Glen Davis Posted February 25, 2025 Report Posted February 25, 2025 I have a G3X and a GTN 750 in my Mooney. I also have the remote transponder and audio panel. This is a certified installation, not experimental. I am not hearing any traffic alerts, 500 foot alert, TOD alert or Obstacle alert. The only alert I hear is the auto pilot disconnect alert. I called Garmin and was told on a certified install, I should hear all those alerts. I called the installer and was told I would need to pay about $19,000 to unlock TAWS. So my qeustion for you with certified installs, what allerts to you hear?
Rick Junkin Posted February 25, 2025 Report Posted February 25, 2025 @Glen Davis I have a G3X and 650Xi and get all of the audio alerts you mentioned. You definitely do NOT need to spend $$$ on TAWS to get the basic alerts. Most alerts are redundant on the G3X/650Xi so I have everything activated on the G3X and the redundant alerts turned off on the 650Xi. This is probably backwards but the way I chose to do it. It requires access to the configuration menus on both boxes, which is easy to access (hold the MENU/HOME buttons in and power up the boxes until the config mode displays). I don’t recommend doing this, especially on your GTN750, if you haven’t seen it before and don’t have the install documentation to guide you. It doesn’t take much to push a wrong selection and mess up some important systems interface settings. I’d ask your installation shop why they didn’t activate the alerts. If they push back show them the G3X Pilot Guide sections that describe the alerts you are supposed to get. There are enough of us here who have worked through this that can help you get to where you want to be. 1
PT20J Posted February 25, 2025 Report Posted February 25, 2025 Sorry, but your installer doesn’t seem to know what he’s doing. The alerts should have been configured during installation. Assuming everything is wired correctly, enter configuration mode, go to the sound configuration page and set up the alerts. 2 1
PT20J Posted February 25, 2025 Report Posted February 25, 2025 18 minutes ago, Rick Junkin said: @Glen Davis I have a G3X and 650Xi and get all of the audio alerts you mentioned. You definitely do NOT need to spend $$$ on TAWS to get the basic alerts. Most alerts are redundant on the G3X/650Xi so I have everything activated on the G3X and the redundant alerts turned off on the 650Xi. This is probably backwards but the way I chose to do it. It requires access to the configuration menus on both boxes, which is easy to access (hold the MENU/HOME buttons in and power up the boxes until the config mode displays). I don’t recommend doing this, especially on your GTN750, if you haven’t seen it before and don’t have the install documentation to guide you. It doesn’t take much to push a wrong selection and mess up some important systems interface settings. I’d ask your installation shop why they didn’t activate the alerts. If they push back show them the G3X Pilot Guide sections that describe the alerts you are supposed to get. There are enough of us here who have worked through this that can help you get to where you want to be. In a G3X installation, all the audio is routed through the G3X GDU and the G3X installation manual calls for only the G3X to be connected to the audio panel. If the GTN is also connected, you will likely get an echo when engaging Smart Glide (that’s how I found out that both of mine were connected. 1
Rick Junkin Posted February 25, 2025 Report Posted February 25, 2025 4 minutes ago, PT20J said: In a G3X installation, all the audio is routed through the G3X GDU and the G3X installation manual calls for only the G3X to be connected to the audio panel. If the GTN is also connected, you will likely get an echo when engaging Smart Glide (that’s how I found out that both of mine were connected. Yup, mine are both connected as well. I was getting an echo on the 500 foot callout, which I then disabled on the GTN. I didn’t realize that isn’t in compliance with the STC so I just learned something from you, again .
1980Mooney Posted February 25, 2025 Report Posted February 25, 2025 36 minutes ago, Rick Junkin said: I don’t recommend doing this, especially on your GTN750, if you haven’t seen it before and don’t have the install documentation to guide you. It doesn’t take much to push a wrong selection and mess up some important systems interface settings. There are enough of us here who have worked through this that can help you get to where you want to be. Sounds like you are speaking from experience.... 1
PT20J Posted February 25, 2025 Report Posted February 25, 2025 8 minutes ago, Rick Junkin said: Yup, mine are both connected as well. I was getting an echo on the 500 foot callout, which I then disabled on the GTN. I didn’t realize that isn’t in compliance with the STC so I just learned something from you, again . It took a lot of sleuthing and phone calls to Mooney to figure it out. The installations can be confusing because the installer has to read the installation manuals for each piece of equipment in the right order as some equipment installations require changes to wiring or configurations of other equipment. 1
Rick Junkin Posted February 25, 2025 Report Posted February 25, 2025 6 minutes ago, 1980Mooney said: Sounds like you are speaking from experience.... Fortunately no! I studied the configuration documentation before jumping in to the systems so I’d know what to stay away from. My background makes me inclined to “tinker”, which is NOT a good thing in this case. 2
Ragsf15e Posted January 21 Report Posted January 21 I've got a question for you guys from a recent "experience" with my G3x and GTN750. I was on a GPS instrument approach into Spokane, AP tracking GPS laterally and GS vertically, just outside the FAF, all was well... except that I was dropping through a layer that potentially held some icing, so I was monitoring the approach and looking outside at the wings. Unbeknownst to me, the GPS dropped WAAS at about 1/2nm from the FAF and reverted to an RNAV lateral only approach. Yes, the GS disappeared and the (very small) "msg" flag on the HSI popped up. I do not remember any sound at all. Meanwhile, the AP reverted to pitch mode and continued to descend so it was not noticeable in aircraft control. I had the FAF altitude set in the altitude window though, so at that altitude it reverted to ALT (sel) and then Alt Hold. I realized what happened about .5nm after the FAF (and now high and late to descend) but was able to descend to MDA and all was well, but I didn't like it. Looking back at the G3X data pull, the whole episode was about 45 seconds before I disconnected the AP and hand flew it. Question... shouldn't there be an audio alert for the message trigger or potentially for the AP changing to PIT mode from GS? I don't remember one but maybe missed it. Pilots guide isn't helpful on this. Thanks, Drew @PT20J @Pinecone @Max Clark @Rick Junkin 1
Ragsf15e Posted January 21 Report Posted January 21 Just to add a little more detail... I read through the installation manual and there are (available) tones for the G3X "msg" alerts, however, the "msg" I got was from the GTN750, so different. Displayed in a slightly different place (also not flashing yellow, just a blue msg box). I could not find anything that says there's an audio alert for a msg from an external device. Now I'm wondering if there's some way to have the GTN750 annunciate that message? From what you guys said before though, it seems that only the G3X is supposed to be connected to the audio panel. I get that I should be very closely monitoring the AP during the approach, and there were some cues, but downgrading the approach and changing AP modes at that critical time (FAF) seems like an audio tone or message could be quite helpful there! It was all pretty subtle when it went down (or stopped going down).
