I have a phantom 3 standard that I've made 30 very successful flights with over about 6 months building up my trust and confidence with it. However- yesterday I had an odd flight that nearly lost me the drone and has hugely knocked my confidence.

I flew the drone from the top of a big local hill. It had a home lock at takeoff and as per all flights I seem to have to calibrate compass before it will let me fly. It took off with 8 satellites locked.

I flew it away from me for 350m, backwards to capture a great zoom out. I then flew it straight back and over my head letting it go just out of sight, then rotated round about 45 deg to fly a triangular course back. I flew another 250m this way. As it was out of site and some trees were between me, I quickly got a weak transmission and video loss, (quicker than usual so maybe some interference at this site?) so tried to return home. But what happened next has baffled me. The weak signal quickly degraded to a red light on the remote and a complete loss of signal. The app said 'aircraft disconnected'

I kept trying to activate RTH but it gave time out errors. RTH is set at 30m which is much higher than the trees there, and it was set as the action for signal loss in the app.

So it was disconnected, and it didn't fly back to me. And I didn't know where it was. I ran around to where I thought it was last heading in case I could re-establish a link, but had no luck.

After 20 mins I assumed it was lost or in a tree, and felt really bad, but by huge chance and luck, some other walkers came all the way back up the hill to tell me they had seen it fly over them and it's now in a field. They showed me where, and sure enough 250m away from it's home point, it had landed itself in a field and was sat there ready to fly again. It was pure chance it was ok as 3 metres less it would have tried to land on trees.

So I'm baffled, why didn't it try to return to home? I downloaded the DAT files and looked for clues but can't see anything.

The home point seems perfectly stable through the flight and is where I started. There are no errors except lots of weak signal errors near the end. Then an auto landing signal. But no RTH notification.

I'm certain it was set to RTH as I used that on the previous flight and I tried it on a test flight as soon as I retrieved the drone and it worked perfectly.

I'm bothered by this as I don't know if I did something stupid, or if the drone malfunctioned.

Can anyone offer any clues?

Cheers

Paul

Go to http://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.
Come back and post a link to the report it provides and someone here might be able to work out what happened.

Labroides Posted at 2017-2-20 00:56
Go to http://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.
Come back and post a link to the report it provides and someone here might be able to work out what happened.

Good idea. The battery was not too empty? If you reach the 10 % marking, the Phantom lands at itself. No matter where it is.

I will upload the flight data as suggested. Battery was at 80% when this happened!

Oh imagine we will hear its something you did not the drones fault....  ;)

Here's an upload of my flight log from DJI Go.

http://www.phantomhelp.com/LogViewer/7N6I4GE33Z0836ZUOVNM/

Are you sure your failsafe is set to RTH?

I'm not sure what the command timeout means.  But it looks like you never lost your control signal.  Next time you want to initiate fail-safe (RTH) and you're not sure what's going on,, you might consider turning your controller off.  

Yes I'm confident failsafe RTH was on. It was on for the flights either side of this one and it's not a setting I have ever turned off and it's set in the app now still. Is that setting stored in any logs?

Really good suggestion about turning controller off. That's a nice trick to have up my sleeve. I did have a solud red led on the controller though so took that as bad news and that I was very disconnected.

The timeout error showed on the app too- it was timing out as I was trying to initiate return to home from the app.

I believe the red lamp means you've lost 2.4 which is FPV / telemetry.  From there, you can only guess about the 5.8 connection, but it normally has better range than the 2.4, so you're probably still connected.  But there may be something else going on.  I don't know why it would auto-land like that.  

Yes the flight logs do look like it was connected the whole time- but if it was it would have responded to my many RTH attempts surely?

Although I was only trying through the app. I would try the suggestion of turning RC off next time.

Even if it was connected when I thought it wasn't, I'd expect it to sit there until battery got low and it would then RTH.

I'm confused by it all.

If you've lost your 2.4 connection, that means your mobile device and app is in effect dead.  So you need to think in terms of the white plastic controller which is still shooting out the 5.8 ghz control signal.  If you can see the bird, you can fly it home, and if not, you can initiate fail safe by turning the white plastic controller off.  Hope this helps.  

On the left side of DJI GO, there is an icon to initiate RTH and an icon to auto land at the current location. Your flight log shows you used the auto land icon.

