Question about the 400 ft. rule

[Cymruflyer]

hi fellow flyers all this discussion on the 400 ft rule AGL i presume stands for above ground level correct me if i am wrong so does that mean the surface of lets say a large body of water or the sea is classed as ground level we could go on and on about this just thought i would throw that into the mix happy flying

Water comes under different rules than land. As a pilot you are allowed to fly right down to the deck over open water, if you are silly enough to do that. An engine out and you better have jam in your pockets because you will be toast! Altitude is safety to a real pilot.

Now that water rule also states that you can not fly right down to the deck if you are coming upon boats or people, you must then veer away because you then go back to the 500ft rule for pilots that sit in aircraft. That is a minimum of 500ft above, but there are more complications to that rule when it comes to built up areas, cities and church spires etc, which is too much to go into here and of no concern to drone flyers.

 

[old man mavic]

thanks for the info on flying over water guess the rules are more complicated than we think being a pilot no matter what we fly

 

[Cymruflyer]

The 400 foot AGL makes sense in the respect, by limiting the drones to 400 permits for a 100 foot separation of fixed wing base. I am not a fixed wing pilot, but I did watch SKYKING when I was a kid! Truthfully, I have had several fixed wing friends inform me their base is 500. True or not, don’t know.

I'm a pilot and yes that 500ft rule is correct, over open land you are not allowed to be below 500ft unless taking off or landing. (EDIT: Well that is unless you are out in open country where there are no people, animals, or structures, because then you can get right down on the deck as in open water). There is more to that rule regarding structures and built up areas and cities etc. but there is no need for such details in this discussion. The FAA 400ft rule is to keep, as you surmised, the 100ft safety separation.

Most pilots don't want to be just 500ft above the ground anyway, as fun as it is to fly low, because that, in itself, is a safety problem in the event of an engine out. Altitude means safety because if there is a problem say reduction in power, you have time to run checks and determine the problem before looking for a landing spot. If you have an engine out, the higher you are the more choices you have and time to get things sorted to put it down safely.

 

[Asgard]

"I'm a pilot and yes that 500ft rule is correct, over open land you are not allowed to be below 500ft unless taking off or landing"

Sorry matey, but the rule is the same over land, in other words you just need to be 500ft away from (not neccesarily above) any person, vessel, vehicle or structure, granted that it is less likely to find an area like that on land than it is over water, but the rule applies to both.

(Different limits over congested areas/crowds of course)

P.S Talking about UK as I assume from your name, in the states I believe the rule still applies to both land and sea, but the restriction is simply height above not distance from as it is over here

PPS..I think the best advice to anyone regarding rules of the air is don't listen to anyone on a forum (myself included), but go look it up in the ANO

 

[old man mavic]

thanks guys as i said complicated

 

[jeplane]

You aren't going to encounter any other aircraft flying close to a cliff edge.

No, but you could meet a glider in the Alps or in the Rockies doing ridge soaring !...

 

[draver]

Or somewhere like the cliffs of Torrey Pines in San Diego and be flying amongst hanggliders. I assume this is a no fly zone, but I don't have a map that accurately defines that area.

 

[991carreradriver]

Part 107 Advisory Circular (AC107-2) specifies multiple ways to determine AGL and remain in compliance with the Regs. In this OP's case, I would rely on this: "Using the known height of local rising terrain and / or structures as a reference"

 

[julius13]

Okay, look at it this way, say you are inspecting a radio tower that’s 500 ft tall. You could then fly over it at a 900 ft but only for a distance of 400 ft horizontal from the structure. So flying up or down a mountainside slope obviously varies as the graphic illustrates. I fly mountains frequently and for me the 400 ft has not been an issue. I usually find a ridge to launch from so I can then fly at negative elevations. You have to be aware of obstacles when flying like this though.

 

[lweekspors]

It's worth pointing out that this (shown below) is a different interpretation than the current AGL guidance in the US. Although it is broadly similar to the Part 107 400 ft rule in relation to structures, I don't think the FAA has ever mentioned it in relation to terrain.

View attachment 55060
CAP1687 July 2018

Your diagram is incorrect, it is really simple, 400' vertical above any object, ground or structure.

 

[sar104]

Your diagram is incorrect, it is really simple, 400' vertical above any object, ground or structure.

