So my altitude problems persist still. Today I  was heading for a bridge in a section I know to be 150 feet. So I  usually drop to 70-80 feet to go under it. Well, as I approached I could  clearly see I was dead on to hit it. My altimeter is showing 70 feet  when I'm at 150. When the flight ended I was -170 feet. I've owned many  drones and never had this issue. Also this is the SECOND M3 to do this.

DJI has addressed this a couple times with me saying it's a change in  barometric pressure and it's HARMLESS. Well I don't think it's harmless  if I fly into a structure because I think I'm at 80 and I'm at 150.  Betting this effects your rth setting too. Here are some images and  DJI's response.

Here is my log from THIS flight. DJI Flight Log Viewer - PhantomHelp.com
  

NGC Posted at 12-4 18:32
Looks like you should go back to an Air2S.

I'm considering it. The ONLY thing I like about the M3 is flight time.

Solid jpeg names lol.

erikjsschneider Posted at 12-4 18:38
Solid jpeg names lol.

First thing that came to mind..ha.

DJI has addressed this a couple times with me saying it's a change in  barometric pressure and it's HARMLESS.
DJI's "help" people aren't much help.
They are as reliable as the moderators here as sources of accurate information.
What they are talking about is changes of 10 feet or so and what yours is demonstrating is quite different.
Don't be fobbed off by their cut and paste response.

And why do they mention GPS height?
There's no GPS height displayed anywhere in the app, so that's completely irrelevant.

BrianKushner Posted at 12-4 18:36
I'm considering it. The ONLY thing I like about the M3 is flight time.

They will fix it for sure.
But it is apparently not the highest priority right now.

It is annoying, but as long as you keep an eye on your drone (and the feed from the camera) you should not run into much troubles.

Montfrooij Posted at 12-5 04:20
They will fix it for sure.
But it is apparently not the highest priority right now.

His  drone's altitude sensor is malfunctioning badly.
It's unacceptable and not safe for flying.

Labroides Posted at 12-5 04:26
His  drone's altitude sensor is malfunctioning badly.
It's unacceptable and not safe for flying.

Ok.
In that case it is back to DJI.

Labroides Posted at 12-5 04:26
His  drone's altitude sensor is malfunctioning badly.
It's unacceptable and not safe for flying.

Yeah, I completely agree. Any atmospheric effect you're going to see in that scenario over the duration of that flight is pretty minimal. Nearly 200ft discrepancy is clearly a hardware defect in the barometric sensor.

RMA for a replacement.

Hi,

Interesting case this high change in barometric values in this flight, agree ; out of the normal at first thought.

But what i notice in your flight that you had changed your max height twice in this flight.

2m16s > FlyApp max height change [ 1640 ft ]
11m59 > FlyApp max height change [ 492 ft ]

Max Height setting changes should not have effect on the baro value.....but who knows....

Just for trouble shooting and fault isolating : can you fly again this route and change the max height in the app before take-off?

Another test is to start a flight, climb to 400 feet, and down to start position ; see the baro height indication. this to rule out baro changes over distance.Baro pressure can vary over distance, and in this flight the max distance out = 15000 feet!.
1 mbar equals 30 feet height change.

cheers
JJB

Montfrooij Posted at 12-5 04:28
Ok.
In that case it is back to DJI.

This is my second bird.

JJB* Posted at 12-5 07:04
Hi,

Interesting case this high change in barometric values in this flight, agree ; out of the normal at first thought.

Where I fly there are 3 different height restrictions...192, 452 and 16something..As I fly in and out of the zones it changes automatically.

NGC Posted at 12-5 07:23
https://m.youtube.com/watch?v=e56C8mjSuOI

3:44-4:20.

4:23 shows the green dot from hell too :-)

BrianKushner Posted at 12-5 20:29
Where I fly there are 3 different height restrictions...192, 452 and 16something..As I fly in and out of the zones it changes automatically.

That is very interesting. So maybe something related to restrictions is causing the change in altitude.... a stretch maybe but possible?

BrianKushner Posted at 12-5 20:27
This is my second bird.

I wonder if it is really hardware related.
Could very well be something with the FW.

BrianKushner Posted at 12-5 20:29
Where I fly there are 3 different height restrictions...192, 452 and 16something..As I fly in and out of the zones it changes automatically.

