Hello Folks,

I am new with drones and I almost lost the Mini2. I have no idea, how I managed not to crash or land it into the water. I already tried to find some answers but did not find the problem and of course, I would like to understand and avoid the "Forced Landing" the next time.
Here is my Logfile for yall to better understand, what might caused the "Forced Landing": https://www.phantomhelp.com/logviewer/38VB013XYJO1YRNNKGBF/#

I would be pleased, if somebody could help.

Thank you for ur time.

Hi there, we are deeply sorry to hear about your loss. If your drone is still in warranty, we may diagnosis the fly data for free and give you the corresponding solution for your loss. Please contact our online support to report the flyaway case: https://www.dji.com/au/support?site=brandsite&from=nav11:15. Thank you.

During a landing you initiated yourself, your flight record on Aidata.com showed the following event: Detected backward shock / possible collision, aircraft is pitching sharply backwards. Maybe you missed something in the surroundings, or the drone had contact with the bird?

But it also looks like you have a semi-hard landing due to dirt or a malfunction on the lower optical proximity sensor VPS. This is what it looks like. Aren't you wearing an accessory under the drone?

djiuser_nO2RdSW5BSUg Posted at 7-23 03:21
But it also looks like you have a semi-hard landing due to dirt or a malfunction on the lower optical proximity sensor VPS. This is what it looks like.

Well, the drone wanted to land on the water and I got managed to hard land it on the ground in the last minute. I don't think, a saw any bird or I hit something. I saw the drone and I was going to fly it back to me

You have a wrong reading from the Visual Positioning System since take-off. Did you not attach something under the drone? If not, then you probably have a malfunction.

djiuser_nO2RdSW5BSUg Posted at 7-23 03:32
From the moment you booted up you had an incorrect reading from the Visual Position Sensor system. Did you not attach something under the drone? If not, then you probably have a malfunction.

No, I definitely did not attach anything to the drone. I started flying off from a table on the balcony and at first, had no problem. Suddenly it wanted to land, for no reason.

1. Please don't ever do that 44% battery launch again. Please, this is a very common reason for losing your bird... Whenever the battery is lower than 90%, it is not a good idea to launch the bird. Unless you're doing really short flights like flying for just 50 meters.

2. You were flying in the canals, and the VPS (Visual Positioning System) reported a dangerously low altitude of just 1 feet before it was confirm landing. This is also a very common reason for losing your bird: The VPS takes over altitude reports against GPS when you're very close to ground.

See here:
4min 35s, GPS 16.1ft, VPS 3.0ft
4min 40s, GPS 14.1ft, VPS 1.0ft!

I think that at this point the vps altitude made the firmware think that you are going to land.

When you're this close to the ground / water surface, the VMU can be tricked. So DON'T fly your Mini 2 that close to water, that's all. Keep it at least a few meters up or it might dive into water at anytime.

FriedChicken_II Posted at 7-23 03:37
1. Please don't ever do that 44% battery launch again. Please, this is a very common reason for losing your bird... Whenever the battery is lower than 90%, it is not a good idea to launch the bird. Unless you're doing really short flights like flying for just 50 meters.

2. You were flying in the canals, and the VPS (Visual Positioning System) reported a dangerously low altitude of just 1 feet before it was confirm landing. This is also a very common reason for losing your bird: The VPS takes over altitude reports against GPS when you're very close to ground.

Got ya, but I didn't fly it close to the Water. I was at least 5-6 meters from the ground and I wanted to fly it back to the balcony. Suddenly it said: "landing, landing..... So i tried to fly it the the ground, befog it hits the water. I couldn't fly it up only to the sides..

That was from my point of you.. being full in panic :/

I think. that the drone wanted to descend due to a temporary fluctuation in pressure. It didn't feel like landing. Normal barometer reading fluctuates. But the VPSystem is not working properly. You can see your conscious pull on the landing stick.

djiuser_nO2RdSW5BSUg Posted at 7-23 03:42
I think. that the drone wanted to descend due to a temporary fluctuation in pressure. It didn't feel like landing. Normal barometer reading fluctuates. But the VPSystem is not working properly. You can see your conscious pull on the landing stick.

