While quick-drains don't generally go bad, there is one at the bottom of the sealed tube (that goes from top skin to bottom skin) from which the top skin pressure is taken... if that quick drain isn't sealing the pressure in that tube will not accurately reflect top-skin pressure, so AOA readings will be in error,  I don't know if that will cause those errors but it is another consideration that is often overlooked when leak testing.  FWIW.

  <marv>



"Greenbacks, UnLtd." <N4ZQ@verizon.net> wrote:

> Hi Bob,
>
> I had never before powered up the AOA while in flight so had never seen
>those error messages.
> The pressure port lines have quick disconnect fittings thanks to Bill H, so
>I'll apply some pressure
> at the fitting and blow toward the wing tip. Will check for loose
>connections today.
>
> Angier
>
> Begin forwarded message:
>
>> From: Robert R Pastusek <rpastusek@htii.com>
>> Date: November 12, 2013 12:48:53 AM EST
>> To: "Greenbacks, UnLtd." <N4ZQ@verizon.net>
>> Subject: FW: [LML] Re: AOA issue
>>
>> Angier,
>>
>> This and the earlier messages accurately describe how the AOA
>>works/self-tests. You'll always get these error messages if you power up the
>>unit in flight, and can get them on the ground in a strong wind as the sensor
>>comparisons for test will fail under windy conditions. Dimming is a
>>sequential function of grounding one of the leads. One grounding causes it to
>>go dim; the next bright, and so on. A loose connection, or intermittent short
>>can cause this, as well as an "un-commanded" self-test. Ditto for an
>>interruption of input power. These are far more likely than a malfunction of
>>the system.
>>
>> BE SURE you don't apply compressed air to the AOA sensors themselves, and
>>I'd strongly recommend against even blowing into the lines when they are
>>attached to the sensors. The pressure differential they are measuring is in
>>millibars/inches of water...in other words, very small. They can be easily
>>damaged by such action.
>>
>> Bob
>>
>> -----Original Message-----
>> From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of John
>>Cooper
>> Sent: Monday, November 11, 2013 7:33 AM
>> To: lml@lancaironline.net
>> Subject: [LML] Re: AOA issue
>>
>> The AoA display getting dim sounds like a separate problem, but the E11 and
>>E33 may have been due to water in the sense lines, or perhaps a loose ground
>>wire at the red and black pushbuttons. The E33 just means that some other
>>error was reported and, (from the manual) the E11 means:
>>> Reasonableness ramp check of the wing
>>> differential pressure transducer is not within acceptable limits. This
>>> may be due to wind or might be due to damage of the differential
>>> pressure transducer. If the system re-tests OK in a hangar, assume the
>>> problem was due to wind.
>>> If the error persists, a re-calibration of the AOA may fix the
>>> problem. If the test function was activated during flight, this error
>>> message is expected and normal.
>> I'd remove the sense lines at the CPU and *gently* blow them out just to be
>>sure, but is it possible that you may have inadvertently touched the black
>>and red push buttons? As you know, the black is the dimmer button and the red
>>is the test button which would account for both your problems. Is it possible
>>that ground wire to those two buttons is loose?
>> I'd closely inspect the wiring to those two push buttons.
>>
>>
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>
>
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