Did I Have a Fly Away or Did the Drone Return to Home?

[Big Bull]

I guess from your awful ability to quote posts that you found it?

Great news, I'm genuinely glad for you.

LOL! Good news, @yellowtennies . Let us know how little Mavic is doing in recovery!

 

[Cyberpower678]

Was it in the given coordinates or near it? Glad you found it.


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[Cyberpower678]

I have some I use in photography. Will blow out the copper coils with the drone in the upside down position.

Keep in mind the on board computer system is the most vulnerable component of the drone. If that's busted the drone is totaled. The water could have gotten into the computer area. It is exposed so the drone can vent the hot air from inside. You want to make sure that's perfectly dry before powering it on, else it may short.


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[Cyberpower678]

When you find it...and you will find it. I would probably use canned air to get the water out of the motors. That should be the only place that water causes an issue.


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Not necessarily. The front back are air vents for the on board computer. Since the drone landed right in a big snow pile and considering the snow was melting and it was raining, it's not unreasonable to suspect that water has gotten into the computer.


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[Cyberpower678]

To all of you who have helped me learn more about my drone, a sincere thanks.
I have benefited greatly from your knowledge and advice. I simply went to where you told me to look and found it, unscathed. None of the rotor were compromised.

I plan on reaching out to DJI directly, sharing the flight logs, to determine what caused the fly away.

Thanks again,
Yellowtennies

I just realized your response was lodged in the quote. I'm glad you found it right where I approximated it would be. As for explaining the fly away, if you ask me, the compass didn't appear to be calibrated correctly. When you take off, you have to wait until the GPS signal is strong enough that the drone can set the RTH point on the map. I assume you are using the DJI GO 4 app in which case it will loudly announce that the home point has been set when it gets set, assuming you have your volume up. You should also ensure your compass is functioning correctly. If the RTH is not working, use the map to guide the drone in manually and don't rely on the RTH to get it right. In the event of a critical battery alert, if you are close to home, you can hold the altitude joystick up to keep it hovering and guide it home. Most importantly, before taking off, make sure you perform your pre-flight checks. Make sure the GPS is connected, make sure there is no system error, and let the drone set the home point before flying up in the air.

 

[BudWalker]

Prior to take off, got a confirmation that a Home Point was established. Flight was uneventful, approx 1/2 mile from home base. Altitude, less than 300ft. Video was recording. Location: take off from a frozen lake in west central MN. Suddenly loss camera image. Immediately hit the RTH button and swiped to confirm. Got 'going home' message. Waited for drone return but heard and saw nothing. Reviewed the map for flight tracking. It showed the flight track returning to home point. The red arrow shaped icon was less than 20 ft from the home point. The landing zone is a stark white barren, frozen lake. The drone is not to be found. Hard place to hide a dark grey object.
Does the red icon on the map confirm that the drone did in fact return to home point? Any thoughts or ideas might help me recover it. Thanks in advance.

I looked at this flight. In summary, the gpsHealth dropped to 1 from 5 setting off a sequence of events that resulted in a drift away, not a fly away. The log shows that the Home Point was set correctly. There is no evidence to support the idea that the compass calibration was an issue.

At 877 the RTH was initiated when the Mavic was 1064 meters from home and at a height of 146 meters. When it got to the home point coordinates there was the drop in gpsHealth causing a switch to ATTI mode. This, in turn, caused the RTH to be cancelled. At this point the distance from home started increasing as the Mavic was not in GPS mode, wasn't being controlled by an RTH and was drifting with the wind.


gpsHealth is not the same as the number of satellites. gpsHealth has a range from 0 to 5 and value of 4 or 5 is required for the GPS to be used for navigation. There have been several Mavic flights with this unexplained gpsHealth drop. There were 4 other gpsHealth drops in this flight. It's almost certainly a hardware issue. You should mention this if it has to be sent to DJI for repair

The pilot stated that he didn't see or hear the Mavic after RTH was initiated. It did return to the HP coordinates but hadn't transitioned to the descent phase when the RTH was cancelled. Maybe 146 meters altitude contributed to the pilot not hearing or seeing the Mavic.

