Narrative:

I was flying alone from ZZZ to ZZZ1 and back to ZZZ on a refueling flight; practicing dead reckoning and lndgs. I had just gotten the ATIS and attempted to transmit my intention to enter and land at ZZZ (a class D airspace and my home base). I did not hear a response from the tower. I decided to switch on the strobe as it was getting a little hazy and I wanted to increase my visibility to other aircraft. When I switched on the strobe the radio went dead. I immediately turned the strobe off as it seemed to be related to the radio failure and I was worried that there might be a short circuit. I was not sure what to do as I had never had any real failure with or without an instructor. I was concerned that there might be an electrical problem behind the panel and so I checked to see if any circuit breakers had popped. None had. I concluded that the radio was dead (the entire radio including both communications and both navs). There was still a dim glow from the back light on the radios so I thought the radio portion had gone bad. As I was 10 mi out; I decided to approach the airport from the west since runway xx was in use and that would put me in a standard left traffic approach. The tower was on the west side as well; so that would give me good visibility to the tower. I was very nervous as I was worried that the electrical problem might get worse. Getting on the ground seemed to be a priority. I went around on the north side and entered the downwind pattern at 45 degrees right at the tower. I flashed my landing light at the tower and looked for a light signal response. I did not see any. I scanned the entire area 360 degrees and saw no traffic in the pattern or approaching from the south or north. Visibility was decent but there was haze. No lights in the air. There did not appear to be any traffic taxiing or any aircraft lit up anywhere on the field. As I had already entered the downwind and did not see any signal from the tower and the approach looked clear; I decided to continue downwind. I scanned the pattern; north and south; and the ground once again and decided on a short approach. The landing went fine and I exited the runway and parked the plane in its normal spot. Tied down and recorded the time; etc. I went inside and saw my instructor and explained what happened. He asked me if the alternator was working correctly. I did not know. He called the tower on my behalf and explained what happened and why I approached and landed without clearance. He told me that everything was ok and I did not have to talk to them myself. As the aircraft is a club aircraft and my instructor is not a club instructor I contacted officials at the club to let them know that the radio was dead and tell them what happened. Upon contemplating what my instructor had asked about the alternator; it occurred to me that I might have switched off the right half of the master switch after takeoff while turning the fuel pump off (the 2 switches are adjacent); thereby disabling the alternator and allowing the battery to drain. To verify this theory; I went out to the aircraft and found the battery dead. I jump started it with a cable and my vehicle. The plane started right up. I switched the master avionics switch on and the radio came on normally. I did a communication check with ground and he read me loud and clear. I ran the plane for 10 mins to charge the battery and shut it down. In hindsight; I went wrong in several ways. First of all; had I checked the emergency checklist for 'lost communication' I would have cycled the master switch and discovered that the right half was off. This would have corrected the problem immediately. Second; I am pretty sure that there might have been an indicator that there was a charge problem or low voltage that I missed as well. Third; I should have circled near the tower and gotten their attention prior to landing. I was nervous and intentionally decided not to wait because the situation looked safe to land immediately. I plan on taking the following corrective actions as a result of this experience: 1) study the checklists more thoroughly and use them dogmatically. 2) do a real practice approach with lost communication using light signals (with my instructor). 3) become more familiar with all available indication lights or sounds for failure modes. 4) become more familiar with all aircraft system. 5) buy a back-up radio.

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Original NASA ASRS Text

Title: PA28 LOST ELECTRICAL PWR; LNDG AT A CONTROLLED ARPT WITHOUT TWR CLRNC. IT WAS LATER DISCOVERED THAT THE ALTERNATOR HAD BEEN DISCONNECTED BY INADVERTENTLY TURNING THE MASTER SWITCH OFF.

