First Crash

[Anthony21078]

I've had some cheapo Holy Stone drones in the past and the Mini is my first "real" drone. I have maybe 15 flights on the Mini so I understand how to fly it. So today I set off for a flight from my backyard and I'm 90% sure I heard the home point location updated audible after take off. Nevertheless, I began flying around the neighborhood never going beyond 600ft in distance and a max flight elevation of 190ft for approximately 6 minutes. My RTH elevation was set at 124ft (This is the elevation I have set from my 1st flight and haven't changed it).

I picked up some interference and lost the camera view for a bit and activated the RTH through the app. The drone started acting strange by slowly traveling further away from the home point and not ascending to the RTH elevation. At that time my current elavation was 93ft. I basically lost control and the drone started slowly descending and eventually went into a tree in roughly the same location it was hovering at when I activated the RTH. I feel like the drone was not responding to my commands when using the joysticks.

Luckily I found it by going through the log and finding the last gps location. The battery wasn't fully seated when I found it the so the find my drone option obviously wasn't working. Any ideas what may have happened?

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[WooZie]

when RTH was activated i saw you were at 176ft alt, so in that case MM will not descend at 124 but will start to go home, but, it was strong wind?

 

[Anthony21078]

when RTH was activated i saw you were at 176ft alt, so in that case MM will not descend at 124 but will start to go home, but, it was strong wind?

Yes your correct I read the log wrong. I was receiving strong wind warnings during the whole flight.

What mode does RTH use? Will it use the last mode the drone was using before RTH was activated? If so, I was in Sport Mode so Im sure the drone would be strong enough to come back ?

But even so, why did the Mini decide to desecend on its on if it didnt return to the home point?

 

[WooZie]

rth procedure is simple, if you are under the rth alt set on the app the drone will lift to that alt and then come home, if you are above that alt the drone imediately will come home, but has nothing to do with the sport mode because the mode is changed automatically in go home, so if is strong wind, will cannot come home, maybe tried to land because of the battery. More specialists here will see that and they will give you an opinion, i am new here

 

[old man mavic]

just loosing camera view would not make it do a rth on its own ,and it waits for a few seconds before it does that anyway, it sounds like you lost connection with the drone between the controller and the drone and also because you were flying in a built up area you could have lost GPS as well and this will put the drone in ATTI mode, this coupled with the height you were at, and the windy conditions caused the drone to drift away from the home point, those high wind warnings are not just for fun, and you should have reacted to them and reduced your height and made your way back home when you saw them sorry if this sounds like a lecture but you need to know certain things if you want your drone to last ,i am only trying to help you in that respect

 

[Meta4]

The drone started acting strange by slowly traveling further away from the home point and not ascending to the RTH elevation. At that time my current elavation was 93ft. I basically lost control and the drone started slowly descending and eventually went into a tree in roughly the same location it was hovering at when I activated the RTH. I feel like the drone was not responding to my commands when using the joysticks.
Any ideas what may have happened?

What happened is that you launched the drone with a battery that was already low and flew downwind at about 180 feet.
At around 3:40 you had flown teh battery down to 25% and were 180 feet up and 474 feet from home.
You turned the drone around to come home in Sport Mode but left the drone hovering for a while.
Looking at the data from 3:51 to 4:08.1, there was no stick input and the drone was unable to hold position because of the wind strength.
At 4:08.2 and 175 feet up you initiated RTH while the drone was 493 ft from home.
At 4:32.3 you cancelled RTH with the drone 28 feet further away because the wind at that height was stronger than the RTH speed.

The drone was also descending without any stick input and no message to explain why.
No other DJI drones do that so I'm not sure why it did but suspect it was because of the low battery level.

