Troubleshooting the Garmin GTX345, GTN650, and Flightstream 510 installation

This page is published as a public repository of all of the information we have concerning the issues we’ve had with our ADS-B install on N54SS. It is intended as a central knowledge reference for any and all technical support who are assisting us in coming to a successful conclusion to our ongoing issues. Nothing stated here is intended as a slight towards anyone or questioning anyone’s expertise or efforts. It is simply a statement of the facts as they are known at the time.

I will update this page, or this blog, with our progress in solving the issues going forward.

All images in this post are clickable to improve detail clarity. Many require clicking to see the needed detail.

Knowledge Leveling Information

N54SS on the ramp in Texas during the purchase pre-buy
N54SS on the ramp

This is a summary of the issues we’ve seen and continue to see in our testing of our new Garmin installation in N54SS, installed by Pee Dee Avionics in Cheraw, SC between August and September of 2017. There has been no indication of issue with the actual installation, only with the devices once they were installed.

This is also detail of the test flight data we’ve collected from multiple test flights (11.4 hours total) over the past months, but primarily it comes from a three flights conducted on 12/1/2017 as these contain the latest information.

The reason for conducting these tests in flight is because our local field (KHRJ) does not have an ADS-B tower in view from the ground. However, immediately upon takeoff we have multiple towers in view. Most flights were conducted orbiting near the airport at 2000 feet MSL.

One of the test flights on 12/1/17, from
One of the test flights on 12/1/17, from

There are two owners of N54SS, Dan Moore, and Daniel Cooke. They live one hour from each other, and the home airport (KHRJ) is directly between the two of them. It is unusual for both owners to be at the airport at the same time due to scheduling conflicts. Most test flights have been conducted by Dan Moore, but thankfully the test flights on 12/1/17 were conducted with both Dan’s in the cockpit.

Typical cockpit setup for the test flights was:

  • All in panel avionics powered and operating normally.
  • Primary iPad mini in panel mount, iOS 11.0.3, connected to GTX345 via bluetooth and Flightstream 510 via bluetooth.
  • Secondary iPad 4, iOS 11.1.1, connected to a Stratus 2 via wifi.
  • Iphone 6s, iOS 11.1.2, connected to GTX345 via bluetooth and Flightstream 510 via bluetooth.
  • All iPads were running the latest version (at the time) of Foreflight, version 9.4.3

Additionally on our last flight on 12/1/17, we connected an additional iPad to the Flight Stream 510 via bluetooth. This iPad was running Garmin pilot. We traditionally only use Garmin Pilot to update the database.

The latest data from ADS-B information block as shown in Foreflight and noted by the arrow. The data has been expanded to show the additional time stamp info in this instance.
The latest data from ADS-B information block as shown in Foreflight and noted by the arrow. The data in this picture has been expanded to show the additional time stamp info in this instance.


We have had several failure modes since the original install of the Garmin products. The first was that data block, as noted in the picture above by the arrow, showed that “no data” was being received despite being connected to multiple towers. We were able to receive and display ADS-B traffic and METARS, etc, but no radar. This issue was corrected, we assume, by a software update performed by Pee Dee Avionics on 11/6/2017. It has not manifested with this particular failure mode since the software update.

After the software update, on the flight home I noted that the data now updated but only on the quarter hour (i.e. 8:00, 8:15, 8:30, 8:45, etc). This was different than previous flights in both N54SS and other aircraft which updated every few minutes, and not on a specific time. This function was explained by Garmin to be normal as “we had zero radar returns in the region and the weather radar only updates every 15 minutes when there is nothing to report.”

Flight from Pee Dee Avionics to home base of KHRJ. Note the weather to the North West
Flight from Pee Dee Avionics to home base of KHRJ. Note the weather to the North West

However the flight home from KCQW to KHRJ is shown above in While there was no weather in SC that day, there were returns in NC, some relatively close to the flight track. This is the flight where the data block only updated every 15 minutes. With weather on the radar, the regional radar should be updating every 2.5 minutes. Also, other aircraft I fly in with GTX345s update much sooner than every 15 minutes. However, this issue has since disappeared and the updates seem to be happening normally. There was no service work performed to explain this change in operation, nor software updates to the panel mount avionics nor the iPads in use so we have no explanation for why the updates are back to being every few minutes. When we flew the last series of test flights, there wasn’t a radar return for 500 miles so by the explanation we were given, it should have updated every 15 minutes instead of the 2-5 minutes it was performing.

On 11/24/17 N54SS was flown to KHEF and back on a trip spanning several days. The pilot reported that his Foreflight display showed “Radar not Available” on his map in Foreflight for the entire flight. This iPad was connected to the GTX345 via Bluetooth.

Radar not available. It's only viewable when zoomed in very closely.
Radar not available. It’s only viewable when zoomed in very closely.

Test Data

On the first test flight on 12/1/2017 I first flew the airplane alone, waiting for the other pilot to arrive from work, and to test another problem that we had (this one was pilot induced). I did not note the “Radar not available” on my iPad but I found when shown by the other owner that it was indeed there. You need to be zoomed in fairly tight in order to see the words. There is also a series of cross grey lines that I had noticed but didn’t recognize for what it was until it was shown to me by the other owner. When in this failure mode, despite showing radar updates per the data block, the entire map is greyed out and “radar not available” covers the entire chart.

