Hey Todd, Sorry to hear about the incident, but glad you came through it unscathed.

Re: the AOA... At power up, when the AOA does its self test, it is looking to see if all 4 pressures are identical.  If they are, it considers their data to be valid and passes the test.  Given your situation with a pinched static line, the only way the instrument could give you an error message would be if there was a significant barometric change at some time prior to power-up that would cause the old pressure to be trapped in the static tube while the pitot and wing ports report the current different barometirc pressure.  Unless the kinked tube is really pinched tight the kink will act more like a flow restrictor than an actual blockage, so that over some period of time the pressure in that tube will equalize to ambient.  The sensors inside the instrument are a pair of differential pressure transducers, one that measures the difference between the pitot and static pressures and one that measures the difference between the upper and lower wing ports.  With your static pressure line restricted the increasing pitot pressure (caused by increased airspeed) could not adequately register in the transducer, as there was a hydraulic lock of sorts that kept the transducer's diaphragm from deflecting. Consequently, your airspeed indicator was seeing airspeed, but the AOA was not, thus the stall warning as wing pressures showed AOA being developed without sufficient airspeed.  Given that the instrument's warning ultimately shut up, the large differential in pitot/static pressures obviously forced the trapped air past the restriction in the kinked line, thus allowing some airspeed to be registered to the instrument.  As altitude increased the amount of pressure available from the pitot port would decrease, consequently the instrument would also see this as a decrease in airspeed until the static line bled down, and when it compared that data to the calibrated data it saw a pressure indication that suggested you were approaching the stall, and again gave you a stall warning.  When you dig out the AOA manual, see if you can find the calibration checklist... one of the first steps on the checklist is to verify all of the pressure connections by disconnecting the hoses from the AOA computer. Blowing into the wing tubes while someone verifies that there is airflow at the respective wing ports tests the wing connections.  The pitot test is to have one person blow into the pitot tube while someone verifies that air is coming out of the pitot hose.  You can do the same test with the static line provided you can also get to its other end.  I think the recommended static tube test is for you to suck on the static hose and put your tongue over the end... if the hose is restricted your tongue will be sucked into the end and seem to be stuck there until the pressure equalizes if at all.  Get the hoses unkinked and all should be well.

I hope this helps.

   <Marv>



"Haywire" <haywire@telus.net> wrote:


 > > >    Next up was the AOA. During the addition of the EM2 & Dynon to my panel,
I required more static & pitot inputs so I reworked this part to provide a
header for each with several spares. During this I re-routed the small 1/8"
tubing for the AOA and when the panel was put into place it kinked and
pinched off the static source to the AOA only. So this allowed it to pass
it's self test, but during climb-out it was missing the rate of change that
it needed to see. I would have expected that to just cause it to give an
error message, but apparently not. I've got to read the instructions on that
thing again as I'm sure that there must be away to silence it. < < <