Thank you for your help

I can see in the photo you took that you are taking off next to the bench. VPS should read 0.0m but sees nothing. These approx. 10 meters are its maximum operating range.

Between the two black dots-eyes on the underside of the drone, there is a small hole with a camera. It's a VPS system. Are there any debris in this hole?

djiuser_nO2RdSW5BSUg Posted at 7-23 03:51
Between the two black dots-eyes on the underside of the drone, there is a small hole with a camera. It's a VPS system. Are there any debris in this hole?

No, looks good to me

True, the VPS does not read the water surface well. I do not understand why, since the drone takes off from the ground, the VPS can not see anything. It's not normal. Do you have any other flight records? Does the drone land gently and softly when landing?

djiuser_nO2RdSW5BSUg Posted at 7-23 04:01
True, the VPS does not read the water surface well. I do not understand why, since the drone takes off from the ground, the VPS can not see anything. It's not normal. Do you have any other flight records? Does the drone land gently and softly when landing?

Yes, I never had any problems so far.

Give me some other flight record.

djiuser_nO2RdSW5BSUg Posted at 7-23 04:07
Give me some other flight record.

https://www.phantomhelp.com/LogViewer/2K7AYDFVXV00X3ZMISNE

Airdata.com reads the flight log a little differently than phanthomhelp.com, which surprised me. But you can see that on the July 21 flight record, VPS works fine. Make a new flight and submit the flight record. If everything looks fine, it will have to be assumed that it was an individual incomprehensible mistake.

moffm Posted at 7-23 03:41
Got ya, but I didn't fly it close to the Water. I was at least 5-6 meters from the ground and I wanted to fly it back to the balcony. Suddenly it said: "landing, landing..... So i tried to fly it the the ground, befog it hits the water. I couldn't fly it up only to the sides..

That was from my point of you.. being full in panic :/

you need to keep above of water for at least 25 feet to avoid vps hazards...

5.9feet on imu, 31feet on vps. The reason that it mismatched this much is that you were launching from a window about 25feet above the ground.

when your drone is too low on both meters (14feet on imu, 1 feet on vps), the drone would be thinking that it's going to land once if it recognized the altitude reported from vps. even  if it's a false report. Many would advice you to keep at least 25 feet above the water to avoid such hazards.

In my opinion, the GPS height indications from the IMU are not taken at all when determining the height of the drone. They are simply too inaccurate to be taken seriously. The main instruments for assessing the height of the drone are the barometer and VPS. The latter apparently failed, which could be related to the water. I just don't understand why the VPS was not working properly when taking off and landing.

djiuser_nO2RdSW5BSUg Posted at 7-23 06:01
In my opinion, the GPS height indications from the IMU are not taken at all when determining the height of the drone. They are simply too inaccurate to be taken seriously. The main instruments for assessing the height of the drone are the barometer and VPS. The latter apparently failed, which could be related to the water. I just don't understand why the VPS was not working properly when taking off and landing.

Hmmm, yes. The GPS/IMU would be ignored if the VPS reported a very low altitude. VPS has a higher priority when it's very close to the ground. I don't remember the actual number, but I did see some figures like 25 feet where the VPS takes over GPS.

djiuser_nO2RdSW5BSUg Posted at 7-23 06:01
In my opinion, the GPS height indications from the IMU are not taken at all when determining the height of the drone. They are simply too inaccurate to be taken seriously. The main instruments for assessing the height of the drone are the barometer and VPS. The latter apparently failed, which could be related to the water. I just don't understand why the VPS was not working properly when taking off and landing.

It was working properly IMO?  It was reporting correct numbers when it's taking off. During landing I think OP crashed the drone somehow so it's not very accurate anymore but still working.

The only place that it wasn't working correctly, was during the flight in the canal where the VPS got interfered by the reflections of water.  Which created a false low altitude report that almost landed the drone in water.