You cancelled RTH and put the drone back in Sport Mode, now at 136 feet and still descending on its own.
You made no effort to fly it back to home and left the drone hovering.
It was being blown backwards at 0-4 mph in the gusty conditions.
RTH initiated again at 4:50.8.
The drone started to ascend to your RTH height, got to 114 feet and came back to 93 ft (still with no joystick input) and resumed the attempt to RTH against the wind while autodescending.
In the gusty conditions it was sometimes making slow headway and sometimes being blown backwards.
As it lost height, it was able to make more headway with the speed increasing to 4.3 mph towards home at 5:36.1.
With the battery level at 17% and falling fast, it was never going to make it home and was autodescending to prevent a fall from the sky when the battery ran out.
Signal was lost at 5:37.5 with the drone 30 feet up and descending.

The drone doesn't appear to have "acted strangely" but there's plenty to suggest the flyer did.
Some of the mistakes were:
Launching with a low battery
Flying downwind in a strong wind
Leaving it hovering up high and blowing further away.
Not being aware of what was happening to the drone.
Not making any effort to bring the drone back manually which would have been faster then RTH.

 

[old man mavic]

What happened is that you launched the drone with a battery that was already low and flew downwind at about 180 feet.
At around 3:40 you had flown teh battery down to 25% and were 180 feet up and 474 feet from home.
You turned the drone around to come home in Sport Mode but left the drone hovering for a while.
Looking at the data from 3:51 to 4:08.1, there was no stick input and the drone was unable to hold position because of the wind strength.
At 4:08.2 and 175 feet up you initiated RTH while the drone was 493 ft from home.
At 4:32.3 you cancelled RTH with the drone 28 feet further away because the wind at that height was stronger than the RTH speed.

The drone was also descending without any stick input and no message to explain why.
No other DJI drones do that so I'm not sure why it did but suspect it was because of the low battery level.

You cancelled RTH and put the drone back in Sport Mode, now at 136 feet and still descending on its own.
You made no effort to fly it back to home and left the drone hovering.
It was being blown backwards at 0-4 mph in the gusty conditions.
RTH initiated again at 4:50.8.
The drone started to ascend to your RTH height, got to 114 feet and came back to 93 ft (still with no joystick input) and resumed the attempt to RTH against the wind while autodescending.
In the gusty conditions it was sometimes making slow headway and sometimes being blown backwards.
As it lost height, it was able to make more headway with the speed increasing to 4.3 mph towards home at 5:36.1.
With the battery level at 17% and falling fast, it was never going to make it home and was autodescending to prevent a fall from the sky when the battery ran out.
Signal was lost at 5:37.5 with the drone 30 feet up and descending.

The drone doesn't appear to have "acted strangely" but there's plenty to suggest the flyer did.
Some of the mistakes were:
Launching with a low battery
Flying downwind in a strong wind
Leaving it hovering up high and blowing further away.
Not being aware of what was happening to the drone.
Not making any effort to bring the drone back manually which would have been faster then RTH.

@Meta4 thank you for your very detailed and comprehensive report on the cause of the crash, i hope that the OP learns from it and i hope his MM is ok after the event

 

[Mori55]

Every time you turn it on you have to reset the RTH height. It doesn’t save it. It defaults to 49 feet.

 

[old man mavic]

Every time you turn it on you have to reset the RTH height. It doesn’t save it. It defaults to 49 feet.

i cant speak for the android app but there is a new app update for IOS ,that addresses that problem ,and now if you set a height then it is stored for the next flight

 

[scooot]

Meta4,
????brilliant.

 

[Anthony21078]

What happened is that you launched the drone with a battery that was already low and flew downwind at about 180 feet.
At around 3:40 you had flown teh battery down to 25% and were 180 feet up and 474 feet from home.
You turned the drone around to come home in Sport Mode but left the drone hovering for a while.
Looking at the data from 3:51 to 4:08.1, there was no stick input and the drone was unable to hold position because of the wind strength.
At 4:08.2 and 175 feet up you initiated RTH while the drone was 493 ft from home.
At 4:32.3 you cancelled RTH with the drone 28 feet further away because the wind at that height was stronger than the RTH speed.