 

[Cyberpower678]

I looked at this flight. In summary, the gpsHealth dropped to 1 from 5 setting off a sequence of events that resulted in a drift away, not a fly away. The log shows that the Home Point was set correctly. There is no evidence to support the idea that the compass calibration was an issue.
View attachment 4707
At 877 the RTH was initiated when the Mavic was 1064 meters from home and at a height of 146 meters. When it got to the home point coordinates there was the drop in gpsHealth causing a switch to ATTI mode. This, in turn, caused the RTH to be cancelled. At this point the distance from home started increasing as the Mavic was not in GPS mode, wasn't being controlled by an RTH and was drifting with the wind.

View attachment 4709
gpsHealth is not the same as the number of satellites. gpsHealth has a range from 0 to 5 and value of 4 or 5 is required for the GPS to be used for navigation. There have been several Mavic flights with this unexplained gpsHealth drop. There were 4 other gpsHealth drops in this flight. It's almost certainly a hardware issue. You should mention this if it has to be sent to DJI for repair

The pilot stated that he didn't see or hear the Mavic after RTH was initiated. It did return to the HP coordinates but hadn't transitioned to the descent phase when the RTH was cancelled. Maybe 146 meters altitude contributed to the pilot not hearing or seeing the Mavic.

It was? I didn't see it get set. There's usually a message in the flight log indicating it getting set. The log indicates that a compass error occurred.


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[Cyberpower678]

It was? I didn't see it get set. There's usually a message in the flight log indicating it getting set. The log indicates that a compass error occurred.


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Oh looks like it was, but yea looking the logs over again, I'm seeing all kinds of errors both GPS and compass related all across the flight. There's clearly a hardware issue here.


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[BudWalker]

It was? I didn't see it get set. There's usually a message in the flight log indicating it getting set. The log indicates that a compass error occurred.


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I'm not sure what you're looking at. There are a couple of ways to look at the .txt log. The most comprehensive is to use TXTlogToCSVtool
[TOOL][WIN] Offline TXT FlightRecord to CSV Converter
I've attached a .zip containing the .csv for this flight.

The DJI Go App has a history of labeling errors as being some kind of compass error when, in fact, they aren't related to the compass. I suspect the "Warning:[compass]data exception (In Flight) please switch to atti mode if craft behave abnormally (Using)" is another of these. Several of these are coincident with the gpsHealth issue in this flight. There aren't any indications of behavior related to compass errors in this flight. The behavior is normal - given that it switches to ATTI because of the gpsHealth issue.

 

[Cyberpower678]

I'm not sure what you're looking at. There are a couple of ways to look at the .txt log. The most comprehensive is to use TXTlogToCSVtool
[TOOL][WIN] Offline TXT FlightRecord to CSV Converter
I've attached a .zip containing the .csv for this flight.

The DJI Go App has a history of labeling errors as being some kind of compass error when, in fact, they aren't related to the compass. I suspect the "Warning:[compass]data exception (In Flight) please switch to atti mode if craft behave abnormally (Using)" is another of these. Several of these are coincident with the gpsHealth issue in this flight. There aren't any indications of behavior related to compass errors in this flight. The behavior is normal - given that it switches to ATTI because of the gpsHealth issue.

How insightful. I'll admit I'm still fairly new at analyzing flight logs. My Mavic is my first RC device with flight recording. I used to just fly simple RC planes, and nano quadcopters.


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[yellowtennies]

I guess from your awful ability to quote posts that you found it?

Great news, I'm genuinely glad for you.

Truth is the folks on this site found it for me. I just walked the field and picked it up. Really great to have it back with virtually no visible sign of damage. Won't if it is air worthy until I try flying it in the next day or so. Raining now with forecast for tomorrow Thanks.

 

[BudWalker]

How insightful. I'll admit I'm still fairly new at analyzing flight logs. My Mavic is my first RC device with flight recording. I used to just fly simple RC planes, and nano quadcopters.


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You might be on to something. I didn't think that compass error message was relevant because it wasn't needed to explain what happened. Maybe the .DAT file that is recorded on the Mavic itself will tell us something more about that error message. @yellowtennies would it be possible for you to retrieve the .DAT file for that flight after you've determined the Mavic is OK? To see how to do that look here. It'll be large so you'll need to Dropbox it and provide a link.

@yellowtennies are you planning on sending the Mavic to DJI to have them fix the gpsHealth problem?

 

[m0j0]

Keep in mind the on board computer system is the most vulnerable component of the drone. If that's busted the drone is totaled. The water could have gotten into the computer area. It is exposed so the drone can vent the hot air from inside. You want to make sure that's perfectly dry before powering it on, else it may short.