Yes I can see that an auto land event happened. It is of course possible I chose that by mistake as my heart sank at the thought of losing control! I can see it's looking like that's the cause here. I still have concerns as I was totally disconnected from the aircraft at the time. Or thought I was!
I think in future I'll use the left hand toggle to initiate RTH to be certain I'm not making a mistake in a panic. I got lucky here that I did that over clear ground, so can treat it as a very good learning excercise.

Yes, initiating RTH via the S2 switch is the best option since the remote controller signal is still connected in many cases when the downlink drops. After the downlink drops, there is no way to initiate RTH from within DJI GO.

That's good to know. I guess also if I had in error  asked to auto land when downlink had dropped, it would keep trying for a bit? My logs show 'downlink restored' just before auto land. So it could have reconnected downlink briefly and delivered the command then? But it also shows command timeout. it doesn't say what command. Can I find out?

As msinger suggests, your best option is to initiate RTH via the white plastic controller's S2 switch rather than the app because your 5.8 signal has a much better chance of being connected than your 2.4 signal.  And if that doesn't work or you're not sure if it's working, turning the whole thing off is sure to work.  There's really no point in fooling around with the app.  

The auto land command does not keep retrying on its own. You most likely tried initiating it multiple times. You can find more details about your flight in the DAT flight log. That log can be viewed via DatCon.

Mark The Droner Posted at 2017-2-20 04:18
I believe the red lamp means you've lost 2.4 which is FPV / telemetry.  From there, you can only guess about the 5.8 connection, but it normally has better range than the 2.4, so you're probably still connected.  But there may be something else going on.  I don't know why it would auto-land like that.

The Light on the RC is the control signal status.

Green connection good and solid
Red LED is NO RC connection

good luck and have fun flying!

I don't see a RTH icon on the GO app. All I see is the auto take off and the auto land.

fansf274e658 Posted at 2017-2-20 03:07
Oh imagine we will hear its something you did not the drones fault....  ;)

only when it is , and it usually is!

btw:
see post # 12 below!

good luck and have fun flying!

Kirk2579 Posted at 2017-2-20 06:42
The Light on the RC is the control signal status.

Green connection good and solid

How does the RC know the 5.8 control signal is lost when there is no 2.4 connection?  

The first thing I did was examine my DAT file with DatCon, but it's the first time I did that and I found it a bit of a challenge  to know what all the values tracked meant. Im hoping if I keep looking I can see what the command that timed out was.

I had a similar experience a day or two ago...I was flying my p3s from my front yard just around my house, and then I took it up to about 128 feet or so and started to fly over to the golf course at the end of the street....the aircraft was about 800 feet from me, and I got a weak remote control signal. btw, I have the ARGtek antenna mod installed and I think I had all three Omni antenna installed....anyways, the aircraft disconnected and I tried the rth function and it would just tell me that it failed. since I knew where the aircraft was, at this point I wasn't too worried. I started to walk down the street towards it and I was hoping that I would restore connection by getting closer but to no avail. after about 5 minutes I started to worry after numerous rth commands all failed. then I was thinking about turning off the controller and turning it back on but I decided to exit the app first and reopen it and see if that worked, but when I did that I also noticed that the controller Wi-Fi had switched and connected to my home Wi-Fi instead of the phantom Wi-Fi. I went into my phone Wi-Fi settings and connected back to the phantom Wi-Fi and that did the trick. it connected and I told it to rth and it did. 10 seconds later it was above me and I cancelled it and manually landed it . that's the first time that's happened to me and it did shake my confidence slightly. I looked at the flight log afterwards and it apparently was just hovering there through the ordeal.

Jasonstarbird Posted at 2017-2-20 09:06
I had a similar experience a day or two ago...I was flying my p3s from my front yard just around my house, and then I took it up to about 128 feet or so and started to fly over to the golf course at the end of the street....the aircraft was about 800 feet from me, and I got a weak remote control signal. btw, I have the ARGtek antenna mod installed and I think I had all three Omni antenna installed....anyways, the aircraft disconnected and I tried the rth function and it would just tell me that it failed. since I knew where the aircraft was, at this point I wasn't too worried. I started to walk down the street towards it and I was hoping that I would restore connection by getting closer but to no avail. after about 5 minutes I started to worry after numerous rth commands all failed. then I was thinking about turning off the controller and turning it back on but I decided to exit the app first and reopen it and see if that worked, but when I did that I also noticed that the controller Wi-Fi had switched and connected to my home Wi-Fi instead of the phantom Wi-Fi. I went into my phone Wi-Fi settings and connected back to the phantom Wi-Fi and that did the trick. it connected and I told it to rth and it did. 10 seconds later it was above me and I cancelled it and manually landed it . that's the first time that's happened to me and it did shake my confidence slightly. I looked at the flight log afterwards and it apparently was just hovering there through the ordeal.

