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Q500 Just fell out of the sky

Joined
Jan 12, 2019
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Age
65
#1
At approximately 5 minutes into the flight and at approximately 300' AGL I selected HOME. The craft flew back to me and when almost directly overhead, it just started tumbling and fell to the ground motors still running all the way down and the drone was still powered up after impact. This was my 19th flight in two years and I had never had a problem before. Before I attempt to repair or replace what's left of my Q500, I just wanted to know if anything like this has been reported before.

Mike
 
Joined
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#2
Oh dear. My commiserations for your loss.

What was the voltage / battery status showing as you called RTH ? Also what was the outside temperature, and had you been looking after the battery packs properly, in terms of storage voltages etc ? Lastly, do you have any telemetry you can post that would help us diagnose what went wrong ?
 

Steve Carr

Brownie Instamatic on a kite.
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#3
Sadly, a small number of Q500's have suffered from ESC failures. I'm confident that is what you experienced. Many times your nose can locate the one that failed by simply sniffing each motor. Generally a faulty ESC on a Q will fail in the first 60 min of flight time.
 
Joined
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#4
At approximately 5 minutes into the flight and at approximately 300' AGL I selected HOME. The craft flew back to me and when almost directly overhead, it just started tumbling and fell to the ground motors still running all the way down and the drone was still powered up after impact. This was my 19th flight in two years and I had never had a problem before. Before I attempt to repair or replace what's left of my Q500, I just wanted to know if anything like this has been reported before.

Mike
All of what AeroJ said but also did you check your props before your flight? I have heard about the ESC thing before and there are a couple of video's on YT of it actually happening, so this also could be a thing to look at. Usually, the Q500 is one of the most reliable drones out there. I've flown 100's of flights with mine without an issue. If you do find it was an ESC, replace all 4, not just the bad one. Although, if it was at 300ft when it came down, I can't imagine that there's be much left to replace?!!
 
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#5
All,
I didn't notice any smell or check the temp of the motors. This was the first flight after having transported the vehicle and I did check the props, but perhaps not good enough. After sifting through the carnage a bit more trying to account for all the parts, I couldn't find the left front prop. Initially, I discounted its absence since that area was the primary impact point. However, further examination reveal that there was no prop hub and the threads on the motor show no signs of damage (a new prop screws on easily).

I'm guessing that when I selected the HOME mode the rapid decel to start a descent may have allowed that prop to spin off from the inertia.
 
Joined
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h-elsner.mooo.com
#6
Some time ago I lost an ESC midair at my Q500. It flips over and fell streight down on his back. Good for the gibal which survived this crash.

Do you have the flight log from your incident. possibly there some more to see what may happened. Flight logs are stored in the SD card beyond the battery in the ST10+.

br HE
 

Steve Carr

Brownie Instamatic on a kite.
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#7
further examination reveal that there was no prop hub and the threads on the motor show no signs of damage
I think you found the cause. If it was an ESC failure all 4 hubs would still be attached. To tighten the blades on the Q, after the prop touches the o-ring I hold the motor with one hand and tighten the prop with the other until if feels snug. I presume the o-ring were all in place?
 
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#8
I retrieved the telemetry. Based on altitude and roll, yaw, and pitch elapsed time from the event to impact was just about 5 sec. Timing from the start of the event, "f_mode" went from 13 to 14 in .654 sec, "error_Flags1" went from "0" to "32" 0.234 sec later, then to "33" 1.0 sec after that. The "motor_status" remained at "15" until 2.1 secs after impact and then went to "13" at the same time as "f_mode" went to "12".

Is there a decoder ring for these status values?
 
Joined
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#9
Is there a decoder ring for these status values?
You need to get the program:
"Q500log2kml ".
A bit confusing for a first time read but easily navigated and error descriptors for most errors can be found.
I doubt the telemetry is going to be of much help in this instance.
Good luck and happy flying,
Jafo
Added: Look here:
PHP:
http://b-drone.nl/wp-content/uploads/2017/02/Q500log2kml-manual.pdf
 
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Joined
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#10
The user manual in the link above is too old:
Use this for latest info:
http://h-elsner.mooo.com/mydat/Q500log2kml_en.pdf

Hold mouse pointer on a cell in the table to get more information. Format of the flight log values as far as I know are described in the Appendix (Chapter 3) of the user manual.

f_mode 12 is the Emergency mode. The copter switches off all motors. Without having the FlightLog I guess, no ESC error.

Error flag 32 means Compass Calibration Warning (CCW) and 33 means CCW+Voltage Warning1.

be HE
 
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#11
I'm on my second Q now. The first one just dropped like a brick into the St. Johns River here in Florida - no recovery. So I bought a new one. A few months later, the second one dropped as well but this time it was over land and only about 15 feet in the air. It was ESC.
I have an H Plus now, too, so I don't fly the Q as much but ever since I got it repaired, it flies fine. I use it for play and I use the Plus for business.
 
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#12
Was finally able to reassemble the Q enough to power it back up and close out the video that was recording at the time of the accident. It clearly shows that there was no prop on the left front motor during its tumble. That lead me to expand my search of the crash scene and I located one undamaged prop approximately 30 meters northwest of the ground impact point.

Case closed. Cause of accident was failure to properly tighten the prop onto the motor spindle. In the future, I will always use the motor holding tool and tighten props snuggly. Further, following each prop removal/replacement, I will run a very short test flight - off the ground to 1 meter and then land and check the props.

This gives me the confidence to buy a replacement. Necessary since the frame and gimbal were completely destroyed and a full refurb system was less than just replacing the camera unit + body + legs.

Thanks to all for the clues and information you provided.

Mike
 

Steve Carr

Brownie Instamatic on a kite.
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#13
In the future, I will always use the motor holding tool and tighten props snuggly.
I would suggest not using the tool. The prop tool is intended to remove the props, not to install them. It's easy to overtighten them with the tool.
Spin the props down until they make contact with the rubber o-ring. Then hold the motor with one hand and turn the prop with the other about 1 full turn. No tighter than that.
 
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