The drone was also descending without any stick input and no message to explain why.
No other DJI drones do that so I'm not sure why it did but suspect it was because of the low battery level.

You cancelled RTH and put the drone back in Sport Mode, now at 136 feet and still descending on its own.
You made no effort to fly it back to home and left the drone hovering.
It was being blown backwards at 0-4 mph in the gusty conditions.
RTH initiated again at 4:50.8.
The drone started to ascend to your RTH height, got to 114 feet and came back to 93 ft (still with no joystick input) and resumed the attempt to RTH against the wind while autodescending.
In the gusty conditions it was sometimes making slow headway and sometimes being blown backwards.
As it lost height, it was able to make more headway with the speed increasing to 4.3 mph towards home at 5:36.1.
With the battery level at 17% and falling fast, it was never going to make it home and was autodescending to prevent a fall from the sky when the battery ran out.
Signal was lost at 5:37.5 with the drone 30 feet up and descending.

The drone doesn't appear to have "acted strangely" but there's plenty to suggest the flyer did.
Some of the mistakes were:
Launching with a low battery
Flying downwind in a strong wind
Leaving it hovering up high and blowing further away.
Not being aware of what was happening to the drone.
Not making any effort to bring the drone back manually which would have been faster then RTH.

Extremely thorough and fantastic breakdown. THANKS

This was my problem...
"The drone was also descending without any stick input and no message to explain why.
You cancelled RTH and put the drone back in Sport Mode, now at 136 feet and still descending on its own."

From what I remember while this was happening, I could not control the drone anymore from the controller and it was going down regardless of what I did.
.
.
.
"You cancelled RTH and put the drone back in Sport Mode, now at 136 feet and still descending on its own.
You made no effort to fly it back to home and left the drone hovering."

I believe I was attempting to fly back home but the drone would not respond. I knew the location was a neighbors backyard based off the camera view and was trying to get home using the street as a guide....unfortunately it didn't work.

"With the battery level at 17% and falling fast, it was never going to make it home"
.
.
At 17% in sport mode I surely could have traveled 500 feet to my location no? Perhaphs not while using RTH at that slower speed though

I completely agree about starting the flight with the low battery is not the best idea.....but at 50% battery and doing a quick fly around the neighboorhood knowing I would not be traveling more then 600-700 feet, don't you think I have ample charge? Well, of course situations like this prove otherwise but your analysis of the log states several times the drone was not responding to the sticks which is eating battery life while the drone is just hovering and not able to repsond

 

[Anthony21078]

Every time you turn it on you have to reset the RTH height. It doesn’t save it. It defaults to 49 feet.

I haven't noticed that being the case on my android galaxy S8.

 

[scooot]

I haven't noticed that being the case on my android galaxy S8.

Yes,this was a iOS issue.It has now been reported by iOS users it has been fixed in the recent update.

 

[zeusfl]

Yes,this was a iOS issue.It has now been reported by iOS users it has been fixed in the recent update.

The same thing happens to me. Every time I fly I have to set the RTH altitude again. Most recent IOS in an iPhone X-Max

 

[Meta4]

This was my problem...
>>"The drone was also descending without any stick input and no message to explain why.
>>You cancelled RTH and put the drone back in Sport Mode, now at 136 feet and still descending on its own."

From what I remember while this was happening, I could not control the drone anymore from the controller and it was going down regardless of what I did.
...
>>"You cancelled RTH and put the drone back in Sport Mode, now at 136 feet and still descending on its own.
>>You made no effort to fly it back to home and left the drone hovering."
I believe I was attempting to fly back home but the drone would not respond. I knew the location was a neighbors backyard based off the camera view and was trying to get home using the street as a guide....unfortunately it didn't work.

