Narrative:

Piper aztec just completed a left engine full overhaul; removal of turbocharger system and replacement with straight exhaust pipes; and annual. Test flew airplane with a pilot/mechanic and pilot on board on the morning of jun/xa/08. Noted throttles not balanced; returned plane to shop for balancing. Filed flight plan. Throttles balanced; took off with 3 passenger from ZZZ1. Activated flight plan about XA40Z. About 15 mins after departure; noted that ammeters were showing battery still charging -- figured battery was low and needed charging; kept eye on ammeters. After 30 mins; ammeter still showed charging. Decided to turn around and return to united states of america. Wanted to turn off alternators but remembered handbook said not to; checked handbook; section ii; electrical system 'the alternator circuit breakers; mounted on the same panel; are of the switch type and should not be turned off while the engines are running.' worried that the alternators might overcharge the battery; turned on navigation; landing; and taxi lights. About 5 mins later; instrument panel started to smoke and electrical system tripped off. Read emergency procedures -- said turn off alternators. Turned on 2 handheld radios and battery powered GPS. About every 5 mins; transmitted on frequency 'aztec on flight plan from ZZZ1 transmitting in the blind; lost battery; no electronics; declaring emergency; my intention is to return to ZZZ2.' flew south while GPS acquired signal; consulted new chart; explained to passenger that my plan was to intersect xx.30N then fly due west which would take me just south of ZZZ1; then approach ZZZ1 at 1000 ft to stay below ZZZ2 airspace. Finally GPS acquired; I intersected; flew west; variable visibility. As neared land broadcasted intentions. As we sighted land; did not recognize landscape; realized not where I thought I was; studied chart and realized I had been flying west on yy.30N instead of xx.30N. Considered whether to go to ZZZ3 or ZZZ1. Decided plane was stable; lots of airports en route; not familiar with ZZZ3 and no electronics; safest to continue to ZZZ1. Noted that I was already in ZZZ mode C area but was under the 3000 ft airspace floor. Flew north staying clear of ZZZ airspace. Approaching ZZZ4; noted airspace and flew out to sea to avoid. Continued to ZZZ2; switched frequency and broadcast 'piper aztec no electrical; using handheld radio; declaring emergency; please stay clear of runway 9; landing runway 9 in 5 mins.' '...3 mins.' '...on final. '...Short final.' landed; taxied to mechanic; disembarked passenger; called customs (received instructions to wait by plane); closed flight plan. Mechanics looked; battery had exploded. After meeting with about 5 sheriff and customs and border agents (they had thought radar had showed me landing in ZZZ3); filed arrival report and cleared to depart. Received a phone call from an agent to call mr X. I explained what had happened. He explained that my mode C was out so they did not know my altitude or intentions. They assumed I was at 3000 ft; closed ZZZ and ZZZ4 airspace until I passed; would file a report. Today called mechanic; learned that alternator switches were fried; that voltage regulators and overload protection may have been bad.

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Original NASA ASRS Text

Title: PA23 PILOT REPORTS ELECTRICAL SYSTEM FAILURE DURING OVERWATER FLIGHT AT LOW ALTITUDE.

