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Line of Sight - Really?

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Maybe this has already be presented, but just in case, here it is:

My Mavic 2Z has a body roughly 0.25 ft wide. This is the most visible part when flying away or toward the pilot. Now the accepted angular resolution of the human eye is about 1/60 degree or 0.000291 radian.
Calculations:
Distance X Angle (in radians) = Arc length
Distance X 0.000921 = 0.25 ft whence distance = 859 ft or 0.16 mile.

Now even if we up the angular resolution of your eye by a factor of 4, we get about .064 mile straight line.

Note: if the drone is at h=300 ft, the horizontal distance is 804 ft.

I challenge anyone to let someone fly your drone out somewhere randomly to a distance of, say 0.64 mile, while you keep your back turned and then you turn around and see the drone.

Who flies their Mavic 2 drone no farther than 1000 feet? As for myself, I have trouble seeing it four or five hundred feet away.

Line of sight has nothing to do with being able to actually see the object. The definition of line of sight is a clear unobstructed line between two points.
So if your drone is hovering only 20 feet away but on the other side of a tree or building, that it is not direct line of sight. If your drone is a thousand feet away from you in a clear field with nothing between you and the drone, you have direct line of sight even though you may not be able to clearly see it unaided.
 
I have been doing some more thinking about the VLOS issues and safety concerns. Does keeping a drone within VLOS really ensure safe operation of a drone? In order to drive a car, most countries require a drivers license yet this does not ensure a safe driver. I believe reasonable laws should be in place for pilots and manufacturers; however, we pilots need to reprimand those who post obvious violations. As long as we watch and encourage such behaviors, it will encourage violators.
Eventually, drone vehicles (autonomous vehicles) will rule the world, as it is argued that they are much safer than human piloted vehicles. This could also be said of our UAVs. In fact, if you program in an autonomous flight, it is probably much more likely to be executed than if you tried to fly it manually. This is an argument that I'm not sure that I have ever seen in public, but the promoters like Amazon and others would certainly suggest this to be true.
 
I'm relatively new to drones but my answer is simple.., if you plan or expect to fly the drone out of your sight then you need observers in the area it is going to fly with some type of direct and live communication to you... at least that's how I read the rules.
 
I'm relatively new to drones but my answer is simple.., if you plan or expect to fly the drone out of your sight then you need observers in the area it is going to fly with some type of direct and live communication to you... at least that's how I read the rules.

The rule states that the visual observer must be within earshot.
 
There are plenty of what-if scenarios that can be brought up, but if you're at or below 400 feet, or within a max of 400 feet above another object such as a building or mountain, there's no way you should encounter any aircraft other than a drone. Of course there are exceptions to this such as a medical helicopter landing at a hospital helipad. But as far as I know, even the police don't fly below 400 feet. My point here is that we need to remember that other aircraft have limits, too, below which they are not allowed to operate. That is typically 400 feet.
If a full sized plane is making a low pass and coming directly at you, many times it can be on you before you hear or see it. If you live in an ag area like I do, it's common to get startled by a crop duster that sneaks up on you. Beside emergency operations, full sized aircraft can legally fly below 400' if over water and/or unoccupied areas so obviously it depends on other factors including terrain. You simply see and avoid to the best of your ability. Our little cameras are not enough to see and avoid while flying BVLOS. Here are a couple of pics of a low flying aircraft who flew right over me.



DSC02767c.jpg
B-17 at low altitude c.jpg
 
Line of sight has nothing to do with being able to actually see the object. The definition of line of sight is a clear unobstructed line between two points.
So if your drone is hovering only 20 feet away but on the other side of a tree or building, that it is not direct line of sight. If your drone is a thousand feet away from you in a clear field with nothing between you and the drone, you have direct line of sight even though you may not be able to clearly see it unaided.
The rule however is VLOS (visual line of sight), not LOS. Mincing terms will eventually lead to infractions and unhappiness. It is also misinforming new drone flyers, potentially causing everyone a problem.

FAA clearly means that you can see your drone with unaided vision which includes your prescription eyeglasses when they define VLOS... and has stated so multiple times.

In your example above the 20’ example is true and you may even get RTH or autolanding depending on your preferences set in your drone. However, in your second example you equate a direct unobstructed path to the drone from your eye with VLOS and you are wrong as the rule is VLOS, not LOS.
 
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There are plenty of what-if scenarios that can be brought up, but if you're at or below 400 feet, or within a max of 400 feet above another object such as a building or mountain, there's no way you should encounter any aircraft other than a drone. Of course there are exceptions to this such as a medical helicopter landing at a hospital helipad. But as far as I know, even the police don't fly below 400 feet. My point here is that we need to remember that other aircraft have limits, too, below which they are not allowed to operate. That is typically 400 feet.

