Narrative:

[The] day before this incident; the airplane sat on the ramp where it was exposed to a light drizzle for an hour or two. I didn't think that the precipitation was heavy enough to warrant covering the static ports. A flight later that day was uneventful.[the next day]; a flight also was uneventful. Later [that day] during cruise; the crew alerting system (cas) gave three advisories: 'altitude disagree'; 'airspeed disagree'; and 'stick pusher fail'. Simultaneously; the autopilot and auto-throttle disconnected. Shortly thereafter the stall warning system gave persistent stall warnings. The maximum speed 'barber pole' came to within 5 knots above the present speed and the red stall warning tape rose to within 5 knots of the present speed. I manually ensured a normal thrust setting to ensure protection from stall or overspeed. The airspeed indicated on the left primary flight display (pfd) differed from the right pfd by about 15 knots. The indicated altitude between the 2 pfds differed by about 100 feet. The standby airspeed and altimeter were about halfway between the indications on the two pfds.I promptly reported the autopilot disconnect to ATC and that I was unable rvsm. Center cleared me to FL280 to get me out of rvsm airspace. During the descent; I was running through checklists and checking circuit breakers. As a consequence; I overshot my level-off altitude by about 700 feet and my altitude control for the next few minutes varied as much as 200 feet above and below FL280. After I exhausted my options for restoring the failed systems; I then concentrated on better altitude control. Approximately fifteen minutes later; the cas messages; airspeed warning tapes; and audible stall warning cleared and I was able to reconnect the autopilot and resume normal flight. Nevertheless; I elected to stay out of rvsm airspace for the rest of the flight.after the flight; I learned that other pilots have had the same problem and that it is related to moisture in the static system. I learned that there are two valves behind the pilot's rudder pedals that drain moisture from the static lines. I also learned that there is a service bulletin (sb) that reroutes the static lines and puts the drain valves in a more accessible location.henceforth; regardless of whether the owner chooses to comply with the above-mentioned sb (cost; about $6000); I will be more diligent in covering the static ports when there is a possibility of precipitation. I will open the static line drain valves every time the aircraft is exposed to precipitation; but not less than once a month. I recommend that; in future production; the manufacturer relocate the static ports to a location that is not subject to collecting precipitation.

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Original NASA ASRS Text

Title: EA500 pilot reported multiple system failures in cruise flight that were apparently related to moisture accumulation in the pitot-static system.

Narrative: [The] day before this incident; the airplane sat on the ramp where it was exposed to a light drizzle for an hour or two. I didn't think that the precipitation was heavy enough to warrant covering the static ports. A flight later that day was uneventful.[The next day]; a flight also was uneventful. Later [that day] during cruise; the Crew Alerting System (CAS) gave three advisories: 'Altitude Disagree'; 'Airspeed Disagree'; and 'Stick Pusher Fail'. Simultaneously; the autopilot and auto-throttle disconnected. Shortly thereafter the stall warning system gave persistent stall warnings. The maximum speed 'barber pole' came to within 5 knots above the present speed and the red stall warning tape rose to within 5 knots of the present speed. I manually ensured a normal thrust setting to ensure protection from stall or overspeed. The airspeed indicated on the Left Primary Flight Display (PFD) differed from the Right PFD by about 15 knots. The indicated altitude between the 2 PFDs differed by about 100 feet. The standby airspeed and altimeter were about halfway between the indications on the two PFDs.I promptly reported the autopilot disconnect to ATC and that I was unable RVSM. Center cleared me to FL280 to get me out of RVSM airspace. During the descent; I was running through checklists and checking circuit breakers. As a consequence; I overshot my level-off altitude by about 700 feet and my altitude control for the next few minutes varied as much as 200 feet above and below FL280. After I exhausted my options for restoring the failed systems; I then concentrated on better altitude control. Approximately fifteen minutes later; the CAS messages; airspeed warning tapes; and audible stall warning cleared and I was able to reconnect the autopilot and resume normal flight. Nevertheless; I elected to stay out of RVSM airspace for the rest of the flight.After the flight; I learned that other pilots have had the same problem and that it is related to moisture in the static system. I learned that there are two valves behind the pilot's rudder pedals that drain moisture from the static lines. I also learned that there is a Service Bulletin (SB) that reroutes the static lines and puts the drain valves in a more accessible location.Henceforth; regardless of whether the owner chooses to comply with the above-mentioned SB (cost; about $6000); I will be more diligent in covering the static ports when there is a possibility of precipitation. I will open the static line drain valves every time the aircraft is exposed to precipitation; but not less than once a month. I recommend that; in future production; the manufacturer relocate the static ports to a location that is not subject to collecting precipitation.

Data retrieved from NASA's ASRS site 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.