Mavic Mini crash into bridge, then river

[Sleve]

I had my first crash today.I was really hoping my first post wouldnt be THIS....

I know I made a few mistakes, and ultimately am always responsible for the safe flight of my UAS, but really I have no idea how this happened. I was only trying to get a quick rapids shot, and was planning a 60-90 second flight. I had stopped a few feet from where I took off, and hovered over the edge of the river and was checking out possible shots when the drone started drifting backwards with no right stick input from me. By the time I realized what was happening, the drone hit the bridge, fell, and started white water rafting in the rapids below, never to be seen again.

DJIFlightRecord_2021-05-14_[13-35-00].txt

Mistakes- after seeing the flight data, I noticed my home point was showing 600-700 feet away, I definitely took off too early, before a new one was established. I "just wanted the quick shot", and got in a hurry. Also, I know taking off with a battery at 50% is bad practice, though, not a factor in this one minute flight. Lastly, I took my eyes off of the drone when I was too close to obstacles. I had seen it hovering and stable, looked down at my controller(fighting glare), and within 10 seconds it had drifted 30 ft backwards and crashed. I have been flying for a bit more than a year, and never had seen it drift that far, even in atti mode. I just didnt think it could happen. It can, and did.

Questions- 1.The bridge was big and metal. Did it factor into this? I took off 10 feet from it, but had just done a compass calibration.
2. Though I have DJI care refresh, since my drone is at the bottom of the river, I'm pretty sure I am SOL. But can I buy just a drone(no controller) to replace, or is each controller specific to each mini?
3. I cannot see the wind data in my log file. Did I get blown into the bridge?
4. Should I upgrade to a Mavic Air 2 or stick with the Mini until I learn to keep my props dry?

Thanks for your help in advance

 

[slup]

Hi there & welcome to the forum.

Sorry to say, but this was totally a pilot error & nothing more.

You launched without a proper confident GPS lock & positioned the AC above streaming water.

The chart below shows the bad horizontal positional hold you had ... a HP will only be recorded when the flight controller rank the GPS positional quality above 3 (of 5). You had at most 3 during the whole flight ... & during longer periods 0 (see the blue graph. The VPS sensors couldn't properly lock on ground to help out with the horizontal positional hold ... and due to all this your AC was drifting.

Never take off before you have a properly recorded HP in the correct place.

(Click on the chart to make it larger)

 

[Meta4]

Mistakes- after seeing the flight data, I noticed my home point was showing 600-700 feet away, I definitely took off too early, before a new one was established.

The data shows that it never actually set a home point and your drone never acquired enough satellites to go into P-GPS mode.
That 700 ft distance comes from some preliminary (and incorrect) location data.

Because the drone never went into P-GPS mode, it never had GPS position holding or "brakes", so it was drifting with any breeze and wouldn't stop when you went hands-off on the sticks.
This wouldn't matter much if it was up high and well away from any obstacles.
But down low and with things to bump into, it's a recipe for trouble.

I'm wondering though, why the drone didn't get enough satellites during the flight?
The collision happened after two minutes of flight.
If the flight was out in the open, with more than half of the sky visible, it should have easily acquired plenty of sats.

Was the flight path down in the river, sheltered by tree cover?

Questions- 1.The bridge was big and metal. Did it factor into this? I took off 10 feet from it, but had just done a compass calibration.

Calibrating the compass was not needed and it wouldn't have mattered if you didn't do it.
The only problem to do with the bridge was that it was big, solid and too close to a drone with no brakes.

2. But can I buy just a drone(no controller) to replace, or is each controller specific to each mini?

You could, but buying a drone only isn't very cost effective.

3. I cannot see the wind data in my log file. Did I get blown into the bridge?

When the crash happened at 124 sec, your drone had been hovering for quite a long time.
It had lost any speed that it had and was just drifting on the breeze.
Your data won't have any wind data because that comes from the degree the drone tilts to resist the wind.
But it needs some kind of position holding to be able to do that.

 

[izometric]

I had my first crash today.I was really hoping my first post wouldnt be THIS....

Well, you had 4 months to post something before this incident

 

[slup]

I'm wondering though, why the drone didn't get enough satellites during the flight?
The collision happened after two minutes of flight.
If the flight was out in the open, with more than half of the sky visible, it should have easily acquired plenty of sats.

Was the flight path down in the river, sheltered by tree cover?

Looking at the location down there in the bottom of the canyon might indicate that a proper sat lock could have taken quite a long time ...

 

[Meta4]

Looking at the location down there in the bottom of the canyon might indicate that a proper sat lock could have taken quite a long time ...

View attachment 129133

Definitely not a factor

Oops ... that was a typo
It was obviously a factor

 

[slup]

Definitely not a factor

Aha ... you've been there?

 

[StantonZ]

Definitely not a factor

Definitely disagree.

 

[Sleve]

Well, you had 4 months to post something before this incident

actually 16, but 2020 shouldnt count;-)

 

[Sleve]

Looking at the location down there in the bottom of the canyon might indicate that a proper sat lock could have taken quite a long time ...

View attachment 129133

The data shows that it never actually set a home point and your drone never acquired enough satellites to go into P-GPS mode.
That 700 ft distance comes from some preliminary (and incorrect) location data.

Because the drone never went into P-GPS mode, it never had GPS position holding or "brakes", so it was drifting with any breeze and wouldn't stop when you went hands-off on the sticks.
This wouldn't matter much if it was up high and well away from any obstacles.
But down low and with things to bump into, it's a recipe for trouble.

I'm wondering though, why the drone didn't get enough satellites during the flight?
The collision happened after two minutes of flight.
If the flight was out in the open, with more than half of the sky visible, it should have easily acquired plenty of sats.

Was the flight path down in the river, sheltered by tree cover?


Calibrating the compass was not needed and it wouldn't have mattered if you didn't do it.
The only problem to do with the bridge was that it was big, solid and too close to a drone with no brakes.

You could, but buying a drone only isn't very cost effective.

When the crash happened at 124 sec, your drone had been hovering for quite a long time.
It had lost any speed that it had and was just drifting on the breeze.
Your data won't have any wind data because that comes from the degree the drone tilts to resist the wind.
But it needs some kind of position holding to be able to do that.

Thank you all for your help and data. Yes, I was at the bottom of the valley, and impatient waiting for a proper lock. It cost me a drone. My mistake hurt my wallet a bit, but its a lesson learned.

 

[hiflyer201]

Sorry for your loss. Hindsight is twenty twenty so it's easy to second guess and say.. That scene is not going to change in the next eight hours and even the lighting will be the same so how could I have done that?

4. Should I upgrade to a Mavic Air 2 or stick with the Mini until I learn to keep my props dry?

That's the question that I liked best....I don't know the answer but we never quit learning and I can see that you're no Quitter!

 

[Jm811]

I bought a replacement drone for $300 on amazon.

 

[Van Belle Jean Marc]

Aha ... you've been there?

Counts both ways. I have good satellite reception almost everywhere in Bulgaria. Even here. +je