Narrative:

Approaching atl for landing (about 10 mins out) the captain discovered that his microphone was sticking, while transmitting on a company frequency. He returned to handling the ATC frequency, and used the hand-held microphone, as that seemed to work ok. We received what we both thought was a vector of 180 degrees from atl approach. When the captain acknowledged the call, I did not hear it through my headset, so I quickly answered our call sign and 1, 8, 0. (In my haste, I may not have said 'heading,' I can't remember.) as it turns out the captain must have inadvertently keyed his yoke microphone toggle, which caused a hot microphone on the ATC frequency. I think he had unplugged the transmit plug of his headset wrong, so we couldn't hear stuck microphone type of sounds. After a min or so on this heading, the captain and I both tried to call ATC a couple of times, but heard no response. The captain then jiggled his yoke switch, and we were able to hear atl approach again. The controller said he had not wanted us on a 180 degree heading, but realizing we had a stuck microphone, cleared out any potentially conflicting traffic. A little later he said we must have misunderstood a speed reduction to 180 KTS as a heading of 180 degrees. He vectored us back on downwind and we landed uneventfully. This was an unfortunate combination of circumstances. A misunderstood command from ATC, followed by what proved to be a stuck microphone, so we couldn't hear the controller try to call us (which I assume he did). This was a busy time of flight anyway, but I think we got things under control fairly quickly. About the only way to avoid it would have been to switch duties after realizing the captain had communication problems, which would have been a good idea. Supplemental information from acn 238233: if we are not sure of a clearance we question it. If we feel the clearance is correct, no reply from the controller is considered verification, which has become normal but improper procedure for a good, safe operation. Controllers need to verbally verify our readbacks regularly to at least let us know we are heard.

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Original NASA ASRS Text

Title: FLC MISINTERPS CLRNC AND THEN LOSES COM BEFORE THEY CAN CONFIRM IT WHICH RESULTS IN A HDG DEV.

Narrative: APCHING ATL FOR LNDG (ABOUT 10 MINS OUT) THE CAPT DISCOVERED THAT HIS MIKE WAS STICKING, WHILE XMITTING ON A COMPANY FREQ. HE RETURNED TO HANDLING THE ATC FREQ, AND USED THE HAND-HELD MIKE, AS THAT SEEMED TO WORK OK. WE RECEIVED WHAT WE BOTH THOUGHT WAS A VECTOR OF 180 DEGS FROM ATL APCH. WHEN THE CAPT ACKNOWLEDGED THE CALL, I DID NOT HEAR IT THROUGH MY HEADSET, SO I QUICKLY ANSWERED OUR CALL SIGN AND 1, 8, 0. (IN MY HASTE, I MAY NOT HAVE SAID 'HDG,' I CAN'T REMEMBER.) AS IT TURNS OUT THE CAPT MUST HAVE INADVERTENTLY KEYED HIS YOKE MIKE TOGGLE, WHICH CAUSED A HOT MIKE ON THE ATC FREQ. I THINK HE HAD UNPLUGGED THE XMIT PLUG OF HIS HEADSET WRONG, SO WE COULDN'T HEAR STUCK MIKE TYPE OF SOUNDS. AFTER A MIN OR SO ON THIS HDG, THE CAPT AND I BOTH TRIED TO CALL ATC A COUPLE OF TIMES, BUT HEARD NO RESPONSE. THE CAPT THEN JIGGLED HIS YOKE SWITCH, AND WE WERE ABLE TO HEAR ATL APCH AGAIN. THE CTLR SAID HE HAD NOT WANTED US ON A 180 DEG HDG, BUT REALIZING WE HAD A STUCK MIKE, CLRED OUT ANY POTENTIALLY CONFLICTING TFC. A LITTLE LATER HE SAID WE MUST HAVE MISUNDERSTOOD A SPD REDUCTION TO 180 KTS AS A HDG OF 180 DEGS. HE VECTORED US BACK ON DOWNWIND AND WE LANDED UNEVENTFULLY. THIS WAS AN UNFORTUNATE COMBINATION OF CIRCUMSTANCES. A MISUNDERSTOOD COMMAND FROM ATC, FOLLOWED BY WHAT PROVED TO BE A STUCK MIKE, SO WE COULDN'T HEAR THE CTLR TRY TO CALL US (WHICH I ASSUME HE DID). THIS WAS A BUSY TIME OF FLT ANYWAY, BUT I THINK WE GOT THINGS UNDER CTL FAIRLY QUICKLY. ABOUT THE ONLY WAY TO AVOID IT WOULD HAVE BEEN TO SWITCH DUTIES AFTER REALIZING THE CAPT HAD COM PROBS, WHICH WOULD HAVE BEEN A GOOD IDEA. SUPPLEMENTAL INFO FROM ACN 238233: IF WE ARE NOT SURE OF A CLRNC WE QUESTION IT. IF WE FEEL THE CLRNC IS CORRECT, NO REPLY FROM THE CTLR IS CONSIDERED VERIFICATION, WHICH HAS BECOME NORMAL BUT IMPROPER PROC FOR A GOOD, SAFE OP. CTLRS NEED TO VERBALLY VERIFY OUR READBACKS REGULARLY TO AT LEAST LET US KNOW WE ARE HEARD.

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.