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Date: Wed, 04 Apr 2007 17:55:44 -0400
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Subject: pitot and static
From: "bob mackey" <n103md@yahoo.com>
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> The correct way to check the static internal lines and equipment
> is to perform the required bi-annual transponder Mode-C reporting
> and TSO'd altimeter concordance tests by an avionics shop.
> BTW, it is good practice to do this check and log it before
> the first flight in a newly certificated experimental, if possible.

If an aircraft passes those tests, it is pretty much guaranteed
that the instruments will read altitude and airspeed correctly
when stopped at any practical altitude. In most Lancairs, the only
good time to be stopped is when on the ground.

Because those tests don't check that the pressure at the
ports is representative of your altitude or your speed,
they do not guarantee accuracy at any speed other than zero.
The appropriate tests for static port and pitot port
accuracy have been described in recent messages...

First check that the altimeter indication is unchanged by airspeed
at a constant altitude. Then check that the (calibrated true)
airspeed matches the actual distance/time.

Another way is to compare pressures to those measured by a
trailing bomb pitot and static source that is unaffected
by the airframe's passage through the air. Dick Johnson explains
how in one of mnay sailplane test articles:
http://www.dg-flugzeugbau.de/dg1000-johnson-e.html