Mavic 2 ignoring maximum altitude limit

[Drbobk]

Before I start, let me give thanks and shoutouts to Mike Singer (@MavicHelp) and Meta4 (@Meta4) for their help in tracking down this problem. In private chats they both offered significant help and virtually all of what you see here is because of their help.

This discussion is about a Mavic 2 Pro with a Smart Controller. I have a COA to operate in Class D airspace, with an altitude limit of 100’. I set my limit in the DJI Go4 app at 30 meters. However, I discovered as I was flying that I had actually exceeded the max altitude by a significant margin. I landed, went through the settings again (yes, set at 30m) and proceeded to fly and try to go above 100’, which I did with no problem. When I discussed the problem online with DJI (on the day they released new firmware), they wanted me to update, which I did. I then tested the 30m limit, and blew right through it again. (I had called the tower to let them know what I was doing and that I expected to briefly but safely exceed the height restriction and then come right back down.)

Meta4 offered to look at the flight logs to determine what was going on. The logs indicated that the aircraft never exceed the maximum altitude because there was no max altitude set. But I have screenshots of the 30m setting, so it was set as far as Go4 was concerned.

DJI suggested trying beginner mode, because that would limit distance to 100’ and altitude to 100’. I set beginner mode, took off, and tried to fly away. The Mavic screeched to a halt just prior to 100’ away. So far so good. I then climbed, and got to almost 150 feet before I stopped and came back down. So somewhere in the system the max height is being set but somewhere else it is being ignored. I toggled Beginner mode off and reset the max to 30m. (Interesting though is that on the screen, Beginner mode only says it sets a speed and distance limit, not altitude.)

Mike Singer directed me to older posts where he showed how to use an earlier version of the “Assistant 2 for Mavic” app to go into debug mode and look at the internal settings in the aircraft itself to see if the Go4 app was passing the information correctly to the aircraft. This showed that the 30m setting was set at the aircraft level, but was being ignored in reality. Mike then suggested changing the setting to see if it would have an effect. The plan was to lower it to 20m.

Today I went out to test it outside of my local Class D airspace (which is inside the Trump Easter weekend TFR). First I tried to climb above 100’, but the Mavic stopped at 98 feet for the first time. Great, I thought, it’s fixed. Then I reset the max height to 20m, and then proceeded to climb. It didn’t stop at 20m, and it continued to climb right through 30m again with no problem. I came home, connected the Mavic to my computer again, and verified that the internal setting was indeed 20m despite its climb to well above that.

I hope that others reading this will test the max height setting to see if it is just my aircraft (unlikely) or something in the software affecting all Mavic 2’s so that we can let DJI know if the problem is widespread. In my case, I don’t want to jeopardize my COA by violating the max altitude. For others with the setting at 400 feet, you’ll want to know whether that is in fact being processed correctly or whether you risk flying higher than you intend if you take your eyes off the height reading while you are flying.

Thanks in advance to those of you who will test your M2 and thanks again to Meta4 and MavicHelp for helping me dig much deeper than I ever could have on my own. (DJI suggested sending the M2P in for repair, but I don’t want to do that until I know that something is wrong with MY Mavic only. This seems more like a software bug.)

 

[Lon Denard]

Before I start, let me give thanks and shoutouts to Mike Singer (@MavicHelp) and Meta4 (@Meta4) for their help in tracking down this problem. In private chats they both offered significant help and virtually all of what you see here is because of their help.

This discussion is about a Mavic 2 Pro with a Smart Controller. I have a COA to operate in Class D airspace, with an altitude limit of 100’. I set my limit in the DJI Go4 app at 30 meters. However, I discovered as I was flying that I had actually exceeded the max altitude by a significant margin. I landed, went through the settings again (yes, set at 30m) and proceeded to fly and try to go above 100’, which I did with no problem. When I discussed the problem online with DJI (on the day they released new firmware), they wanted me to update, which I did. I then tested the 30m limit, and blew right through it again. (I had called the tower to let them know what I was doing and that I expected to briefly but safely exceed the height restriction and then come right back down.)

