Strange, Scary event during flight with litchi

[GWTX]

P3A two years old.
I am new to litchi, but it has been going very well. I don't do anything fancy, just flying around pastures, usually in the same route each time. The drone works really well at moving the cows out of an area where I don't want them. I think the sound reminds them of a giant swarm of bees
So, I took off on a routine flight, but flying lower than normal. I haven't had time to look at the flight log yet. About 1500' distance and 100' altitude, the screen had some trash flicker across it(weak signal I guess) and then the normally "green" dialog box turned blue with the dreaded words LANDING. I tried to climb, realizing that I had forgot to go to my normal altitude, but it didn't appear to be climbing, so I flipped to "atti' and back to "P", the box tuned green and I was climbing hard. I turned to head back home, and the same thing happened again. Again I flipped the switch and recovered. After it appeared to be back to normal, I hit RTH and it responded. When it was overhead I cancelled and landed. There was no "disconnected" message, or any other messages other than the audibles I have enabled, like "distance, altitude, battery level, etc. I'm sure it was caused by being too low in an area with trees, but I don't understand why I didn't get any warnings. like "weak signal" etc. I always have RTH set to return home, However I did not verify before flight this time.
I'll look at the log as soon as I have time.

 

[Fly Dawg]

There was no "disconnected" message

Without seeing the logs, you really won't know. But initially, this sounds like a momentary loss of downlink, and may have caused an erroneous "Landing" display from the app. Just a WAG without seeing the logs, however, that said, there will not be any data for that momentary loss, only just before and after the app responded again. As for the "Appeared to not be climbing" statement, that you would most certainly need the logs.

 

[gmonatl]

Was it a preplanned mission you were flying? If so, Litchi will finish executing the mission, even with loss of signal, and take whatever instruction is entered in the mission settings once complete, ie land, Rth, hover, trace back through the waypoints, return to the 1st waypoint. It sounds like your we’re in the GPS Mode however, but just making sure.

 

[Fly Dawg]

Was it a preplanned mission you were flying?

For now one would "assume" that it was not a waypoint mission by the following statement.

"so I flipped to "atti' and back to "P", the box tuned green and I was climbing hard. I turned to head back home, and the same thing happened again. Again I flipped the switch and recovered."

The switch would have to be in "F" for a mission, and if it were, once flipping to Atti would cancel the mission.

 

[GWTX]

Was it a preplanned mission you were flying? If so, Litchi will finish executing the mission, even with loss of signal, and take whatever instruction is entered in the mission settings once complete, ie land, Rth, hover, trace back through the waypoints, return to the 1st waypoint. It sounds like your we’re in the GPS Mode however, but just making sure.

Just a manual flight. I don't do missions yet,,,maybe not ever now !
No changes in the log until the "LANDING" . Downlink and uplink were 100 until the altitude got down to 39' (yikes, not LOS). At that point both went way low,,12 or so. Thanks Gary

 

[GWTX]

For now one would "assume" that it was not a waypoint mission by the following statement.

"so I flipped to "atti' and back to "P", the box tuned green and I was climbing hard. I turned to head back home, and the same thing happened again. Again I flipped the switch and recovered."

The switch would have to be in "F" for a mission, and if it were, once flipping to Atti would cancel the mission.

No, Just a manual flight. I don't do missions yet,,,maybe not ever now !
No changes in the log until the "LANDING" . Downlink and uplink were 100 until the altitude got down to 39' (yikes, not LOS). At that point both went way low,,12 or so. I've been out to 6000 ft without any problems, but I have had the video break up before. I normally just climb until it clears up.

 

[gmonatl]

Just a manual flight. I don't do missions yet,,,maybe not ever now !

FWIW, I have had 100% success (knocks on wood) with the waypoints and missions, even at times when it loses contact, it always returns faithfully after the mission. So don’t be daunted. My personal experience has been great with Litchi.

 

[Fly Dawg]

No changes in the log until the "LANDING"

This part does not make any sense in what you are saying. Can you share the log? I "might" can tell you why.

