Narrative:

On flight en route to rpmm from rjaa, airway A590 at AM20 Z I (first officer) called tokyo control to make position report at guleg and received no reply. Approximately 15 seconds later center answered and said we had an open microphone for the past 15 mins. During that period I had been monitoring frequency 121.5 and 128.95 and heard nothing to alert us to this problem. If it was in fact my microphone that was open I probably would not have known as it sits normally on the throttle quadrant in an area that prevents accidental activation.

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Original NASA ASRS Text

Title: ACR WDB FLC HAD PROBLEM WITH RADIO FREQ MONITORING GUARDED DUE TO STUCK MIKE.

Narrative: ON FLT ENRTE TO RPMM FROM RJAA, AIRWAY A590 AT AM20 Z I (FO) CALLED TOKYO CTL TO MAKE POS RPT AT GULEG AND RECEIVED NO REPLY. APPROX 15 SECONDS LATER CTR ANSWERED AND SAID WE HAD AN OPEN MIKE FOR THE PAST 15 MINS. DURING THAT PERIOD I HAD BEEN MONITORING FREQ 121.5 AND 128.95 AND HEARD NOTHING TO ALERT US TO THIS PROBLEM. IF IT WAS IN FACT MY MICROPHONE THAT WAS OPEN I PROBABLY WOULD NOT HAVE KNOWN AS IT SITS NORMALLY ON THE THROTTLE QUADRANT IN AN AREA THAT PREVENTS ACCIDENTAL ACTIVATION.

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.