I thought I understood permissable flight altitude?

[Mt-Ed]

I had my first flight this morning with my MA2.....what a trip!! It left me baffled, however. I took off from a location that was 4457' elevation. I wanted to fly up a nearby mountain, which topped out at 5760' elevation. I was not able to do so. I set my maximum elevation to the max., but I could not get more than a few feet above 400' elevation? At the location, I checked B4Ufly, but there was no internet. I did get an "all clear to fly" msg. in the upper left screen. I'm out in an area where there is nothing but gravel roads and cows! When I got home, I rechecked B4Ufly, and it said there was nothing to interfere, and I was free to fly. I did notice at the bottom of the screen (B4Ufly), there was a "details" button and I clicked it. Come to find out that .94mi away from my takeoff spot, there was a "landing strip", on somebodies ranch! Just a dirt field, probably used once or twice a year type of thing. B4Ufly did NOT indicate that this was any reason I could not fly at my location?

So, is it possible that the location of this strip had some effect on the fact that I couldn't get above 400'? The elevation, in the lower left of my screen, turned red! My understanding was that the 400' ceiling was AGL, and even though I would eventually be flying just over 1300' above my take off elevation when I flew up the mountain, I just had to maintain my 400' max along the way?

I really hope that this constraint will not be an ongoing problem as I live in a very mountainous area and this 1300' elevation change in less than 1 mi. distance is a mere bump, and if I cannot ever get above 400' from my take off location, I won't be able to fly it much of anyplace!!

Thoughts, ideas, suggestions?
Thanks so much in advance.

 

[THE CYBORG]

Dont know why you had problems, it should be like this.

 

[iaincaradoc]

Dont know why you had problems, it should be like this.

"Should be."

Sadly, the MA2 measures altitude only from the homepoint, so if you fly laterally 300 yards and the actual "ground" level has risen 1000', you can't fly that direction any more because the 400' maximum is measured from the homepoint, not from the spot directly under the aircraft.

It's messy.

 

[PhantomFandom]

I set my maximum elevation to the max.

What does this mean? You set it to 400 feet?

he elevation, in the lower left of my screen, turned red! My understanding was that the 400' ceiling was AGL, and even though I would eventually be flying just over 1300' above my take off elevation when I flew up the mountain, I just had to maintain my 400' max along the way?

That is the issue. The maximum altitude that the drone/controller/firmware are set to is in reference to AGL from the HOME POINT. So if you start flying up the incline of the mountain, as soon as you reach 400 feet above the home point, you will reach the max. The drone determines altitude by barometric pressure and the reference point is the launch altitude.

If you want to fly up the slope of the mountain then you need to set the maximum altitude in the app to the maximum you need to fly above the home point. In this case that seems to be 1,500 feet (or approximately 396 meters). Of course you probably want some distance above the peak so set accordingly. Then it is up to you to make sure you do not exceed 400 feet true AGL above the ground which is directly below the drone.

This allows you to do what you are looking for and stay legal.

 

[ChrisOutdoors]

The UAS uses a barometer and makes decisions based on pressure. The barometer sets the 0 point at your homepoint. If you increase your altitude higher than 400' from your homepoint you'll be restricted. It's also worth mentioning that at your altitude temperature differences can sometimes change pressure by up to 15% from standard values, impacting your perceived max AGL.

Altitude Real Feel: Physical Altitude vs. Pressure Altitude | 8K Peak

Comparison of Denali, K2, Everest, Chimborzo, Aconcagua, and Mt Vinson. Latitude, temperature, and weather affect the altitude that you really feel and the variances can be significant enough to move peaks in and out of various lists.

8kpeak.com

 

[hiflyer201]

That's the way it is in the mountains.. I think you could get a waiver in your location if you had a 107...and then you would understand the rules too. They are pretty clear on that point.

