Mavic Mini Dive Bombed my Pool!

Collyde · Jun 28, 2020

Hadn't flown for a while. Decide to do a little fly from the deck with the safety cages on. Checked battery etc., FW levels, all up to date.

Flew up to about 100, 120 ft. up and and cruised a little in a 50 ft radius - not far. It seemed a little sluggish and I could see the breeze (about 7.5mph according to my weather station) in the tree tops, time to bring it in. But before it could get it back over the deck the drone just rapidly descended straight into our pool one level lower (we are on a hill side.) I was able to fish it our in less than 60s and the light was still on, but ( Mod Removed Language) Should be ok and I have coverage, if not.

What happened? Anybody have any idea?

Starz · Jun 28, 2020

Place to start.

Crash & Flyaway Assistance

mavicpilots.com

sar104 · Jun 28, 2020

It sounds like this - a known problem:

Mavic Mini uncommanded descent tests

After a little experimentation I was able to replicate the uncommanded descent problem under 0400 firmware by loading the rear props for a few hours as might happen in the flymore case. The props did appear slightly flattened compared to the front props. The problem quickly manifested itself in...

mavicpilots.com

lowellton · Jun 28, 2020

Collyde said:
Hadn't flown for a while. Decide to do a little fly from the deck with the safety cages on. Checked battery etc., FW levels, all up to date.

Flew up to about 100, 120 ft. up and and cruised a little in a 50 ft radius - not far. It seemed a little sluggish and I could see the breeze (about 7.5mph according to my weather station) in the tree tops, time to bring it in. But before it could get it back over the deck the drone just rapidly descended straight into our pool one level lower (we are on a hill side.) I was able to fish it our in less than 60s and the light was still on, but ( Mod Removed Language) Should be ok and I have coverage, if not.

What happened? Anybody have any idea?

i feel you man. This morning i did crash my mini and damaged the front left arm (my fault), good thing i have dji care refresh and contacted them via email. Hopefully they will email me back soon. Missed flying the mini. Have a good day

EyesWideShut · Jun 29, 2020

Collyde said:
Hadn't flown for a while. Decide to do a little fly from the deck with the safety cages on. Checked battery etc., FW levels, all up to date.

Flew up to about 100, 120 ft. up and and cruised a little in a 50 ft radius - not far. It seemed a little sluggish and I could see the breeze (about 7.5mph according to my weather station) in the tree tops, time to bring it in. But before it could get it back over the deck the drone just rapidly descended straight into our pool one level lower (we are on a hill side.) I was able to fish it our in less than 60s and the light was still on, but ( Mod Removed Language) Should be ok and I have coverage, if not.

What happened? Anybody have any idea?

Couple of thoughts. You say it "was time to bring it in". What was the battery level? Or did you activate RTH? If it was within 60ft of home it doesn't return, it just lands.

Alan_M · Jun 29, 2020

Flying outdoors with the prop guards on in wind is a recipe for disaster, but as EyesWideShut asks, did you press RTH? You say you stayed within a 50 foot radius, which means pressing RTH would just land the AC immediately.

Collyde · Jun 29, 2020

Nope, no RTH. It had only been flying for <5min. Battery was not an issue. I just had a bad feeling.

Dronernator · Jun 29, 2020

Where was it stored for the while it wasn't used? If

Collyde · Jun 29, 2020

ToBAS said:
Where was it stored for the while it wasn't used? If

It's in its case under my desk.

Dronernator · Jun 29, 2020

If that was the flymore case then one explanation would be the props weren't folded across the drone and they've been bent out of shape. Lots of discussion about this already.

Collyde · Jun 29, 2020

Yes, that is the case. I am normally careful with propellor folding. I do suspect an uncontrolled emergency descend in an unfortunate location. It was still functional when I pulled it from the short submersion but I immediately pulled the battery, dried it, I blew out the motors etc. Today I and am waiting for the outside to warm up to give it a further good airing and drying. Hope that all is well later today. There are currently no winds and I will attempt to fly carefully over dry land. Will also pull a report once I feel comfortable powering it back up.

shb · Jul 5, 2020

Collyde said:
Hadn't flown for a while. Decide to do a little fly from the deck with the safety cages on. Checked battery etc., FW levels, all up to date.

Flew up to about 100, 120 ft. up and and cruised a little in a 50 ft radius - not far. It seemed a little sluggish and I could see the breeze (about 7.5mph according to my weather station) in the tree tops, time to bring it in. But before it could get it back over the deck the drone just rapidly descended straight into our pool one level lower (we are on a hill side.) I was able to fish it our in less than 60s and the light was still on, but ( Mod Removed Language) Should be ok and I have coverage, if not.

What happened? Anybody have any idea?

I've flown my mavic fairly low over water many times with no problem. This seems to happen a lot with the mini. DJI should investigate and fix this.

HWCM · Jul 5, 2020

shb said:
I've flown my mavic fairly low over water many times with no problem. This seems to happen a lot with the mini. DJI should investigate and fix this.

It's not a water issue. It's a flattened prop issue from being stored in the fly more case. Even when stored correctly, the mini rests on the props. In a short period of time the props deform. This is more so if the mini is put in the case warm. With hot batteries. Zip it all up in the case and you have a heater heating up the props enough to accelerate the process.
I have put a small piece of foam over the hump in the middle where the mini rests in the case. Zero problems since.
Before this simple fix, I was having to put new props on every single time I flew. I would get the warnings and uncontrollable decent.
I have a bag of deformed props that look fine by themselves. But comparison to new ones, they are flat.

Dronernator · Jul 5, 2020

The mini doesn't rest on the props when folded correctly. The flymore case is raised just behind where the folded props should sit, the underside of the mini sits on it. That's why they bend when folded wrong, the weight of the mini rests on the props.

HWCM · Jul 5, 2020

ToBAS said:
The mini doesn't rest on the props when folded correctly. The flymore case is raised just behind where the folded props should sit, the underside of the mini sits on it. That's why they bend when folded wrong, the weight of the mini rests on the props.

[emoji849]

Collyde · Jul 5, 2020

So far it looks like the Mini survived. Took it for a short flight. Still have to pull the logs.
The battery is not charging any more, but I have two more.
Have to call support to see, whether it is covered in their Care program.

Ajkari · Jul 5, 2020

Keep us posted

Collyde · Jul 5, 2020

Looks like it took more serious damage. I tried to fly it today in great conditions and got a warning that the propellors were rotating too fast. Land immediately.
The second battery was also dead.
Will contact support tomorrow.