Lowest Maximum Altitude Setting

[MotoSavy]

I had never really paid much attention, but recently noticed that both the Mini 4 Pro and Air 3 and I suppose others have a lowest maximum altitude of 65 feet and also for RTH.

Last week I was doing in job in Controlled Airspace and was flying in a 50 feet grid. This the lowest grid I had worked at before this was in 100 feet grids.

I'm used to doing an RTH when I'm done with a job and know there are no obstacles to reach my landing pad. During the entire job I made sure to stay below 50 feet, but at the end of the job I was hot and just wanted to get out of there.

Not thinking, I looked and knew that from where the drone was at it could safely reach the landing pad.

However my thinking wasn't clear and as soon as I initiated and RTH and the Air 3 instantly started climbing to 65 feet (RTH also cannot be set lower than 65 feet and RTH can never be higher than maximum altitude). I quickly stopped it before it reached 60 feet. No calls from the FAA, so I think I'm okay.|

So, why a minimum of 65 feet when here in the USA all controlled grids start at 50 feet. I know, the USA is not the only market that DJI sells to but why 65 feet and not 50 feet lowest maximum altitude to at least help pilots is the USA not breaking 50 grid limit.

Actually, I would like to see it go as low as 10 feet.

Any idea why DJI would pick 65 feet as the lowest maximum altitude and RTH? Are there laws in other countries and the reason for 65 feet?

 

[Droning on and on...]

"lowest maximum altitude" was confusing to me, so to clarify: You are referring to the maximum altitude setting in DJI Fly, under the Safety section; a slider that can be set at maximum 500m/1640ft, correct?

Your issue is that it's minimum setting is 65ft, correct?

You wanted to set this to 50ft to enforce a hard ceiling in a 50ft grid in controlled airspace, is that right?

Sorry I have nothing helpful to contribute, but I wasn't sure exactly what you were talking about.

 

[MotoSavy]

"lowest maximum altitude" was confusing to me, so to clarify: You are referring to the maximum altitude setting in DJI Fly, under the Safety section; a slider that can be set at maximum 500m/1640ft, correct?

Your issue is that it's minimum setting is 65ft, correct?

You wanted to set this to 50ft to enforce a hard ceiling in a 50ft grid in controlled airspace, is that right?

Sorry I have nothing helpful to contribute, but I wasn't sure exactly what you were talking about.

Yes, you are correct, that if what I was referring. Maybe I should have also include the word setting.

It would be nice if DJI allowed setting it to lower than 65 feet. At least down to 50 feet.

 

[mavic3usa]

You may not know this but the DJI FPV drones have hard specific RTH settings (among other settings) which are as follows: 20m, 30m, 40m, 50m, etc which translates to 66 ft, 98 ft, 132 ft, 164 ft, etc. so in the US, we have to pick somewhere in between which means if you are in a 150 feet grid, you may want to choose 132 ft. This tells me DJI may not be thinking RTH altitude is a big deal as long as you are able to estimate and for sure, it doesn't seem like they key off any of our grid altitudes (or they may not be aware since grids are "relatively" recent to recreational drones. My guess is if it is safe to RTH at 10 feet, then it's probably safe to return to home at 66 feet (with little impact to battery); notice I didn't say "legal." The thinking also could be this: Given that a drone will never descend to a lower altitude to RTH, it's hard to imagine you are flying at 10 ft and you are far enough away that you would "want" it to RTH at 10 ft....or even 50 ft; grids notwithstanding.

Honestly I wouldn't worry about it. Going 15 ft above is not a deal breaker (for most) and even though the grids aren't that large in area, it's hard to imagine somewhere in the grid (or the adjacent equivalent grids) there isn't some point that is 15 feet higher/lower AGL so legally, that's a challenge. Remember, you flew at 65 feet higher than your home point controller....who's to say exactly where your drone was.

And there is this: Often I get multiple LAANC across different grids with different altitudes. If you get one LAANC, you know your max altitude regardless where you fly. But if you get 3 LAANC, you can fly at 50, 100, and 150 depending on which grid you are flying in. If you launch in 50 (because there's a nice, comfortable, shady isolated spot there) and you are flying in 150 at 120 (because that's where all the good shots are) and you drop your controller in lake and your drone RTH at 120, when it arrives in your 50 grid, what height will it be? 120. And there is nothing you can do to prevent it. I believe DJI is working on improving their smart RTH but it will take real AI to completely mitigate this "problem."

 

[AeroJ]

Any idea why DJI would pick 65 feet as the lowest maximum altitude and RTH? Are there laws in other countries and the reason for 65 feet?

It's only a guess, but I am going to posit that the 65 ft minimum RTH might have been chosen based on the average height of trees. For example the average Oak tree is 50-70 ft high, which seems 'interestingly' close to that value.

 

[Droning on and on...]

It's only a guess, but I am going to posit that the 65 ft minimum RTH was chosen based on the average height of trees.
For example the average Oak tree is 50-70 ft high.

But but but... what about Godzilla?

Oh wait, that's Japanese manufactured drones.

Never mind

 

[MotoSavy]

...My guess is if it is safe to RTH at 10 feet...

I don't think that I would use 10 feet for RTH. However on that job that I was doing in the 50 feet grid, as part of the job I was also walking down several streets and taking photos of homes. Just the front of some from several angles.

The place was actually a Mobile Home Park and a potential buyer wanted comprehensive photos of the homes in the MHP.

I was yawing right and left, forwards and backwards to get photos and often flew over my head to get the right angles. There were low trees and I could have easily set 10-20 max and not have to pay as much attention to the trees, or worry about getting a haircut.

50 feet would be nice, but even lower would be better. In probably 99.9% of the cases this is not an issue, but it would be nice to be able to set a ceiling lower than 65 feet.

 

[Droning on and on...]

In the case where you're lower than 65ft there's always the option to set LOS RTH to hover in place, while you head toward the drone and re-establish the connection.

For the mission you described, this would be my choice, rather than pierce the 50ft ceiling, and risk (very slightly) some trouble.