Last week, I flew my P4 and my Mavic 2 Pro on the same Litchi mission at an altitude of 160'. I was able to see the P4 up to about 2200' feet away before I lost sight of it due to a change in the background. I lost track of my M2P at about half that distance for the same reason. I had someone watching the P4 with me and he, too, lost track of it. Yes, we have rules. But the reality of it all is that rules are often made by committees that have no experience with what they're trying to regulate. In my humble opinion, a BVLOS waiver should be included with Part 107 certification. I'd jump on taking the test if such a waiver were included with certification. I know you can apply for a waiver, but apparently the process is long (it is the government we're talking about) and few are granted.

And I tire of people saying that this type of discussion should be banned or deleted. Nothing positive comes from censorship. If you don't like this topic, go read something else. Nowhere does it say we have to like the rules under which we operate. And it is through discussion that rule changes are made.



With all due respect a lot of what you stated above is wrong.

A) A helicopter could be below 500' (Manned aviation this is the key # and drones is 400) and be there legally.
B) There are MANY areas of our country where fixed wing could be below 500' for various legal reasons.
C) Waivers aren't part of certification. That's not how it works my friend.
D) Manned aircraft have the Right of Way at any altitude and that's probably never going to change.
 
With all due respect a lot of what you stated above is wrong.

A) A helicopter could be below 500' (Manned aviation this is the key # and drones is 400) and be there legally.
B) There are MANY areas of our country where fixed wing could be below 500' for various legal reasons.
C) Waivers aren't part of certification. That's not how it works my friend.
D) Manned aircraft have the Right of Way at any altitude and that's probably never going to change.

A) Yes, and I did state there are exceptions. I just didn't state all of them.
B) Yes, but most of us live in cities and that was the focus of my comment.
C) I didn't state waivers were a part of certification, I just wish they would be.
D) Absolutely, and that should never change! My apologies if my comments seemed to suggest otherwise.
 
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FAA clearly means that you can see your drone with unaided vision which includes your prescription eyeglasses when they define VLOS... and has stated so multiple times.

I respectfully disagree with this portion of your comment. So, those not fortunate enough to be born with 20/20 vision aren't allowed to fly? Did I misread that? I take "unaided" to mean without the use binoculars or similar devices.
 
Eventually, drone vehicles (autonomous vehicles) will rule the world, as it is argued that they are much safer than human piloted vehicles. This could also be said of our UAVs. In fact, if you program in an autonomous flight, it is probably much more likely to be executed than if you tried to fly it manually. This is an argument that I'm not sure that I have ever seen in public, but the promoters like Amazon and others would certainly suggest this to be true.

Blade Runner!
 
So, those not fortunate enough to be born with 20/20 vision aren't allowed to fly? Did I misread that? I take "unaided" to mean without the use binoculars or similar devices.
I think he meant to say you have to visually see your aircraft w/o aided vision other than a normal eyewear which is allowed.
 
I respectfully disagree with this portion of your comment. So, those not fortunate enough to be born with 20/20 vision aren't allowed to fly? Did I misread that? I take "unaided" to mean without the use binoculars or similar devices.
Please don’t misconstrue my post. That is not what I said.
FAA has clarified that... only “regular” eyeglasses to correct vision may legally be used to constitute VLOS. Binoculars may find a drone but cannot constitute the FAA definition of VLOS.
Recommend you contact FAA and ask them.
 
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It's really not too hard to work out what VLOS and the spirit of what it is designed to prevent.

If anyone thinks they can fly more than say 500m to 800m away from their location, as a sole drone pilot, depending on surrounding terrain / visibility etc, and be able to see a manned aircraft approaching from any angle (even straight ahead in the viewing device screen), then we are likely to get much more draconian rules imposed in the future.

You might have more chance of winning lotto than this actually ever happening to you, but of course as the skies get more and more crowded, the chances of 'winning' that lottery is not something anyone would want !

An average helicopter or small light plane travels at average speeds of 250km/hr (about 150mph).
If you are flying true VLOS, then you have a chance of hearing one approaching low, and bring down the drone to a safe level to avoid the chance of an incident.

I wonder too about the autonomous drone deployments / trials we are seeing Worldwide now for deliveries of all sorts of consumer goods and fast food etc.
Here in Australia, tests are / have been conducted in a few places so far.
Without ads-b on all small aircraft, and integrated with delivery software however it needs to be done, I'm not sure it is going to work safely with other manned flights, or with our normally piloted drones during BVLOS automated flight.

It may take many years before a truly safe system can be put in place to work with autonomous drones, piloted drones, and light aircraft.
(Larger aircraft should NEVER be an issue of course.)

The biggest problem areas are going to be around non regular manned flights like small fixed wing tourist flight planes / helis, medical / law enforcement / news / agricultural type aircraft flights . . . manned aircraft that can occasionally fly into sub 120m (400') airspace.
Everything else is separated well by other means like restricted airspace and NFZs.
 
