questions abt pitot static system???

Discussion in 'Instruments / Avionics / Electrical System' started by ling, Jul 7, 2006.

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  1. Jul 7, 2006 #1

    ling

    ling

    ling

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    I need help for all these questions abt pitot static system...
    Can any1 explain?


    thanx...:)

    1) the connection from pitot/static probe to the (Central) Air Data Computer (CADC or ADC) to the various indicating instruments.

    2) how the system support the Captain and the First Officer (F/O).

    3) how the system continue to give altitude indication when there is a failure in static air pressure from the captain or F/O static port.
     
  2. Jul 19, 2006 #2

    IanJ

    IanJ

    IanJ

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    Location:
    Seattle, WA (5 nm N KBFI)
    The static system (ignore the pitot for now) is very very basic. It's a tube. It runs from a point of neutral pressure on the hull of the aircraft (usually) to one or more instruments. Being just a tube, it's split with tubing Ts, similar to what you'd find in plumbing pipe (at least in concept).

    There are only a few failure modes for a static system. One is if the static port is covered up -- by ice, or dead bugs, or dirt, or whatever. The other is if a tube breaks, perhaps due to metal fatigue, age, or whatever.

    If the static system seems to be failing, some airplanes have an alternate static system, which can be engaged by moving a control. This switches the static system to use a different static port, as I understand it.

    That's the system in a light plane with steam gauges.

    I don't have experience with jets, but I imagine they're a variation on the theme: a tube runs from a point of neutral pressure on the hull to the air data computer. The air data computer processes that information via a sensor, and sends the appropriate signals to electrically-controlled instruments in front of the pilot and co-pilot. I'm quite sure big planes have at least one alternate static source, possibly a number of them. I bet they even have systems which automatically detect a failed static system, and switch over to alternate sources until they find data which matches what other sources are indicating.

    Other sources of altitude information would come directly from GPS, or could be calculated via DME, LORAN, or anything else which provides a definite distance from a known point.

    Does that answer your question?
     

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