In terms of legal altitude limits, is that referring to height from the controller AGL or from the drone AGL?

[shadow3467]

What I mean is, say I take off from a low point and fly over a hill, the hill is 30m tall

Is my effective legal altitude then 120+30=150? Or is it still 120 even though at the drone's location it is only 90m above ground level?

Does that question make sense?

The reason I ask is because the drone gets better signal reception the higher above obstacles it is obviously, which would maintain line of sight and direct connection to remote, but this is sometimes not possible if the groundlevel at the drone's position is higher than yours

 

[MAvic_South_Oz]

Drone AGL.
Applies in every airspace / drone rules worldwide.

 

[shadow3467]

Drone AGL.
Applies om every airspace / drone rules worldwide.

So with that said, should I increase the max altitude above 120 and just kind of eyeball it?

 

[Eagle Eye 62]

Remember, the controller records ground level from the takeoff point. For example, If you take off from the edge of a cliff and it is 300 feet below you to the ground level, the controller "thinks" you are near or just above ground level even though you would be around 300 feet above true ground level. The opposite is also true, if you climb to the top of a 500 foot hill, the controller says 500 feet but you are actually at or near ground level. Just keep that in mind and the software does not compensate for that and your readings will not be accurate in terms of true ground level. You can increase the max altitude limit if you want to climb above the peak, yes.

 

[MAvic_South_Oz]

So with that said, should I increase the max altitude above 120 and just kind of eyeball it?

Yes, you can open up the max alt above take of point to 500m, just work out roughly what alt you need for that hill, and set it with a safety margin up to that max.

Signal LOS is important obviously (besides keeping VLOS if you follow that to the letter), there are ways to reset home point by landing and taking off again, but LOS is very important there especially.

You need to estimate our drones AGL altitude, there's no way to tell from telemetry just how far that is to the 120m max.

The reverse allies if you fly out over a valley, you need to drop height to keep the drone max 120m AGL, and LOS signal is as important, meaning you need to get close to the valley edge to keep the controller / drone in LOS of each other reasonably.

All a matter of experience to guess the alt of the drone AGL, mostly you might be better to keep it say half what you think the drone is flying at.

 

[MS Coast]

What I mean is, say I take off from a low point and fly over a hill, the hill is 30m tall

Is my effective legal altitude then 120+30=150? Or is it still 120 even though at the drone's location it is only 90m above ground level?

Does that question make sense?

The reason I ask is because the drone gets better signal reception the higher above obstacles it is obviously, which would maintain line of sight and direct connection to remote, but this is sometimes not possible if the groundlevel at the drone's position is higher than yours

The altitude limit applies to the distance from the drone to the ground directly below it, regardless of where you took off.

 

[Meta4]

What I mean is, say I take off from a low point and fly over a hill, the hill is 30m tall

Is my effective legal altitude then 120+30=150? Or is it still 120 even though at the drone's location it is only 90m above ground level?

Perhaps this diagram makes things easier to understand?

The reason I ask is because the drone gets better signal reception the higher above obstacles

???

 

[Meta4]

Remember, the controller records ground level from the takeoff point. For example, If you take off from the edge of a cliff and it is 300 feet below you to the ground level, the controller "thinks" you are near or just above ground level

Neither the controller nor the drone "thinks" that at all.
The app will indicate how much higher or lower the drone is relative to the launch point.
How high the drone is relative to the ground below is something you have to think about because the drone doesn't have a sensor to measure that .. just like most small planes..

 

[Yorkshire_Pud]

Imagine a 400ft long weighted string tied to the bottom of the drone.
Where the "400ft above the ground" rule applies, the lower end of that string must always be in contact with the ground directly beneath the drone.

 

[zocalo]

Imagine a 400ft long weighted string tied to the bottom of the drone.
Where the "400ft above the ground" rule applies, the lower end of that string must always be in contact with the ground directly beneath the drone.

Actually, at least in the UK, the ground has to be within 400ft *of* the drone. e.g. if you go over a >400ft high cliff, as long as you are within 400ft of the cliff face you are fine. The image on this page makes that a bit more explicit than the current image in the drone code that omits the additional diagonal line, IMHO, but if you read the CAA's text it does cover this.

From the CAA (emphasis mine):

"If you fly where the ground falls or rises, such as over hills, mountains or cliffs, you may need to adjust your flight path so that your drone or model aircraft is never more than 120m (400ft) from the closest point of the earth’s surface."

 

[crusen8]

What I mean is, say I take off from a low point and fly over a hill, the hill is 30m tall

Is my effective legal altitude then 120+30=150? Or is it still 120 even though at the drone's location it is only 90m above ground level?

Does that question make sense?

The reason I ask is because the drone gets better signal reception the higher above obstacles it is obviously, which would maintain line of sight and direct connection to remote, but this is sometimes not possible if the groundlevel at the drone's position is higher than yours

The FAA is referring to Above Ground Level below the aircraft. It is not allowed to raise your elevation above 400 feet inorder to go over a structure that you can fly around and remain at 400 feet.

 

[Crashdummytest]

What I mean is, say I take off from a low point and fly over a hill, the hill is 30m tall

Is my effective legal altitude then 120+30=150? Or is it still 120 even though at the drone's location it is only 90m above ground level?

Does that question make sense?

The reason I ask is because the drone gets better signal reception the higher above obstacles it is obviously, which would maintain line of sight and direct connection to remote, but this is sometimes not possible if the groundlevel at the drone's position is higher than yours

That would be drone AGL. The height between the drone and the ground. The 120M/400feet limit is reasonable. The 500M limit regarding how high the drone can go from take-off is completely unreasonable, it introduces unnecessary extra work on mountainous terrain shots/video.

 

[wardtom084]

It is simple, a parallel line between the ground and the drone.

 

[Yorkshire_Pud]

Actually, at least in the UK, the ground has to be within 400ft *of* the drone. e.g. i

Yep I know thanks but the OP is in Canada and I think they are AGL. The UK rule seems sensible to me and allows for climbing a tall vertical cliff.

 

[MAvic_South_Oz]

Yep I know thanks but the OP is in Canada and I think they are AGL. The UK rule seems sensible to me and allows for climbing a tall vertical cliff.

It’s a sensible version of the rule, other countries should adopt this.

 

[Yorkshire_Pud]

It’s a sensible version of the rule, other countries should adopt this.

Indeed, which probably means its the last thing they will do lol. I'd guess most have their own Sir Humphrey Appleblys.

 

[Sensii Fly]

Excellent discussion. It occurs to me that it would be lovely to have a topographical map—at least a rough one—for the map option on the controller. Lacking that, I have a hiking app I can use to download those and having one handy for planning certain flights might be interesting and useful.