What is minimum altitude?

[AntonyEbne]

Having just read that the 400 foot altitude limit for the Phantom is "relative to take off position" and not sea level, I was wondering if there is a MINIMUM altitude limit ? Perhaps minus 400 foot?
(for people living in flat terrain, this may not be relevant, but if I take off from the top of a mountain or cliff, then I need to be sure that there won't be some weird glitch as I descend).

 

[Paul60]

I would imagine it references altitude from sea level. So if your take off point is 100ft above sea level it would calculate 300ft from that location effectively putting you at 400ft ASL. Sea level being the minimum and reference. ?

 

[hooligans]

It refers to 400 feet above ground level. You can fly 400 feet above a structure as long as that is the structure you intend to observe.


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[Paul60]

It refers to 400 feet above ground level. You can fly 400 feet above a structure as long as that is the structure you intend to observe.


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400ft AGL

Thanks, I wasn't sure.

 

[ChiefStealth]

The 400 ft limit is usually AGL, above ground level. Not relative to take off position. Relative to the ground below the drone. If you fly over a 400 ft hill, you can be 400 ft above that. Fly away from the hill, you gotta come back down to 400 ft above that ground level. Never heard of a minimum altitude.

 

[With The Birds]

I would imagine it references altitude from sea level. So if your take off point is 100ft above sea level it would calculate 300ft from that location effectively putting you at 400ft ASL. Sea level being the minimum and reference. ?

We don't need to imagine, depicted altitude in the GO app (or third party app) is directly referenced to that recorded when the home point is set (0 ft).

 

[Slackware]

-4000 miles, any lower and you are gaining altitude in china.
So basically minimum altitude is the ground.
The only problem you might encounter is low battery emergency landing. Drone thinks ground is 2000 feet higher than it really is. You might run out of juice before reaching the ground.

-42 feet is my record so far.

 

[With The Birds]

-4000 miles, any lower and you are gaining altitude in china.
So basically minimum altitude is the ground.
The only problem you might encounter is low battery emergency landing. Drone thinks ground is 2000 feet higher than it really is. You might run out of juice before reaching the ground.

-42 feet is my record so far.

I think the earths diameter is over twice that.... Critical battery landing will still work fine- if yiur flying from the highest terrain however you are best advised to set your RTH to a low value, save wasting power in a RTH situation climbing much higher than required. I set mine to 5m when flying out below cliff faces.

 

[Slackware]

I think the earths diameter is over twice that.... Critical battery landing will still work fine- if yiur flying from the highest terrain however you are best advised to set your RTH to a low value, save wasting power in a RTH situation climbing much higher than required. I set mine to 5m when flying out below cliff faces.

yes, but after midway you are CLIMBING again. I think the clouds below you is what I miss the most about the mountains.

 

[Dan cutter]

OP asked about glitches. Was that electronic glitches or FCC related? Or both. I have flown -400 feet (from take off) without incident though still 7000 feet above sea level and never more than 100 feet AGL. I routinely fly to 1500 feet ceiling set by software--without going over 50 feet AGL--some think that is illegal. I flew at Badwater Death Valley without any warnings or glitches (250 feet below sea level). It didn't even get wet.

 

[WilliamM]

I would imagine it references altitude from sea level. So if your take off point is 100ft above sea level it would calculate 300ft from that location effectively putting you at 400ft ASL. Sea level being the minimum and reference. ?

ASL has nothing what so ever to do with drone flying, normally. We talk in terms of AGL only.

 

[Paul60]

ASL has nothing what so ever to do with drone flying, normally. We talk in terms of AGL only.

Thanks for that. I wasn't sure.

 

[Alex Baxter]

It refers to 400 feet above ground level. You can fly 400 feet above a structure as long as that is the structure you intend to observe.

I thought it was Above ground level, not above the structure, if there was a 1000 foot pyramidal building, I don't think you can fly up the side of it then 400 feet above it, making it 1400 feet AGL. I'll be happy to be proved wrong..

 

[tevek]

I thought it was Above ground level, not above the structure, if there was a 1000 foot pyramidal building, I don't think you can fly up the side of it then 400 feet above it, making it 1400 feet AGL. I'll be happy to be proved wrong..

Given that the max height above sea level for a P4 as an example, is 6000m, I think you would be fine. Your reference point for take off and your max ceiling height are dictated from where you take off from, so theoretically 1400 ft is fine (at a max of 500m/1700ft in FCC mode).

