DFC90/DFC100 Digital Autopilot

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Overspeed Warning

Printed From: Avidyne
Category: Avidyne General
Forum Name: DFC90/DFC100 Digital Autopilot
Forum Description: Topics on the Avidyne DFC Digital Autopilots
URL: https://avidynelive.com/forum_posts.asp?TID=1973
Printed Date: 26 Mar 2026 at 10:42am
Software Version: Web Wiz Forums 12.07 - https://www.webwizforums.com

Topic: Overspeed Warning

Posted By: daveS
Subject: Overspeed Warning
Date Posted: 15 Apr 2020 at 2:22pm

Just completed my 3rd flight with my newly installed DFC90 in my SR22 G1 Aspen 1000. It’s working well but on my last flight I got an overspeed warning while cruising with an IAS of 150kts and the flaps were up. 3 voice warnings and the she went quiet. It happened once more later in the flight at 140 KIAS and zero flaps. Thoughts?

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dave

Replies:

Posted By: AviSteve
Date Posted: 17 Apr 2020 at 4:43am

It depends upon whether you heard "Caution Flap Overspeed" or "Caution Overspeed".

If flap overspeed, it's most likely a loose wire in the flap switch circuit. You may be able to diagnose it by jiggling the switch in flight.

"Caution overspeed", is based strictly on the data that we get via serial bus from the Aspen. Verify that the Aspen software is up to date for both the MAP and the IOP. Might be worth asking Aspen to see if they have had any other reports of this behavior. We did spend some time earlier this year tracking down a problem with integration of the Aspen Max units and the DFC90, which resulted in a new Aspen IOP software version. The problem we tracked down would cause a disconnect, not an overspeed, but it may be related.

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Steve Lindsley
Avidyne Engineering

Posted By: daveS
Date Posted: 17 Apr 2020 at 4:50am

It was flap overspeed so I’ll check out the switch.

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dave