AOA Alarm stays on after landing

[jbrady]

RV-8 with D180/AP74/HS34 and heated pitot. I often get a brief STALL/STALL call out just as the aircraft is touching down in a near 3-point attitude. But recently that call out and the flashing red triangle on the AOA display often (but not always) stay on after landing, all the way through taxy until the aircraft is shut down. I could not find a way to stop that!

I though that setting the MINSPD higher (50kts) might stop that but of course, if the warning is on as speed reduces through MINSPD, it stays on - in my case until shut down. I have recently disconnected and reconnected all the pitot/static/AOA connections to the D180 when the instrument panel was removed for wiring access but pitot and static systems have been checked OK for leaks on reassembly. AOA not checked as not sure how to do that. Is there a way to correct this behaviour please?

John
RV-8 G-RUVE

 

[djones]

John,
I would start with a fresh AOA calibration to make sure the data is valid. The procedure begins on page 9-30 of the install manual.
Here is the link: https://dynonavionics.com/includes/guides/FlightDEK-D180_Installation_Guide_Rev_H.pdf

 

[jbrady]

John,
I would start with a fresh AOA calibration to make sure the data is valid. The procedure begins on page 9-30 of the install manual.
Here is the link: https://dynonavionics.com/includes/guides/FlightDEK-D180_Installation_Guide_Rev_H.pdf

Thanks for that. I have done the recalibration twice now with the same result. The only way I seem to be able to stop the STALL STALL continuously after landing is to put the MIN SPEED above the stalling speed. I get no stall warning but that is not critical in the RV-8 which has good natural buffet. Anytime the alarm is sounding during the landing flare (and the aircraft is close to the stall at that point) it stays on until the aircraft is powered down.

 

[jbrady]

As I could not fix this I have had the stall warning set to a high AOA so it does not come on during landing. But I should fix this. I now know it is not the audio warning that is the problem but the AOA which shows flashing red all the time after landing. That is part of the EMS not the EFIS so could there be a way to discover why it remains in a stall warning position even when the aircraft is stationary after landing? Is it something physical with the pitot head or in the D-180 unit itself? There are no leaks in the pipework .
John