It's not my diagram - as I noted it's copied directly from the UK Civil Aviation Authority Air Navigation (Amendment) Order 2018 - Guidance for small unmanned aircraft users, so you can take it up with them if you think it's wrong. There's a chance that they will ignore your objections though.

 

[iowahill]

The scenario you describe sounds fine to me in theory. In practice, Mavics only calculate their 400 AGL from the home point. So, to scale a mountain like in your scenario, you'd have to land, reset your home point, climb 400 feet higher, land, then repeat. You would need to keep following that process over and over to get to the top of the mountain.

Totally agree. And one other VERY IMPORTANT consideration... RTH altitude. Suppose you take off from your home point and set your RTH altitude to 300'. Then you start following terrain that ascends to 1000', but always maintaining 400' or less AGL. If RTH kicks in for any reason I believe at best you're going to be in for a long hike if the bird is above your 300' setting.

In another scenario suppose you take off and set RTH as above, but decide to fly down below home point and RTH is set for 300' , but the bird is down say, 300' below home point. Though I haven't experimented yet my belief is that if RTH kicks in, the bird will have to climb 600' before heading back. Could be a critical matter if battery level is low.

 

[jsh102]

I was at a friend's ranch in central CA, and since it's fairly remote, I increased the altitude to the limit of the Mavic, which turns out to be about 1600'. I'm wondering if there is a way to go beyond this height. There is a peak that I'd love to get a closer look at.

 

[dondi]

I wonder about pilots who are so afraid of violating policy that I without proof suspect they have poor flying skills, therefore stop asking "mother may I", questions, and practice, practice and practice.

 

[sar104]

I wonder about pilots who are so afraid of violating policy that I without proof suspect they have poor flying skills, therefore stop asking "mother may I", questions, and practice, practice and practice.

Did you somehow just come to the conclusion that pilots who follow the regulations are poor pilots?

 

[dondi]

Did you somehow just come to the conclusion that pilots who follow the regulations are poor pilots?

YES I DID

 

[sar104]

YES I DID

Surely you have something better to do than trolling on discussion forums.

 

[cGould]

I'm wondering if following the terrain at less than 400 feet is in compliance with the letter & spirit of the 400 ft. AGL rule for drones. If I choose to fly up a mountainside, say to a 2,500 foot summit at 300 ft. AGL, am I an outlaw? Also, in this discussion, if my Return To Home altitude is set for 30 meters Above Ground Level, will the drone hug the mountainside at 30 meters AGL returning to me? Or, will it suppose I meant 30 meters above it's launch altitude? Any support for your opinions would be appreciated.

Does this make sense?

 

[skiptv]

How about this. Take a certified drone course. Get your 107 and learn the law.
400 foot above ground is a hard number. If you take off from a 1000 foot cliff and fly out over the ocean at sea level you must drop down to 400 feet. But if you studied the FAA rules went to a course and got a license you would know that if you fly within 400 feet laterally of an object you can then fly 400 feet over that object.
Example there is a cell phone tower that is 1000 feet high and you want to take a picture of the top of it, that’s not a problem take off and fly up within 400 feet of the tower and you can fly up to 400 feet over that tower if you want. However that’s in uncontrolled airspace if that tower is in controlled airspace you’ll still need authorition.

 

[tcope]

I was at a friend's ranch in central CA, and since it's fairly remote, I increased the altitude to the limit of the Mavic, which turns out to be about 1600'. I'm wondering if there is a way to go beyond this height. There is a peak that I'd love to get a closer look at.

There is no limit in feet... it is in meters. So if you were at the max, you'd have set it to 500m, which is 16,400'.

 

[sar104]

There is no limit in feet... it is in meters. So if you were at the max, you'd have set it to 500m, which is 16,400'.

1,640 ft.

 

[tcope]

How about this. Take a certified drone course. Get your 107 and learn the law.
400 foot above ground is a hard number. If you take off from a 1000 foot cliff and fly out over the ocean at sea level you must drop down to 400 feet. But if you studied the FAA rules went to a course and got a license you would know that if you fly within 400 feet laterally of an object you can then fly 400 feet over that object.

Or... we could understand that flying for hobby or commercial flight are two different things. Rather than thinking taking a course makes you an expert on all flight.

Question for you... for hobby flight, what restrictions are there are how high you can fly and when do they apply? Simply for someone who took a test, right?