Descent automatically slows to less than 1 mph

Meta4 · May 6, 2022

tonydeli7 said:
Had the same problem… It was descending at around 0.3m/s after going straight down with 3m/s. The cause of this was that I had fitted Air2s props on and not the ones from Air2. Maybe a coincidence but now it’s working fine. It might be because of turbulence

Turbulence won't almost stop your descent and it's unlikely that the difference in props would either.
Post flight data to find out what it shows.

SkyPath Studios · May 6, 2022

tonydeli7 said:
Had the same problem… It was descending at around 0.3m/s after going straight down with 3m/s. The cause of this was that I had fitted Air2s props on and not the ones from Air2. Maybe a coincidence but now it’s working fine. It might be because of turbulence

That’s an interesting thought, though the props are exactly the same. This happened at the time when I fitted air 2S props on. It was also extremely cold.

MS Coast · May 6, 2022

Merrill277 said:
No I meant 1,000 ft agl and actual flight not more than 200 ft actual ground level. i.e. mountains go very high, even above 400 ft. MA2 tops out at 1640 ft agl.

AGL is Actual Ground Level. It's the actual altitude of the aircraft above the ground directly below the aircraft.

If you're saying 1000' is the number you saw on the controller, that's the altitude of the aircraft above the takeoff location. The controller does not indicate altitude relative to ground level.

Merrill277 · May 8, 2022

MS Coast said:
AGL is Actual Ground Level. It's the actual altitude of the aircraft above the ground directly below the aircraft.

If you're saying 1000' is the number you saw on the controller, that's the altitude of the aircraft above the takeoff location. The controller does not indicate altitude relative to ground level.

Oh, I understood it to mean "above ground level"

MS Coast · May 8, 2022

Merrill277 said:
Oh, I understood it to mean "above ground level"

Well, having a Covid fever seems to have affected my typing, or thinking, skills. Yes, it is definitely above ground level. Thanks for catching that and letting me know.

I tried to edit the original post to avoid confusion but the option isn't available.

mfreed · May 25, 2022

I have this same issue. Was there any resolution found?

Meta4 · May 25, 2022

mfreed said:
I have this same issue. Was there any resolution found?

If you have a problem, post your flight data to help identify the cause.
Instructions are in post #2

mfreed · May 26, 2022

Meta4 said:
If you have a problem, post your flight data to help identify the cause.
Instructions are in post #2

I located my Mav Air 2 flight log (attached) but the phantomhelp.com log uploader failed when I tried to upload the file so i've just attached the txt file. I flew higher than usual/allowed in this flight to test this issue I've been experiencing where the descent rate drops <1m/s for a few hundred feet during the descent. Once the speed reduces, the Return to Home/Landing warning shortly after (30-60 seconds later) is enabled. I've had to cancel this automated landing since I'm still several hundreds of feet in the air and continue to descent at <1m/s until at some point the Mav Air 2 returns to descent at normal speeds. My concern is that if I had low battery, it seems possible that the battery could die while still in the air/descending. I'd greatly appreciate any assistance here and can reach out to DJI if necessary too.

Meta4 · May 26, 2022

mfreed said:
I've had to cancel this automated landing since I'm still several hundreds of feet in the air and continue to descent at <1m/s until at some point the Mav Air 2 returns to descent at normal speeds.

Your incident was caused by the VPS sensors giving a false reading.
It should read as N/A when above the limited range of the VPS sensors but yours started reading incorrectly at 7:06.8 and progressively got worse until it made the drone slow its descent as it thought it was just 1-2 ft off the ground and trying to land gently.
At 18:17.2 the error went away and the VPS height went back to normal.

Unfortunately DJI Fly doesn't allow for disabling the VPS sensors, which would be the easy way to solve the problem and descend normally.
Was there a fog that could have been fooling the sensors?

If not, I would recommend checking the sensors to make sure they are clean and recalibrate the VPS.

mfreed · May 26, 2022

Meta4 said:
Your incident was caused by the VPS sensors giving a false reading.
It should read as N/A when above the limited range of the VPS sensors but yours started reading incorrectly at 7:06.8 and progressively got worse until it made the drone slow its descent as it thought it was just 1-2 ft off the ground and trying to land gently.
At 18:17.2 the error went away and the VPS height went back to normal.

Unfortunately DJI Fly doesn't allow for disabling the VPS sensors, which would be the easy way to solve the problem and descend normally.
Was there a fog that could have been fooling the sensors?

If not, I would recommend checking the sensors to make sure they are clean and recalibrate the VPS.

Thank you for the quick response! There was not fog- it was a clear day. I've cleaned the sensors as well and still having this issue. Regarding VPS, calibration, do you have insight on how to do this? Within the DJI Fly app, I see an ability to calibrate the compass and IMU (not sure if VPS is part of either of those?). **Update** I just conducted both a compass and IMU calibration and still experienced this slow descent issue on my next flight. Any thoughts?

Meta4 · May 26, 2022

mfreed said:
Thank you for the quick response! There was not fog- it was a clear day. I've cleaned the sensors as well and still having this issue. Regarding VPS, calibration, do you have insight on how to do this? Within the DJI Fly app, I see an ability to calibrate the compass and IMU (not sure if VPS is part of either of those?). **Update** I just conducted both a compass and IMU calibration and still experienced this slow descent issue on my next flight. Any thoughts?

p16-17 of the manual explain the process:

https://dl.djicdn.com/downloads/Mavic_Air_2/Mavic_Air_2_User_Manual_v1.6_enIII.pdf

mfreed · May 27, 2022

Meta4 said:
p16-17 of the manual explain the process:

https://dl.djicdn.com/downloads/Mavic_Air_2/Mavic_Air_2_User_Manual_v1.6_enIII.pdf

Thanks! The manual indicates that vision systems calibration is performed automatically by the drone but if there are still persistent issues, an advanced calibration can be completed using the DJI Assistant 2 desktop/laptop software. However, DJI indicates that this software is not currently compatible with macOS version 11 or later, which is essentially any modern Mac (and I don't have a Windows computer): DJI Assistant 2 For Mavic - Download Center - DJI. Since it doesn't appear I can conduct an advanced calibration, any other thoughts/recommendations?

