PA-46 Malibu/Malibu Mirage/Malibu Matrix
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Private
Flight Crew Last 90 Days 60; Flight Crew Total 6100; Flight Crew Type 4000
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Flight Crew Overcame Equipment Problem
Aircraft
While on a IFR flight from ZZZ to ZZZ1; I suffered a rapid / full cabin decompression at 27;000 feet approximately 20 miles SW from ZZZ2.  The event happened about an hour into a routine flight in clear weather conditions in level flight on a direct course to ZZZ3.  The complete decompression happened in a matter of a few seconds with a large pressure change inside the cabin (5.5 psi) and a simultaneous pitch noise change in the cabin. The 10;000 ft cabin altitude warning on the warning panel illuminated including the simultaneous high pitch warning from the portable 'Alt Alert' unit. The oxygen mask was deployed within seconds of concluding total cabin pressure loss by cross checking the cabin pressure control gauge. ATC was informed of the failure with a request for an immediate descent to 12;000 feet due to loss of cabin pressure. Due to the immediate request notified ATC whilst I was descending.  The autopilot was set for a rapid descent to 12;000 feet. Whilst in the descent I checked if any circuit breakers had tripped but none were noted including the cabin pressure dump valve circuit breaker.  Given the yearly recurrent training and surmising that the failure could be caused by a faulty squat switch for the emergency dump valve the circuit breaker was pulled for the switch and the cabin altitude was set to 1;000 feet to see if the cabin would re-pressurize.  However due to the descent and low power setting the cabin would not re-pressurize until power was added back on leveling out at 12;000 feet.  After leveling at 12;000 ft and analysis of the situation under the controlled descent; it was concluded that it was safe to continue flight under the present circumstances of a non pressurized cabin until further analysis of the situation could be made. With cruising power set for 12;000 feet the cabin started re-pressurizing due to the added power still with the squat switch circuit breaker pulled. At this point ATC was informed that the flight will continue to the filed destination. After the cabin reached full differential for the 12;000 foot altitude. The flight continued and the STAR into ZZZ1 was initiated and followed. Once reaching 10;000 feet the circuit breaker was re-engaged for the cabin dump squat switch with no impact and the cabin remained pressurized at full differential for the cruising altitude and the remaining flight. Suspecting that the squat switch had failed intermittently at high altitude causing the emergency dump of the cabin at flight it was decided to replace the switch and a test flight is still pending to assure that full cabin pressure can be maintained.
Pilot flying PA-46 aircraft reported a rapid decompression event in cruise flight. After descending pilot was able to restore pressurization and continued flight to destination.