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       #1  

    Water blocking fresh air vents, what to do.

    Thought I'd share this as the flying characteristics changed.
    I was on some choppy water yesterday and the temperature was high 80s. We were 40 pounds under gross. Nothing too severe on the chop, but there were a few waves over the bow. I ran the bilge pump until no more water was coming out, then took off. My passenger and I noticed there was no air coming out of the fresh air vents on either side. The plane was flying normally with a good rate of climb.

    I will tell you what I think should be done first, rather than what I did:
    Slight negative G's seemed to do the trick. Water gushed out of the vent and airflow was restored.

    What I actually did:
    30 degree turns to start. A left 30 degree seemed to do the trick, at least on the pilot side. But I continued to do left and right turns as the right fresh air vent didn't clear. So I continued to increase the bank. (I was taught steep (impossible) turns in the advanced training at Icon and practice them regularly.) As the bank steepened, the plane became less much less stable than I expected.

    Thats what I wanted to point out. I couldn't really tell how much water was in the nose. All I know is that the extra weight was about as far forward as you could get and the steep turn characteristics were quite different.

    The steep turns didn't clear the water from the passenger air vent either. So that's went I tried the slight negative g's.

    So if you're air vents aren't working, slight negative g's first and 30 degree banks if they still aren't cleared.
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    Gabriel Silverstein's Avatar
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    #2  
    (I'm going based on memory here and it's been a long time since I looked at this, but...)

    If you look under the panel you can see the air duct coming in from the front and splitting off to each side, orange SKEET hoses I think. There should be a "down" section on both sides as I remember it as well, and without being at the plane to look at it now, I think it even angles back towards the front so as not to capture the airflow and divert it from the vents. That is supposed to catch and divert the water, but if you get enough in at once it wild come out the vents anyway and on the pilot side that nicely spills all over the ignition, smart design, but I digress

    Something could be blocking your connection there or the ducting coming down somehow - I'd check each side on that. Otherwise maybe the duct sagged (or broke free and sagged?) from too much water too many times and now leaves a dip in the hose up front that the water can collect in and block without getting back to the "down" drain section? That would block it and either a hard push over (not necessarily negative G required) or a high G (as you did it) maneuver could force it back, and again may do so hard enough to go past the drain hose connection, or if the drain is blocked, it will only have the vent to exit?
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    Michel Gadbois's Avatar
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    #3  
    Here is what I found out... The 4 inch scat pipe from the air vent to the nose landing gear bay can contain about a gallon or so of water. the drain hole between it and the gear bay is small (1/2 inch or so). The idea is that it will drain over a minute but not allow water in the nose gear bay to "Rush" up into the vent space. I would check your 1/2 inch hole to make sure no seaweed entering the nose vent blocked it. you may have to have someone remove the scat to really get there and see... If the hole is free of obstructions, it should completely drain in the time it takes you to reach rotation speed or soon after. Happy hunting!
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       #4  
    Thanks to Gabriel and Michel for the additional info. I'll be checking both areas!

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