Hello Fellow Yuneec Pilot!
Join our free Yuneec community and remove this annoying banner!
Sign up

Result of testing low battery initiated RTL on H520

Joined
Mar 9, 2017
Messages
93
Reaction score
19
Location
Burlington VT
Well, well, well. I just experienced a similar issue, only I did it on purpose. I was curious to see if the 520 would behave similarly to my Typhoon H when the battery reached a critically low point. In the case of my Typhoon H, it will take over control of the
UAV, land, and shut down. So I put the 520 into a hover over the landing pad at an altitude of less than a foot when the battery was winding down and waited. At the critical moment I heard "RTH" from the controller and the 520 attempted to go straight up. Having considered this might occur I was prepared for the possibility, or so I thought. I immediately reduced power, which I believed should have commanded the 520 to abort the RTH command. It stopped the ascension of the 520 but it then began to fly erratically in different directions and altitudes. I attempted to apply correcting inputs to counteract the 520 but was essentially unsuccessful. The 520 flew into the roof of my house, tumbled down where two roof lines come together, rolled off the edge of the roof and hit the sidewalk before I could get into position to catch it. The damage was not severe and can be repaired with the necessary replacement parts. My guestion is why it did what it did. I can't believe the 520 is programmed to go to its RTH altitude as doing so is only going to let it fall out of the sky from a higher altitude. Even if that is the case I expected that inputting a command would cancel the RTH command and I would be able to simply descend and land. I was surprised I was not able to control its flight. As a veterinary surgeon I learned many years ago to expect the worst and you are never disappointed. My disappointment here is that I was not able to successfully land the 520. I am not convinced it was pilot error, as far as the flying goes. Retrospectively, I should have set the RTH to about 10' which might have saved my butt, and the 520. I have attached the crash log from the controller, I think. My controller will not maintain the correct date and time and I neglected to reset it to the correct date and time before flying yesterday. I have the ulog and tlog files as well but they appear to be too large to attach to this post. I would appreciate any comments. I was aware of a Pix program that would open these files for review but have forgotten what it is and can't find the paper I wrote it down on so I have not viewed the file.

Thanks in advance.

Paul
 

Attachments

  • Crash 3-12-21.zip
    1.5 MB · Views: 7
  • Like
Reactions: mdavud

DoomMeister

Moderator/Tech Junkie
Staff member
Premium Pilot
Joined
Dec 25, 2017
Messages
6,417
Reaction score
3,696
Location
Genesee, MI USA
You will have to upload your ulog file (.ulg) to the PX4 FlightReview site ( Flight Review ) and post the link here for us to take a look. The crash file you posted above is a crash log for the Android system of your controller and appears to me to be a crash during an attempt to use the firmware update system from Yuneec. Not surprised that you may have had a crash of the OTA update as the OTA servers have been a bit dodgy for the past few months. Not sure if they are back up yet or not.

I moved this from @mdavud 's thread as it was related, but should have been a new thread to begin with.

The one thing you failed to pick up from that thread is that toggling the Flight Mode switch out of Angle mode and back to Angle mode should have put you back into Angle mode where you would have been able to control the flight.

I await your post with the link of your ulog file to PX4 FlightReview.
 
Joined
Mar 9, 2017
Messages
93
Reaction score
19
Location
Burlington VT
I hope this is the format you want it in. Thanks for the help.

I was under the belief that if you moved either toggle while in RTH mode it would immediately exit the RTH mode and return to angle mode. Is that not correct?

 

DoomMeister

Moderator/Tech Junkie
Staff member
Premium Pilot
Joined
Dec 25, 2017
Messages
6,417
Reaction score
3,696
Location
Genesee, MI USA
Which toggle switch are you referring to?

According to FlightReview the mode switch was never changed and remained in the Angle mode position for the entire flight. Only the Flight Mode switch can make you exit the auto RTL mode.

Looking at the satellite view it appears this was done close to the house and with a lot of trees which would tend to reduce GPS acquisition.

I will look at this on my computer later this afternoon.
 
Joined
Mar 9, 2017
Messages
93
Reaction score
19
Location
Burlington VT
Toggle switch was a poor choice of words. I am referring to either of the 2 control "sticks" with which we maneuver the UAV. In the RTL mode, any input to either of the 2 control sticks will terminate the RTL command and cause the 520 to go into a hover.

You are correct, the 520 was being flown in my front yard. At this time of year there are no leaves on the trees and getting 10 or more satellites is not a problem. I have flown in and out of the front yard previously multiple times without any issues. The 520 responded to any and all of my control inputs for the several minutes right up until I heard the RTL command. Are you suggesting that the 520 lost GPS positioning which initiated the RTL command and was unrelated to the battery level? I am guessing not since with no GPS signal the 520 can't find its way home.

My main question regarding this episode is why, when the battery reached a critically low level, did the 520 execute a RTL command. Unless the RTL altitude was set to a very low altitude, it is/was highly unlikely there would be sufficient battery power to ascend to a more typical RTL altitude (in excess of 100', or at least to 66' as a Typhoon H would have) and then descend and land. The more likely scenario would be a complete loss of power before the 520 made a controlled descent to terra firma.
 

DoomMeister

Moderator/Tech Junkie
Staff member
Premium Pilot
Joined
Dec 25, 2017
Messages
6,417
Reaction score
3,696
Location
Genesee, MI USA
Moving the control sticks will allow you to maneuver the aircraft, but do not cancel RTL. The mode switch has to be moved.
 

New Threads

Members online

Forum statistics

Threads
19,762
Messages
228,817
Members
23,716
Latest member
WilliamG75930