400' AGL

[sar104]

I just want to be clear with everyone. I fly Mountain terrain and I have a hard time with some jobs getting the data i need while remaining 400 AGL. Here is one example. If I am doing a wide shot of a property on the mountain side which is very steep. And from the total height of the mountain side is 1,300” with a 60 degree slope. Say your target is in the middle at when you fly 400 above the site to get the widest shot directly above your at 400. But if you go out away from the slope within 100’ you could technically be over 800’+ AGL (Directly below.). This is just an example. Now I posed this question to my local FISDO and the answer I got was as long as I stayed within 400‘ of the mountain side I would never have any problems. Now I know answers vary by who you talk to on any given day. So that what I do. My DJI data says I was flying at 1000+ ft for that flight but usually I never go over 300 AGL. Also, keep in mind that the top of the mountain is still 500‘ above my drone and any manned aircraft that would come into my flight area has way bigger problems then my drone. I do get the occasional helicopter doing power line or chemical spraying. So VLOS is paramount in any situation. Where 400 I have inquired about a flight height waiver but last time I checked the probability was low to get anything general for the area and is more per flight specific. Hopefully the FAA will get the rules defined a little better for situations like mine.

That's interesting. Part 107 doesn't say anything about allowance for higher AGL in the vicinity of steep terrain, but it's been quite widely assumed that the same 400 ft guidance that applies to structures would be valid. It's good to know that your FSDO has the same opinion.

 

[Sprocket]

Just in case no one has realized it. Using the illustration above. Your drone setting is max. 400'. If you take off from the water edge and immediately ascend to 400' then it becomes impossible to fly 400' above the top of the hill.

 

[sar104]

Just in case no one has realized it. Using the illustration above. Your drone setting is max. 400'. If you take off from the water edge and immediately ascend to 400' then it becomes impossible to fly 400' above the top of the hill.

No - the firmware altitude limit is 500 m (1640 ft).

 

[Sprocket]

No - the firmware altitude limit is 500 m (1640 ft).

No. Read it again. The max altitude is set at 400'. Obviously one can change the max, but that wasn't what I posted.

 

[sar104]

No. Read it again. The max altitude is set at 400'. Obviously one can change the max, but that wasn't what I posted.

Read what again? Who set the maximum to 400 ft AGL? What does that have to do with the illustration - there is no mention there of the maximum altitude setting? Maybe I'm missing your point - can you elaborate?

 

[Lets Fly]

That’s exactly what I was attempting to pass on to lets fly in post number 45.
Some people struggle a bit with simple math, which is what AGL is based on.

What I was referring to in post 45 about it being from the controller was that I am assuming the drone is at your feet. I don't know anyone who goes up a building or mountain leaving the drone down below and then starts the takeoff. If so of course it's from the ground. My point was about reading off the side of an inclining mountain, you have know way of knowing your distance from the side other than guessing, your height is from the take off point and reads negative if you go below it. Nothing to do with the math.

 

[rfc]

Not to take the thread too far off the path, but here's a question about staying "legal" within the regulations in an "emergency": You fly up a mountain, carefully staying below 400' all the way up to the top of the mountain which is say 1000 above your elevation. You lose signal. The bird returns to home at the altitude at the time of loss (plus three seconds), flying back to the home point at greater than 400 AGL, breaking that rule. Does loss of signal constitute an "emergency", which would therefore open the door wider for subsequent courses of action to get it home safely? Do part 93 or 107 even apply in such circumstances?

 

[BigAl07]

Not to take the thread too far off the path, but here's a question about staying "legal" within the regulations in an "emergency": You fly up a mountain, carefully staying below 400' all the way up to the top of the mountain which is say 1000 above your elevation. You lose signal. The bird returns to home at the altitude at the time of loss (plus three seconds), flying back to the home point at greater than 400 AGL, breaking that rule. Does loss of signal constitute an "emergency", which would therefore open the door wider for subsequent courses of action to get it home safely? Do part 93 or 107 even apply in such circumstances?

That "Emergency" clause would not apply there. The Emergency would be if you were trying to avoid a mid-air situation and had to ascend above the 400', into controlled airspace, over people, over traffic etc.

Loss of Signal with the sUAS does not constitute an emergency situation allow the operator to bust the regs.

 

[FoxhallGH]

Just to try and remove some confusion from the posting of a CAA diagram earlier ...

This diagram is 100% correct - arrow angles and all - for the UK Drone Code. The description that we fly by here (recreational use) states "400 ft (120 metres) from the Surface". The 'imagine a 400ft long string ...' thing doesn't quite work here ... So to take this to extremes, it actually means that if you were to fly out over a cliff face 500 ft high, as long as you stayed within a 400 ft distance from that cliff face, you'd be legal. Another way to look at it is this diagram (green area = OK to fly) ...

