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After flight time low warning RTLactivated and H520 crashed

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Here some screenshots. Take screenshots in building, so GPS coordinates of RC are not 100% accuracy.Position of dron is last position before dron crashed.
All I can conclude is that the dron for some reason lost GPS coordinates of RC, and the drone go somewhere totally unexpected.Personally in that scenario it is worst option.
So I will change safety option "Return to GCS" to "Return to takeoff position" immediately.

Here is link:
 

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Here some screenshots. Take screenshots in building, so GPS coordinates of RC are not 100% accuracy.Position of dron is last position before dron crashed.
All I can conclude is that the dron for some reason lost GPS coordinates of RC, and the drone go somewhere totally unexpected.Personally in that scenario it is worst option.
So I will change safety option "Return to GCS" to "Return to takeoff position" immediately.

Here is link:
The information in the full Flight Review agrees with your narrative and I am surprised at the quick switch to RTL on the first battery warning. At 20 minutes you were getting good flight time from the battery. Uploading the FlightLog may give us more to go on in trying to understand what caused the flight away from the controller.
 
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I have posted a similar situation although I purposely induced a low battery situation.


It is (although maybe no longer) my belief that when the 520 is in the RTL mode you can terminate RTL by performing any input to either of the control sticks. It is my recollection that my Typhoon H would respond that way but it has been a long time since I have flown it and tried to disengage the return to home command while in HOME mode. I have started to look for a reference regarding exiting the RTL mode but as yet have not found any that mention this. I can tell you in my situation I immediately closed the throttle when the 520 began its RTL ascent and it did stop the ascent but subsequently it was not responding to my control inputs or was doing so in a delayed and inaccurate manner. When my 520 has recovered from its injuries and is in flying shape again I'll take both out to a large field with fully charged batteries and do some testing.

A few years ago I did the same low battery test with my Typhoon H and also encountered the same situation while flying at ground level while following a truck in my parking lot. Both times the H stopped its forward motion, lowered the gear, descended the minimal distance to the ground, and shut down. To me this is the appropriate response but you better hope you are not flying over water.

The little booklet that accompanies the H says that when HOME mode is activated it will respond as follows:
when flying higher than 66' the H will fly back to the home point descend and land
when flying lower than 66' the H will climb to 66' fly back to the home point, or active home position, descend and land.

What makes no sense to me is why, at a certain critically low battery level, RTL is activated. Unlike the H, I suspect the 520 will go to whatever altitude you have set for your RTL altitude. The remaining battery power is going to get consumed very quickly and you will have mdavud's situation for sure; it is only going to be a matter of how high the 520 is before it shuts down. I am looking for someone to confirm that the 520 is programmed to respond in that manner, dumb as it is, or did the 520 respond incorrectly by initiating a RTL command to begin with.
 
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I had a similar incident, whilst performing a test hover at around 10ft altitiude (landing gear down, payload on board) I flicked to RTL to ensure that function was working prior to a full flight, and the H520e increased altitude (10m RTL altitude set, return to take off position, 14 sats linked) and it raised the landing gear! Poor piloting and panic at not wanting it to land on the camera meant a tree collided with it. All my fault, but why would the RTL command raise the landing gear? I would expect it to lower the gear should they be raised, or leave them down if they are down. Doesn’t make much sense to me.
 
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I had a similar incident, whilst performing a test hover at around 10ft altitiude (landing gear down, payload on board) I flicked to RTL to ensure that function was working prior to a full flight, and the H520e increased altitude (10m RTL altitude set, return to take off position, 14 sats linked) and it raised the landing gear! Poor piloting and panic at not wanting it to land on the camera meant a tree collided with it. All my fault, but why would the RTL command raise the landing gear? I would expect it to lower the gear should they be raised, or leave them down if they are down. Doesn’t make much sense to me.
Possible cause. When you flicked it over to RTL the fact that it raised up in altitude the landing gear goes up as far as I know this is normal. Panic can set in when it does something you didn't want it to doo. When it reaches the height that you have set the Altitude to it should stop and before it lands the fear goes down? I hope : )
 
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Possible cause. When you flicked it over to RTL the fact that it raised up in altitude the landing gear goes up as far as I know this is normal. Panic can set in when it does something you didn't want it to doo. When it reaches the height that you have set the Altitude to it should stop and before it lands the fear goes down? I hope : )
Thanks Mike. It was certainly my fault, only the 2nd time I'd flown it. Thankfully it was private land so no people, just a couple of trees. If course, I managed to find 1 of them up close!
 
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I am waiting for someone(s) smarter than I to address my original question - why is it in a low battery situation when RTH is automatically activated the 520 immediately ascends to the programmed RTH altitude? Yes, I know, because that is what it is told to do. But why is it directed to ascend. Makes no sense when you are being warned that you are about to exhaust the power supply to the 520 and when you do, the 520 is going to come crashing down. The only questions are from how high and how big a mess are you going to make when the 520 is introduced, abruptly, to terra firma.

I fly a Mavic Enterprise Dual for my state Urban Search and Rescue Task Force. This model has 3 types RTH: Smart RTH, low battery RTH, and Failsafe RTH. From the User Manual:

Smart RTH - If the GPS signal is sufficiently strong, Smart RTH can be used to bring the aircraft back to the Home Point by pressing and holding the RTH button on the controller.

Low battery RTH - This mode is triggered when the Intelligent Flight Battery is depleted to the point that the safe return of the aircraft may be affected. Return home or land the aircraft immediately when prompted. DJI Pilot (the flight app) displays a warning when teh battery is low. The aircraft will automatically return to the Home Point if no action is taken after a ten-second countdown. The user can cancel RTH by pressing the RTH button or Flight Pause button on the remote controller.

