Narrative:

Aircraft radio was stolen 3 weeks ago and replaced with a 'new' radio. Radio volume was below former volume output and could not be heard at highest volume level at high RPM engine setting (on speaker). Since I had a headset, I plugged it in and handled communications while my instrument student flew the airplane. All seemed to work fine on the round-robin instrument flight otherwise until established on the localizer and cleared for the ILS to the airport of origin. At the outer compass locator radio frequency digital display began to flicker and backgnd noise of static heard on headset as the 'brand new' radio totally failed. Frequency display went haywire with nothing that resembled a legible 4 digit frequency flashing nonsense via liquid crystal. I checked circuit breakers -- all ok. Turned radio on and off, even cycling master did no good. Pushing on the radio did nothing -- it was gone. I squawked 7700 for 1 min and then 7600. I transmitted in the blind that I was 'lost communication' and continuing on approach. We were in actual IMC conditions in cloud, fog, and haze. Neither my student remembers nor I remembered an off flag on #1 navigation display, although needles were perfectly centered. Since we were established we remained on heading and rate of descent. We broke out on about 1 1/2 mi final where we should be. We flew the approach at the top of green arc since controller requested best forward speed. We could hear approach controller slowing numerous acrs behind us in sequence before failure. I landed without verbal landing or light signal landing clearance, taxied off active at closest intersection, still no light from tower, taxied to ramp across taxiway without taxi clearance or light. We stopped on ramp normally requiring city authorization or prior permission. We then saw red light from tower. Operations vehicle then escorted to GA parking. I should have held short of taxiway off runway until light signal or escort. I was in too big a hurry and should have calmed down on the ground. I vividly imagined the big metal bearing down on us and all my logic and reason damaged by thinking too much behind the aircraft, rather than what was in front of me. It didn't happen (the failure) while on vectors prior to approach. #2 navigation was inoperative.

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Original NASA ASRS Text

Title: RADIO FAILURE ON INST APCH IN IMC. AFTER LNDG TAXI WITHOUT CLRNC LIGHTS FROM TWR.

Narrative: ACFT RADIO WAS STOLEN 3 WKS AGO AND REPLACED WITH A 'NEW' RADIO. RADIO VOLUME WAS BELOW FORMER VOLUME OUTPUT AND COULD NOT BE HEARD AT HIGHEST VOLUME LEVEL AT HIGH RPM ENG SETTING (ON SPEAKER). SINCE I HAD A HEADSET, I PLUGGED IT IN AND HANDLED COMS WHILE MY INST STUDENT FLEW THE AIRPLANE. ALL SEEMED TO WORK FINE ON THE ROUND-ROBIN INST FLT OTHERWISE UNTIL ESTABLISHED ON THE LOC AND CLRED FOR THE ILS TO THE ARPT OF ORIGIN. AT THE OUTER COMPASS LOCATOR RADIO FREQ DIGITAL DISPLAY BEGAN TO FLICKER AND BACKGND NOISE OF STATIC HEARD ON HEADSET AS THE 'BRAND NEW' RADIO TOTALLY FAILED. FREQ DISPLAY WENT HAYWIRE WITH NOTHING THAT RESEMBLED A LEGIBLE 4 DIGIT FREQ FLASHING NONSENSE VIA LIQUID CRYSTAL. I CHKED CIRCUIT BREAKERS -- ALL OK. TURNED RADIO ON AND OFF, EVEN CYCLING MASTER DID NO GOOD. PUSHING ON THE RADIO DID NOTHING -- IT WAS GONE. I SQUAWKED 7700 FOR 1 MIN AND THEN 7600. I XMITTED IN THE BLIND THAT I WAS 'LOST COM' AND CONTINUING ON APCH. WE WERE IN ACTUAL IMC CONDITIONS IN CLOUD, FOG, AND HAZE. NEITHER MY STUDENT REMEMBERS NOR I REMEMBERED AN OFF FLAG ON #1 NAV DISPLAY, ALTHOUGH NEEDLES WERE PERFECTLY CENTERED. SINCE WE WERE ESTABLISHED WE REMAINED ON HDG AND RATE OF DSCNT. WE BROKE OUT ON ABOUT 1 1/2 MI FINAL WHERE WE SHOULD BE. WE FLEW THE APCH AT THE TOP OF GREEN ARC SINCE CTLR REQUESTED BEST FORWARD SPD. WE COULD HEAR APCH CTLR SLOWING NUMEROUS ACRS BEHIND US IN SEQUENCE BEFORE FAILURE. I LANDED WITHOUT VERBAL LNDG OR LIGHT SIGNAL LNDG CLRNC, TAXIED OFF ACTIVE AT CLOSEST INTXN, STILL NO LIGHT FROM TWR, TAXIED TO RAMP ACROSS TAXIWAY WITHOUT TAXI CLRNC OR LIGHT. WE STOPPED ON RAMP NORMALLY REQUIRING CITY AUTHORIZATION OR PRIOR PERMISSION. WE THEN SAW RED LIGHT FROM TWR. OPS VEHICLE THEN ESCORTED TO GA PARKING. I SHOULD HAVE HELD SHORT OF TAXIWAY OFF RWY UNTIL LIGHT SIGNAL OR ESCORT. I WAS IN TOO BIG A HURRY AND SHOULD HAVE CALMED DOWN ON THE GND. I VIVIDLY IMAGINED THE BIG METAL BEARING DOWN ON US AND ALL MY LOGIC AND REASON DAMAGED BY THINKING TOO MUCH BEHIND THE ACFT, RATHER THAN WHAT WAS IN FRONT OF ME. IT DIDN'T HAPPEN (THE FAILURE) WHILE ON VECTORS PRIOR TO APCH. #2 NAV WAS INOP.

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.