Meta4 offered to look at the flight logs to determine what was going on. The logs indicated that the aircraft never exceed the maximum altitude because there was no max altitude set. But I have screenshots of the 30m setting, so it was set as far as Go4 was concerned.
View attachment 70153View attachment 70153
DJI suggested trying beginner mode, because that would limit distance to 100’ and altitude to 100’. I set beginner mode, took off, and tried to fly away. The Mavic screeched to a halt just prior to 100’ away. So far so good. I then climbed, and got to almost 150 feet before I stopped and came back down. So somewhere in the system the max height is being set but somewhere else it is being ignored. I toggled Beginner mode off and reset the max to 30m. (Interesting though is that on the screen, Beginner mode only says it sets a speed and distance limit, not altitude.)

Mike Singer directed me to older posts where he showed how to use an earlier version of the “Assistant 2 for Mavic” app to go into debug mode and look at the internal settings in the aircraft itself to see if the Go4 app was passing the information correctly to the aircraft. This showed that the 30m setting was set at the aircraft level, but was being ignored in reality. Mike then suggested changing the setting to see if it would have an effect. The plan was to lower it to 20m.

Today I went out to test it outside of my local Class D airspace (which is inside the Trump Easter weekend TFR). First I tried to climb above 100’, but the Mavic stopped at 98 feet for the first time. Great, I thought, it’s fixed. Then I reset the max height to 20m, and then proceeded to climb. It didn’t stop at 20m, and it continued to climb right through 30m again with no problem. I came home, connected the Mavic to my computer again, and verified that the internal setting was indeed 20m despite its climb to well above that.

I hope that others reading this will test the max height setting to see if it is just my aircraft (unlikely) or something in the software affecting all Mavic 2’s so that we can let DJI know if the problem is widespread. In my case, I don’t want to jeopardize my COA by violating the max altitude. For others with the setting at 400 feet, you’ll want to know whether that is in fact being processed correctly or whether you risk flying higher than you intend if you take your eyes off the height reading while you are flying.

Thanks in advance to those of you who will test your M2 and thanks again to Meta4 and MavicHelp for helping me dig much deeper than I ever could have on my own. (DJI suggested sending the M2P in for repair, but I don’t want to do that until I know that something is wrong with MY Mavic only. This seems more like a software bug.)

Heck yea! I'll take mine out tomorrow and see if it will go above 500 meters first and then dial down from there. I'll let you know.

 

[raven swe]

I have a m2z and smart controller set to 120 meters and it wont go above that, it also wont go above that using the std rc and a 9,7 ipad or iPhone 6 plus. indicator for the height on smart or std rc turn red when limit is reached and audio says max height limit reached or something like that.

 

[THE WOMBLE]

My m2z max height is set to 100m and it won't go over that. Checked flight logs and they show max heights within a couple of meters.

 

[sar104]

If @Meta4 has checked the txt log and found nothing obviously amiss then the next step is to look at the mobile device DAT log and event stream.

Mobile device DAT file: How to retrieve a V3.DAT from the tablet

 

[Drbobk]

Well, something is amiss because the txt files show that there is no limit set:



Unfortunately, I cannot connect to the SC directly to get the .dat files. The SC refuses to show up on my iMac or MacBookPro using the USB connection. The USB port might be bad. So to get the txt files I had to synchronize with the cloud, then use my iPad to sync again and bring the files down to it. I can see the txt files on the iPad's FlightRecords folder but the MCDatFlightRecords folder is empty. I'm heading over to a friend who has PCs and is more familiar with android to see if he can get at these files. I'll let you know.

 

[Kilrah]

To access android devices on a mac you need Android File Transfer

Apple STILL doesn't support MTP natively.

 

[Drbobk]

I have a m2z and smart controller set to 120 meters and it wont go above that, it also wont go above that using the std rc and a 9,7 ipad or iPhone 6 plus. indicator for the height on smart or std rc turn red when limit is reached and audio says max height limit reached or something like that.