Meta4 · May 27, 2022

mfreed said:
Since it doesn't appear I can conduct an advanced calibration, any other thoughts/recommendations?

A friend's Windows computer ??

Jarek44 · Jun 3, 2022

Hi All,
I am just having the same problems. Exactly with descent rate.
No there is no influence with weather.
No there is no influence of turbulence.
No there is no issue that I have attached something to my drone.
This are pictures from iPhone recording sadly on this site you are unavailable to attached video.
Situation:
So this is in hilly region in Poland, weather: nice sunny with partly cloudy
Well I started My drone I hoover it above surface then info came about : "Home Point has been updated......." and I flew to do panoramic photos of valley.
But when I wanted to return and land this what has happen:
Drone is going strange rate of descending max 0.1 or 0.2 m/s (sorry metric scale

) even still being so high up above ground alt. 13 meter . You can see on Pictures
Below there is no strange surface like waves on water or electric cables etc.
It is solid ground with bushes (on picture) going with this speed from 13m or even higher takes very long and it is very annoying.
No matter what type of mode C, N or S in all modes descending is problematic. I could normally go up with speeds up to 4 m/s left, right, forward, backward no problem but to descent there is a huge problem.
When finally drone was close enough to ground I ve noticed that it is not landing but it just slams on ground.?!
I had this situation happened couple times already.
My thoughts:
- After last update of safety settings and firmware I could notice that drone starts to behave in this strange way with descent rate. around of 30-50 meters from controller If I go further there is no problem but going closer to landing place rate of descend decrease dramatically.
- Even If I push return home button it behaves the same like belly sensors don't know how far is surface.
- Back to point when instead of landing it slams on ground. What I've noticed sensors are ok but If you take off before this announcement "Home Point has been updated......." and you are hoovering above ground drone will take this hovering altitude as its default ground level (zero level). So later belly sensors will show that there is still some gap between default ground level and what sensors are reading. So that's why drone is going crazy. But still I should be able to fly below zero for example: If am on clif and want to go lover than i started to shoot clifs, dams etc.
- While drone is on the ground and receive: "HP has been....." and then takeoff there is no problem later with landing and descent speed this what I ve noticed.
I am sure since this safety updated it all has been twitchy with descent rate.
@mfreed try to wait on ground until You hear this info about HP and then takeoff and see whats happen.
I know sometimes you have to wait a while on ground to get this info or soon just after takeoff straight away you receive this info about update of HP but there is risk that altitudes will be messy.
Sorry for long post hope this helped. Good to know I am not alone with that issue

Meta4 · Jun 3, 2022

Jarek44 said:
Drone is going strange rate of descending max 0.1 or 0.2 m/s (sorry metric scale ) even still being so high up above ground alt. 13 meter . You can see on Pictures

The recorded flight data will make things a lot easier to understand and help eliminate unrelated things.

Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report of the flight.
Come back and post a link to the report it gives you.
Or .. just post the txt file here.

Jarek44 said:
If you take off before this announcement "Home Point has been updated......." and you are hoovering above ground drone will take this hovering altitude as its default ground level (zero level).

The zero altitude is set before and independent of the GPS recording a home point.
There is no connection between them.

Jarek44 · Jun 5, 2022

Meta4 said:
The recorded flight data will make things a lot easier to understand and help eliminate unrelated things.

Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report of the flight.
Come back and post a link to the report it gives you.
Or .. just post the txt file here.

The zero altitude is set before and independent of the GPS recording a home point.
There is no connection between them.

Hi,
Thx for answer, here is file and link.
What you read from it? there is no message that something is going wrong with sensors or altitude.
btw is it possible to change settings to metric in this log viewer?

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Meta4 · Jun 5, 2022

Jarek44 said:
Hi,
Thx for answer, here is file and link.
What you read from it? there is no message that something is going wrong with sensors or altitude.
btw is it possible to change settings to metric in this log viewer?

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

This sort of problem is usually caused by false VPS data that indicates the drone is close to the ground and landing protection slows the descent.
You can compare the actual altitude (IMU altitude) with the VPS altitude in the flight summary.
Unfortunately it's not possible to display in metric units.

From 8:35.5 when the drone is high up, you can see that the VPS altitude starts to show numbers that indicate the drone is 25 feet above the ground.
At 10:55, when the drone is 100 feet up, the VPS is indicating only 3 ft.

Fog can be one situation that causes this problem..
If there was no fog, try cleaning the VPS sensors and recalibrating the VPS

BaconatorYummy · Jun 7, 2022

Unfortunately I have same issue. This is replacement drone. Sometimes it happens sometimes it doesn't. I still can't get patterns. But usually it starts around 70 meters, it goes down with normal speed and then suddenly speed starts to slow down to 0.4 and after some time it gets back to normal descent speed. Sensors are clean, weather is good, no fog. I recalibrated IMU, sensors and still had this issue. Changing between modes doesn't help . If it's a faulty sensor it would happen every time, but now it happens every now and then.