Do you ever fly over 400 ft in US?

[gnirtS]

So on instruments-only how do you know how high off the ground you are?

Real aircraft? If so barometric altitude set to QNH (height above msl), flight level cruising set to standard pressure or more rarely, QFE (above aerodrome). That and minimum safe altitudes off the charts and plates. Other than the RA on bigger aircraft you dont really have an indication of exact altitude above the ground directly underneath you. You also dont need it.

 

[Tombie]

This image is taken at 1,300ft AGL
Approval was given to do this.

 

[arcticfrost]

View attachment 101781

I'm sure this has been discussed to death, but since this discussion is timely I thought I would ask again.

If I take off from a hillside that's 400ft ASL and fly to 400ft AGL (which as I understand it in the DJI world to be the Homepoint) I'm actually at 800ft above the ground below the drone.

I'm still legal, right?

Now if there is another higher hill (within VLOS, of course) that's more than 800ft ASL and more that 400ft AGL (Homepoint) I don't think the software will currently allow me to fly high enough to clear the hill.

What am I missing?

Correct, because it records the home point as the ground level at take off, you couldn’t fly over the hill unless you adjusted the limiter. So you would have to take off from the higher point around you or set the max height to be able to fly over the hill.

 

[kidroc]

I might break VLOS because I have hindreds of acres to fly home n but I never ever fly above 120m usually I stay at 50m meters to many helis.. and they sometimes fly way to low. That’s why airsence is great imo.

 

[dronerdave]

Correct, because it records the home point as the ground level at take off, you couldn’t fly over the hill unless you adjusted the limiter. So you would have to take off from the higher point around you or set the max height to be able to fly over the hill.

Mine is set to max for that reason. I fly over 400 feet of my home point often when climbing a hill (say 1000'above HP) but directly below the aircraft it's visually obvious I'm just above the tree tops or terrain and well below 400AGL. I'm pretty sure NTSB is going to figure out where a collision or encounter happened at any altitude so I make an effort to fly in compliance. For that reason I avoid putting myself in a situation where I might end up in court.

One thing I'd like to see change for hobby fliers is being able to fly within a reasonable horizontal distance from a structure and still be legal. Sheer cliffs taller that 400' for instance.

 

[swooshdave]

Real aircraft? If so barometric altitude set to QNH (height above msl), flight level cruising set to standard pressure or more rarely, QFE (above aerodrome). That and minimum safe altitudes off the charts and plates. Other than the RA on bigger aircraft you dont really have an indication of exact altitude above the ground directly underneath you. You also dont need it.

Is that why Kobe's helicopter crashed? They didn't know where the ground was in relationship to the aircraft? Seems like something that would be "nice to have" as opposed to "...don't need it". ?

 

[RkyMtnHigh]

I looked like the pilot in the movie "Airplane" when he had sweat pouring down his face when I was brave enough to come out of "Beginner Mode" with my MA. I'm fairly comfortable at about 200' now, and 400' is overkill for me personally. I'll go up to 400' when I need to sweat off a couple of pounds. ? ? ? Just my opinion, but I see no reason why one would need to go over the 400 foot limit.

 

[DaveS]

I have shot above 400' ONLY when shooting above a crane (for our client) that was just over 400' tall. That is allowed under the FAA rules. The rest of the time I find the best video (and photos) I shoot often come from being as low as safely possible. As an example, I was shooting both photos and video of a restaurant we're doing promotion for and, frankly, the roof is so ugly, I had the Mavic 2 Pro just below roof height, about 30'.

 

[sar104]

Is that why Kobe's helicopter crashed? They didn't know where the ground was in relationship to the aircraft? Seems like something that would be "nice to have" as opposed to "...don't need it". ?

The issue there is that the aircraft should not have been anywhere near the ground in the first place, especially in limited visibility. You certainly don't want to rely on height AGL even if you know it - it doesn't tell you whether there are rocks in the clouds ahead.

 

[swooshdave]

The issue there is that the aircraft should not have been anywhere near the ground in the first place, especially in limited visibility. You certainly don't want to rely on height AGL even if you know it - it doesn't tell you whether there are rocks in the clouds ahead.

If you don't have visibility how do you know where the rocks are if you don't have radar? At the very least they must have charts? I guess navigation systems aren't advanced enough to show where the rocks are, clouds or no clouds?

Aside from the whole "they shouldn't have been there in the first place" thing. If people where were they were suppose to be there'd never be accidents.

 

[sar104]

If you don't have visibility how do you know where the rocks are if you don't have radar? At the very least they must have charts? I guess navigation systems aren't advanced enough to show where the rocks are, clouds or no clouds?

Aside from the whole "they shouldn't have been there in the first place" thing. If people where were they were suppose to be there'd never be accidents.

That was my original point - you plan your flight to be significantly higher than the highest obstacle around so you don't need radar. That's the main reason for the terrain maximum markings on the sectionals, referenced to MSL so that the aircraft altimeter relates directly. In the unfortunate recent helicopter crash, if the pilot really was flying around down amongst the terrain obstacles in fog then it was major pilot error.

 

[gnirtS]

That’s why airsence is great imo.

Great for the roughly 40% of aircraft that will be shown by it. Not so great for the other 60% in the area that wont be...

 

[Mr.H.]

Yes at times., but I know my area - no airports, rural areas, and other areas where the ground elevation drasticly changes, such when I am near mountatins. I usually fly at 350ft when I use litchi to make sure I don't fly into anything and when I am flying several miles out.

 

[BigAl07]

Yes at times., but I know my area - no airports, rural areas, and other areas where the ground elevation drasticly changes, such when I am near mountatins. I usually fly at 350ft when I use litchi to make sure I don't fly into anything and when I am flying several miles out.

You do realize you're not only violating a very significant FAA Regulation you've also now admitted it on an open forum?????

 

[allenface]

You do realize you're not only violating a very significant FAA Regulation you've also now admitted it on an open forum?????

Burn!

 

[molson]

what does it mean when you say 400 feet?
is that relative to the location of the drone.
if i fly up a hill or mountain i may be under 400 feet but over 400 feet with respect to my location.
what's the guidance here?

 

[old man mavic]

what does it mean when you say 400 feet?
is that relative to the location of the drone.
if i fly up a hill or mountain i may be under 400 feet but over 400 feet with respect to my location.
what's the guidance here?

its 400 ft AGL and you would just descend as you come back down the mountain to keep in that zone

 

[molson]

Thanks for that quick reply....
(i'm new to this, but loving it)
the Mavic 2 smart controller seems to maintain height data relative to the launch point.
is there a feature that gives elevation with respect to the drone as it travels?

 

[SkyeHigh]

.
Not above 30ft or so no.

(Its actually not good to try, things like buildings and trees would make it change all the time whilst flying so not overly useful).
Thats one reason why real aircraft dont (other than the radar altimeter for final approach stages).

So what about the Barometric sensor on board? It measures altitude based on air pressure similar to commercial aircraft. It’s not 100% accurate and in the commercial world the pressure at the runway altitude is taken as a reference. Not used for landing though - there are cases where aircraft have crashed when the altitude of the runway has not been correctly set.

Then there is the altitude calculated by the GPS.

 

[SkyeHigh]

Biggest problem is knowing the altitude at the launch point. GPS should be able to give you this combined with the barometric sensor. Are we saying sea level is not taken into account?