Unexplained fall from the sky.

[MisterMavic]

Had an unexplained fall from the sky on my Mavic today. Mavic just spun out of the sky and landed on a lawn. Mavic came out of it undamaged which is even harder to explain. Video shows Mavic flying well above any obstacles, it almost looks like something knocked it from the sky or a motor malfunctioned and sent it into a spin and fall. If anyone can make heads or tails of the data I would appreciate it greatly. I attached AirData and CSV file.
Airdata UAV - Flight Data Analysis for Drones
Well it won't let me upload the csv file, says it is unsupported file extension. I'll try it as a text file. I'm at work now and can upload the DAT file tomorrow or late tonight if needed.

 

[Cerberus]

wats your firmware version?

 

[MisterMavic]

I was using the Litchi app if it helps. Which I will NEVER use again! I also had an incident a few weeks ago when I used it instead of DJI GO and the app froze and the drone returned to home. I've never had any problems with the DJI Go app and had problems 2 of the 3 times using Litchi.

 

[MisterMavic]

I just updated the firmware yesterday so it is the latest unless a new firmware came out today.

 

[MisterMavic]

I think it was v01.03.0700, but that is off the top of my head.

 

[Cerberus]

well, consideriing litchi was broken in firmware .500 to .550
so its possible the latest firmwares, though lets u use Litchi again, is not fully problem-free.

maybe you should fly normally using DJI go first and see whether such problems happen again or not..

if not... its probably litchi with the new Firmware issue...

did you bring this issue up at Litchi's forum or customer service or whatever they have?

 

[MisterMavic]

I hope it is Litchi but I don't understand how the app could cause the movement of the drone before the crash. It almost looked like something knocked it from the air or a motor froze up or failed.

 

[Cerberus]

I hope it is Litchi but I don't understand how the app could cause the movement of the drone before the crash. It almost looked like something knocked it from the air or a motor froze up or failed.

Well, what we can do is wait for some pro in here to take a look at your log..
then we will probably get more detail as to what happened..

Fly safe, my friend.

 

[Cyberpower678]

Please upload the DAT file from the Mavic to a dropbox and link it here.

How to retrieve a .DAT

 

[MisterMavic]

Please upload the DAT file from the Mavic to a dropbox and link it here.

How to retrieve a .DAT

Will do, late (early morning) tonight or tomorrow morning.

 

[MisterMavic]

Dropbox - Mavic Crash 5-23
Hope this is correct. I never used Dropbox before. The flight went bad around 9 minutes to 9 minutes 6 seconds I'm guessing.

 

[MisterMavic]

I also put a copy of the video it was shooting at the time of the crash. As you can see in the video there was clearly no obstacles that I could have hit. I believe I was over 250 feet in the air. How the Mavic came away without a scratch except for 3 broken props, is beyond me, but I'm afraid to put it back in the air again until I know the reason for the crash. I did test it at 5ft and everything responds and acts like normal. The Mavic landed right in front of the driveway with the white shed (1st white shed, car in driveway) on the right side. The guy had a really nice thick lawn that was about 3 days overdue a mowing which I'm sure cushioned it's landing somewhat. The Mavic was on its back and still on (other than motors) and recording when I recovered it. I walked up the drive way expecting the worse for my little buddy and was surprised when I gave him a look over he looked to be in great shape except for the broken props. One more piece of information the Litchi app froze up with the image of the Mavic spinning in the air. I couldn't reconnect with Litchi but was able to connect with the GO 4 app to locate the drone on the map. I could tell before the app froze that the Mavic was in serious trouble. I was hoping it was just the gimbal going crazy and the Mavic would return home. After a few minutes I knew we had a Blackhawk Down situation and I jumped in my truck and headed for area. To make matters worse my DJI Goggles will be here around noon and I will not fly the Mavic until I have some peace of mind or a resolution. I would love nothing more than the cause to be a Litchi issue or pilot error. If it was a drone malfunction or cannot be determined by the DAT file its grounded until DJI checks it out. My little buddy could have hit someone or something and caused serious problems for me as well as them.

 

[_milo_]

I didn't look at the DAT file, that will narrow it down a lot more, but I did note, that you were pulling some much higher amps, then I've ever seen on my flights, and your battery temp was higher than I've ever noticed on my flights.

You started with less than full battery, were you flying aggressive in sport mode? If not I'd check the motors are spinning freely, no grinding, or binding.

Looks like battery pushed past its limits, but the Cyber should have more from the DAT file.

 

[Clinton1]

Watched the video, i am no expert, but almost looks like motor fault or prop that broke.

 

[HFMan]

I looked at the DAT file... there is nothing out of the ordinary. It looks to me like either something hit your Mavic or a prop broke at 546.437 based on accelerometer data. At 546.466 the flight controller began to take action to correct for the problem. It was total chaos at this point.

 

[MisterMavic]

Prop or motor is what I was thinking, looking above is that the power of each motor, RFront 80, LFront 9.9, LBack 8,563 and RBack 9892? Do the values of the RFront compared to the LFront look right?

 

[_milo_]

I just watched your video, I've pushed a battery before too hard past its C limit, and had a quad come down, it doesn't come down abruptly like your video. I looked at the amps/volts/batt temp, which is what I noticed was higher than my flights on airdata, see the attached (zoomed at end, and entire flight), which, from your DAT file, at the end there you settled down, and battery was recovering. Earlier in the flight you can see how high your amp draw went and the voltage sagged to really low.

I've not pushed my mavic that hard in sports mode, I've got some flights hitting 40mph in sports, but don't have a DAT file, so I can't compare it, I'd recommend a fully charged pack, prior to take off, especially if your gonna hit some WOT runs.

Does it power up and spin motors normal, I'd suspect, motor, esc, prop failure.

 

[MisterMavic]

I wasn't flying aggressively and I think I took it up for a very short flight and brought it back down before taking off again. I believe my battery was high 80's when I took off for this flight.

 

[_milo_]

I think hover pulls around 7-8 amps,

I haven't slept, I was looking at the wrong color, when I commented earlier, YES to me your amp draw was abnormally high before crash and voltage sagged to critical at the 550 timeline.

 

[_milo_]

Even so, I've flattened a lipo, and over stressed a lipo, and crashed, but both times it was a slower crash, your looks like what a prop/motor/esc failure looks like, it could be that high amps was a symptom of one of those, I'm on 1.5 hours of sleep, so bear with me, if I'm missing something.