Erroneous Terrain Warnings

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   We've had our Bonanza back from Avionics Upgrade for about 3 months.  We have an IFD-440 integrated with Dynon glass.  My partners and I love the Terrain Features of the Avidyne and have extensive experience with EGPWS with the Airlines.  When I've tested the system by pointing it at small mountain I have gotten the caution terrain as advertised.  Never pointed it long enough to get the Pull-up warning.  Not that brave or stupid as one might gather.  But now we've gotten two erroneous terrain warnings.  One was on a base turn to Chandler Airport KCHD Right base 22R VFR pointed at the SanTan Range (SanTan's are about 7-8 miles Southeast about 3100 MSL Peak).  I was probably about 1800-1900'MSL.
The other incident happened a couple days ago with my partner VFR into Cottonwood (P52) on a long final into runway 32 where he was high on final.  Both included the pull-up.  At night or IMC were trained to not question and immediately take action for obvious reasons.  Can I get some clarity on why this might have occurred?  Have you seen this on other aircraft?  Can you talk about the algorithm?

Thank you,

Kenneth Morris

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kjmorris2023 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 17 Apr 2021 Location: AZ Status: Offline Points: 5	Post Options Post Reply Quote kjmorris2023 Report Post Thanks(0) Quote Reply Topic: Erroneous Terrain Warnings Posted: 19 Apr 2021 at 1:20pm
	We've had our Bonanza back from Avionics Upgrade for about 3 months. We have an IFD-440 integrated with Dynon glass. My partners and I love the Terrain Features of the Avidyne and have extensive experience with EGPWS with the Airlines. When I've tested the system by pointing it at small mountain I have gotten the caution terrain as advertised. Never pointed it long enough to get the Pull-up warning. Not that brave or stupid as one might gather. But now we've gotten two erroneous terrain warnings. One was on a base turn to Chandler Airport KCHD Right base 22R VFR pointed at the SanTan Range (SanTan's are about 7-8 miles Southeast about 3100 MSL Peak). I was probably about 1800-1900'MSL. The other incident happened a couple days ago with my partner VFR into Cottonwood (P52) on a long final into runway 32 where he was high on final. Both included the pull-up. At night or IMC were trained to not question and immediately take action for obvious reasons. Can I get some clarity on why this might have occurred? Have you seen this on other aircraft? Can you talk about the algorithm? Thank you, Kenneth Morris

AviSteve Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 12 Feb 2018 Location: Melbourne, FL Status: Offline Points: 2146	Post Options Post Reply Quote AviSteve Report Post Thanks(0) Quote Reply Posted: 19 Apr 2021 at 9:35pm
	I'll have tech support contact you so that you'll have a place to send logs. We'll take a look at them and get back with you regarding why the warnings triggered.
	Steve Lindsley Avidyne Engineering

birddog486 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 23 Jan 2021 Location: 53511 Status: Offline Points: 10	Post Options Post Reply Quote birddog486 Report Post Thanks(0) Quote Reply Posted: 01 May 2021 at 12:53pm
	Let us know what they come up with. I get this warning often flying into small airports which is really annoying

safari Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 28 Apr 2014 Location: Sedona Status: Offline Points: 55	Post Options Post Reply Quote safari Report Post Thanks(0) Quote Reply Posted: 01 May 2021 at 3:17pm
	I get the terrain warning every time I fly in to Sedona unless I am on the gps approach. I just figured it was because there are rocks all around not that far away but it is very annoying.
	Dave

kjmorris2023 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 17 Apr 2021 Location: AZ Status: Offline Points: 5	Post Options Post Reply Quote kjmorris2023 Report Post Thanks(0) Quote Reply Posted: 03 May 2021 at 1:25pm
	They haven't got back to me. I uploaded a bunch of logs also.

birddog486 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 23 Jan 2021 Location: 53511 Status: Offline Points: 10	Post Options Post Reply Quote birddog486 Report Post Thanks(0) Quote Reply Posted: 14 Jul 2021 at 10:00pm
	Did you ever get a reply from Avidyne?