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That is true but the Mavic didn't land upside down or in a pool of water. My money is on, "its fine." Use some canned air to lightly blow out the motors.. they face up and are most likely to catch snow and rain. The bottom side could get wet but just thinking about the dynamics leads me to believe melted snow is unlikely to flow up. If you really want to be safe the bag of rice trick..

That pups fine. Dry it out and fly it.


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[Cyberpower678]

That is true but the Mavic didn't land upside down or in a pool of water. My money is on, "its fine." Use some canned air to lightly blow out the motors.. they face up and are most likely to catch snow and rain. The bottom side could get wet but just thinking about the dynamics leads me to believe melted snow is unlikely to flow up. If you really want to be safe the bag of rice trick..

That pups fine. Dry it out and fly it.


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It doesn't need to flow up to get in. The front and back of the drone are air vents and they go straight to the computer. So the water need only to flood sideways which what water tends to do when it rains on snow and the Mavic submerged itself in it.


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[yellowtennies]

Was it in the given coordinates or near it? Glad you found it.


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The drone sat just as the photo shows. It was approx 40 yds from where your GPS coordinates were pinpointed on my iPhone

 

[yellowtennies]

You might be on to something. I didn't think that compass error message was relevant because it wasn't needed to explain what happened. Maybe the .DAT file that is recorded on the Mavic itself will tell us something more about that error message. @yellowtennies would it be possible for you to retrieve the .DAT file for that flight after you've determined the Mavic is OK? To see how to do that look here. It'll be large so you'll need to Dropbox it and provide a link.

@yellowtennies are you planning on sending the Mavic to DJI to have them fix the gpsHealth problem?

I will go to your link and try do do what you are requesting. Heavy fog this morning. Regarding sending the drone back to DJI.., have you determined the drone malfunctioned?

 

[yellowtennies]

Keep in mind the on board computer system is the most vulnerable component of the drone. If that's busted the drone is totaled. The water could have gotten into the computer area. It is exposed so the drone can vent the hot air from inside. You want to make sure that's perfectly dry before powering it on, else it may short.


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As well as using canned air pointed at the rotor motors, I used a hair dryer on low for about an hour, then left the drone on a heated floor for the last 12 hours

 

[BudWalker]

I will go to your link and try do do what you are requesting. Heavy fog this morning. Regarding sending the drone back to DJI.., have you determined the drone malfunctioned?

gpsHealth dropped from 5 to 1 four times during this flight. That's not supposed to happen at all. One of those gpsHealth drops resulted in a drift away and finally crashing at the end. If my Mavic did any of this I wouldn't fly it until it had been repaired by DJI.

 

[yellowtennies]

I just realized your response was lodged in the quote. I'm glad you found it right where I approximated it would be. As for explaining the fly away, if you ask me, the compass didn't appear to be calibrated correctly. When you take off, you have to wait until the GPS signal is strong enough that the drone can set the RTH point on the map. I assume you are using the DJI GO 4 app in which case it will loudly announce that the home point has been set when it gets set, assuming you have your volume up. You should also ensure your compass is functioning correctly. If the RTH is not working, use the map to guide the drone in manually and don't rely on the RTH to get it right. In the event of a critical battery alert, if you are close to home, you can hold the altitude joystick up to keep it hovering and guide it home. Most importantly, before taking off, make sure you perform your pre-flight checks. Make sure the GPS is connected, make sure there is no system error, and let the drone set the home point before flying up in the air.

Thanks. I'm learning more with each new posted. I have not yet powered up the drone. heavy fog now. when it clears I'll do so.
I would not have found it if not for the coordinates you supplied. Your coordinates were roughly 125 yds from were I was looking all morning.., where I thought was the terminal end of the green flight track line.

 

[Cyberpower678]

gpsHealth dropped from 5 to 1 four times during this flight. That's not supposed to happen at all. One of those gpsHealth drops resulted in a drift away and finally crashing at the end. If my Mavic did any of this I wouldn't fly it until it had been repaired by DJI.

The Mavic didn't crash. The battery reached critical level and the drone landed. Halfway through, it disconnected from the controller. That was how I was able to approximate its landing location. If it truly crashed it would have landed in a random location, and likely be in pieces.


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