M20 PLT SWITCHES OFF THE AVIONICS MASTER WHEN REACHING FOR THE FUEL BOOST PUMP.

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ON MY AIRPLANE THE AVIONICS MASTER SWITCH IS ADJACENT TO THE FUEL BOOST PUMP SWITCH. BOTH ARE LOCATED TO THE L OF THE YOKE. THOUGH IT WAS VMC AND I WAS NOT ON A FLT PLAN; I WAS USING THE ILS FOR REF AS I APCHED RDU. THE ILS INDICATOR WAS DRIVEN BY A GARMIN GNS480. AS I FLEW DOWN THE FINAL; I REACHED TO TURN ON THE BOOST PUMP AND ACCIDENTALLY TURNED OFF THE AVIONICS MASTER. SINCE I USUALLY FLY WITH MY L HAND ON THE YOKE; I REACHED ACROSS WITH MY R HAND FOR THE BOOST PUMP SWITCH. I MAY HAVE HIT A LITTLE TURB; OR MAY JUST HAVE BEEN INATTENTIVE; I'M NOT SURE WHICH. OF COURSE; WHEN THE GNS480 LOSES PWR; IT TAKES AT LEAST SEVERAL SECONDS BEFORE IT IS OPERATIONAL AGAIN; AND THERE IS NO NAV GUIDANCE IN THE MEANTIME. WHEN IT DOES RE-INITIALIZE; IT IS NO LONGER PROGRAMMED TO TRACK THE ILS. FORTUNATELY; 1) IT WAS VMC; AND 2) THE #2 NAV RECEIVER; A KING KX-155; WAS ALSO TUNED AND IDENTED. THE #2 RECEIVER IMMEDIATELY PROVIDED NAV GUIDANCE AS SOON AS PWR WAS RESTORED. CORRECTIVE ACTIONS: 1) DEVELOP THE HABIT OF OPERATING THE FUEL BOOST PUMP SWITCH WITH MY L HAND; WITH WHICH I CAN MORE ACCURATELY LOCATE THE SWITCH. 2) BE AWARE THAT WHEN FLYING WITH DIGITAL AVIONICS LIKE THE GNS480; A MOMENTARY LOSS OF PWR CAN LEAD TO AN EXTENDED NAV OUTAGE. 3) KEEP THE #2 NAV (THE KX-155) TUNED AND READY. 4) PERHAPS THE TSO FOR DIGITAL NAV C129; C145; C146 SHOULD SPECIFY THAT WHEN PWR IS RESTORED THEY SHOULD RESUME OP IN THE SAME MODE (TUNED TO ILS; IN MY CASE) AS WHEN PWR WAS LOST; OR SHOULD SPECIFY A MAX TIME TO BECOME OPERATIONAL AFTER A PWR LOSS.