The autodescent started around 4:26 with the battery at 22%.
It's different from what happens with other DJI drones which would come home at RTH height (or above if above RTH height) until directly above home or until the critically low battery level initiates autolanding to protect the drone.
This might be a new way for DJI to program the Mini but I can't be certain as I don't have one to test.
From 4:26, while autodescending, the drone is still attempting to RTH but being blown further away.
I suspect you could have had control even if not able to stop the autodescent.
There are several times when you gave it joystick input but they were too brief to see how they affected the flight.

>>"With the battery level at 17% and falling fast, it was never going to make it home"
At 17% in sport mode I surely could have traveled 500 feet to my location no? Perhaps not while using RTH at that slower speed though

Probably not against a headwind that was blowing it backwards in RTH mode.
At 17% you should already be home.
The battery is too low and would not last long pushing hard in Sport Mode.
You would have soon hit critical low battery level (if it wasn't already there) and the game would be over.

Strong headwinds are a serious problem that you have to understand and plan to avoid being stuck like this.
If it's a strong wind on the ground, it will be stronger up high. (Don't leave your drone up high when battling a strong headwind).
If you fly away going downwind, you have forced yourself to battle against a headwind for the return flight.

I completely agree about starting the flight with the low battery is not the best idea.....but at 50% battery and doing a quick fly around the neighboorhood knowing I would not be traveling more then 600-700 feet, don't you think I have ample charge? Well, of course situations like this prove otherwise but your analysis of the log states several times the drone was not responding to the sticks which is eating battery life while the drone is just hovering and not able to repsond

You started at 42% which really limits your flight options before you start.
Something goes wrong or you see something interesting that tempts you to stay up a little longer and before you know it, the drone is at critical low battery level and you have no options.
But it's probably more serious than that.
I don't know about the Mini, but the % indicator for all other DJI drones is only reliable if you start with a full battery.
It's very common to see fall-from-the-sky incidents when people launch with a battery that's been sitting around and actually has much less power than the % indicator suggests.

You should treat your fuel level as if you were flying in a real plane.
Only launch with a fully charged battery and always land with a healthy reserve fuel level.

 

[DanMan32]

The same thing happens to me. Every time I fly I have to set the RTH altitude again. Most recent IOS in an iPhone X-Max

Actually it was found before the recent fix in the iOS update that even when it showed 15m/49ft, it still retained your last setting in the AC, even if you viewed the setting without any changes. So if you were to forget but your last setting was suitable, no issue.
But its fixed now.

 

[DanMan32]

I have yet to see the Mini do a critical battery landing. I've gotten it down to 0 and it still wouldn't land on its own.
The reason I was at 0 was that RTH wasn't on target (launched from Combo case) so I cancelled RTH when it was several feet off the ground and tried getting it right over the case to land.

One thing I noticed about the Mini is that it keeps itself about 18" to 2 feet off the ground and won't descend any further until you tell it to actually land. That doesn't give me much to get it over small targets and be sure I am actually over them.

 

[DanMan32]

I get why it didn't ascend on RTH because it was already over the RTH altitude. I also get why it didn't come back because it was fighting the wind.
By the way RTH as was said, is its own mode with same or similar attack angle limit which limits its airspeed. This is probably chosen as it is probably optimal for distance over energy. Sport mode allows a bigger attack angle which allows it more airspeed.

What I don't get is why it kept trying to land if it still had energy in the battery.

 

[Meta4]

I get why it didn't ascend on RTH because it was already over the RTH altitude.

Look at RTH initiated at 4:50.8, which climbed from 93 feet to 115 ft at 5:04.1 (all the time trying to fly forward) and then started descending.
It never reached RTH height.

RTH as was said, is its own mode with same or similar attack angle limit which limits its airspeed.
This is probably chosen as it is probably optimal for distance over energy.

In all other DJI drones the RTH speed is significantly less than optimal speed for max distance.
No-one has ever come up with a credible reason for DJI to set RTH speed as slow as they do.

 

[DanMan32]

But why the descent? Doesn't make sense. Maybe there was a downdraft along with the push outward?