I noticed the red and the voice warning on the one and only flight that limited me.

 

[Drbobk]

If @Meta4 has checked the txt log and found nothing obviously amiss then the next step is to look at the mobile device DAT log and event stream.

Mobile device DAT file: How to retrieve a V3.DAT from the tablet

It's difficult to tell which files are from my test flight on 4/20 because the files were all dated 1/18/2013 again, as are many of my other flights. But using the date, the precise time, and the height reached, these are the txt files. The DAT files don't use the same naming convention, but I think that the DAT files ending in 77 and 78 correspond to the two text files. However, since there's also a 79 DAT file on the controller, it's possible that is the actual second flight, and 78 is the first (where it stopped at 30m). My flight records show that I took 3 flights that day, but only the first two are of interest. Flight 1 had the 30m limit that actually stopped the ascent, and flight 2 had a 20m setting that was ignored, and I climbed to about 40m. Once again, thanks for your help.

 

[sar104]

The txt files describe a couple of flights as you mentioned. Those DAT files are unrelated to the txt files. The flights in the two txt files are actually both from the same power up cycle - you landed and took off again. For the first flight the maximum height setting is noted as 30 m. For the second there is no message on maximum height and the home point was not reset. The Home:heightLimitStatus field that you mentioned above is a flag, not a height, and not relevant.

However, on the first takeoff the FC clearly stopped the climb and limited the aircraft to 30 m, while on the second takeoff it did not. That looks a bit like a firmware bug. I recombined the flight records and the two flights are shown together below:



I wonder if a second takeoff results in ignoring the hard limit of 500 m too.

 

[kilomikebravo]

I wonder if a second takeoff results in ignoring the hard limit of 500 m too.

Now that is an interesting question and quite possibly the answer. Do we know what the firmware does when you touchdown but don't power down and then takeoff again? I'd be curious to see what is in the altitude limit field at that moment.

 

[sar104]

Now that is an interesting question and quite possibly the answer. Do we know what the firmware does when you touchdown but don't power down and then takeoff again? I'd be curious to see what is in the altitude limit field at that moment.

On touch down and takeoff the FC resets the barometer, but that shouldn't affect the height limit.

 

[kilomikebravo]

Thanks, SAR, the barometer is what I figured would be reset. But I wonder what Go4 would show as the altitude limit after touchdown but before power down and whether it changes. This can't be hardware so it just about has to be in firmware. I'll have to give it a try if the wind ever settles down around here.

 

[Drbobk]

Thanks sar104. I would have expected the dat files to be numbered consecutively, and the three I attached were the highest three, so I assumed they were the flights in question.

If I remember correctly, I reset the max height to 20m after touchdown. I simply went up, tested th 30m limit, and then came back down. There was no reason to turn power off.

This morning I flew and had no trouble breaking 100', but it may have been on second or third flights without powering down. I'll go test that right now.

 

[Drbobk]

I just tried it - new battery, definitely was powered off. It broke 100' on the first attempt, so it doesn't appear to be related to landing and taking off again.

 

[sar104]

I just tried it - new battery, definitely was powered off. It broke 100' on the first attempt, so it doesn't appear to be related to landing and taking off again.

So whether it respects the setting is random?

 

[Drbobk]

I have had it respect the setting only once that I know of. I always have it set at 100 (30m) because that's what my COA allows. But several times I found myself higher than that without realizing it. Only last week did I start testing it, and the only time it stopped me at 30m was the test flight that you graphed.

 

[sar104]

I have had it respect the setting only once that I know of. I always have it set at 100 (30m) because that's what my COA allows. But several times I found myself higher than that without realizing it. Only last week did I start testing it, and the only time it stopped me at 30m was the test flight that you graphed.

I'll run some tests on my M2P.

 

[kilomikebravo]

FWIW, mine has always stopped and told me I've reached maximum altitude, never been above it.

 

[Dur8an Poison]

Sho. Strange issue for sure. Please keep us posted.