Narrative:

Scheduled passenger flight cvg-mem. Departed 1 hour late due to mechanical problem. Crew members had been on duty 10 hours at time of incident. Shortly after takeoff, the captain complained about a loud noise in his headset, which was not noticed in first officer's headset. It was an obvious distraction to him during the climb out to FL310, as I noted he did not notice that the radar had malfunctioned, giving an antenna right/T fault indication. After level-off, the radar was turned off and subsequently reset to clear the malfunction. We discussed possible causes and solutions, and decided that it was caused by audio bleed-over from the ACARS datalink. We could not eliminate it from the captain's intercom, so he decided to turn his intercom and overhead speaker off and I would turn my speaker vol up. This seemed a reasonable solution, as we were both fatigued and annoyed with the constant stream of gremlins. We started the STAR middy 7 arrival into mem and were monitoring ZME on 133.05. Unknown to us, ZME called to switch us to 124.26, and handoff to another memphis sector. We still don't know whether a passenger announcement muted my speaker, some other malfunction caused a loss of vol on my intercom, or I inadvertently lowered my vol control. My vol increased when the captain selected his VHF again to check if the noise had disappeared. We were startled by ZME directing us to 'expedite descent to FL280' and 'where have you been?' no traffic was called out to us and center did not mention any conflict. He handed us off to 124.27. The incident highlighted to me the necessity of ensuring someone is always monitoring ATC, even with abnormal situations. Also, an absence of radio conversations should be an indication of possible receiver problems.

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Original NASA ASRS Text

Title: ACR MLG MISSED FREQ CHANGE AND HANDOFF TO NEW ARTCC SECTOR..

Narrative: SCHEDULED PAX FLT CVG-MEM. DEPARTED 1 HR LATE DUE TO MECHANICAL PROB. CREW MEMBERS HAD BEEN ON DUTY 10 HRS AT TIME OF INCIDENT. SHORTLY AFTER TKOF, THE CAPT COMPLAINED ABOUT A LOUD NOISE IN HIS HEADSET, WHICH WAS NOT NOTICED IN F/O'S HEADSET. IT WAS AN OBVIOUS DISTR TO HIM DURING THE CLBOUT TO FL310, AS I NOTED HE DID NOT NOTICE THAT THE RADAR HAD MALFUNCTIONED, GIVING AN ANTENNA R/T FAULT INDICATION. AFTER LEVEL-OFF, THE RADAR WAS TURNED OFF AND SUBSEQUENTLY RESET TO CLR THE MALFUNCTION. WE DISCUSSED POSSIBLE CAUSES AND SOLUTIONS, AND DECIDED THAT IT WAS CAUSED BY AUDIO BLEED-OVER FROM THE ACARS DATALINK. WE COULD NOT ELIMINATE IT FROM THE CAPT'S INTERCOM, SO HE DECIDED TO TURN HIS INTERCOM AND OVERHEAD SPEAKER OFF AND I WOULD TURN MY SPEAKER VOL UP. THIS SEEMED A REASONABLE SOLUTION, AS WE WERE BOTH FATIGUED AND ANNOYED WITH THE CONSTANT STREAM OF GREMLINS. WE STARTED THE STAR MIDDY 7 ARR INTO MEM AND WERE MONITORING ZME ON 133.05. UNKNOWN TO US, ZME CALLED TO SWITCH US TO 124.26, AND HDOF TO ANOTHER MEMPHIS SECTOR. WE STILL DON'T KNOW WHETHER A PAX ANNOUNCEMENT MUTED MY SPEAKER, SOME OTHER MALFUNCTION CAUSED A LOSS OF VOL ON MY INTERCOM, OR I INADVERTENTLY LOWERED MY VOL CTL. MY VOL INCREASED WHEN THE CAPT SELECTED HIS VHF AGAIN TO CHK IF THE NOISE HAD DISAPPEARED. WE WERE STARTLED BY ZME DIRECTING US TO 'EXPEDITE DSNT TO FL280' AND 'WHERE HAVE YOU BEEN?' NO TFC WAS CALLED OUT TO US AND CENTER DID NOT MENTION ANY CONFLICT. HE HANDED US OFF TO 124.27. THE INCIDENT HIGHLIGHTED TO ME THE NECESSITY OF ENSURING SOMEONE IS ALWAYS MONITORING ATC, EVEN WITH ABNORMAL SITUATIONS. ALSO, AN ABSENCE OF RADIO CONVERSATIONS SHOULD BE AN INDICATION OF POSSIBLE RECEIVER PROBS.

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.