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Could a drone landed remotely relaunch itself to fly home?
589 33 10-17 06:35
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fans0ed2511b
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Recently I was out flying my Mavic Air 2s on a misty morning. Once it was the air, I realized how difficult it would be to re-land the drone at the homepoint due to poor visibility caused by the thick mist and numerous trees around the homepoint. Instead, I navigated the drone to a different location about a half-mile away. As the battery got low, the drone went into auto-return mode and began to return to the homepoint. I overroad this and instead landed the drone at the remote location by holding down the LAND button on the app, verifying the landing visually as well.
  
  
I immediately got into my car and drove to the landing site, a cleared hilltop with and asphalt drive leading to a viewpoint. There was no sign of anyone when I arrived 4-5 minutes after landing -- but neither was there any sign of my drone! I used the "Find My Drone" feature in the DJI app but the landing point was exactly where it should have been. After searching the nearby woods and speaking to area residents I still have not turned up the drone. My question is, with it's battery low, could the imperative of the auto-return feature have caused the drone to relaunch and try return to the homepoint a second time, even after landing? Is that even possible?

I should add that both locations, the homepoint and the landing point, were on the same rural private property making theft of the drone unlikely.

This raises another question: if a drone returned automatically to its homepoint and found that it couldn't make a vertical landing due to trees what would it do? Hover until its battery died and then crash?

10-17 06:35
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rent
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You said you verified the landing visually. Does this mean that you saw the drone touching down on the ground with props stopped? Did you continue to receive video signal on your remote during the 4-5 minute drive to reach it?

Once landed and props stopped, it's practically impossible for it to take off again without user input. I say the likelihood of that happening is less than someone snatching up your drone.

Could it have landed on sloped terrain and rolled somewhere? But you said you verified the landing visually...
10-17 19:07
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GaryDoug
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No way it could restart if it was actually stopped. It is possible that the landing location is different from the last know location recorded since it probably lost comms. Can you post the log file here?
10-17 19:37
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rent Posted at 10-17 19:07
You said you verified the landing visually. Does this mean that you saw the drone touching down on the ground with props stopped? Did you continue to receive video signal on your remote during the 4-5 minute drive to reach it?

Once landed and props stopped, it's practically impossible for it to take off again without user input. I say the likelihood of that happening is less than someone snatching up your drone.

Thank you. To be more clear, I only verified the landing through the drone's camera, watching as it came down to earth. I assume that the propellers stopped. I had my finger on the LAND button on the DJI app until the landing was complete. I believe I turned off the controller at that point and didn't turn it back on until I arrived at the landing site and saw the drone was missing. It was the first time I've landed the drone remotely, so perhaps my protocols were lax in turning off the controller. It didn't cross my mind to keep a connection between the two.


And the landing spot was clear and level ground. It could not have rolled anywhere.

10-18 03:16
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GaryDoug Posted at 10-17 19:37
No way it could restart if it was actually stopped. It is possible that the landing location is different from the last know location recorded since it probably lost comms. Can you post the log file here?
I'm looking...
10-18 03:33
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JJB*
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Hi,

Good question!

If the drone is manual landed as you did   and in the last part it looses connection to the RC than it will stop the landing and RTH.....
Or, as you did, turning off the RC when still in connection to the drone and not with motor stopped ; it will initiate a RTH!
So if you did not actually landed with motors stopped....

No need to enable flightlogs, they are always on the mobile device.But if you lost connection at the end and closed down the app than the RTH is not logged.
So probably in RTH low batt so than an autoland.\
If you can find the log, mayby it is possible to calculate where it has landed.

BTW  what do you mean with "...by holding down the LAND button on the app...."Uh, you can use the soft button on the screen to autoland, but once selected it does not need to hold it down...

cheers
JJB

10-18 03:58
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GaryDoug Posted at 10-17 19:37
No way it could restart if it was actually stopped. It is possible that the landing location is different from the last know location recorded since it probably lost comms. Can you post the log file here?

Here is a link to the unencrpyted log file: https://app.airdata.com/share/cNaXPh

If you'd prefer, here's the encrypted file: https://drive.google.com/file/d/1N6yljuT8OgBesZZKJzKgDOHS153zlkKS/view?usp=sharing

Thank you for taking the time.

