Lost signal, RTH, aircraft lost...possibly crashed in the river

[Paulark]

Hello there. I've had my Mavic air for about six months and this has never happened. I launched my Air from my boat, set the home point as my current location, and set it to active track so it would shoot video of me running down the river. After canceling the first RTH warning, I stopped the boat and began manually flying, bringing it in towards the boat so I could land into my hand. I've successfully done this over a dozen times. Approximately 10 seconds before landing into my hand and 37% battery remaining, the signal drops, it ascends yo 30 meters, and begins its RTH. That was the last I saw of it. There is no telemetry after it lost the signal, so I don't know if it made it or not.

Question 1: when it began the RTH, are the obstacle avoidance sensors still active or do they disengage? Since we had gone around a bend in the river, it ascended and took a direct line back to home rather than back up the river. There is a ridgeline that is higher than 30m that it would have had to get over if it made it home. The answer to this question will determine if I have to look on land or in the drink.

 

[sar104]

The answers to those questions depend on several factors, that would most easily be answered by the flight log.

 

[Paulark]

Copy that, I will research how to upload.

 

[umanbean]

Follow that link in his signature... that should be all the research you need

 

[timinator]

Hello there. I've had my Mavic air for about six months and this has never happened. I launched my Air from my boat, set the home point as my current location, and set it to active track so it would shoot video of me running down the river. After canceling the first RTH warning, I stopped the boat and began manually flying, bringing it in towards the boat so I could land into my hand. I've successfully done this over a dozen times. Approximately 10 seconds before landing into my hand and 37% battery remaining, the signal drops, it ascends yo 30 meters, and begins its RTH. That was the last I saw of it. There is no telemetry after it lost the signal, so I don't know if it made it or not.

Question 1: when it began the RTH, are the obstacle avoidance sensors still active or do they disengage? Since we had gone around a bend in the river, it ascended and took a direct line back to home rather than back up the river. There is a ridgeline that is higher than 30m that it would have had to get over if it made it home. The answer to this question will determine if I have to look on land or in the drink.

Oh it will likely be in the water. Setting a home point while on a boat is dicey at best. With it being a rive, I would have set the HP to the adjacent shore so that if things went sideways, at least it wouldn't return to the river.

 

[Paulark]

Honestly, when I reset the home point to the remote, the button where you click the human figure rather than the arrow, I thought that meant that it would return to where the remote and myself were located. Turns out that's not the case. I'm not sure why you can't set the home point to the remote's location and have it always return to the remote. That makes too much sense I guess.

Been driving all day. I'll get that log up as soon as I can. Thanks for the help.

 

[Simmo]

What device (screen) are you using?

 

[Paulark]

Samsung A20 phone

 

[MAvic_South_Oz]

Copy that, I will research how to upload.

Follow that link in his signature... that should be all the research you need

This link is in sar104's sigline, it's possibly the easiest one to use for the txt log . . .

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

 

[Meta4]

Honestly, when I reset the home point to the remote, the button where you click the human figure rather than the arrow, I thought that meant that it would return to where the remote and myself were located. Turns out that's not the case. I'm not sure why you can't set the home point to the remote's location and have it always return to the remote. That makes too much sense I guess.

The wording that shows when you reset the home point looks like this:

Current is the key word.
It's not following you and updating, just resetting to where the controller is at that moment.
If you can post that .txt file, it will clearly show where the set home point was.

 

[bigswifty]

Current is the key word.
It's not following you and updating, just resetting to where the controller is at that moment.
If you can post that .txt file, it will clearly show where the set home point was.

Exactly. A lot of my flights I have to manually fly the drone somewhere safer than the launch point after takeoff and manually set Home. A particular example would be operating over water within 5 metres of your position.

 

[Paulark]

The answers to those questions depend on several factors, that would most easily be answered by the flight log.

I uploaded the flight log to Phantom help. This is the link to that analysis. As you can see, there is no data once the signal was dropped.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Here is the log file itself. It shows a RTH altitude of 98ft. after the home point was set. If the obstacle sensors were active, then it made it home and crashed in the drink. If they were NOT active, it may be in a tree up on the ridgeline.

 

[sar104]

I uploaded the flight log to Phantom help. This is the link to that analysis. As you can see, there is no data once the signal was dropped.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Here is the log file itself. It shows a RTH altitude of 98ft. after the home point was set. If the obstacle sensors were active, then it made it home and crashed in the drink. If they were NOT active, it may be in a tree up on the ridgeline.

Two possibilities, depending on whether you had RTH OA enabled. Firstly, the terrain between the home point and the disconnect location was higher by around 30 m than your RTH height of 30 m:



The maximum flight height was set at 500 m, so if RTH OA was enabled then the aircraft should have been able to climb to clear the terrain. In that case it will have returned to, and landed, at the home point - i.e. in the river.

It RTH OA was not enabled then it will have crashed on RTH somewhere between the river and the road, depending on the height of the trees.

 

[Paulark]

Two possibilities, depending on whether you had RTH OA enabled.

It RTH OA was not enabled then it will have crashed on RTH somewhere between the river and the road, depending on the height of the trees.

Yes, that's correct. I never adjusted any of the sensor settings for RTH, so their default, whatever that is, is likely where they remained.

I'm trying to find a submersible light online that is powerful enough to light up the bottom where I can see it. The water is very clear, but it's still 20 feet. Hate to spend $200 on a light without being sure that's where it is, though.

 

[sar104]

Yes, that's correct. I never adjusted any of the sensor settings for RTH, so their default, whatever that is, is likely where they remained.

I'm trying to find a submersible light online that is powerful enough to light up the bottom where I can see it. The water is very clear, but it's still 20 feet. Hate to spend $200 on a light without being sure that's where it is, though.

If RTH OA was on then it is likely to be in the river, unless it encountered an obstacle that it was unable to detect and clear properly. Trees with thin or overhanging branches can cause that problem. I would check along the red line to the road before investing in diving lights.

 

[Paulark]

Copy that...thanks for the guidance. I'm headed back to look in the morning and will keep you all posted.

 

[robert2]

Yes, that's correct. I never adjusted any of the sensor settings for RTH, so their default, whatever that is, is likely where they remained.

I'm trying to find a submersible light online that is powerful enough to light up the bottom where I can see it. The water is very clear, but it's still 20 feet. Hate to spend $200 on a light without being sure that's where it is, though.

save your time and money, if it's in the river, it's toast, I dropped one in a canal and retrieved it, did everything to dry it out, waited three days, applied power, MADE REAL NICE SPARKS, P3 pro.

 

[umanbean]

applied power, MADE REAL NICE SPARKS, P3 pro.

Well then, it wasn't completely dried out.

 

[robert2]

Well then, it wasn't completely dried out.

If he gets it back, we shall see.

 

[Paulark]

I had several delays yesterday so I only got an hour of ground search time in before having to call it for the night. I was able to make contact with the property owners and they're super cool. Headed out to spotlight in the river now.

@robert2 I have the DJI care refresh, but I have to find the old one to initiate that.