Flying over cliff

[Eduardo]

OK chaps, I think there is a bit of confusion here......

Somehow this thread has turned into a 'Mountain' thread instead of a 'Cliff' thread.
The OP question was what happens if he flies over the edge of an 800' cliff. Cliffs (in my world) a pretty vertical in nature and hence my answer that you would be illegal almost immediately since as soon as you flew over the (vertical) cliff it would put your aircraft over 800' above the ground below.
However...... Flying up or down a mountain or incline is a completely different kettle of fish and different arguments/rules/legality would apply.

Hope that clears things up.

Agree (about the start of the post and being about a cliff).

The latest comments (including mine) were based on a diagram presented, which showed some slope (not vertical), that's why I used the term mountain.

 

[RuneWold]

There was so much back and forward here. I have been flying over a cliff that stands over 800 meters above the sea and other places on the coast and the height is for SURE calculated from your take of height. Same as if you fly up the height is calculated from where you are taking of. Want be many who could film in the mountains if it was otherwise.

Here is a video im flying over a cliff: SkyPixel - Connecting Creativity

 

[InspiredOne]

OK chaps, I think there is a bit of confusion here......

Somehow this thread has turned into a 'Mountain' thread instead of a 'Cliff' thread.
The OP question was what happens if he flies over the edge of an 800' cliff. Cliffs (in my world) a pretty vertical in nature and hence my answer that you would be illegal almost immediately since as soon as you flew over the (vertical) cliff it would put your aircraft over 800' above the ground below.
However...... Flying up or down a mountain or incline is a completely different kettle of fish and different arguments/rules/legality would apply.

Hope that clears things up.

And your final remark, for me, clearly illustrates the lunacy of it all, whether cliff or mountain.

 

[ATU]

And your final remark, for me, clearly illustrates the lunacy of it all, whether cliff or mountain.

Lunacy or not, the regs are as such. Not all regulations are logical in every situation. Flying a drone above 400' AGL is illegal which makes flying one over a cliff higher than 400' illegal regardless of it's MSL or even if it was below 400' MSL for that matter.

In your previous question about a drone legally at 400' AGL (800' MSL) meeting an approaching Skyhawk at 800' MSL (400' AGL), the Skyhawk would be illegal as a manned aircraft cannot fly below 500' AGL unless for the purpose of take-off or landing (special purpose flying such as crop dusting, practice force landing, exigencies, etc. aside). However, the lawyers from both sides would have a hard time fighting the case. It's not about what/who is right or wrong, it's about what you can prove.

 

[licensed pilot]

Lunacy or not, the regs are as such. Not all regulations are logical in every situation. Flying a drone above 400' AGL is illegal which makes flying one over a cliff higher than 400' illegal regardless of it's MSL or even if it was below 400' MSL for that matter.

In your previous question about a drone legally at 400' AGL (800' MSL) meeting an approaching Skyhawk at 800' MSL (400' AGL), the Skyhawk would be illegal as a manned aircraft cannot fly below 500' AGL unless for the purpose of take-off or landing (special purpose flying such as crop dusting, practice force landing, exigencies, etc. aside). However, the lawyers from both sides would have a hard time fighting the case. It's not about what/who is right or wrong, it's about what you can prove.

The Cessna would not, necessarily, be illegal at 500 feet, FAR 91.119 (c) makes an exception:

Sec. 91.119 — Minimum safe altitudes: General.
Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes:

(a) Anywhere. An altitude allowing, if a power unit fails, an emergency landing without undue hazard to persons or property on the surface.

(b) Over congested areas. Over any congested area of a city, town, or settlement, or over any open air assembly of persons, an altitude of 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet of the aircraft.

(c) Over other than congested areas. An altitude of 500 feet above the surface, except over open water or sparsely populated areas. In those cases, the aircraft may not be operated closer than 500 feet to any person, vessel, vehicle, or structure.

(d) Helicopters, powered parachutes, and weight-shift-control aircraft. If the operation is conducted without hazard to persons or property on the surface—

(1) A helicopter may be operated at less than the minimums prescribed in paragraph (b) or (c) of this section, provided each person operating the helicopter complies with any routes or altitudes specifically prescribed for helicopters by the FAA; and

(2) A powered parachute or weight-shift-control aircraft may be operated at less than the minimums prescribed in paragraph (c) of this section.

 

[ATU]

Thanks for pointing that part out. How does the FAR define a person, vessel, vehicle or structure? Would another aircraft such as a drone constitute as one of the above? If a drone is classified as another (unmanned) aircraft sharing the sky, I opine that it would be near impossible for the Skyhawk pilot to see a sUAS far enough away to avoid it. So as a matter of good airmanship, would it not be foolish to fly a manned aircraft below 500' AGL?

 

[licensed pilot]

How does the FAR define a person, vessel, vehicle or structure? Would another aircraft such as a drone constitute as one of the above?
Beats me, but those are pretty clear and common words... AND YES.
So as a matter of good airmanship, would it not be foolish to fly a manned aircraft below 500' AGL?
YES! Pilots do stupid things every day, sometimes they get lucky and no one knows about it, and sometimes they don't (and we read about another plane crash)

 

[belgarion_11]

Hi Guys, new to the forum, having read the "legalities" etc I have a question..... If you were indeed to fly off the edge of an 800 foot cliff (legalities aside) and allow the drone to descend down the cliff face by say 450 feet.... would it be able to climb back up taking that the drone was calibrated at the top of the cliff or would it not be able to ascend past the 400 foot ceiling to the top?