According to the data the battery was still at 25% on landing. If the battery was still on and the drone was moved by someone from its landing location, or took off again, then wouldn't this movement have been tracked and recorded somewhere? I think I turned my controller off after the apparent landing. Is there another place flight data is recorded from the drone?

10-18 06:25
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JJB* Posted at 10-18 03:58
Hi,

Good question!

Thank you. But if the drone returned to the air and attempted to go to the homepoint shouldn't that info have been recorded somewhere as the drone was traveling using satellite? I believe I turned my controller off after the (apparent) landing, so I don't have a record on my flight log. Is that info recorded somewhere else?
10-18 06:33
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JJB*
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fans0ed2511b Posted at 10-18 06:33
Thank you. But if the drone returned to the air and attempted to go to the homepoint shouldn't that info have been recorded somewhere as the drone was traveling using satellite? I believe I turned my controller off after the (apparent) landing, so I don't have a record on my flight log. Is that info recorded somewhere else?

Hi,

FlightLogs are saved on your mobile device! so try to find that log.
After closing down the app or the swichting off the RC or a connection loss to the drone, no data is recorded on your mob device.

So a drone flying not connected to the RC/FlyApp = no data saved.
There is data saved in the drone but only DJI can read that out....(afaik)

can you put a cloud link to your flightlog on here?

On AIrData i can read this > "AutoLanding,Aircraft not connected to RC. RC not connected to mobile device"  This means that your drone started a RTH !!And on the way to home, i guess,  into an autolanding bc of low battery.
Must be possible to estimate where it had landed.....




cheers
JJB
10-18 07:02
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JJB* Posted at 10-18 07:02
Hi,

FlightLogs are saved on your mobile device! so try to find that log.

Yes, here's the link:

https://app.airdata.com/share/cNaXPh

And here's the encrypted file, if you prefer: https://drive.google.com/file/d/1N6yljuT8OgBesZZKJzKgDOHS153zlkKS/view?usp=sharing

Thank you for any thoughts!

10-18 07:08
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JJB*
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grrr.   your txt file gives an error loading it.

At Loosing connection your drone was flying at baro height of 15 meter, with 25% batt level.
Your RTH set at 191meter, so at RTH drone starts to climb to 191. takes time and batt level!

My guess is (use that map view on AirData) ; straight line last point to HP, landing point cannot be far from the last point. My guess is within 40 meters along that direct line to home.

Good luck searching!  Around the orange marker.
cheers
JJB
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10-18 07:26
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GaryDoug
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The last record shows the drone being about 6 feet above the ground according to the ground sensor. Then it disconnects. I think JJB is right that it went RTH at that time, back up to the RTH altitude, and then straight toward home.

p.s. At that time, the barometric reading is 45 feet but I am guessing it was on a hill as you said ("cleared hilltop"), about 40 feet higher than at the launch location.
10-18 14:42
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GaryDoug Posted at 10-18 14:42
The last record shows the drone being about 6 feet above the ground according to the ground sensor. Then it disconnects. I think JJB is right that it went RTH at that time, back up to the RTH altitude, and then straight toward home.

p.s. At that time, the barometric reading is 45 feet but I am guessing it was on a hill as you said ("cleared hilltop"), about 40 feet higher than at the launch location.

Thank you. I have begun search and rescue operations. I greatly appreciate the help you've given.
10-18 15:11
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JJB* Posted at 10-18 07:26
grrr.   your txt file gives an error loading it.

At Loosing connection your drone was flying at baro height of 15 meter, with 25% batt level.

Thank you. I appreciate all your help here.
10-18 16:19
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GaryDoug
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I am going to use this opportunity to preach about something that may help you or others in the future. I always have a lit small strobe on the top front of my drone, even in the daytime. I have one on every drone. The cheap model that I use, in the link below, can flash white for up to 72 hours. The time stated in the ad is wrong, I have tested them and they do last 72 hours. It is not FAA approved since it is not bright enough for nighttime use but it trades that for longevity. With a full charge I can see it at a distance of about 1/2 mile in clear dark sky.  In one test, after about 24 hours, I could spot the strobe light in thick grass from at least 100 meters in total darkness. If one of my drones goes down somewhere difficult to search, I can come back that night to see if I can spot the flashing light. I then have up to two more nights to do that on one charge of the strobe. $10 insurance policy.
https://www.amazon.com/gp/produc ... title?ie=UTF8&psc=1