After being shown the failure mode, both owners took the airplane back up for another test flight on 12/1/17 and were able to demonstrate the “radar not available” issue readily. We compared the iPads connected to the Garmin panel mount avionics to an iPad connected to a Stratus 2. The picture below is a side by side comparison from in flight. This picture is full resolution so you can click on it to make it bigger. Only at full size do you notice the grey line pattern on the left iPad. It’s much easier to see on the screen capture above.

iPad mini on the left connected to GTX345. iPad 4 on the right connected to a Stratus
iPad mini on the left connected to GTX345. iPad 4 on the right connected to a Stratus

If you click on the image to view it full size, you can see that there are faint gray lines on the chart on the left iPad. The iPad on the right shows no such lines, it is receiving radar.

For testing purposes, we connected and disconnected various iPads to the panel mount avionics, and to the Stratus. When the iPads were connected to the panel mount avionics, the radar not available issue was consistent regardless of the iPad in use. Also, when the iPad not receiving radar was connected to the Stratus, the “radar not available” went away immediately. This does not appear to be an iPad issue.

iPhone connected to GTX345 and Flight Stream 510
iPhone connected to GTX345 and Flight Stream 510

In addition, we grabbed a screen capture of the failure mode on the iPhone. Here the grey cross hatch lines can be seen easily. However it is not zoomed in enough to see the words “radar not available” except at the very bottom of the map behind the glide information. You can also note that the iPhone showed no data. There was a period of time on the second test flight where all the connects and disconnects seemed to disrupt everything. Devices didn’t match each other, some had issues connecting, etc. This was a test environment with lots of button pushing. We landed, powered down the airplane and avionics, and powered down all portable devices and booted them fresh for the last test flight.

GTN650 and ipad mini
Picture taken at 4:37. The time is just cut off in this picture.

We also tried to compare the data from the GTN650 to the data shown in Foreflight. This picture is also full resolution meaning you can click on it and get a better view. The FIS-B data on the GTN650 shows three minutes old at 4:37 or it was received at 4:34. The latest data block on the iPad shows 4:25, 9 minutes older than the data shown in the GTN. Again, this iPad is connected to the Flightstream 510 and GTX345 via bluetooth so I have no explanation for why the data on the iPad would be older or at a different refresh rate than the GTN.

When we landed again, we decided a last test would be to install Garmin Pilot on one of the iPads and fly again with Garmin Pilot connected to the panel mount avionics. Neither of us are very familiar with Garmin Pilot so there was some time spent trying to find similar information in the application. These screen shots are as close as we could come to showing some helpful information on Garmin Pilot, because of our limited familiarity. 

Lastly, I routinely fly with the Civil Air Patrol’s NC wing. NC Wing has equipped all 17 of their aircraft with Garmin GTX345s. I connect my iPad, the same one used in these tests, to the Civil Air Patrol aircraft via bluetooth when flying. My experience in the CAP aircraft is that everything discussed here works flawlessly. The data block updates every 2-5 minutes regardless of weather conditions, or lack of weather, radar is shown (no grey lines, no radar not available), METARS update, etc.

Also, in flying with the Stratus 2, I find that the issue discussed above also do not happen. In our testing on 12/1/17, we found that the Stratus began transmitting data to the iPad almost immediately upon takeoff whereas the GTX345 took several minutes to begin transmitting data. We never once had an issue with update rates, radar not received, etc. from the Stratus.


There have been several theories submitted for what is going on.

  1. Radar data only updates every 15 minutes because there is no weather to report.
  2. There are too many devices using Bluetooth, and it’s causing a bandwidth issue.

For the first theory, the track from 11/6/17 for N54SS shows weather in the region. Per the details forwarded by Pee Dee Avionics, updates should have been happening at 2.5 minute intervals because there were radar returns in the immediate area. I do not believe the update rate from the FAA is  the issue.

For theory #2, We tried several things to mitigate connectivity issues.

  • We flew with only one iPad connected to the panel mount avionics, and nothing else powered up.
  • We removed several devices from the bluetooth page on the GTN, narrowing down to the test device or devices depending on the individual test.
  • We connected different devices at different times to eliminate any issue related to one device. Basically we rotated all connections through all devices to make sure no problem stayed with one iPad.
  • We powered everything up, Stratus, all iPads, iPhones, a non-apple phone, everything. With the exception of the non-apple phone, everything worked as before with no inconsistencies other than the problems described. We were not able to connect the phone during our test, but it had been connected previously. It is the one we utilize to update our databases.
  • Finally we connected devices that were not showing radar to the Stratus. They would immediately eliminate the “no radar” message and the grey lines. We would then reconnect to the Garmin and the “no radar” message and lines would reappear.

The issue is repeatable and tied directly to the Garmin products installed in N54SS this summer. From a customer’s experience, these issues have been present, in one form or another, since the products were newly installed. We have eliminated iPad issues and Foreflight issues via our testing. These issues are a direct result of our initial install with these products and I believe are a software issue internal to the Garmin products. I do not know at this time if the issue is related to the Flight Stream 510, or the GTX345. After 11.4 hours of testing, I’d like a better opinion of what we are going to fix before I make another flight to either test or reposition to maintenance in SC.

2 Replies to “Troubleshooting the Garmin GTX345, GTN650, and Flightstream 510 installation”

  1. I just had a GTX 345 installed and had the same Radar Not Available issue in my maiden flight. Is is also not displaying weather on the 430W. Were you able to solve this?

  2. I have occasionally had this problem. Now I intermittently get a “ADS-B Signal Lost” message and loose the “IN” portion, loosing weather, traffic, location, and Ground speed parameters.

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