However, the CAA will not allow us to fly up and over the likes of a communications tower that is higher than 400ft. If I want to fly close to a 600ft comm's tower, I could only fly the first 400ft of it and cannot (legally) go up and over ... I have to keep within the '400ft from the surface' ruling.

 

[gajman]

I have a hill close to my home and would like to go up to the top of it. The height is 982' above sea level. I understand that if we stay within 400' of the surface, we can continue to fly up and stay close to the hill. Is this an allowable thing to do? I also understand that I could go an additional 400' above the top of the hill and still remain legal. Sure would like to know if I am on the right track. Maybe this only applies to a structure such as a tower or the like. The altitude where I live is 80'.

I don't think you get any bonus with a tower on the top of the hill. If you are a 107 pilot and have a reason to be within 400 feet of the tower, you may fly above the tower, within that 400-foot cone, but there is no exception to HAGL outside that 400 feet. As a matter of course, you are not supposed to near a tower without permission from the owner. The suggestion is that you stay away from towers because of guy lines, etc.

The reason you can fly over a tower, at that higher altitude, is that aircraft are not supposed to fly near the tower, but could fly at 400 feet over the hill. No bonus there for recreational flyers. No bonus there for 107 pilots without permission, and then limited to the 400-foot cone surrounding the tower.

 

[BigAl07]

........ As a matter of course, you are not supposed to near a tower without permission from the owner.

I'm not saying orbiting random towers/structures is a good idea but I'm going to have to ask you to CITE your source for this portion of your post...

........ The suggestion is that you stay away from towers because of guy lines, etc.

They are like Drone Magnets . . . LOL

 

[Mossiback]

This has been an entertaining (although redundant) post to read. My take is, since there is no accurate measurement available to the pilot (except, of course, in a perfectly flat environment) the best you can do is estimate your height AGL by looking down. Fly straight up to 375' (using 375' will give you a buffer with your estimate), look down, and notice what standard reference points (people, streets, cars, etc) look like. With practice and experience you should be able to tell when you are too high.

 

[FoxhallGH]

This has been an entertaining (although redundant) post to read. My take is, since there is no accurate measurement available to the pilot (except, of course, in a perfectly flat environment) the best you can do is estimate your height AGL by looking down. Fly straight up to 375' (using 375' will give you a buffer with your estimate), look down, and notice what standard reference points (people, streets, cars, etc) look like. With practice and experience you should be able to tell when you are too high.

Or - you could learn to read a map and use contour lines to tell you how much to deduct from your altitude with respect to your takeoff point. If your map tells you that the valley floor below is 200 ft down from you, then simple maths (or math in the USA), will tell you that you should be reading a max of 200ft to maintain your 400ft AGL when over that valley floor. I remember doing a lot of training about how to read maps when I did my flying training for a Private Pilot License. If you want to use the airspace, use the tools ...

 

[Mossiback]

Or - you could learn to read a map and use contour lines to tell you how much to deduct from your altitude...

Maps and math would be the way to pre-plan a flight, but for spontaneous flying I find it easier to just look down.

 

[FoxhallGH]

Maps and math would be the way to pre-plan a flight, but for spontaneous flying I find it easier to just look down.

Too true ... But it's amazing how much flying takes place without learning references. When I learned to fly light aircraft for a Private Pilot License, I was taught to use the size, shape and direction of waves on the local lakes and sea to judge wind speed and direction, as well as how to judge height in case of an altimeter fail. It's a good idea to do similar things when flying your drone e.g. Fly down into a valley and see what -200ft looks like, see what a 20kt wind does to the different types of trees in your area.

 

[kensteele]

please keep in mind their are hobbyist in the field and unlike you and i, most of them don't have an undergrad in math and quite a few don't even have a diploma/degree.

america today is quite a bit different than the america you and i grew up in....unfortunately.

 

[FoxhallGH]

please keep in mind their are hobbyist in the field and unlike you and i, most of them don't have an undergrad in math and quite a few don't even have a diploma/degree.

america today is quite a bit different than the america you and i grew up in....unfortunately.

Just for the record - I didn't grow up in America, and Math's was my worst subject - but I know what you mean. When I started flying models as a young lad, it ignited a real desire to learn more about real aircraft and flying. I find it strange that there wouldn't be a desire in anyone flying drones or model aircraft, to learn more about what they like doing ...

 

[kensteele]

Just for the record - I didn't grow up in America, and Math's was my worst subject - but I know what you mean. When I started flying models as a young lad, it ignited a real desire to learn more about real aircraft and flying. I find it strange that there wouldn't be a desire in anyone flying drones or model aircraft, to learn more about what they like doing ...

sorry i see your profile i should have said the western world. most people today can't even add. the drone is just another tool in their inventory to have fun with because everything has to be automatic. gone are the days where you learned gps coordinates, understood aperture/shutter priority, even things like measuring the height of a flag pole using the length of the shadow. m2 drone has a ton of settings, many of them are complex, i hope that doesn't go away.