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Mavic dropped mid air -> destroyed

In the second two flight logs, the motors were not running. Are you sure they were running? If so, do you have other DAT logs?
Every time i try to retrieve DAT, some others are created. Also the craft disconnect by itself after a certain time (i presume internal fan error, due to server damage).

I am 100% sure the motors just started again 1 sec before impact. Really short time before impact. Maybe nothing was recorded in the DAT due to shock ? However, here is a ZIP file with all the DAT from today.

Dropbox - dat.zip

If it helps, i did an active track, spotlight mode and move the aircraft during the first part of the flight. then the subject was lost, so i decide to cancel activ track and come back using the sticks (normal flight mode) then the craft dropped
 
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A new DAT log is created each time the Mavic is powered on. The fact that you have two DAT logs at the same location means the Mavic was powered off and back on again.

I cannot explain the motors restarting. Your DAT log does not show that.
 
I dont know what to say. I saw them and hear them restart. One thing is sure, the front leds were red while falling, as I was not recording. When i recovered the craft on the ground, there was also the big yellow led still blinking. So the craft was still powered. I remind me shut the battery down to turn off the lights before picking the craft.
 
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I dont know what to say. I saw them and hear them restart. One thing is sure, the front leds were red while falling, as I was not recording. When i recovered the craft on the ground, there was also the big yellow led still blinking. So the craft was still powered. I remind me shut the battery down to turn off the lights before picking the craft.

Well, DJI should replace this free of charge. Hopefully you'll get a properly working one. It's sort of a lottery really with the refurbished ones, especially with camera element alignment (focus issues).
 
"laceyboy" on DJI forum pointed the following out, drop in battery voltage :

Mavic dropped mid air -> destroyed

083857xpmfmmxhcaaaamm2.png
 
Without looking at any of your data, I will pretty much guarantee you depleted the necessary volts needed to fly. Example, lets say the battery has 14 volts fully charged. And lets say the Mavic requires a minimum of 11 volts to function. Now, when you go full throttle Forward or full throttle Upward for a length of time it will eventually drop below the needed 11 volts. Should you be at full throttle on both Forward and Upward at the same time, the volts will drop rapidly.
Depending on how charged up the battery is at start up will determine how soon you might reach that say 11 volts point. Cold weather is another huge factor in this situation.

Somebody else will need to chime in and let us know what the volt drop off amount is on the Mavic. This is why I kept referring to the word "say". I'm pretty sure it is 11.0 volts, but I'm not a 100% sure. Btw, I need to point out that this issue is actually based on the amount of volts in each battery cell. With the numbers I gave above such as 11.0 volts, would mean the cutoff point for each battery cell would be 3.66 volts. Even though my numbers might be off you should be able to get the idea about limited volts.

At this point the only other thing to mention is about return volts. When you are say full throttle and drawing a lot of current, as mentioned the volts are dropping. But if you bring the throttle sticks back some to say 70-80% the volts will usually become steady and not drop. The GO4 app has a option to display live volts in the upper right corner of the flight screen. It will change colors based on the amount of usable volts. It goes from green, to yellow, to orange, to red. You should make a habit of monitoring the volts display and never allow it to reach the red color. Remember to let off some will allow the Volts to Return to a safe operating level.
 
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We need the last largest .dat file you have downloaded from the aircraft. It will be above 150MG most likely. ALL other files are completely useless. If the motors are not running, it's not an actual flight. As I say, the largest dat file is usually the hot ticket.
 
Without looking at any of your data, I will pretty much guarantee you depleted the necessary volts needed to fly. Example, lets say the battery has 14 volts fully charged. And lets say the Mavic requires a minimum of 11 volts to function. Now, when you go full throttle Forward or full throttle Upward for a length of time it will eventually drop below the needed 11 volts. Should you be at full throttle on both Forward and Upward at the same time, the volts will drop rapidly.
Depending on how charged up the battery is at start up will determine how soon you might reach that say 11 volts point. Cold weather is another huge factor in this situation.

Somebody else will need to chime in and let us know what the volt drop off amount is on the Mavic. This is why I kept referring to the word "say". I'm pretty sure it is 11.0 volts, but I'm not a 100% sure. Btw, I need to point out that this issue is actually based on the amount of volts in each battery cell. With the numbers I gave above such as 11.0 volts, would mean the cutoff pint for each battery cell would be 3.66 volts. Even though my numbers might be off you should be able to get the idea about limited volts.

At this point the only other thing to mention is about return volts. When you are say full throttle and drawing a lot of current, as mentioned the volts are dropping. But if you bring the throttle sticks back some to say 70-80% the volts will usually become steady and not drop. The GO4 app has a option to display live volts in the upper right corner of the flight screen. It will change colors based on the amount of usable volts. It goes from green, to yellow, to orange, to red. You should make a habit of monitoring the volts display and never allow it to reach the red color. Remember to let off some will allow the Volts to Return to a safe level.
Thank you for your input. But, how come this is mentionned nowhere ? I mean, how could I know that ? I should have some warning saying that the props are going to fast or whatever. My battery was 100% charged from the same morning. Do you think that is a resonable point for DJI not to take the craft underwarranty ?
 