Narrative: I WAS FLYING ALONE FROM ZZZ TO ZZZ1 AND BACK TO ZZZ ON A REFUELING FLT; PRACTICING DEAD RECKONING AND LNDGS. I HAD JUST GOTTEN THE ATIS AND ATTEMPTED TO XMIT MY INTENTION TO ENTER AND LAND AT ZZZ (A CLASS D AIRSPACE AND MY HOME BASE). I DID NOT HEAR A RESPONSE FROM THE TWR. I DECIDED TO SWITCH ON THE STROBE AS IT WAS GETTING A LITTLE HAZY AND I WANTED TO INCREASE MY VISIBILITY TO OTHER ACFT. WHEN I SWITCHED ON THE STROBE THE RADIO WENT DEAD. I IMMEDIATELY TURNED THE STROBE OFF AS IT SEEMED TO BE RELATED TO THE RADIO FAILURE AND I WAS WORRIED THAT THERE MIGHT BE A SHORT CIRCUIT. I WAS NOT SURE WHAT TO DO AS I HAD NEVER HAD ANY REAL FAILURE WITH OR WITHOUT AN INSTRUCTOR. I WAS CONCERNED THAT THERE MIGHT BE AN ELECTRICAL PROB BEHIND THE PANEL AND SO I CHKED TO SEE IF ANY CIRCUIT BREAKERS HAD POPPED. NONE HAD. I CONCLUDED THAT THE RADIO WAS DEAD (THE ENTIRE RADIO INCLUDING BOTH COMS AND BOTH NAVS). THERE WAS STILL A DIM GLOW FROM THE BACK LIGHT ON THE RADIOS SO I THOUGHT THE RADIO PORTION HAD GONE BAD. AS I WAS 10 MI OUT; I DECIDED TO APCH THE ARPT FROM THE W SINCE RWY XX WAS IN USE AND THAT WOULD PUT ME IN A STANDARD L TFC APCH. THE TWR WAS ON THE W SIDE AS WELL; SO THAT WOULD GIVE ME GOOD VISIBILITY TO THE TWR. I WAS VERY NERVOUS AS I WAS WORRIED THAT THE ELECTRICAL PROB MIGHT GET WORSE. GETTING ON THE GND SEEMED TO BE A PRIORITY. I WENT AROUND ON THE N SIDE AND ENTERED THE DOWNWIND PATTERN AT 45 DEGS R AT THE TWR. I FLASHED MY LNDG LIGHT AT THE TWR AND LOOKED FOR A LIGHT SIGNAL RESPONSE. I DID NOT SEE ANY. I SCANNED THE ENTIRE AREA 360 DEGS AND SAW NO TFC IN THE PATTERN OR APCHING FROM THE S OR N. VISIBILITY WAS DECENT BUT THERE WAS HAZE. NO LIGHTS IN THE AIR. THERE DID NOT APPEAR TO BE ANY TFC TAXIING OR ANY ACFT LIT UP ANYWHERE ON THE FIELD. AS I HAD ALREADY ENTERED THE DOWNWIND AND DID NOT SEE ANY SIGNAL FROM THE TWR AND THE APCH LOOKED CLR; I DECIDED TO CONTINUE DOWNWIND. I SCANNED THE PATTERN; N AND S; AND THE GND ONCE AGAIN AND DECIDED ON A SHORT APCH. THE LNDG WENT FINE AND I EXITED THE RWY AND PARKED THE PLANE IN ITS NORMAL SPOT. TIED DOWN AND RECORDED THE TIME; ETC. I WENT INSIDE AND SAW MY INSTRUCTOR AND EXPLAINED WHAT HAPPENED. HE ASKED ME IF THE ALTERNATOR WAS WORKING CORRECTLY. I DID NOT KNOW. HE CALLED THE TWR ON MY BEHALF AND EXPLAINED WHAT HAPPENED AND WHY I APCHED AND LANDED WITHOUT CLRNC. HE TOLD ME THAT EVERYTHING WAS OK AND I DID NOT HAVE TO TALK TO THEM MYSELF. AS THE ACFT IS A CLUB ACFT AND MY INSTRUCTOR IS NOT A CLUB INSTRUCTOR I CONTACTED OFFICIALS AT THE CLUB TO LET THEM KNOW THAT THE RADIO WAS DEAD AND TELL THEM WHAT HAPPENED. UPON CONTEMPLATING WHAT MY INSTRUCTOR HAD ASKED ABOUT THE ALTERNATOR; IT OCCURRED TO ME THAT I MIGHT HAVE SWITCHED OFF THE R HALF OF THE MASTER SWITCH AFTER TKOF WHILE TURNING THE FUEL PUMP OFF (THE 2 SWITCHES ARE ADJACENT); THEREBY DISABLING THE ALTERNATOR AND ALLOWING THE BATTERY TO DRAIN. TO VERIFY THIS THEORY; I WENT OUT TO THE ACFT AND FOUND THE BATTERY DEAD. I JUMP STARTED IT WITH A CABLE AND MY VEHICLE. THE PLANE STARTED RIGHT UP. I SWITCHED THE MASTER AVIONICS SWITCH ON AND THE RADIO CAME ON NORMALLY. I DID A COM CHK WITH GND AND HE READ ME LOUD AND CLR. I RAN THE PLANE FOR 10 MINS TO CHARGE THE BATTERY AND SHUT IT DOWN. IN HINDSIGHT; I WENT WRONG IN SEVERAL WAYS. FIRST OF ALL; HAD I CHKED THE EMER CHKLIST FOR 'LOST COM' I WOULD HAVE CYCLED THE MASTER SWITCH AND DISCOVERED THAT THE R HALF WAS OFF. THIS WOULD HAVE CORRECTED THE PROB IMMEDIATELY. SECOND; I AM PRETTY SURE THAT THERE MIGHT HAVE BEEN AN INDICATOR THAT THERE WAS A CHARGE PROB OR LOW VOLTAGE THAT I MISSED AS WELL. THIRD; I SHOULD HAVE CIRCLED NEAR THE TWR AND GOTTEN THEIR ATTN PRIOR TO LNDG. I WAS NERVOUS AND INTENTIONALLY DECIDED NOT TO WAIT BECAUSE THE SITUATION LOOKED SAFE TO LAND IMMEDIATELY. I PLAN ON TAKING THE FOLLOWING CORRECTIVE ACTIONS AS A RESULT OF THIS EXPERIENCE: 1) STUDY THE CHKLISTS MORE THOROUGHLY AND USE THEM DOGMATICALLY. 2) DO A REAL PRACTICE APCH WITH LOST COM USING LIGHT SIGNALS (WITH MY INSTRUCTOR). 3) BECOME MORE FAMILIAR WITH ALL AVAILABLE INDICATION LIGHTS OR SOUNDS FOR FAILURE MODES. 4) BECOME MORE FAMILIAR WITH ALL ACFT SYS. 5) BUY A BACK-UP RADIO.

Data retrieved from NASA's ASRS site as of May 2009 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.