 

[Mt-Ed]

Yes Doc, it would appear that this is the case. This does generate the following question, however. Why is it possible, in the Safety section, to set the max altitude to 1600'? When I attempt to set the max alt. over 400' here, I DO get a "warning" message stating that I'm exceeding the 400' ceiling, and then asks if I'm willing to accept all responsibility for doing so?

Since this was my first flight, I'm going to go to another location next time, with significant elevation variation, and see what happens there. I'm also going to do a test, where once I take off from a location, I'm going to do directly up from that point to see what happens, if I've set the max>400'. I'll report back.....

Oh, and to further muddy these waters....in the Appendix of the users manual it states that the Max Service Ceiling ASL is 5000M (16,404'), so that cannot be an issue as I'm only working at 1/4 to 1/3 of that maximum.

More to come......

 

[iaincaradoc]

That's the way it is in the mountains.. I think you could get a waiver in your location if you had a 107...and then you would understand the rules too. They are pretty clear on that point.

A 107 Waiver wouldn't help - it's the software limitation in DJI's code that's the problem.

You couldn't even *apply* for a 107 Waiver in this case, because he's still not flying > 400' AGL.

 

[sar104]

Yes Doc, it would appear that this is the case. This does generate the following question, however. Why is it possible, in the Safety section, to set the max altitude to 1600'? When I attempt to set the max alt. over 400' here, I DO get a "warning" message stating that I'm exceeding the 400' ceiling, and then asks if I'm willing to accept all responsibility for doing so?

Since this was my first flight, I'm going to go to another location next time, with significant elevation variation, and see what happens there. I'm also going to do a test, where once I take off from a location, I'm going to do directly up from that point to see what happens, if I've set the max>400'. I'll report back.....

Oh, and to further muddy these waters....in the Appendix of the users manual it states that the Max Service Ceiling ASL is 5000M (16,404'), so that cannot be an issue as I'm only working at 1/4 to 1/3 of that maximum.

More to come......

The warning is just a reminder in case you are unaware that flying over 400 ft AGL is not legal. You can ignore it if you are flying in varying terrain and will be remaining within 400 ft AGL.

 

[hiflyer201]

So he's stuck climbing on foot to the top and flying down then. Bummer
I have a 107 but I've never applied for a waiver or even used it for that matter. I do run into that problem where I live but I can usually get to the higher terrain without much trouble. I have a ATP as well and actually I think we're lucky to get as high as we do. I can't see that rule changing for the better.

 

[Deleted member 103366]

An example, if you take off from the base of a 400ft hill and want to fly to 100ft above the top of the hill then you need to set you maximum height to 500ft plus, the "height" is measured relative to the home point. Taking off at the foot of a 400ft or so cliff I have had my mini ascend to maybe 30 ft above the top of the cliff by increasing the maximum height to maybe 480ft.
The "height" of the ceiling in this context has nothing to do with height of the drone above the ground at any other particular point during the flight. Your local laws perhaps stipulate a maximum height above the ground and that is where the Cyborgs diagram come in. Assuming the MA2 is set up like other DJI drones there is one other thing you should remember, there is a 500m height above the home point ceiling built into the drone and it can not be beaten unless you hack the software, which I do not recommend.

With regards to "Max Service Ceiling ASL is 5000M (16,404') ", the air gets less dense as you ascend, to use your figures the 5000m is the point at which it air becomes too thin for the MA2 to safely lift itself etc. It is an entirely separate thing from ceilings impose by software and legislation

 

[PhantomFandom]

So he's stuck climbing on foot to the top and flying down then. Bummer

No it does not mean that at all. Please see Post #4 above.

 

[Mt-Ed]

What does this mean? You set it to 400 feet?


That is the issue. The maximum altitude that the drone/controller/firmware are set to is in reference to AGL from the HOME POINT. So if you start flying up the incline of the mountain, as soon as you reach 400 feet above the home point, you will reach the max. The drone determines altitude by barometric pressure and the reference point is the launch altitude.

