPOSED I'M LOOKING FOR A LITTLE MORE PATIENCE FROM THE FLT CREWS IN A SCENARIO LIKE MINE; BUT IT IS DIFFICULT TO ARGUE AGAINST THE DECISION TO SEEK A CLR FREQ AS OTHER SCENARIOS COULD HAVE IMMINENT SITUATIONS WHICH WOULD REQUIRE IMMEDIATE CTL INSTRUCTIONS FROM ATC.

Data retrieved from NASA's ASRS site as of May 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.