Narrative:

Total loss of electrical power at FL240 caused autoplt to disengage; pressurization to climb from 6000 ft cabin to FL220 cabin in just a few seconds; and communication interruption with center. I could not get oxygen mask on with one hand while hand flying with the other. Turned away from jet and low altitude airways toward an MOA which I thought was safer for my aircraft and others that may be in the area. Once I was able to secure my mask and free up a hand; I was able to get the electrical power restored and contact ATC once again. The problem occurred by my turning the generator off instead of the igniters; switches next to each other; and the high amp load heaters and fans I had just switched on due to cabin conditions. Once I was able to turn off all the electrical and avionics equipment; I was able to bring on line the other battery system and then the back-up alternator before the generator once again. With all power restored and both electrical producing sources working properly; I chose to continue in VFR conditions to my destination and landed without further incident. Once on the ground; I did a run-up and verified what I had suspected happened and confirmed that both batteries were holding full charge. Upon shutdown; I contacted the maintenance shop that does all the maintenance on the P46T and approximately 300 other P46 aircraft annually. This manager confirmed with me giving him instrument readings and with his questioning me determined that the electrical system was functioning normally. How the problem arose: by turning the generator off. The only way to know it is off is to notice that a green annunciator light is out and the ammeter is blank. Glare on the panel from over my shoulder kept me from noticing this for the 2 1/2 mins it took to drain the battery. The first sign of trouble was low fuel pressure. I do believe that under the circumstances after my original error of not confirming I turned off the igniters; when in fact I had turned off the generator; I acted in the safest interest of my flight and that of other IFR and VFR traffic around and below me. Stable with all system working normally and all indicators reading in the green including mostly full tanks; I continued on to my destination in contact with ATC.

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Original NASA ASRS Text

Title: PA46 PLT SUFFERS COMPLETE ELECTRICAL FAILURE; LOSS OF PRESSURIZATION AND AUTOPLT WHEN THE GENERATOR IS INADVERTENTLY SHUT OFF INSTEAD OF THE ENGINE IGNITERS.

Narrative: TOTAL LOSS OF ELECTRICAL PWR AT FL240 CAUSED AUTOPLT TO DISENGAGE; PRESSURIZATION TO CLB FROM 6000 FT CABIN TO FL220 CABIN IN JUST A FEW SECONDS; AND COM INTERRUPTION WITH CENTER. I COULD NOT GET OXYGEN MASK ON WITH ONE HAND WHILE HAND FLYING WITH THE OTHER. TURNED AWAY FROM JET AND LOW ALT AIRWAYS TOWARD AN MOA WHICH I THOUGHT WAS SAFER FOR MY ACFT AND OTHERS THAT MAY BE IN THE AREA. ONCE I WAS ABLE TO SECURE MY MASK AND FREE UP A HAND; I WAS ABLE TO GET THE ELECTRICAL PWR RESTORED AND CONTACT ATC ONCE AGAIN. THE PROB OCCURRED BY MY TURNING THE GENERATOR OFF INSTEAD OF THE IGNITERS; SWITCHES NEXT TO EACH OTHER; AND THE HIGH AMP LOAD HEATERS AND FANS I HAD JUST SWITCHED ON DUE TO CABIN CONDITIONS. ONCE I WAS ABLE TO TURN OFF ALL THE ELECTRICAL AND AVIONICS EQUIP; I WAS ABLE TO BRING ON LINE THE OTHER BATTERY SYS AND THEN THE BACK-UP ALTERNATOR BEFORE THE GENERATOR ONCE AGAIN. WITH ALL PWR RESTORED AND BOTH ELECTRICAL PRODUCING SOURCES WORKING PROPERLY; I CHOSE TO CONTINUE IN VFR CONDITIONS TO MY DEST AND LANDED WITHOUT FURTHER INCIDENT. ONCE ON THE GND; I DID A RUN-UP AND VERIFIED WHAT I HAD SUSPECTED HAPPENED AND CONFIRMED THAT BOTH BATTERIES WERE HOLDING FULL CHARGE. UPON SHUTDOWN; I CONTACTED THE MAINT SHOP THAT DOES ALL THE MAINT ON THE P46T AND APPROX 300 OTHER P46 ACFT ANNUALLY. THIS MGR CONFIRMED WITH ME GIVING HIM INST READINGS AND WITH HIS QUESTIONING ME DETERMINED THAT THE ELECTRICAL SYS WAS FUNCTIONING NORMALLY. HOW THE PROB AROSE: BY TURNING THE GENERATOR OFF. THE ONLY WAY TO KNOW IT IS OFF IS TO NOTICE THAT A GREEN ANNUNCIATOR LIGHT IS OUT AND THE AMMETER IS BLANK. GLARE ON THE PANEL FROM OVER MY SHOULDER KEPT ME FROM NOTICING THIS FOR THE 2 1/2 MINS IT TOOK TO DRAIN THE BATTERY. THE FIRST SIGN OF TROUBLE WAS LOW FUEL PRESSURE. I DO BELIEVE THAT UNDER THE CIRCUMSTANCES AFTER MY ORIGINAL ERROR OF NOT CONFIRMING I TURNED OFF THE IGNITERS; WHEN IN FACT I HAD TURNED OFF THE GENERATOR; I ACTED IN THE SAFEST INTEREST OF MY FLT AND THAT OF OTHER IFR AND VFR TFC AROUND AND BELOW ME. STABLE WITH ALL SYS WORKING NORMALLY AND ALL INDICATORS READING IN THE GREEN INCLUDING MOSTLY FULL TANKS; I CONTINUED ON TO MY DEST IN CONTACT WITH ATC.

Data retrieved from NASA's ASRS site as of January 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.