Narrative:

I departed lgd, or, en route to huf, in, with a fuel stop in cys, wy. IFR at 21000 ft. Shortly after leveloff at 21000 ft I was unable to reach ZLC or receive on any frequency. The communication radios were dead. I proceeded on top of a mostly overcast layer with mountain obstruction. I am familiar with the plains area east of denver but not with the terrain in the area of cheyenne. There were breaks in the overcast southeast toward the denver area, and I proceeded in that direction, preparing to let down over the plains, then the cheyenne area. I found an area large enough to make a visual descent, leveling off about 30 mi east of ftg and proceeding back to land at ftg. Upon touchdown my radios came on and I could hear another aircraft on the unicom frequency. The radios then worked normally as transmit and receive radio checks. I flew the remainder of the flight with no other problems. It is difficult to fix an electronics problem that is intermittent and not malfunctioning at the moment. What I think happened was the audio panel speaker/phone toggle switch was not firmly seated in the phone position. I had moved the individual radio toggle switches to the alternate position but not the master speak/phone selector. That switch may have been slightly off its full down position. Apparently, when radio failure occurs I need to move every possible switch to check its function.

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Original NASA ASRS Text

Title: DIVERSION TO ALTERNATE AFTER LOSING 2-WAY COM WITH CTR.

Narrative: I DEPARTED LGD, OR, ENRTE TO HUF, IN, WITH A FUEL STOP IN CYS, WY. IFR AT 21000 FT. SHORTLY AFTER LEVELOFF AT 21000 FT I WAS UNABLE TO REACH ZLC OR RECEIVE ON ANY FREQ. THE COM RADIOS WERE DEAD. I PROCEEDED ON TOP OF A MOSTLY OVCST LAYER WITH MOUNTAIN OBSTRUCTION. I AM FAMILIAR WITH THE PLAINS AREA E OF DENVER BUT NOT WITH THE TERRAIN IN THE AREA OF CHEYENNE. THERE WERE BREAKS IN THE OVCST SE TOWARD THE DENVER AREA, AND I PROCEEDED IN THAT DIRECTION, PREPARING TO LET DOWN OVER THE PLAINS, THEN THE CHEYENNE AREA. I FOUND AN AREA LARGE ENOUGH TO MAKE A VISUAL DSCNT, LEVELING OFF ABOUT 30 MI E OF FTG AND PROCEEDING BACK TO LAND AT FTG. UPON TOUCHDOWN MY RADIOS CAME ON AND I COULD HEAR ANOTHER ACFT ON THE UNICOM FREQ. THE RADIOS THEN WORKED NORMALLY AS XMIT AND RECEIVE RADIO CHKS. I FLEW THE REMAINDER OF THE FLT WITH NO OTHER PROBS. IT IS DIFFICULT TO FIX AN ELECTRONICS PROB THAT IS INTERMITTENT AND NOT MALFUNCTIONING AT THE MOMENT. WHAT I THINK HAPPENED WAS THE AUDIO PANEL SPEAKER/PHONE TOGGLE SWITCH WAS NOT FIRMLY SEATED IN THE PHONE POS. I HAD MOVED THE INDIVIDUAL RADIO TOGGLE SWITCHES TO THE ALTERNATE POS BUT NOT THE MASTER SPEAK/PHONE SELECTOR. THAT SWITCH MAY HAVE BEEN SLIGHTLY OFF ITS FULL DOWN POS. APPARENTLY, WHEN RADIO FAILURE OCCURS I NEED TO MOVE EVERY POSSIBLE SWITCH TO CHK ITS FUNCTION.

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.