Rick Junkin Posted January 21 Report Posted January 21 I'm going to shoot from the hip on this one until I have a chance to review the AFMS for both the GTN and the GFC500. From the GFC500 perspective, the only tone I'm aware of is the disconnect tone. I don't recall any tones for when the A/P changes modes, even for a reversion like this. I've been troubleshooting GFC500 anomalies with a buddy of mine in his Bonanza and there haven't been any tones when his reverts to PIT and ROL from NAV and ALT. For the GTN, I recall reading a caution/note that talked about verifying the approach type annunciation at the FAF to confirm you are getting the guidance you are expecting. In this case it must have changed from LPV / LNAV/VNAV / LNAV+V, which ever WAAS was allowing, to LNAV just prior to the FAF. I believe the AFMS gives the range from the FAF that the box performs this check and downgrades the approach guidance. However, to your question about audio alerts, no, there are none when this happens. I'll do some studying and see if I can find something more definitive. 1
Max Clark Posted January 21 Report Posted January 21 I don't know, but I pasted your question and the Garmin manuals into Gemini and this is what came back. Rick might have a better answer. 1 1
Rick Junkin Posted January 21 Report Posted January 21 21 minutes ago, Rick Junkin said: I'll do some studying and see if I can find something more definitive. @Ragsf15e Here's an excerpt from the GTN Xi Pilot Guide that details what happens in the event of an approach downgrade due to lack of position integrity. There should have been an advisory message on your 750, but I think it's easy to miss if you aren't looking at it because it isn't persistent. 2
Ragsf15e Posted January 21 Report Posted January 21 So it appears all that stuff happened and there’s no audio warning. I should be more cognizant of this in the future, but I will tell you, in the soup with any distraction, it was subtle. Im pretty glad (lucky really) that I had the FAF altitude set as normally Id have the missed altitude set, but the FAF altitude was the last one I had been given before getting on the GS. When the airplane leveled off, I realized it was doing something I didn’t like! 1
StParkin Posted January 21 Report Posted January 21 (edited) As Max's reply mentions, didn't the vertical glidepath guidance on the G3X disappear? I agree that a small "MSG" indication without an aural alert would be easy to miss, but shouldn't the lack of vertical guidance being displayed on the PFD be something noticed within 10-20 seconds or so based on scanning the instruments? Edited January 21 by StParkin
Ragsf15e Posted January 21 Report Posted January 21 9 minutes ago, StParkin said: As Max's reply mentions, didn't the vertical glidepath guidance on the G3X disappear? I agree that a small "MSG" indication without an aural alert would be easy to miss, but shouldn't the lack of vertical guidance being displayed on the PFD be something noticed within 10-20 seconds or so based on scanning the instruments? Yes, agreed. I should have caught that more quickly. However, it was surprisingly subtle. The autopilot was captured on the GS and coming down for ~a minute nice and stable. I looked outside at the wing, back inside and everything was continuing down nice and stable except now there was no magenta GS arrow on the right side of the pfd. I was still descending and the flight director was perfectly lined up, only now it was in pitch mode. It was a pretty subtle change and took me longer than I wanted to find/fix it.
StParkin Posted January 21 Report Posted January 21 Definitely understandable, and I agree that there should be a more clear indication when there is an approach downgrade/change in autopilot vertical mode while on an approach. The avionics shouldn't make this an easy thing to miss! 1
PT20J Posted January 21 Report Posted January 21 Yeah, there's no tone for that. The GFC 500 has the following alerts: 1. Autopilot disengage tone 2. "Engaging Autopilot" voice alert 3. "Airspeed" voice alert 4. Altitude alert tone In a G3X installation, the GTN audio is not connected. The terrain, traffic, "minimums" and "five hundred" alerts come from the G3X. I think Garmin probably figures it's enough to flag the indicator as would happen with an analog panel. 1 1
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