Narrative:

Our descent clearance from ATC was pilot's discretion to 6000 ft MSL. We were up at FL350 and it was late at night with only our aircraft on frequency that I could tell. When we started down out of FL350; I called center and said that we were leaving FL350. I heard no response from the controller; which in my mind was not unusual seeing how it was so late. I think it was around FL270 that we got a call from center that said 'company flt # are you up?' I responded that we were and he informed us that we had a stuck mike for quite a while and he was trying to get ahold of us to level us off because he had traffic that had taken off from another airport that could have been a conflict with us. He informed us that everything was just fine and that he moved the other aircraft instead of leveling us off. I apologized to him and asked him if he heard anything bad from us while we had a stuck mike and he laughed and said; 'no' and he was not ready to call out the fighters just yet. I asked him again if he was sure we were not in trouble and he said; 'there was no problem and don't worry.' after this my first officer and I tried to figure out the stuck mike issue and I knew it was not coming from my side and that is when my first officer figured it out. He had his right leg up on the foot rest and his knee was keying the hand mike that was underneath his (sliding window) release. I guess he took the mike and strung the cord around the release handle for the sliding window and his paperwork was covering up the mike. So when his knee hit the mike he did not think he was pressing the mike button because the paperwork was masking the sensation of that action.

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Original NASA ASRS Text

Title: Temporary loss of communication with ATC is tracked down to an inadvertently keyed First Officer hand held microphone.

Narrative: Our descent clearance from ATC was pilot's discretion to 6000 FT MSL. We were up at FL350 and it was late at night with only our aircraft on frequency that I could tell. When we started down out of FL350; I called Center and said that we were leaving FL350. I heard no response from the Controller; which in my mind was not unusual seeing how it was so late. I think it was around FL270 that we got a call from Center that said 'Company flt # are you up?' I responded that we were and he informed us that we had a stuck mike for quite a while and he was trying to get ahold of us to level us off because he had traffic that had taken off from another airport that could have been a conflict with us. He informed us that everything was just fine and that he moved the other aircraft instead of leveling us off. I apologized to him and asked him if he heard anything bad from us while we had a stuck mike and he laughed and said; 'No' and he was not ready to call out the fighters just yet. I asked him again if he was sure we were not in trouble and he said; 'There was no problem and don't worry.' After this my First Officer and I tried to figure out the stuck mike issue and I knew it was not coming from my side and that is when my First Officer figured it out. He had his right leg up on the foot rest and his knee was keying the hand mike that was underneath his (sliding window) release. I guess he took the mike and strung the cord around the release handle for the sliding window and his paperwork was covering up the mike. So when his knee hit the mike he did not think he was pressing the mike button because the paperwork was masking the sensation of that action.

Data retrieved from NASA's ASRS site as of April 2012 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.