Narrative: PIPER AZTEC JUST COMPLETED A L ENG FULL OVERHAUL; REMOVAL OF TURBOCHARGER SYS AND REPLACEMENT WITH STRAIGHT EXHAUST PIPES; AND ANNUAL. TEST FLEW AIRPLANE WITH A PLT/MECH AND PLT ON BOARD ON THE MORNING OF JUN/XA/08. NOTED THROTTLES NOT BALANCED; RETURNED PLANE TO SHOP FOR BALANCING. FILED FLT PLAN. THROTTLES BALANCED; TOOK OFF WITH 3 PAX FROM ZZZ1. ACTIVATED FLT PLAN ABOUT XA40Z. ABOUT 15 MINS AFTER DEP; NOTED THAT AMMETERS WERE SHOWING BATTERY STILL CHARGING -- FIGURED BATTERY WAS LOW AND NEEDED CHARGING; KEPT EYE ON AMMETERS. AFTER 30 MINS; AMMETER STILL SHOWED CHARGING. DECIDED TO TURN AROUND AND RETURN TO UNITED STATES OF AMERICA. WANTED TO TURN OFF ALTERNATORS BUT REMEMBERED HANDBOOK SAID NOT TO; CHKED HANDBOOK; SECTION II; ELECTRICAL SYS 'THE ALTERNATOR CIRCUIT BREAKERS; MOUNTED ON THE SAME PANEL; ARE OF THE SWITCH TYPE AND SHOULD NOT BE TURNED OFF WHILE THE ENGS ARE RUNNING.' WORRIED THAT THE ALTERNATORS MIGHT OVERCHARGE THE BATTERY; TURNED ON NAV; LNDG; AND TAXI LIGHTS. ABOUT 5 MINS LATER; INST PANEL STARTED TO SMOKE AND ELECTRICAL SYS TRIPPED OFF. READ EMER PROCS -- SAID TURN OFF ALTERNATORS. TURNED ON 2 HANDHELD RADIOS AND BATTERY POWERED GPS. ABOUT EVERY 5 MINS; XMITTED ON FREQ 'AZTEC ON FLT PLAN FROM ZZZ1 XMITTING IN THE BLIND; LOST BATTERY; NO ELECTRONICS; DECLARING EMER; MY INTENTION IS TO RETURN TO ZZZ2.' FLEW S WHILE GPS ACQUIRED SIGNAL; CONSULTED NEW CHART; EXPLAINED TO PAX THAT MY PLAN WAS TO INTERSECT XX.30N THEN FLY DUE W WHICH WOULD TAKE ME JUST S OF ZZZ1; THEN APCH ZZZ1 AT 1000 FT TO STAY BELOW ZZZ2 AIRSPACE. FINALLY GPS ACQUIRED; I INTERSECTED; FLEW W; VARIABLE VISIBILITY. AS NEARED LAND BROADCASTED INTENTIONS. AS WE SIGHTED LAND; DID NOT RECOGNIZE LANDSCAPE; REALIZED NOT WHERE I THOUGHT I WAS; STUDIED CHART AND REALIZED I HAD BEEN FLYING W ON YY.30N INSTEAD OF XX.30N. CONSIDERED WHETHER TO GO TO ZZZ3 OR ZZZ1. DECIDED PLANE WAS STABLE; LOTS OF ARPTS ENRTE; NOT FAMILIAR WITH ZZZ3 AND NO ELECTRONICS; SAFEST TO CONTINUE TO ZZZ1. NOTED THAT I WAS ALREADY IN ZZZ MODE C AREA BUT WAS UNDER THE 3000 FT AIRSPACE FLOOR. FLEW N STAYING CLR OF ZZZ AIRSPACE. APCHING ZZZ4; NOTED AIRSPACE AND FLEW OUT TO SEA TO AVOID. CONTINUED TO ZZZ2; SWITCHED FREQ AND BROADCAST 'PIPER AZTEC NO ELECTRICAL; USING HANDHELD RADIO; DECLARING EMER; PLEASE STAY CLR OF RWY 9; LNDG RWY 9 IN 5 MINS.' '...3 MINS.' '...ON FINAL. '...SHORT FINAL.' LANDED; TAXIED TO MECH; DISEMBARKED PAX; CALLED CUSTOMS (RECEIVED INSTRUCTIONS TO WAIT BY PLANE); CLOSED FLT PLAN. MECHS LOOKED; BATTERY HAD EXPLODED. AFTER MEETING WITH ABOUT 5 SHERIFF AND CUSTOMS AND BORDER AGENTS (THEY HAD THOUGHT RADAR HAD SHOWED ME LNDG IN ZZZ3); FILED ARR RPT AND CLRED TO DEPART. RECEIVED A PHONE CALL FROM AN AGENT TO CALL MR X. I EXPLAINED WHAT HAD HAPPENED. HE EXPLAINED THAT MY MODE C WAS OUT SO THEY DID NOT KNOW MY ALT OR INTENTIONS. THEY ASSUMED I WAS AT 3000 FT; CLOSED ZZZ AND ZZZ4 AIRSPACE UNTIL I PASSED; WOULD FILE A RPT. TODAY CALLED MECH; LEARNED THAT ALTERNATOR SWITCHES WERE FRIED; THAT VOLTAGE REGULATORS AND OVERLOAD PROTECTION MAY HAVE BEEN BAD.

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.