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We need the last largest .dat file you have downloaded from the aircraft. It will be above 150MG most likely. ALL other files are completely useless. If the motors are not running, it's not an actual flight. As I say, the largest dat file is usually the hot ticket.
the largest DAT from today (date of the crash) is number 17 (71 MO). Do you need DAT from previous days ?

Largest DAT file from date of crash here -> Dropbox - FLY017.DAT
 
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Why did the relative_h dropped while the Mavic was still up in the air ?

Dropbox - relative_h.jpg

I'm sorry....I was not aware you were on here. Otherwise I would've responded much sooner!

The relative_h you have referred to comes from the "Avoidance" section. It has nothing to do with the battery, and I can only guess what it might mean. I'm thinking "relative_h" is referring to Horizontal, or something similar. The Graph would be showing that the aircraft was increasing altitude until power was lost and it dropped.

If I was viewing that same data, from the battery section which is just above the avoidance section, I would select the (bat_voltage, bat_current, and bat_cap_percentage) from the list and view the graph data of the 3 combined. If the FLY017.DAT is indeed the right file, I will be looking for this same data info I just mentioned.
 
Thank you for your input. But, how come this is mentionned nowhere ? I mean, how could I know that ? I should have some warning saying that the props are going to fast or whatever. My battery was 100% charged from the same morning. Do you think that is a resonable point for DJI not to take the craft underwarranty ?

This is the type of info a manufacturer will never tell you. It is forums and communities like this one is where you learn about these type of issues. And unfortunately this kind of info is a result of someone else misfortune.

Technically, when your aircraft reaches the volt limit with the battery, it is suppose to go into failsafe mode and land. However, as you now know that just isn't always the case. But if the data is what I think it is, then I don't see why your aircraft would not get replaced.
 
The cutoff voltage is a lot lower than 11v. In sport mode it drops below 11v easily. I've seen Litchi log 9.978v during flight and I don't even run my batteries below 20% where it would drop even quicker during full throttle.
litchivoltage.JPG
 
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Either way give this man a free mavic.. You should never be able to exceed the voltage requirements to stay in the air. The craft should automatically reduce the demand if it gets near that point!
 
The cutoff voltage is a lot lower than 11v. In sport mode it drops below 11v easily. I've seen Litchi log 9.978v during flight and I don't even run my batteries below 20% where it would drop even quicker during full throttle.
View attachment 13283
So you actually think it is a lot lower then 11v?



Either way give this man a free mavic.. You should never be able to exceed the voltage requirements to stay in the air. The craft should automatically reduce the demand if it gets near that point!
The way they will jack him on this will be from the HighWind Warning boxes that so easily pop up. They may say that he ignored them which ended up causing the battery into a more stressed flight. Who knows?
 
WOw. seems like being too close to the water confused the mavic and it wewnt in for a landing

Yeah.. perhaps?

I was very close to it.. I flew it closer to the bridge then the water.. it also "crashed into water" rather then landed?
 
@smh FLY017 and FLY018 are the files for this incident. The end of FLY017 shows that there was an abrupt loss of power just like several other incidents lately. This can be seen by looking at the motorVolts data where the volts dropped from around 11.5 to around 6.3 at the very end.
upload_2017-5-20_21-27-22.png

FLY018 is the next .DAT. By looking at the eventLogs for both FLY017 and FLY018 it's possible to estimate that the gap between the end of FLY017 and the start of FLY018 is about 4 seconds. Different data starts being reported at different times after the recording starts. The motor data didn't start until about 9 seconds into FLY018 so the motor restart that you reported wasn't captured,
upload_2017-5-20_21-34-21.png

FLY018 is abnormal in that the battery data isn't being recorded.
 
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Yeah.. perhaps?

I was very close to it.. I flew it closer to the bridge then the water.. it also "crashed into water" rather then landed?


Flying under a bridge means it could have lost GPS signals. Then it goes into ATTI mode, and if it was windy and/or if it got confused, and since you were very low to the water, the sensors sometimes mistake that for you are inches above the ground, then it automatically goes into landing mode, and thinks it is landing onto ground, when it is landing into water. Doesn't help that under the bridge the lighting conditions are suboptimal, and in the low light conditions the Mavic's downward sensors are not reliable sometimes. It seems like the perfect storm of conditions that caused your Mavic to crash into water. Very tragic. Unfortunately, I've been flying Mavic for a long time, and still I would not have taken that sort of risk that you seemed to have taken in the video.

It is not a good idea to fly under a low bridge, especially where there is nothing but water underneath. If you really wanted to do it, you should have at least turned off downward sensors, the water plays tricks on the sensors sometimes at low altitudes.
 
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