Narrative:

Northwest of bty VOR (beatty, nv) given clearance by ATC to cross fuzzy intersection at 16000 ft and 280 KTS. First officer read back instructions. He then went off #1 radio, using #2 radio to get las ATIS and communicate with company. Meanwhile, I was monitoring #1 radio using the speaker (first officer had switched to headset for communication). After setting 16000 ft in altitude alerter and checking the FMC for crossing restr at fuzzy, I noted that the restr had dropped out. Because 16000 ft was in the altitude window, the new cruise altitude in FMC was 16000 ft and the FMC would not accept a 16000 ft crossing restr. It took me a short period of time to figure out why the computer was not accepting the restr. At this point we were approaching FL280 so I leveled at FL280, input FL280 in FMC as cruise altitude, reinserted 16000 ft crossing restr which worked. I then reset 16000 ft in altitude window. At this time I put my headset on to hear center controller calling our flight. I responded, he issued instruction to descend to FL270 and cross fuzzy at 16000 ft. He then said he had made several calls to our flight. At this point I realized that the volume on my speaker was turned down. (I had been hearing the first officer's during the flight prior to his switching to headset.) I would have caught this situation sooner had I not been reprogramming the computer. If the STAR chart had reflected the crossing restr I would have programmed it in earlier in the flight and avoided the confusion. Also, first officer was having difficulty picking up las ATIS due to terrain and this significantly increased the time he was off center frequency. The A320's radios do not have squelch capability, which I think would aid in this situation.

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Original NASA ASRS Text

Title: ACR LOSES COM WITH ATC WHEN OPERATING WITHOUT HEADSET AND SPEAKERS ARE TURNED DOWN.

Narrative: NW OF BTY VOR (BEATTY, NV) GIVEN CLRNC BY ATC TO CROSS FUZZY INTXN AT 16000 FT AND 280 KTS. FO READ BACK INSTRUCTIONS. HE THEN WENT OFF #1 RADIO, USING #2 RADIO TO GET LAS ATIS AND COMMUNICATE WITH COMPANY. MEANWHILE, I WAS MONITORING #1 RADIO USING THE SPEAKER (FO HAD SWITCHED TO HEADSET FOR COM). AFTER SETTING 16000 FT IN ALT ALERTER AND CHKING THE FMC FOR XING RESTR AT FUZZY, I NOTED THAT THE RESTR HAD DROPPED OUT. BECAUSE 16000 FT WAS IN THE ALT WINDOW, THE NEW CRUISE ALT IN FMC WAS 16000 FT AND THE FMC WOULD NOT ACCEPT A 16000 FT XING RESTR. IT TOOK ME A SHORT PERIOD OF TIME TO FIGURE OUT WHY THE COMPUTER WAS NOT ACCEPTING THE RESTR. AT THIS POINT WE WERE APCHING FL280 SO I LEVELED AT FL280, INPUT FL280 IN FMC AS CRUISE ALT, REINSERTED 16000 FT XING RESTR WHICH WORKED. I THEN RESET 16000 FT IN ALT WINDOW. AT THIS TIME I PUT MY HEADSET ON TO HEAR CTR CTLR CALLING OUR FLT. I RESPONDED, HE ISSUED INSTRUCTION TO DSND TO FL270 AND CROSS FUZZY AT 16000 FT. HE THEN SAID HE HAD MADE SEVERAL CALLS TO OUR FLT. AT THIS POINT I REALIZED THAT THE VOLUME ON MY SPEAKER WAS TURNED DOWN. (I HAD BEEN HEARING THE FO'S DURING THE FLT PRIOR TO HIS SWITCHING TO HEADSET.) I WOULD HAVE CAUGHT THIS SIT SOONER HAD I NOT BEEN REPROGRAMMING THE COMPUTER. IF THE STAR CHART HAD REFLECTED THE XING RESTR I WOULD HAVE PROGRAMMED IT IN EARLIER IN THE FLT AND AVOIDED THE CONFUSION. ALSO, FO WAS HAVING DIFFICULTY PICKING UP LAS ATIS DUE TO TERRAIN AND THIS SIGNIFICANTLY INCREASED THE TIME HE WAS OFF CTR FREQ. THE A320'S RADIOS DO NOT HAVE SQUELCH CAPABILITY, WHICH I THINK WOULD AID IN THIS SIT.

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.