 

[Fly Dawg]

I say that the message makes no sense, unless it was a critical battery autoland or when you hit RTH you were too close to the home point. That is what needs to be looked at. Being that this was a Litchi flight you should be able to share the .csv here directly. (Depending on the file size)

 

[GWTX]

Problem uploading file.
The uploaded file does not have an allowed extension.
2018-07-31_19-43-41_v2[1].csv
Try this:
DJI Flight Log Viewer - PhantomHelp.com

What would happen if I accidentally "fat fingered" the AutoTakeOff/AutoLand button with the bird 1600 ft away ? FPV mode.

 

[Fly Dawg]

What would happen if I accidentally "fat fingered" the AutoTakeOff/AutoLand button with the bird 1600 ft away ? FPV mode.

That appears to be exactly what you did. Tell the AC to land, and it will attempt to do so. The charts below should tell the story:

The first chart shows the flight status, and the RC mode switch. Notice you never actually switched to ATTI, but changing the mode switch did cancel the landing command. You did command RTH as well, but cancelled it as you mentioned.
The second chart shows that your RC throttle commands were ignored while in landing mode. But once switched out of landing, it returned to normal.

 

[GWTX]

That appears to be exactly what you did. Tell the AC to land, and it will attempt to do so. The charts below should tell the story:

The first chart shows the flight status, and the RC mode switch. Notice you never actually switched to ATTI, but changing the mode switch did cancel the landing command. You did command RTH as well, but cancelled it as you mentioned.
The second chart shows that your RC throttle commands were ignored while in landing mode. But once switched out of landing, it returned to normal. View attachment 102002 View attachment 102003

 

[GWTX]

I had pretty much decided that is what happened after looking at the litchi log in the file reader I have (csvViewer). Actually, I switched to F-GPS according to the log. That's because I was in a panic and just flipped the switch right thru ATTI to FGPS, and back to PGPS very quickly. I am amazed that the signal was recovered, as the bird was down to 39 ft at the time of the switch, and there is about 5 acres of trees that are 30-40 ft tall between the RC and the bird at that point. I have since turned
off the "AutoTakeOff/AutoLand" setting. I will definitely test to see if that will keep this from happening again. If not, I'll try to be sure not to touch it again. I never use auto land, and very seldom use auto take off. Still not sure how, or why I hit that button. I guess the log I tried to upload directly was too large? 1.27MB. Thank you very much for your help. I appreciate you guys that share your experience and knowledge on the forum. Gary

 

[GWTX]

I can see where I might have initiated the landing accidentally,, the first time, but am confident I didn't do it again. The second occurrence was while I was trying to climb and head back home. The signal was weak, but never disconnected, just got the blue "LANDING" msg again. I am thinking the battery might be the culprit. The voltages looked a little "flaky" at times during the flight. Especially the balance between them. It is usually VERY close, like 0.02- 0.04,,if I recall from other flights. I will be watching everything more closely from now own.

 

[Fly Dawg]

I am thinking the battery might be the culprit.

Don't think so. Although the levels were low, it never wen't to "autoland". That is a different scenario. In that instance, there is no recovery. It lands where it is and doesn't care what you do.

 

[GWTX]

Still can't figure out why it went to "LANDING" , flystate 12 the second time., and I quickly flipped the switch back and forth, and recovered.

 

[Fly Dawg]

Still can't figure out why it to "LANDING" , flystate 12 the second time.

The only way that can happen is to manually command it from the app. It is possible you hit it again to cancel, but you already had cancelled it by flipping the mode switch. So you actually initiated it again. I would have to look back very closely at the time line to say that for certain, but that is my guess without doing so.

 

[GWTX]

Another thing I thought about,,, as best as I can figure out, I was over a rural power line which are known to have noisy insulators in dry dusty weather, the bird was low, the video became garbled without any weak signal alerts, and the PGPS icon turned blue and displayed "LANDING". Do you think emf from the power line could have induced a false command?
I cannot be positive but I really don't think I touched the autoland icon to start with, much less twice. In my flying, especially since being new to litchi, I don't ever touch that part of the screen. I tap the map screen occasionally, and I hold the RC with my left hand with my thumb on the throttle. I have only taken pictures/video one time just to see if was working. I have no reason to touch the left side of the screen. And from now on I'll use the C2 button to switch to the map and back. Will turning off the AutoTakeOff/AutoLand setting eliminate the possibility of this happening again? When I get time, I'll do some testing. Thanks again, Gary