 

[NickU]

It sees it as a negative altitude - in your hypothetical case -450ft, so will happily return to 0 (take off level).

 

[licensed pilot]

Take-off point is irrelevant. The drone will climb just fine until it hits the manufacturer's performance ceiling, just like any aircraft.

 

[belgarion_11]

Ok, sorry if I was not clear, let me try again, the cliff is not a sheer drop but a steep slope as in the (apologies) plagiarized diagram below, am I correct in thinking that, as long as the distance 'a' does not change as the drone is flown down towards sea level then the drone would be able to make it back up following the same trajectory as the downward journey?

 

[NickU]

Ok, you have your max height set to 400ft in Dji Go at take off. The drone marks the take off point as being its baseline, which is 0ft. You can now fly to +400ft above the take off point, or fly as low as you can remain in transmitter range. As you fly lower down the slope towards the sea, the height is shown by the drone as being --ve. If the sea is 500ft below you and you fly down till you're 10ft above wave height, then Dji Go will show a height of -490ft. It will quite happily ascend back to you at which point it will return to 0ft (more or less).

The only time you would have a problem with the height restriction is if you landed the drone on the beach below you, then took off again. the landing would reset the 0ft base point to the new take off point. In that case you would be 100ft too high...so you'd either remove the height restriction in the djigo settings, or land and take off again.

To be honest, in that sort of scenario, you might be better unsettling the height limiter anyway as it'd basically be pointless.

Irrespective of the setting in Dji Go, the Inspire is firmware limited to 500m/1640ft above take off point anyway.

Hope that helps.

 

[natnatroswell22]

Are you 100% sure nothing will happen? and how can I be breaking the law when my max attitude is set to 400ft?

Follow rules don't reach twice as max altitude limit

 

[kattz]

OK chaps, I think there is a bit of confusion here......

Somehow this thread has turned into a 'Mountain' thread instead of a 'Cliff' thread.
The OP question was what happens if he flies over the edge of an 800' cliff. Cliffs (in my world) a pretty vertical in nature and hence my answer that you would be illegal almost immediately since as soon as you flew over the (vertical) cliff it would put your aircraft over 800' above the ground below.
However...... Flying up or down a mountain or incline is a completely different kettle of fish and different arguments/rules/legality would apply.

Hope that clears things up.

My understanding in the US - if you are within 400' of an obstacle higher than 400' AGL, you are permitted to fly/climb/descend to clear it, remaining within 400' or less of distance toward/away from said obstacle. It's like flying over a 1200' radio antenna - it's legal to fly a maximum of 400' higher than the tip of the antenna as long as you remain inside that 400' radius to the antenna.

I am not sure how the airspace type affects that restriction.

Kev

 

[natnatroswell22]

My understanding in the US - if you are within 400' of an obstacle higher than 400' AGL, you are permitted to fly/climb/descend to clear it, remaining within 400' or less of distance toward/away from said obstacle. It's like flying over a 1200' radio antenna - it's legal to fly a maximum of 400' higher than the tip of the antenna as long as you remain inside that 400' radius to the antenna.

I am not sure how the airspace type affects that restriction.

Kev

Typically we must able to know what is the exact explanation.

 

[kattz]

OK. For the exact explanation, please read the following:

Per Part 107: "You can fly during daylight or in twilight (30 minutes before official sunrise to 30 minutes after official sunset, local time) with appropriate anti-collision lighting. Minimum weather visibility is three miles from your control station. The maximum allowable altitude is 400 feet above the ground, and higher if your drone remains within 400 feet of a structure. The maximum speed is 100 mph (87 knots)."

Anything other than Class G airspace requires ATC approval (in US). If not in a classified (that means class of airspace, not that it's secret) airspace, no ATC consideration is required.

Officially.

Regards,

Kev

 

[Keith Chirsan]

When I first read the OP I thought of the regulations as they apply to general aviation.

As a private pilot in a small airplane flying in a non-populated area, not taking off or landing, I am to stay at least 500 feet above the highest object on the ground, which could be a building or a tower or whatever.

So to me the 400' AGL drone rule made sense because that would leave a safety buffer of 100' between how high drones can fly and how low planes can fly.

I could be wrong but it would be my opinion that if our drone in the OP scenario flies over a cliff he does not need to immediately descend to 400' above the new deck which is the ground below the cliff, but he has to stay 400' above the point from which he took off as long as he stays in the immediate area.

I know there are a lot of assumptions in here but that's what makes sense to me. I say this knowing full well that the FAA doesn't really care about what makes sense to me and I could be way off base.

 

[kattz]

In accordance with the regulations, the pilot would be OK as long as he stayed within 400 feet of a vertical cliff face. If the cliff tapers downward, then he's expected to maintain 400 feet above the tapered face after exceeding 400 feet distance out from the cliff edge... In the US.

Obviously, he's not going to maintain that relationship exactly as it's not possible, so he's expected to approximate as much as possible. My interpretation.

 

[natnatroswell22]

OK. For the exact explanation, please read the following:

Per Part 107: "You can fly during daylight or in twilight (30 minutes before official sunrise to 30 minutes after official sunset, local time) with appropriate anti-collision lighting. Minimum weather visibility is three miles from your control station. The maximum allowable altitude is 400 feet above the ground, and higher if your drone remains within 400 feet of a structure. The maximum speed is 100 mph (87 knots)."

Anything other than Class G airspace requires ATC approval (in US). If not in a classified (that means class of airspace, not that it's secret) airspace, no ATC consideration is required.

Officially.

Regards,

Kev

Very well explained kattz thank you so much