 

[Alex Baxter]

Given that the max height above sea level for a P4 as an example, is 6000m, I think you would be fine. Your reference point for take off and your max ceiling height are dictated from where you take off from, so theoretically 1400 ft is fine (at a max of 500m/1700ft in FCC mode).

I'm not certain I follow what you're saying.
I was referring to the regulations, not what's possible. c. 20,000 feet is a maximum altitude (ASL), not a maximum height (AGL). You could take off on a 19,000 foot mountain, but regulations would restrict you to 19,400 feet. 400 feet maximum AGL is the FAA/CAA/IAA rule. Minimum height for aircraft not coming in to land is 500 feet AGL, so there should be no crossover, given that there are NFZs around airports.

 

[tevek]

I'm not certain I follow what you're saying.
I was referring to the regulations, not what's possible. c. 20,000 feet is a maximum altitude (ASL), not a maximum height (AGL). You could take off on a 19,000 foot mountain, but regulations would restrict you to 19,400 feet. 400 feet maximum AGL is the FAA rule. Minimum height for aircraft not coming in to land is 500 feet AGL, so there should be no crossover, given that there are NFZs around airports.

Sorry I was referring to your particular query WRT to acheiving the height required to climb up to 1400' at the take off point, not considering the ASL limitations. As for the restrictions to the 400 AGL limit, not sure how many structures exist at 19000' that you want to fly from. Then again, I don't live in the Andes or anywhere close to that height. My ASL here is 270 Mtrs, so I may need to get out more.

 

[Alex Baxter]

Sorry I was referring to your particular query WRT to acheiving the height required to climb up to 1400' at the take off point, not considering the ASL limitations. As for the restrictions to the 400 AGL limit, not sure how many structures exist at 19000' that you want to fly from. Then again, I don't live in the Andes or anywhere close to that height. My ASL here is 270 Mtrs, so I may need to get out more.

Oh, this is getting more and more incomprehensible .
In reference to structures, I reckon if you took off when on the roof of a 500' building, you would, even if hovering alongside, be breaking the rules, as you would be over 400' AGL. That was my only point...

 

[tevek]

Oh, this is getting more and more incomprehensible .
In reference to structures, I reckon if you took off when on the roof of a 500' building, you would, even if hovering alongside, be breaking the rules, as you would be over 400' AGL. That was my only point...

I can see where you are coming from, but my take off point is referenced from where I fly from, it is 0 mtrs. I use that point as a guide to set my ceiling, not the fact that I am sitting on a building at 120 mtrs. Otherwise my RTH setting is going to be a challenge. I have no idea what the rules are for you flying at 120 AGL, but the drone does not see anything other than its launching point, and at your height I would be assuming that any aircraft would be seeing the same reference point i.e buildings, mountains and the like.

 

[Alex Baxter]

I can see where you are coming from, but my take off point is referenced from where I fly from, it is 0 mtrs. I use that point as a guide to set my ceiling, not the fact that I am sitting on a building at 120 mtrs. Otherwise my RTH setting is going to be a challenge. I have no idea what the rules are for you flying at 120 AGL, but the drone does not see anything other than its launching point, and at your height I would be assuming that any aircraft would be seeing the same reference point i.e buildings, mountains and the like.

Now we're singing from the same hymn sheet, my only reference was to the legality of flying above 400' AGL, (a universal rule set by the IATA, and followed by almost every country. I realise the difficulty this causes with RTH altitudes in hilly terrain. I reckon we're sorted...

 

[solentlife]

Given that the max height above sea level for a P4 as an example, is 6000m, I think you would be fine. Your reference point for take off and your max ceiling height are dictated from where you take off from, so theoretically 1400 ft is fine (at a max of 500m/1700ft in FCC mode).

You can leave out the "above sea level" ... as no Phantom or other such machine has any idea about Sea level what soever .......... it only knows to register the pressure at GROUND level and take that as its 'zero' reference. Forget structures .. sea level .... all that ...

OP asked about MINIMUM altititude - there are many videos on YT showing people taking off on hills and mountains and then flying down to video lower or even to land. It appears there is no lower limit. Lets be fair - what would it do IF there was ?

ASL / AGL .... sorry but these make me smile ... we are not proper pilots. And quite a number would not know an AGL from a ferret in their trousers !! But if words like Height above Ground - the everyone knows the words !!

I could talk Fuel Abbreviations to you ... 99.9999% of you wouldn't know what I was talking about ...

Simple is good chaps ...

Cheers
Nigel