If you want to fly up the slope of the mountain then you need to set the maximum altitude in the app to the maximum you need to fly above the home point. In this case that seems to be 1,500 feet (or approximately 396 meters). Of course you probably want some distance above the peak so set accordingly. Then it is up to you to make sure you do not exceed 400 feet true AGL above the ground which is directly below the drone.

This allows you to do what you are looking for and stay legal.

Hi Phantom, I set my max altitude to 1600' which is as high as it went in the safety category of the Fly app. If I'm following your suggestion, I set this proactively because I knew my overall altitude from home would be >400' and I didn't want to bother trying to adjust it once I was half way to my destination.

Even though it was set >400', once the drone reached 400', the elevation, in the lower left screen went red, and I could not go higher.

 

[Mt-Ed]

An example, if you take off from the base of a 400ft hill and want to fly to 100ft above the top of the hill then you need to set you maximum height to 500ft plus, the "height" is measured relative to the home point. Taking off at the foot of a 400ft or so cliff I have had my mini ascend to maybe 30 ft above the top of the cliff by increasing the maximum height to maybe 480ft.
The "height" of the ceiling in this context has nothing to do with height of the drone above the ground at any other particular point during the flight. Your local laws perhaps stipulate a maximum height above the ground and that is where the Cyborgs diagram come in. Assuming the MA2 is set up like other DJI drones there is one other thing you should remember, there is a 500m height above the home point ceiling built into the drone and it can not be beaten unless you hack the software, which I do not recommend.

With regards to "Max Service Ceiling ASL is 5000M (16,404') ", the air gets less dense as you ascend, to use your figures the 5000m is the point at which it air becomes too thin for the MA2 to safely lift itself etc. It is an entirely separate thing from ceilings impose by software and legislation

This is the way I understood the elevation to work, but in this case it did not! Something else is going on here, which is why I plan to go to a different location and try the experiments I mentioned. I'm just wondering if the "landing strip" < 1mi. away was causing the firmware in DJI to act like it was some kind of restricted air space and creating the limitation?

 

[Deleted member 103366]

When you increased the maximum height to 1600ft did it stay there? I have a recollection of seeing an adjustment not 'take' but I can not remember the circumstances.
Perhaps try working up in increments over the 400ft 'norm' to see if there is some threshold?

 

[Starz]

Wow.

 

[iaincaradoc]

This is the way I understood the elevation to work, but in this case it did not! Something else is going on here, which is why I plan to go to a different location and try the experiments I mentioned. I'm just wondering if the "landing strip" < 1mi. away was causing the firmware in DJI to act like it was some kind of restricted air space and creating the limitation?

The "landing strip" shouldn't have any impact at all in-flight. It'd only show up as an "authorization zone" on take-off, if at all, and it shouldn't even do that.

 

[brett8883]

This is the way I understood the elevation to work, but in this case it did not! Something else is going on here, which is why I plan to go to a different location and try the experiments I mentioned. I'm just wondering if the "landing strip" < 1mi. away was causing the firmware in DJI to act like it was some kind of restricted air space and creating the limitation?

From what you said it sounds like it didn’t prevent you from exceeding 400ft it just gave you a warning that you MAY be breaking the rules because it has no way of telling how high it is above ground level.

This is a recent addition to the DJI apps. It use to not say anything if you exceeded 400 feet. It’s pretty annoying if you fly in the mountains.

Bottom line is it didn’t prevent you from flying to that height after changing the max altitude it just warned you. This is expected behavior. Annoying as it is there’s no way to stop if from happening.

 

[commsz344]

As per previous comment - Your drone knows where it is relative to home point so will advise once you reach your ‘Legal Ceiling’ which is 400’ you can exceed this if you set your maximum height above this. You will start get a warning at 398’ but can ignore this as long as you are less than 400’ above the ground under the Drone at any given time.

 

[Zbip57]

Were you possibly in a gray-shaded "altitude zone" like these? You can fly under them no problem, but climbing higher than 150m will trigger a GEO restriction.