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10-18 19:00
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Rolling Blue Posted at 10-18 07:08
Yes, here's the link:

https://app.airdata.com/share/cNaXPh

Sadly I think you suffered the same issue I did when I lost my original Mavic Pro over the white cliffs of dover 5 years ago; I thought it had landed, didn't wait for the props to stop, turned off the remote and it went into RTH mode, rising back up into the air and heading in a straight line back to the take off Home Point, but then ran out of battery enroute.  Lost forever as the terrain was impossible to search.  
As JBB has helpfully said, your best bet is to follow the RTH line from the 'landing spot' back to the take off Home Point.  It will have gone into a final depleted battery  forced landing at some point along that line.
Best of luck
Ian
10-19 22:34
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Ian in London Posted at 10-19 22:34
Sadly I think you suffered the same issue I did when I lost my original Mavic Pro over the white cliffs of dover 5 years ago; I thought it had landed, didn't wait for the props to stop, turned off the remote and it went into RTH mode, rising back up into the air and heading in a straight line back to the take off Home Point, but then ran out of battery enroute.  Lost forever as the terrain was impossible to search.  
As JBB has helpfully said, your best bet is to follow the RTH line from the 'landing spot' back to the take off Home Point.  It will have gone into a final depleted battery  forced landing at some point along that line.
Best of luck

Thanks, Ian. I've been searching but the terrain is wooded and extremely rugged. Lesson learned.  
10-20 04:17
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Rolling Blue Posted at 10-20 04:17
Thanks, Ian. I've been searching but the terrain is wooded and extremely rugged. Lesson learned.

If you have another drone or know someone who has, maybe you could do an aerial search from the landing spot. Because of the heavy forest it might just be stuck up in a tree and still be visible from the air.
10-20 05:45
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Today, in some tall grass along a hiking trail, I found my missing drone. After a week and a half of searching, and with heavy rain forecast this afternoon, this was literally the last time I was going to look for it. Of all the places it could have fallen on this densely wooded and hilly property, it's somewhat of a miracle that in the mile between the HP and where I tried to land it, the drone would come down right beside a trail.

And the damage to the drone is not too bad: busted landing spur on the front arm now hanging on by wires. After putting a fresh battery in the drone, it flew perfectly -- even with the broken part. These things may be plastic but they're very durable! To top it off, I got the contents of the memory card uploaded to my computer and was able to watch video of exactly what happened, as the drone relaunched itself and tried to fly home on a low battery. The video cuts off before the crash but it is enough to confirm what other commenters here had theorized: the drone did indeed remain active after I'd turned off the controller.

Thanks again to everyone who offered help and suggestions in this thread!

@GaryDoug

@JJB*

10-25 12:25
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Rolling Blue Posted at 10-25 12:25
Today, in some tall grass along a hiking trail, I found my missing drone. After a week and a half of searching, and with heavy rain forecast this afternoon, this was literally the last time I was going to look for it. Of all the places it could have fallen on this densely wooded and hilly property, it's somewhat of a miracle that in the mile between the HP and where I tried to land it, the drone would come down right beside a trail.

And the damage to the drone is not too bad: one busted heel spur (my terminology) now handing on by wires. After putting a fresh battery in the drone, it flew perfectly -- even with the broken part. These things may be plastic but they're very durable! To top it off, I got the contents of the memory card uploaded to my computer and was able to watch video of exactly what happened, as the drone relaunched itself and tried to fly home on a low battery. The video cuts off before the crash but it is enough to confirm what other commenters here had theorized: the drone did indeed remain active after I'd turned off the controller.

Glad you got it back!
10-25 12:57
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Rolling Blue Posted at 10-25 12:25
Today, in some tall grass along a hiking trail, I found my missing drone. After a week and a half of searching, and with heavy rain forecast this afternoon, this was literally the last time I was going to look for it. Of all the places it could have fallen on this densely wooded and hilly property, it's somewhat of a miracle that in the mile between the HP and where I tried to land it, the drone would come down right beside a trail.

And the damage to the drone is not too bad: busted landing spur on the front arm now hanging on by wires. After putting a fresh battery in the drone, it flew perfectly -- even with the broken part. These things may be plastic but they're very durable! To top it off, I got the contents of the memory card uploaded to my computer and was able to watch video of exactly what happened, as the drone relaunched itself and tried to fly home on a low battery. The video cuts off before the crash but it is enough to confirm what other commenters here had theorized: the drone did indeed remain active after I'd turned off the controller.

