C172 PLT TAXIES WITHOUT RADIO OR LIGHT SIGNAL CLRNC AFTER SUFFERING A COMPLETE ELECTRICAL FAILURE ON LNDG.

Narrative

PLT LANDED C172 ON RWY 32R AND SUFFERED A COMPLETE ELECTRICAL FAILURE UPON LNDG. PRIOR RADIO XMISSIONS APPEARED NORMAL BTWN PLT AND APCH; AND PLT AND TWR; PRIOR TO LNDG. AS ACFT IS EQUIPPED WITH A MODERN DIGITAL PANEL; ALL INDICATORS AND PUSH BUTTONS BECOME INEFFECTIVE UPON LOSS OF PWR. ALL CIRCUIT BREAKERS WERE CHKED AND FOUND TO BE IN THEIR NORMAL OPERATING POS. I TAXIED TO NEXT AVAILABLE OFF RAMP; AND CLRED ACTIVE RWY ASAP. STOPPED TO INSPECT FOR INTERFERING TFC. UPON SEEING NONE; AND SEEING NO RED OR GREEN OR WHITE LIGHT FROM THE TWR; I PROCEEDED SLOWLY VIA TXWY C TO PARKING SPACE. NO LIGHTS FROM TWR WERE OBSERVED; ALTHOUGH SEEING TWR IS DIFFICULT FROM TXWY C NBOUND; AS PLT IS TALL AND HIGH WINGS OF THE C172 BLOCK A CLR VIEW. XMITTED BLINDLY SEVERAL TIMES TO TWR ON WHAT I THOUGHT MAY HAVE BEEN A SEVERELY DEGRADED RADIO (SYS VOLTAGE IN COCKPIT READING LESS THAN 7.5 VOLTS). NO RESPONSE WAS HEARD. NO BACKUP HANDHELD RADIO ON BOARD. NO CONTACT WITH 'GND' WAS POSSIBLE; NOR WAS 7700 SQUAWK POSSIBLE. THE ONLY POSSIBLE ACTION TO AVOID THIS IN THE FUTURE APPEARS TO BE TO REQUIRE A BACKUP BATTERY BE PRESENT IN RADIOS AND/OR XPONDERS.