PA46 PILOT REPORTS PRESSURIZATION LOSS AT FL270 AND RAPID DESCENT TO 12000 FEET. OXYGEN MASK CAUSES HEADSET TO FALL OFF AND NO COM UNTIL IT IS RETRIEVED.

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I WAS CRUISING AT FL270 AND HAD A RAPID TOTAL DEPRESSURIZATION. I IMMEDIATELY NOTIFIED ATC AND TOLD THEM I WAS MAKING A RAPID DSCNT. WHILE PUTTING ON THE EMER OXYGEN; MY HEADSET WAS KNOCKED OFF AND IT WAS SEVERAL MOMENTS UNTIL I RE-ESTABLISHED CONTACT WITH ATC. I CHKED MY TCAS; MAKING SURE THERE WERE NO OTHER ACFT IN MY PATH. WHEN I RE-ESTABLISHED CONTACT; ATC TOLD ME TO TURN TO 90 DEGS AND DSND TO 12000 FT AS REQUESTED; AND ASKED IF I WANTED TO DECLARE AN EMER. I TOLD ATC THINGS WERE UNDER CTL AND I DIDN'T NEED TO DECLARE AN EMER. DSNDED TO A NON OXYGEN ALT AND CONTINUED THE FLT TO MY DEST. ATC WAS VERY HELPFUL AND DID NOT TAKE ISSUE WITH MY DSCNT; AND MAY HAVE AUTH IT; BUT I'M NOT SURE BECAUSE MY HEADSET WAS OFF FOR A FEW MOMENTS WHILE PUTTING ON THE OXYGEN; SO I'M NOT SURE IF I DSNDED WITH OR WITHOUT CLRNC. THE PRESSURE LOSS WAS THE RESULT OF THE MICROSWITCH ON THE GEAR THAT DEPRESSURIZES WHEN THE GEAR IS LOWERED FAILING INFLT WITH THE GEAR UP. I MAY NOT HAVE DSNDED WITHOUT PERMISSION; BUT AM NOT SURE; EVEN THOUGH ATC DID NOT SAY I DID ANYTHING WRONG AND WAS VERY HELPFUL.