Serious bug in the Mavic's "Home Point Me" function - caused loss of drone!

Lykus · Oct 16, 2017

Not sure if you had tried the emergency stop button, which is supposed to stop the drone in a situation like this.

scjerry · Oct 16, 2017

msinger said:
That information is from the Mavic manual. You can download the manual here.

Thanks, but I'm well into the manual and did a word search for "20 meters" and got one hit on RTH height. I did a more extensive search on Google instead. This advice from DJI is not in the v1.8 Mavic manual you reference.

scjerry · Oct 16, 2017

Lykus said:
Not sure if you had tried the emergency stop button, which is supposed to stop the drone in a situation like this.

Only if you can see it. Sun glare, behind a building etc.

msinger · Oct 16, 2017

scjerry said:
Thanks, but I'm well into the manual and did a word search for "20 meters" and got one hit on RTH height

See page 16 of the current Mavic manual.

scjerry · Oct 16, 2017

msinger said:
See page 16 of the current Mavic manual.

View attachment 23294

Thanks. Holding my hand is useful, But a whole new set of parameters.

It'll fail safe RTH to the current HP if between 5-20 meters away horizontal. With FVS disabled it'll fail safe RTH to current position?

That's why pointing to the specific page in the manual is useful in exchanges.

Still not certain whether any of this is pertinent given the title of this thread, i.e. "Serious bug in the Mavic's "Home Point Me" function - caused loss of drone!". Resetting HP introduces additional complications with fail safe RTH. Trying to avoid gotchas so I don't lose my MP when using it from a boat.

msinger · Oct 16, 2017

scjerry said:
Still not certain whether any of this is pertinent given the title of this thread

It's not. I was just answering your question

scjerry · Oct 16, 2017

msinger said:
It's not. I was just answering your question

Well, here's why I asked. Note the dramatic change in distance to HP triggered by an attempt to set HP to me, when my RC/mobile device was within the 5-20 meter range. This flight was with firmware v01.03.0900 . I realize the latest v01.04.0000 is reputed to have fixed this behavior, but maybe not. I managed to abort. Not shown is the launch HP.

Zonian · Oct 16, 2017

scjerry said:
Well, here's why I asked. Note the dramatic change in distance to HP triggered by an attempt to set HP to me, when my RC/mobile device was within the 5-20 meter range. This flight was with firmware v01.03.0900 . I realize the latest v01.04.0000 is reputed to have fixed this behavior, but maybe not. I managed to abort. Not shown is the launch HP.

Yikes! So if I am reading this correctly, your HP was reset to a location that was 2 miles away from you?? Sounds like exactly was the OP's problem was...
I hope v01.04.0000 has fixed this...does anyone have verification from DJI ?? I did not see any "fix" mentioned in the v01.04.0000 release notes...

scjerry · Oct 16, 2017

Zonian said:
Yikes! So if I am reading this correctly, your HP was reset to a location that was 2 miles away from you?? Sounds like exactly was the OP's problem was...
I hope v01.04.0000 has fixed this...does anyone have verification from DJI ?? I did not see any "fix" mentioned in the v01.04.0000 release notes...

Yes, you are reading it correctly. The location was a HP for a flight 2 days prior!

Not the only instance. Trying to convince DJI customer service. So far, they tell me that they don't know what I'm talking about....their words.

I haven't got my drone back from them ( a different S/N as usual) but will conduct new tests with v01.04.0000. I tried before sending it back, but didn't do a competent test.

Chunter · Dec 18, 2017

it happened again with two homepoints yesterday,this time managed to take a pic with my phone. if i chose current position it wanted to fly to the lower right distance of 7915 metres and if i chose original home point it would land where i was.
I'm curious if you're in this postion when you lose connection and its rth'ing could this be why drones are flying off into the distance?