You certainly kept your cool there...... very impressive. Wonder why the failsafe RTH didn't work..... bit worrying.  I think I'd have lost it completely!

GeoffN Posted at 2017-2-20 09:13
You certainly kept your cool there...... very impressive. Wonder why the failsafe RTH didn't work..... bit worrying.  I think I'd have lost it completely!

I don't know either....I think if I'd been somewhere else I would have been more worried, but since it was close and over the golf course I figured I would find it....still. I am going to start reading more to get a better understanding of what exactly is supposed to happen when it disconnects.

Jasonstarbird Posted at 2017-2-20 09:32
I don't know either....I think if I'd been somewhere else I would have been more worried, but since it was close and over the golf course I figured I would find it....still. I am going to start reading more to get a better understanding of what exactly is supposed to happen when it disconnects.

There are two signals.
Your control signal and the downlink carrying video.
It's usual for the downlink to fail first and it's possible to be in a situation where you lose downlink but still have control signal and control of the Phantom with the controller.
The Phantom will initiate RTH after it has lost control signal but if you only lose downlink, it will hover until you give it some control input.

Labroides Posted at 2017-2-20 15:32
There are two signals.
Your control signal and the downlink carrying video.
It's usual for the downlink to fail first and it's possible to be in a situation where you lose downlink but still have control signal and control of the Phantom with the controller.

'...it will hover until you give it some control input.'

Or you accidentally hit Auto Land, which looks to be the most likely scenario in this case.

dcarter0001 Posted at 2017-2-20 06:43
I don't see a RTH icon on the GO app. All I see is the auto take off and the auto land.

It's there.  It has the H symbol in the icon.

Geebax Posted at 2017-2-20 16:26
'...it will hover until you give it some control input.'

Or you accidentally hit Auto Land, which looks to be the most likely scenario in this case.

Yep It's easy when you are not familiar to use a command thinking it's the RTH command.

Pretty much all the threads I read of a crashed or lost drone have been pilot induced errors.
One guy was complaining he flew into a restricted aircraft area. His drone auto landed and hit a tree on the way down.  He blames DJI. Even though the App warns him he kept on flying into a no go area. The drone did what it is supposed to do.   One guy flew his drone into the river. He claims that at 2200ft away he could have line of sight and tell how high it was above the water.  To bad he flew behind a bridge and lost contact with his drowned drone.

I never mess with the app when I want to RTH.  Its way too easy to use the RC and initiate a RTH.  I recommend practicing RTH using the RC.  You can also cancel RTH with the RC.

Vikassi Posted at 2017-2-20 20:01
I never mess with the app when I want to RTH.  Its way too easy to use the RC and initiate a RTH.  I recommend practicing RTH using the RC.  You can also cancel RTH with the RC.

Well it's all about learning the control functions of both app and RC.

This was just a simple case of the OP issuing a land command and not an RTH command.
Fortunately no harm done.

Mark The Droner Posted at 2017-2-20 04:18
I believe the red lamp means you've lost 2.4 which is FPV / telemetry.  From there, you can only guess about the 5.8 connection, but it normally has better range than the 2.4, so you're probably still connected.  But there may be something else going on.  I don't know why it would auto-land like that.

Actually,  red light on the controller means loss of control signal.  Loss of telemetry is self evident by loss of telemetry.

dcarter0001 Posted at 2017-2-20 06:43
I don't see a RTH icon on the GO app. All I see is the auto take off and the auto land.

I think you will find that the auto take-off is replaced by RTH after you take off. If you are looking at it before you take off there is no RTH (as there is no need to RTH when landed).

I'm comfortable that I caused the landing by mistake, but I'm still confused about the connection status, as there seems to be differing views here. How can I find out exactly what the red light on RC means? Is it just downlink loss or total loss? It' feels like important info to know! The manual suggests total loss but it doesn't really say that clearly.

I've also studied my DAT file with DATCon and can't see any reference to the timeout messages. I guess as the DAT file is recorded by the drone that makes sense- it wouldn't record it in the log if it never received it.

