IFD 5 Series & IFD 4 Series Touch Screen GPS/NAV/COM

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LPV downgrade

Printed From: Avidyne
Category: Avidyne General
Forum Name: IFD 5 Series & IFD 4 Series Touch Screen GPS/NAV/COM
Forum Description: Topics on Avidyne's IFD 5 Series and IFD 4 Series Touch Screen GPS/NAV/COM
URL: http://forums.avidyne.com/forum_posts.asp?TID=2503
Printed Date: 09 May 2024 at 5:19am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com

Topic: LPV downgrade

Posted By: Craig767
Subject: LPV downgrade
Date Posted: 23 Apr 2023 at 7:31pm

Was doing practice apps the other day when the IFD540 downgraded the LPV. Got an alert message about the issue and IFD showed GPS-LNAV+V. Except there was no +V.

Does the IFD default to LNAV only, even though it had a +V. I think Garmin does this, not sure about Avidyne.

Craig

Replies:

Posted By: AviSteve
Date Posted: 23 Apr 2023 at 9:50pm

The FMS will go to LNAV+V and provide advisory vertical deviations only if there is a descent angle associated with the approach (i.e. specified in the database).

I did get confused by the wording of your question. What does "Except there was no +V" mean? Does that mean that the +V didn't appear in the upper right corner or does it mean that you didn't get advisory vertical deviations during the approach?

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Steve Lindsley
Avidyne Engineering

Posted By: Craig767
Date Posted: 23 Apr 2023 at 10:40pm

There was no advisory vertical deviation although the IFD showed LNAV+V. Though it was curious that although the IFD determined the LPV criteria was not met, it still showed +V. Would have made more sense to have seen just LNAV.