Youser · Dec 18, 2017

Chunter said:
it happened again with two homepoints yesterday,this time managed to take a pic with my phone. if i chose current position it wanted to fly to the lower right distance of 7915 metres and if i chose original home point it would land where i was.
I'm curious if you're in this postion when you lose connection and its rth'ing could this be why drones are flying off into the distance?

What did you do? Cancel and then return manually?

Chunter · Dec 18, 2017

clicked original home point then it landed next to me.

scjerry · Dec 18, 2017

Chunter said:
clicked original home point then it landed next to me.

Can u snd flight rec or airdata lnk?

sar104 · Dec 18, 2017

Chunter said:
it happened again with two homepoints yesterday,this time managed to take a pic with my phone. if i chose current position it wanted to fly to the lower right distance of 7915 metres and if i chose original home point it would land where i was.
I'm curious if you're in this postion when you lose connection and its rth'ing could this be why drones are flying off into the distance?

The problem here appears to be the usual one where the app thinks the controller is located, since it has the aircraft and the original homepoint in the correct locations. So firstly, it's only going to be an RTH problem if you reset the RTH location to current controller position. As to why it happened, I thought that this bug had been fixed. Which app version are you using?

Chunter · Dec 18, 2017

version 4.14, never knew they'd addressed the problem. only had it twice. where would the craft return to though if the goapp crashed or the rc failed? maybe its time to set to hover only.
Anyhoo here are the two logs from when i took this photo, only went there to test a video setting but after noticing this my flight became messy trying to get my head around it.

Airdata UAV - Flight Data Analysis for Drones
Airdata UAV - Flight Data Analysis for Drones

i honestly thinks that when i connect my wifi nexus to update other apps it keeps the internet home point of my wifi somehow, thats about 7900 metres away.

i want to stay on 4.14 so if anyone knows a fool proof way,apart from using a cellular device which always works, i'm all ears.

cheers guys.

sar104 · Dec 18, 2017

Chunter said:
version 4.14, never knew they'd addressed the problem. only had it twice. where would the craft return to though if the goapp crashed or the rc failed? maybe its time to set to hover only.
Anyhoo here are the two logs from when i took this photo, only went there to test a video setting but after noticing this my flight became messy trying to get my head around it.

Airdata UAV - Flight Data Analysis for Drones
Airdata UAV - Flight Data Analysis for Drones

i honestly thinks that when i connect my wifi nexus to update other apps it keeps the internet home point of my wifi somehow, thats about 7900 metres away.

i want to stay on 4.14 so if anyone knows a fool proof way,apart from using a cellular device which always works, i'm all ears.

cheers guys.

Neither of those logs shows any problems in AirData, but then the information presented doesn't include anything about the location of the controller.

Chunter · Dec 18, 2017

ok i've found how to get rc logs off, where would i upload them for someone to look at?

scjerry · Dec 18, 2017

Chunter said:
ok i've found how to get rc logs off, where would i upload them for someone to look at?

dropbox. r they .txt files?

Chunter · Dec 19, 2017

trying to extract the logs off of rc atm but its taking forever ( ie don't think its working) and truth be told after googling i don't think there's any software for us users to read them with,they're .dat files and encypted by the looks of things

scjerry · Dec 19, 2017

Chunter said:
trying to extract the logs off of rc atm but its taking forever ( ie don't think its working) and truth be told after googling i don't think there's any software for us users to read them with,they're .dat files and encypted by the looks of things

See Bud Walker's tools for reading & analyzing .dat and .txt files. DatCon Introduction
Only .dat files off the Mavic using DJI Assistant 2 See How to retrieve a V3 .DAT File from the AC
Only .txt files off your mobile device. See ferraript's [TOOL][WIN] Offline TXT FlightRecord to CSV Converter
You can upload .txt files to Mike Singer's PhantomHelp site: DJI Flight Log Viewer and wonderful things will happen.
I think they both .txt and .dat files are encoded and encrypted,, so yes you need the help of these tools.