So is there more detail available in the app logs? I'm still keen to know why I was getting command timeouts, and what those commands were.

Cheers

Kneepuck Posted at 2017-2-20 21:02
Actually,  red light on the controller means loss of control signal.  Loss of telemetry is self evident by loss of telemetry.

My point is, you could have a red lamp and a perfectly good control signal.  

Phantom_menace Posted at 2017-2-21 01:13
I'm comfortable that I caused the landing by mistake, but I'm still confused about the connection status, as there seems to be differing views here. How can I find out exactly what the red light on RC means? Is it just downlink loss or total loss? It' feels like important info to know! The manual suggests total loss but it doesn't really say that clearly.

I've also studied my DAT file with DATCon and can't see any reference to the timeout messages. I guess as the DAT file is recorded by the drone that makes sense- it wouldn't record it in the log if it never received it.

5.8 is the control signal.  It comes out of your white plastic controller.  It's a one way signal.  That means if your AC is not getting the signal, there is no way for the controller to know it via 5.8.  Makes sense right?

2.4 is everything else.  It comes from the AC and goes to the 2.4 transceiver inside the white plastic controller and then is transmitted to your mobile device (this is a simplified explanation).  If the AC loses the 5.8 control signal, the AC can communicate this unfortunate fact to the pilot via the 2.4 signal because the 2.4 signal is a two-way network.  Without the 2.4 network, there is no way for the AC to communicate a loss of the 5.8 signal.

Let's say you lose 2.4.  Everything you see is meaningless other than the fact that it's telling you there's a break in the 2.4 connection.  That includes everything you see on your screen and it includes the little red lamp on your controller.  There is only one thing that will work correctly on your screen, and that is the 2.4 signal strength indicator.  This is useful, because if you see no bars, you know you have no 2.4 connection.  If you see one bar, you know you have a very weak 2.4 connection.  It may be so weak that it can't give you any other info, but at least you know your AC is still in the air out there somewhere, and this is always nice to know.   So if you are calm and collected, you could try to fail-safe/RTH with the S2 switch.  If you are in a panic, you can just turn off the white plastic controller and then your AC must fail-safe/RTH.  

That's a great explanation. Makes total sense now. That knowledge will help a lot of people diagnose in-flight dramas and hopefully help them take the right next action, Thanks!

Mark The Droner Posted at 2017-2-21 03:27
5.8 is the control signal.  It comes out of your white plastic controller.  It's a one way signal.  That means if your AC is not getting the signal, there is no way for the controller to know it via 5.8.  Makes sense right?

2.4 is everything else.  It comes from the AC and goes to the 2.4 transceiver inside the white plastic controller and then is transmitted to your mobile device (this is a simplified explanation).  If the AC loses the 5.8 control signal, the AC can communicate this unfortunate fact to the pilot via the 2.4 signal because the 2.4 signal is a two-way network.  Without the 2.4 network, there is no way for the AC to communicate a loss of the 5.8 signal.

So when I look at my flightlog files from Lichi (*.csv files) and see a column labeled "downlinkSignalQuality" with a value of 100%  while the other column "uplinkSignalQuality"  has a value of 0% what is this telling me. It seems to suggest I am getting signal from my drone to the controller but the controller cant send a signal to the drone. Is this correct?

I confess - I don't have a P3S.  If we assume the columns are both in reference to the 2.4 signal only, it sounds like for some reason the AC is not receiving a 2.4 signal from the controller at that particular moment.  

If we assume the uplinkSignalQuality" is 5.8, then it's telling you the control signal isn't reaching the AC at that particular moment.  

Something to know about those Litchi logs - if you have no 2.4 signal, the data you see will be redundant.  As you scroll down the log, it will show the same data as you move down the columns.  Only the time will change.  It's just like the frozen screen.  All that data is meaningless and misleading.  

Phantom_menace Posted at 2017-2-21 04:40
That's a great explanation. Makes total sense now. That knowledge will help a lot of people diagnose in-flight dramas and hopefully help them take the right next action, Thanks!

We all learn from our own experiences and from the forums.  Happy that your Auto land was a safe landing for your drone.  I did an auto land but when my drone was above me.  Worked great.

So does the RTH.   I also recommend you get the Argtek Antenna setup.  Gives you a lot more range. I get 4 times what I got with the stock setup.