" The video cuts off before the crash but it is enough to confirm what other commenters here had theorized: the drone did indeed remain active after I'd turned off the controller."

What in fact happened is that although you landed the aircraft, the act of turning off the controller invoked Return To Home, exactly as it is designed to do.
10-25 13:38
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Rolling Blue Posted at 10-25 12:25
Today, in some tall grass along a hiking trail, I found my missing drone. After a week and a half of searching, and with heavy rain forecast this afternoon, this was literally the last time I was going to look for it. Of all the places it could have fallen on this densely wooded and hilly property, it's somewhat of a miracle that in the mile between the HP and where I tried to land it, the drone would come down right beside a trail.

And the damage to the drone is not too bad: busted landing spur on the front arm now hanging on by wires. After putting a fresh battery in the drone, it flew perfectly -- even with the broken part. These things may be plastic but they're very durable! To top it off, I got the contents of the memory card uploaded to my computer and was able to watch video of exactly what happened, as the drone relaunched itself and tried to fly home on a low battery. The video cuts off before the crash but it is enough to confirm what other commenters here had theorized: the drone did indeed remain active after I'd turned off the controller.

Good for you in persisting to search! You could probably just superglue the spur onto the arm. If not, a new arm/motor is only about $40 if you install it.

Can you post the video on youTube and give us a link? I see no way this could have landed and shut off the motors and took off again. Perhaps that is not what you meant. I would very much like to see the video, even a lower resolution one. Thanks
10-25 18:37
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Rolling Blue Posted at 10-25 12:25
Today, in some tall grass along a hiking trail, I found my missing drone. After a week and a half of searching, and with heavy rain forecast this afternoon, this was literally the last time I was going to look for it. Of all the places it could have fallen on this densely wooded and hilly property, it's somewhat of a miracle that in the mile between the HP and where I tried to land it, the drone would come down right beside a trail.

And the damage to the drone is not too bad: busted landing spur on the front arm now hanging on by wires. After putting a fresh battery in the drone, it flew perfectly -- even with the broken part. These things may be plastic but they're very durable! To top it off, I got the contents of the memory card uploaded to my computer and was able to watch video of exactly what happened, as the drone relaunched itself and tried to fly home on a low battery. The video cuts off before the crash but it is enough to confirm what other commenters here had theorized: the drone did indeed remain active after I'd turned off the controller.

Hi

Great news, love to see that part of the video.

Do you have a LatLon position where it has landed ?

cheers
JJB
10-25 23:31
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@GaryDoug
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Here's the video link.  https://youtu.be/IZfN79ggbSA

It looks like the drone landed but didn't shut off its propellers. Maybe I cut off connection with the controller too soon and triggered its RTH function. Anyway, after almost two weeks of not knowing what happened it's fascinating for me to watch this footage. At the end the drone seems to be hovering in the mist. You can just make out the shadow of a hill on the right, but it doesn't seem to get any closer. I presume, where the footage cuts off is where the battery failed and the drone dropped from the sky.

I used some super glue on the busted leg and it's now back in business.
10-26 07:08
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Hi Rolling Blue,

Wow, if only 1 second later you powered down the RC, than the rotors were stopped.!
So it reached it RTH height, flew for about 1 minute, landed due to critical battery.

Good luck with the repaired leg and many happy landings,

cheers
JJB
10-26 07:39
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GaryDoug
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Interesting video, Like JJB said, just a second or two more without losing comms and it would have stayed there. A lesson for us all. Thanks for posting it.

I do have a question. And maybe that is for JJB to help answer. Was the drone put into auto-landing mode? In other words, did you press the auto landing virtual button? Or was it just maneuvered close to the ground? I have wondered how to land remotely without causing an RTH action. I assumed that auto-landing would happen even if comms was lost but I could be wrong.

Update minutes later. I was wrong. I just tried to auto land a MA2 about 100 meters away from the home point from a height of about 15 meters. The drone started down, then I switched off the controller. Seconds later, the landing was aborted and RTH was started. I guess the only way to prevent that is to first change the signal-lost action to land instead of RTH.
Or....Maybe a better plan would be to set it to hover and then try to get close before it lands and take control, to avoid any problems that landing might cause (theft, impact, injury, etc).

