For my second ever flight with my mini 4 pro it just kept climbing immediately from take off without me touching any of the controls, it didn't stop to hover it just kept going up.
I checked all the controls were centred, and even tried to bring it down, which worked for a while but as soon as I let go it started to climb again.
Eventually when it got to about 21m I panicked and told it to land, which it did very slowly, presumably it was still trying to fight the land command and go even higher.
Why would it do that?
It behaved correctly on the first flight and then again on a later flight that day.
Someone suggested that it might be the downward sensors were dirty - would that cause it? Seems odd for it to keep going higher with the controls centred even so.

Hi,

Best to get help / advice is to share your flightlog.
Use this link > https://www.phantomhelp.com/LogViewer/Upload/
Post the uploaded link on here

cheers
JJB

JJB* Posted at 1-9 13:32
Hi,

Best to get help / advice is to share your flightlog.

I have attempted to upload the log file, here's the link
https://www.phantomhelp.com/logviewer/20250109YAN0CYLNTMGQ62W7FI44EHQ20FRJNVKW

lenmro Posted at 1-9 13:50
I have attempted to upload the log file, here's the link
https://www.phantomhelp.com/logviewer/20250109YAN0CYLNTMGQ62W7FI44EHQ20FRJNVKW

Your downward sensors are showing a false indication that the drone is only centimetres above the ground throughout that flight.
Have you fitted some accessory that is blocking their downward view?

lenmro Posted at 1-9 13:50
I have attempted to upload the log file, here's the link
https://www.phantomhelp.com/logviewer/20250109YAN0CYLNTMGQ62W7FI44EHQ20FRJNVKW

Hi,

had a look at your log too.

Your IR height sensors data shows throughout the whole flight a distance below the drone of 10 or 20 cm.

In a normal flight (with good function of the IR sensor) the landing protection will raise the craft up when IR height measures a height (drone<>surface below) less than 50 cm.

Simulate this yourself by hovering drone at shoulder height and put your hand direct under the drone ; it will clinmb to distance approx 50 cm drone<>hand.

So or your IR height sensor is faulty or dirty or wet mayby.
As it did already shows 0.1 at start (drone on the ground) and 0.2 direct after feet of the ground i do not think it sees something attached under your drone.

See my chart of your data.
cheers
JJB   [ Charts by FRAP ; the 'best' software for data and visual flightlog analysis (www.jjbfrap.eu) ]

JJB* Posted at 1-10 01:25
Hi,

had a look at your log too.

Wow, you and Labroides are amazing to find that out, thanks!
I don't have anything attached underneath the drone obscuring the sensors, and since it was my first ever time flying that day and the first flight was ok, possibly I made the sensor dirty when I landed on frosty grass and then took off again for this flight where the problem occurred. Also the drone has behaved correctly since that day, so hopefully the IR sensor is functioning correctly and it was just dirty? Or did you think there is a problem with the sensor? I didn't quite follow the 0.1 / 0.2 comment at the end
Really glad I came here for help!

lenmro Posted at 1-10 02:03
Wow, you and Labroides are amazing to find that out, thanks!
I don't have anything attached underneath the drone obscuring the sensors, and since it was my first ever time flying that day and the first flight was ok, possibly I made the sensor dirty when I landed on frosty grass and then took off again for this flight where the problem occurred. Also the drone has behaved correctly since that day, so hopefully the IR sensor is functioning correctly and it was just dirty? Or did you think there is a problem with the sensor? I didn't quite follow the 0.1 / 0.2 comment at the end
Really glad I came here for help!

Hi,

Must be dirt of some frosty grass to the sensor.
As it works now oke, no problem with the IR sensor.

The IR sensor measures the distance between drone and surface below.
Fly your drone towards a garden table at a height just above table height.
Notice that your drone raise height to 50 cm when flying over the table.
This is part of the Landing Protection feature.

Or

Hover at 10 meter and lower drone with RC down stick AND keep stick down all the time.
Notice that the decsend speed is reduced when reachinbg the ground and drone will stop at 50 cm, with RC stick still down. Shortly after that drone will perfrom a landing. (in this stage the landing protection is disabled)

So bc of landing protection a dji drone will raise height if IR measure height < approx 50 cm. of course at reaching 50 cm it stop to  raise height.But if the sensor continue to  'measure' a value < 50 cm than it will not stop climbing.....

cheers
JJB

lenmro Posted at 1-10 02:03
Wow, you and Labroides are amazing to find that out, thanks!
I don't have anything attached underneath the drone obscuring the sensors, and since it was my first ever time flying that day and the first flight was ok, possibly I made the sensor dirty when I landed on frosty grass and then took off again for this flight where the problem occurred. Also the drone has behaved correctly since that day, so hopefully the IR sensor is functioning correctly and it was just dirty? Or did you think there is a problem with the sensor? I didn't quite follow the 0.1 / 0.2 comment at the end
Really glad I came here for help!

The sensors probably got a touch of frost on them from the grass and a bit of water sat on them the whole time, or dried with a stain.

you need to be careful about fog as well, the drone will think it's near the ground and descending will be at a silly slow speed.

I wipe the bottom sensors every time I unfold the drone in case of an accidental fingerprint