Ultrasonic sensors failure in flight

DroneForceOne · Dec 31, 2017

Hi guys,

Few minutes ago i was flying with my MP and got an "ultrassonic sensors failure, land immediately" message.

Just landed with caution, the sensors were really not working, the MP didn't detect the ground, had to hover as low as possible, about 2cm - 5cm from the ground and them cut off engines.

I turned off the Mavic, and them turned on again, the problem was gone...

I just updated the firmware, this may be related?

Anyone else got something similar?

Thanks again, any help is appreciated.

BD0G · Dec 31, 2017

I have read a few thread postings that sound eerily similar. I am starting to suspect that the common denominator may be the latest firmware update , but have no proof of that other than a few rumblings here on the forum.

Dariof · Dec 31, 2017

I recently started threads about this in both the discussion and help sections. This is also all over the Internet.

When I contacted DJI, they told me to fly in sports mode, turn off all sensors, recalibrate the sensors, IMU and compass. None of that worked.

There are theories it’s the new firmware upgrade, but I don’t think so. This has been going on for well over a year.

In my case, it was the landing gear extensions I had put on the drone. When removed, all was well.

Don’t know if this will help you but hope it does.

DroneForceOne · Dec 31, 2017

BD0G said:
I have read a few thread postings that sound eerily similar. I am starting to suspect that the common denominator may be the latest firmware update , but have no proof of that other than a few rumblings here on the forum.

Thats my suspects too...

It was working fine...

DroneForceOne · Dec 31, 2017

Dariof said:
I recently started threads about this in both the discussion and help sections. This is also all over the Internet.

When I contacted DJI, they told me to fly in sports mode, turn off all sensors, recalibrate the sensors, IMU and compass. None of that worked.

There are theories it’s the new firmware upgrade, but I don’t think so. This has been going on for well over a year.

In my case, it was the landing gear extensions I had put on the drone. When removed, all was well.

Don’t know if this will help you but hope it does.

I have those landing gear extensions, but i was not using then...

Thats weird...

Dariof · Dec 31, 2017

DroneForceOne said:
I have those landing gear extensions, but i was not using then...

Thats weird...

It is strange. It could be multiple issues......in my case it was the landing gear. IT could be the firmware or who knows what. But this issue has been posted online since 2014.

DroneForceOne · Dec 31, 2017

I'll try a couple of flying sessions, thats really a concern, but if that happens again, at least i know what to do

Dariof · Dec 31, 2017

UPDATE.

I’m out flying now into abandoned mine pits at 300’ below takeoff level.

I put the landing Gear extensions on with the springs removed. I still got the ultrasonic sensor error.

I then took the landing gear off completely and the error went away. This tells me the landing gear was somehow affecting the ultrasonic sensors.

I won’t use them anymore.

DroneForceOne · Dec 31, 2017

Dariof said:
UPDATE.

I’m out flying now into abandoned mine pits at 300’ below takeoff level.

I put the landing Gear extensions on with the springs removed. I still got the ultrasonic sensor error.

I then took the landing gear off completely and the error went away. This tells me the landing gear was somehow affecting the ultrasonic sensors.

I won’t use them anymore.

Do you have pics of this place?

Good to know, ill try more flights today

Lets see what we get!

Chips · Jul 1, 2018

I had the problem today and am now looking through all the threads about the ultrasonic sensor error.

Many people report that the extenders with springs are the cause as the problem goes away when they are not present.

However, I have had them on before and never seen such a message before although I have to say that on many flights before today, I didn't put the extenders on.

Then there is always the firmware update to blame and this could also be the case. It could be that the latest firmware has widened the sensor field of coverage to reach up to the legs and anything sticking into the field will trigger the sensor error.

If it's the spring extenders, that is a pity since they are useful. The body of the MP is rather low to the ground so the camera and gimbal are at risk of damage when landing. Also, if the ultrasonic sensors are not working, I guess the drone doesn't have an accurate reading of its height from the ground and cannot adjust its speed to slow down for a soft landing. Mine sort of hit the ground hard and I was glad the extenders were on.