Hi Brian,

Thanks for your reply.

uh, is that what i want as a remote pilot?  my own max height setting changes automatically ?
Wonder what the logic is behind this to change this setting like this.
cheers
JJB

JJB* Posted at 12-6 00:50
Hi Brian,

Thanks for your reply.

Where I fly if I go left towards an airport the height lowers. If I go right Upriver aware from Airport the height increases until there is no restriction.

GaryDoug Posted at 12-5 21:51
That is very interesting. So maybe something related to restrictions is causing the change in altitude.... a stretch maybe but possible?

Wish I knew. One thing is for certain, I usually only see the altitude discrepancy when during the flight I had a lot of starts and stops from sensors. The flight the other day was something like this.

I take off and max out at 10 mph....then I have to kick into sports to get up to speed. Then I can drop down to normal mode and get my 33 mph. However when I was photographing a ship on the river for instance, drone would fly 10mph, then drop to 0, I'd pump the stick get back to 10-20 mph then it would stop..When that occurs is when I see the crazy altitude issue.  Also as I mentioned it doesn't do this as much or not at all in bright sunlight. It's the dusk flights that kills the sensors. I think when it says sensors not available due to light it stops and starts the drone everytime I get that message.

BrianKushner Posted at 12-6 01:34
Where I fly if I go left towards an airport the height lowers. If I go right Upriver aware from Airport the height increases until there is no restriction.

In my country its legal to fly up to 120 meter AGL.
So my setting in the app is 120 meter.

What will happen if i fly towards a zone with a max height of 400 meter?
If my setting of 120 is automatically set to a higher value ; not pleased woth that.

Have to try this out myself.

BTW If i set manual my max height in app to a lower value than the RTH height, the RTH height is changed automatically to that lower max setting.But if i reset the max height to a higher value than the RTH height does not change. Nice to know if you fly into a alt zone with a max height lower than your RTH height setting.


Read you last post on here, barometric sensor does not know if it is dark or not....
Hope DJI can explain what is wrong with your M3.

cheers
JJB

Just heard back from DJI Support ESCALATION and they tell me the same thing. It's all normal and rest assured IF YOU CRASH and it isn't your fault we will replace the drone under warranty. Keep in mind in addition to the barometer issue I reported the stopping and starting, drops in altitude while flying level etc...This has been a month of them telling me it's all normal don't worry. HAHA.

BrianKushner Posted at 12-7 04:04
Just heard back from DJI Support ESCALATION and they tell me the same thing. It's all normal and rest assured IF YOU CRASH and it isn't your fault we will replace the drone under warranty. Keep in mind in addition to the barometer issue I reported the stopping and starting, drops in altitude while flying level etc...This has been a month of them telling me it's all normal don't worry. HAHA.
[view_image]

Well keep the reply’s, a bit strange they don’t want to track the problems.

BrianKushner Posted at 12-7 04:04
Just heard back from DJI Support ESCALATION and they tell me the same thing. It's all normal and rest assured IF YOU CRASH and it isn't your fault we will replace the drone under warranty. Keep in mind in addition to the barometer issue I reported the stopping and starting, drops in altitude while flying level etc...This has been a month of them telling me it's all normal don't worry. HAHA.
[view_image]

That reply is what they would normally send in response to someone overly concerned about the common and normal slight variance in indicated altitude.
It's very clear that your drone has a real and serious issue.
Whoever was responsible for their answer has no idea what they are saying.

BrianKushner Posted at 12-7 04:04
Just heard back from DJI Support ESCALATION and they tell me the same thing. It's all normal and rest assured IF YOU CRASH and it isn't your fault we will replace the drone under warranty. Keep in mind in addition to the barometer issue I reported the stopping and starting, drops in altitude while flying level etc...This has been a month of them telling me it's all normal don't worry. HAHA.
[view_image]

I would ask them directly if the technical team is happy that atmospheric pressure fluctuations would repeatably cause height errors in excess of 180ft?

By my back of a napkin calculations, I make that a swing of around 600 Pascals, which is meteorologically significant.

Yeah remember, this is level 2. When I had this cookie cutter response initially they sent cascaded it...ha... They ignore my other complaint like stopping and starting and altitude drops.  For what it's worth:

After much playing around I've found that the drone performs 90% better when sensors are TURNED OFF. I've said all along this is a sensor issue. When flying at dusk the sensors are switching on and off constantly as light changes and it's causing the stops and starts and declines in altitude. Tonight I few 1/2 hour after sunrise so getting pretty dark and did not have a single anomaly.