10-26 08:49
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GaryDoug Posted at 10-26 08:49
Interesting video, Like JJB said, just a second or two more without losing comms and it would have stayed there. A lesson for us all. Thanks for posting it.

I do have a question. And maybe that is for JJB to help answer. Was the drone put into auto-landing mode? In other words, did you press the auto landing virtual button? Or was it just maneuvered close to the ground? I have wondered how to land remotely without causing an RTH action. I assumed that auto-landing would happen even if comms was lost but I could be wrong.

Its a DJI software 'fault' mayby....

If i want to land my drone somewhere else than at HP (low battery, bad weather, ect); manually land than this landing is only succesfull if my RC does not loose contact with my drone!!
But contact is lost when the radio signal is hampered by building, trees, behind hill,  and so on....

So i am a good responsible remote pilot, try to land safely instead of flying back home risky and my drone will start a RTH wich i don`t want ; that`s why i choose to land!As you said, change the FailSafe RTH to land before starting to land.....(how many pilots will think about this while mayby bit stressed...)

cheers
JJB
10-26 10:54
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GaryDoug Posted at 10-26 08:49
Interesting video, Like JJB said, just a second or two more without losing comms and it would have stayed there. A lesson for us all. Thanks for posting it.

I do have a question. And maybe that is for JJB to help answer. Was the drone put into auto-landing mode? In other words, did you press the auto landing virtual button? Or was it just maneuvered close to the ground? I have wondered how to land remotely without causing an RTH action. I assumed that auto-landing would happen even if comms was lost but I could be wrong.

If you were to need to perform the routine just like you did initially, to shut off the aircraft and stop it returning home, you should pull the sticks down and inwards to stop the motors once it has landed. Then it will stay put. Once the motors have stopped it will not re-start and try to come home.
10-26 13:32
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Geebax Posted at 10-26 13:32
If you were to need to perform the routine just like you did initially, to shut off the aircraft and stop it returning home, you should pull the sticks down and inwards to stop the motors once it has landed. Then it will stay put. Once the motors have stopped it will not re-start and try to come home.

That does not work if you have no signals. The problem with the OP and with my expectations are that the comms are likely lost while landing far away. The remote then has no effect. Unless I have VLOS, I would have to e-stop the motors while still high in the air, not a good idea.
10-26 18:35
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GaryDoug Posted at 10-26 18:35
That does not work if you have no signals. The problem with the OP and with my expectations are that the comms are likely lost while landing far away. The remote then has no effect. Unless I have VLOS, I would have to e-stop the motors while still high in the air, not a good idea.

My comment was specific to the OP's situation, he did have control and a video feed, as per his statement in the opening post:

"I overroad this and instead landed the drone at the remote location by holding down the LAND button on the app, verifying the landing visually as well."
10-31 16:48
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Geebax Posted at 10-31 16:48
My comment was specific to the OP's situation, he did have control and a video feed, as per his statement in the opening post:

"I overroad this and instead landed the drone at the remote location by holding down the LAND button on the app, verifying the landing visually as well."

No, it was not specific to the OP. You were responding to my statement about a hypothetical situation. Apples and oranges.
10-31 18:22
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GaryDoug Posted at 10-31 18:22
No, it was not specific to the OP. You were responding to my statement about a hypothetical situation. Apples and oranges.

I replied to the wrong person.
11-1 12:59
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Bob-Mini-2
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Well . . . thank goodness he found and retrieved the drone - HOORAY!  I think we all received some food for thought as well.
11-1 13:45
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GaryDoug Posted at 10-18 19:00
I am going to use this opportunity to preach about something that may help you or others in the future. I always have a lit small strobe on the top front of my drone, even in the daytime. I have one on every drone. The cheap model that I use, in the link below, can flash white for up to 72 hours. The time stated in the ad is wrong, I have tested them and they do last 72 hours. It is not FAA approved since it is not bright enough for nighttime use but it trades that for longevity. With a full charge I can see it at a distance of about 1/2 mile in clear dark sky.  In one test, after about 24 hours, I could spot the strobe light in thick grass from at least 100 meters in total darkness. If one of my drones goes down somewhere difficult to search, I can come back that night to see if I can spot the flashing light. I then have up to two more nights to do that on one charge of the strobe. $10 insurance policy.
https://www.amazon.com/gp/produc ... title?ie=UTF8&psc=1

Good point, I use one as well.
11-1 13:49
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