Let's clarify, the inertial measurement unit (IMU) is a separate plate, the barometer is on the motherboard outside the IMU. The barometer and VPS system are used to assess the current height of the drone. Can we agree?

djiuser_nO2RdSW5BSUg Posted at 7-23 06:36
Let's clarify, the inertial measurement unit (IMU) is a separate plate, the barometer is on the motherboard outside the IMU. The barometer and VPS system are used to assess the current height of the drone. Can we agree?

The barometer is not used to calculate the height in this situation. In lower altitudes there's no point to use the barometer at all. It's usually used in places where the GPS failed to connect.

Generally, drones use VPS when it's very close to ground, and then use GPS when it gets higher. Lastly it uses barometer as the backup.

Is this the first time you have flown from this location? How far away are you from the airport?

djiuser_jNcSwhSvSI1q Posted at 7-23 11:40
Is this the first time you have flown from this location? How far away are you from the airport?

yes, it was the first time. The Airport is not near, so no restricted area as far as I checked

I don't trust phantomhelp.com Open the flight log on airdata.com like me and you will learn more about your flight issues. Airdata reports that the height of the drone was from the barometer and the VPS had problems. Do you already have more flights?

djiuser_nO2RdSW5BSUg Posted at 7-23 12:47
I don't trust phantomhelp.com Open the flight log on airdata.com like me and you will learn more about your flight issues. Airdata reports that the height of the drone was from the barometer and the VPS had problems. Do you already have more flights?

Sorry but I don't see anything about the barometer on AirData. Which page were you looking at?

From what I've seen, decoded by AirData:

The height_sonar (which means the VPS) reported an altitude of 1.312 feet which initiated the forced / confirm landing procedure.  

Height_Sonar = VPS = 1.312 feet
altitude_above_seaLevel = barometer altitude = 37.38 feet
height_above_ground_at_drone_location(feet) = barometer altitude - barometer altitude of the homepoint =  11.25feet.

It's pretty clear that it's the VPS who initiated the landing procedure. VPS failed during flying dangerously close to water which is indeed said to be avoided in manual. And that's all.

Again, keep your distance against water. Never fly the drone this close to water again.

FriedChicken_II Posted at 7-24 01:56
Sorry but I don't see anything about the barometer on AirData. Which page were you looking at?

Select "HD flight player" This is the most accurate flight report. Access to this option is only via www. There is a record of a hard touchdown at the end of the report. It is certain that VPS was not working. Export your flight log from phantomhelp.com of course.

moffm Posted at 2021-7-23 03:41
Got ya, but I didn't fly it close to the Water. I was at least 5-6 meters from the ground and I wanted to fly it back to the balcony. Suddenly it said: "landing, landing..... So i tried to fly it the the ground, befog it hits the water. I couldn't fly it up only to the sides..

That was from my point of you.. being full in panic :/

Mine did exactly the same thing 3 days ago off my boat. No warnings. Inputs from my controller were ignored. About 10m altitude and just descended into the water. I've had it near 3 years.

djiuser_kZxkjGs7pxMf Posted at 3-20 17:39
Mine did exactly the same thing 3 days ago off my boat. No warnings. Inputs from my controller were ignored. About 10m altitude and just descended into the water. I've had it near 3 years.

Post your recorded flight data and it might provide some insight into what happened in your incident.

Go to: https://www.phantomhelp.com/LogViewer/Upload/
... where you'll find instructions.
That will give a report you can post a link for the report here.

Or if you use Airdata, post a link to the Airdata report for the flight.

Or just post the .txt file.

Were you able to retrieve the drone?

djiuser_kZxkjGs7pxMf Posted at 3-20 17:39
Mine did exactly the same thing 3 days ago off my boat. No warnings. Inputs from my controller were ignored. About 10m altitude and just descended into the water. I've had it near 3 years.

Hi. Sorry about what happened to your aircraft. If you're able to retrieve it, we suggest sending it back to DJI to get it fixed. You can also request for Data Analysis. Please use the following link to submit a Repair Request: https://repair.dji.com/. We appreciate your patience and support.