If RTH is cancelled following a low battery level warning, the Intelligent Flight Battery may not have enough charge for the aircraft to land safely, which may lead to the aircraft crashing or being lost. The thresholds for the battery level warnings are automatically determined based upon the aircraft's current altitude and distance from the Home Point.

The aircraft will land automatically if the current battery level can only support the aircraft long enough to descend from its current altitude. The user cannot cancel the auto landing but can use the remote controller to a lter the aircraft's orientation during the landing process.

Failsafe RTH - to summarize this one - this is activated if the remote signal is lost for more than 2 seconds. The Forward Vision System of the Mavic allows the aircraft to create a real time map of the flight route as it flies if the Home POint was successfully recorded and the compass is functioning normally.When this mode is activated the aircraft will begin to reverse its flight path along the original route. If the signal is not reestablished within 60 seconds, the aircraft will RTH from that point in a straight line.

The RTH procedure is as follows:
1. The aircraft adjusts its orientation.
2. If the aircraft is more than 20 meters from the Home Point when RTH is activated the aircraft will ascend to its predetermined altitude. It will fly to the Home Point at 12 m/ssec. If the aircraft is higher than the preselected altitude at the time RTH is activated, the aircraft will return at the higher altitude.
If the aircraft is between 5-20 meters from the Home Point the aircraft will fly to the Home Point at its current altitude unless st he current altitude is less than 2 meters, in which case the aircraft will ascend to 2 meters and fly to the Home Point at 3 m/sec, if the Current Altitude option has been selected. If the Current altitude option was not selected, the aircraft will land immediately.
If the aircraft is less than 5 meters from the Home Point when the RTH command is initiated, the aircraft will and immediately.
3. One the aircraft has landed the motors will automatically shut down.

As I mentioned previously, when I flew a Typhoon H I, on more than 1 occasion, purposely exhausted the battery at about 1-2 feet off the ground. The H took control of itself, landed and shut down. This is what I expected the 520 to do as it makes sense. I think the Mavic protocol is far superior.
 

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I am waiting for someone(s) smarter than I to address my original question - why is it in a low battery situation when RTH is automatically activated the 520 immediately ascends to the programmed RTH altitude? Yes, I know, because that is what it is told to do. But why is it directed to ascend.
The ascent is an effort to clear all obstacles between the aircraft and the home point so the craft can proceed in a straight line and minimize the need for pilot intervention. It is a simple program to operate, and works well if the pilot had the foresight to program in an appropriate RTH level for the flight area, and did not take off from under a bunch of trees.
 
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I understand your point but when the battery is about to go t*&s up, it is not the time for the drone to begin an ascent to 90’, 100’ or whatever because the aircraft is unlikely to achieve the RTH altitude and then descend and land without losing power and crashing, even if it is only straight up and then straight down. I understand all about not putting the aircraft in that position but that doesn’t negate the fact that the RTH response in the situation I have described is a likely death sentence for the aircraft.
 

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The Yuneec Typhoon 520 and H Plus have the same RTH profile tied to the third low battery warning. Whether it makes sense or not, it is what it is, and I am not a fan for the exact same reasons mentioned - at low battery, the last thing you want to do is rocket skyward. But as pilots we need to be proactive not reactive.

Personally I think it is a manufacturers response to mask poor pilot operational skills and behaviors - lets face it, some pilots treat battery percentages like gas left in a tank - as if it can be flown to zero/empty. In any case there is a remedy, and one that I mentioned early on in the summer of 2018 and that is: In the event you get to third 'Low Battery' warning - be prepared to flip the flight mode switch to another mode then back to the one you want. For instance if you are in Angle and continue to fly past the second warning, you should know you have 30 seconds before RTH will be automatically selected - all one needs to do is flip the mode switch away from the current mode and back - this will end the RTH - until 30 seconds later then it will repeat.

For those that don't know - once the first 'Low Battery' warning happens on the 520 (or the H Plus) - they then come every 30 seconds. So from the first Low battery warning you have just 60 seconds before the RTH initiates and; if you elect to fly past this, you need to be ready to cancel every 30 seconds more that you fly. Personally I would suggest any pilot of one of these systems never, under any circumstance - plan to fly past the first warning but rather be on the ground by then.

However IF a circumstance presents itself that requires a little more flight one can be prepared and proactive.
 
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Ty Pilot

Thanks for your response. As a commercial pilot I completely agree with your proactive comment, which prompted my “test” in the first place, not being aware of your 2018 posting on the subject. Other than your post, under what rock would I have found this information? I saw nothing related to your described low battery scenario in the manual.

As much as I am not a big fan of DJI, I must admit they are superior to Yuneec in some areas, this being one of them.
 
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Fortunately, that rock where everything is hidden - is this forum. ;) Many of us believe that; of all of Yuneec's faults, their greatest is the lack of a thorough manual, and I believe their second greatest fault is making slight changes to subsequent drones and telling no one. My knowledge is mainly the Typhoon H and H Plus and back when this forum was at it's most active, topics like these were daily. Many of the things we found were later adopted into the user generated manuals to help those coming on board get through the weeds, I know there are differences between the 520 and Plus but I found out about the 'hidden' RTH and later read that the 520 had that same feature.


The only way I arrested my first RTH was that I remembered reading about how to cancel a RTH, (I believe) in the 480 manual. There are stickies in the Typhoon H Plus section, one of them has the updated manual, not sure if there is a similar 520 manual but if there is, I would suggest downloading it or the updated Plus manual.

I agree that DJI supports and documents their systems far better and overall, their products are very well refined compared to Yuneec and that is just a shame because I, and many others think the Typhoon H platform is one of the best Prosumer drones ever and if they would just support it correctly. . . .
 

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