Narrative:

We departed stockville, ms, and picked up our IFR clearance en route from memphis center. Our initial clearance was to 6000'. We lost the use of both our navigation/communications due to overheating. We leveled at 6000' and tried to reset a least one navigation/communication for use. No cbs had popped and we noticed that both face plates were very hot and touch on the radios. Neither communications radio would receive or transmit. We turned of the #2 navigation/communication to cool but left the #1 on. We also turned on the air conditioner to vent cool air through the defroster duct which runs behind the instrument panel to aid in cooling. During this time we were navigating by use of a north STAR LORAN. We were shaving a bearing to montgomery VOR of 118 degree. We continued our flight with a heading of 118 degree and altitude of 6000' until reestablishing radio contact with memphis center. We were then handed off to atlanta center and I believe given our climb clearance to 17000'. Atlanta center advised us they were receiving intermittent readouts from our mode C. The transponder face plate was also very hot and we asked if atlanta wanted us to recycle or unit to see if it was working correctly. They advised yes and we did. We turned the transponder to the off position then back to altitude. After a few mins atlanta advised they now had continuous readout of our mode C. Atlanta then advised us to call memphis quality assurance control when we reached our destination or on monday morning. The number was called as soon as we reached tampa, fl, and I spoke to the area manager. He advised me that we had only 4 1/2 mi lateral sep from another aircraft and attempts to contact us by radio failed. I explained our situation and he advised me to call mr X monday morning at this same number. We continued on to miami, and were advised by FBO in miami that our blower fan had probably quit working and the XXX series radios had overheated. On the return flight from miami the next day, we experienced no problems with the navigation/communications but our transponder had to be reset 2 times. Our squawk code was afcb and 2 times it was squawking afcj. This occurred while we're under miami departure.

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Original NASA ASRS Text

Title: PLT ON IFR FLT PLAN HAS RADIO OVERHEAT PROBLEM, LOSES NAV AND COM. ALSO EXPERIENCES MODE C INCORRECT READOUT. LESS THAN STANDARD SEPARATION.

Narrative: WE DEPARTED STOCKVILLE, MS, AND PICKED UP OUR IFR CLRNC ENRTE FROM MEMPHIS CTR. OUR INITIAL CLRNC WAS TO 6000'. WE LOST THE USE OF BOTH OUR NAV/COMS DUE TO OVERHEATING. WE LEVELED AT 6000' AND TRIED TO RESET A LEAST ONE NAV/COM FOR USE. NO CBS HAD POPPED AND WE NOTICED THAT BOTH FACE PLATES WERE VERY HOT AND TOUCH ON THE RADIOS. NEITHER COMS RADIO WOULD RECEIVE OR XMIT. WE TURNED OF THE #2 NAV/COM TO COOL BUT LEFT THE #1 ON. WE ALSO TURNED ON THE AIR CONDITIONER TO VENT COOL AIR THROUGH THE DEFROSTER DUCT WHICH RUNS BEHIND THE INSTRUMENT PANEL TO AID IN COOLING. DURING THIS TIME WE WERE NAVIGATING BY USE OF A N STAR LORAN. WE WERE SHAVING A BEARING TO MONTGOMERY VOR OF 118 DEG. WE CONTINUED OUR FLT WITH A HDG OF 118 DEG AND ALT OF 6000' UNTIL REESTABLISHING RADIO CONTACT WITH MEMPHIS CTR. WE WERE THEN HANDED OFF TO ATLANTA CTR AND I BELIEVE GIVEN OUR CLB CLRNC TO 17000'. ATLANTA CTR ADVISED US THEY WERE RECEIVING INTERMITTENT READOUTS FROM OUR MODE C. THE XPONDER FACE PLATE WAS ALSO VERY HOT AND WE ASKED IF ATLANTA WANTED US TO RECYCLE OR UNIT TO SEE IF IT WAS WORKING CORRECTLY. THEY ADVISED YES AND WE DID. WE TURNED THE XPONDER TO THE OFF POS THEN BACK TO ALT. AFTER A FEW MINS ATLANTA ADVISED THEY NOW HAD CONTINUOUS READOUT OF OUR MODE C. ATLANTA THEN ADVISED US TO CALL MEMPHIS QUALITY ASSURANCE CTL WHEN WE REACHED OUR DEST OR ON MONDAY MORNING. THE NUMBER WAS CALLED AS SOON AS WE REACHED TAMPA, FL, AND I SPOKE TO THE AREA MGR. HE ADVISED ME THAT WE HAD ONLY 4 1/2 MI LATERAL SEP FROM ANOTHER ACFT AND ATTEMPTS TO CONTACT US BY RADIO FAILED. I EXPLAINED OUR SITUATION AND HE ADVISED ME TO CALL MR X MONDAY MORNING AT THIS SAME NUMBER. WE CONTINUED ON TO MIAMI, AND WERE ADVISED BY FBO IN MIAMI THAT OUR BLOWER FAN HAD PROBABLY QUIT WORKING AND THE XXX SERIES RADIOS HAD OVERHEATED. ON THE RETURN FLT FROM MIAMI THE NEXT DAY, WE EXPERIENCED NO PROBS WITH THE NAV/COMS BUT OUR XPONDER HAD TO BE RESET 2 TIMES. OUR SQUAWK CODE WAS AFCB AND 2 TIMES IT WAS SQUAWKING AFCJ. THIS OCCURRED WHILE WE'RE UNDER MIAMI DEP.

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.