The camera has a very limited Field Of View... what if an approaching aircraft is coming at your UAS from some direction other than straight on? To think that you have better situational awareness with a single camera fixed forward is just kidding yourself and trying to convince everyone else to follow your flawed beliefs.



Well you interpreted it partially wrong. It's not about an imaginary line connecting your eyes to the aircraft You could in theory fly to the moon in that scenario)... It's being able to See YOUR Aircraft and being able to know it's attitude, altitude, direction of travel so that you can See & Avoid any type of potential conflict. If you can't do the above you are unable to AVOID manned aircraft and you become a DANGER to other aircraft.

See & Avoid is our most fundamental requirement to help minimize risk in the NAS.
I am wondering if you have really thought this through. The minute any pilot launches a UAV they have created an inherit risk. The air craft is no more or less dangerous just because you can see it. Visibility is a very poor litmus test to determine if a UAV is safe. The only mitigating safety factor that any of us can employ is that it be flown responsibly. The 400 foot ceiling is the deviding line vertically for manned aircraft avoidance. . But more importantly the distant at which an individual should fly has more to do with the environment and pilots skill level than being able to see the aircraft. Have you never looked down at your camera to make an adjustment and looked back up and not been able to see your aircraft. At that point were you unsafe. Did you RTB and pack up and go home because u lost sight of your aircraft. If not then you are no more safe than someone flying a mile out in the right environment with proper control of the aircraft.
 
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The only mitigating safety factor that any of us can employ is that it be flown responsibly.
But more importantly the distant at which an individual should fly has more to do with the environment and pilots skill level than being able to see the aircraft.

I agree with this certainly to an extent.
Really like flying looking at my screen, and feel I'm pretty good at it too, I feel very comfortable flying by what I can see and the info displays on my various pieces of equipment.
To be totally honest (any pilot filming video or composing photos) you will more likely be looking at your screen, rather than the aircraft . . . it's totally needed to do those activities !!

In the very few times I have flown beyond say 600m to 800m, I have been very low, under 30m, and very remote with pretty much no chance of anything else being in the air for many hundreds of kms.

"The 400 foot ceiling is the deviding line vertically for manned aircraft avoidance. . "

This is incorrect of course, as outlined in other posts, many manned aircraft can and do fly below 400', just not that often in manned flight as a whole.
If it was true, this whole conversation / debate wouldn't even be necessary.

The overall trouble is authorities need to put blanket rules in place for lowest common denominators . . . and they need to have fairly set targets to allow clear cut guidelines for prosecuting when they feel the need.

Road rules are designed this way, look at some ridiculously low speed limits put in place, still won't stop the people that either break those rules, or those totally inept at driving, from hurting themselves or others.

I'm really surprised the US and Australia don't have a set distance, like the UK 500m distance / 120m alt for VLOS.
120m / 400' is the max alt also as it is on most countries with advanced airspace rules.
 
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Please don’t misconstrue my post. That is not what I said.
FAA has clarified that... only “regular” eyeglasses to correct vision may legally be used to constitute VLOS. Binoculars may find a drone but cannot constitute the FAA definition of VLOS.
Recommend you contact FAA and ask them.

Sorry, I just misunderstood the way it was stated. Nowhere in my comment did I say binoculars were acceptable. Please don't misconstrue my post.
 
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I am wondering if you have really thought this through. The minute any pilot launches a UAV they have created an inherit risk. The air craft is no more or less dangerous just because you can see it. Visibility is a very poor litmus test to determine if a UAV is safe. The only mitigating safety factor that any of us can employ is that it be flown responsibly. The 400 foot ceiling is the deviding line vertically for manned aircraft avoidance. . But more importantly the distant at which an individual should fly has more to do with the environment and pilots skill level than being able to see the aircraft. Have you never looked down at your camera to make an adjustment and looked back up and not been able to see your aircraft. At that point were you unsafe. Did you RTB and pack up and go home because u lost sight of your aircraft. If not then you are no more safe than someone flying a mile out in the right environment with proper control of the aircraft.

LOL I can assure you I’ve thought this comment and many more through thoroughly! I didn’t just get into this industry last month and I don’t just dabble in this industry for fun. I eat, sleep, breathe, and teach this day in and day our.

Visibility is a very important part of UAS operations. What happens when your training wheels (telemetry, video, compass etc) fail you? You resort back to VISUAL flight or you scream Fly Away and demand malfunction!! Which do you resort to?

For longer flights or more risky flights I employ VO or multiple VO.

While I’m focused on the telemetry my co-located VO has eyes on the aircraft and through communication I am able to quickly regain acquisition of my UAS. If I don’t have the luxury of a dedicated Co-locates VO I don’t push the limits.

Honestly most of my flying is relatively close to my location and not pushing my visual or physical limits.

To each their own ...
 
What happens when your training wheels (telemetry, video, compass etc) fail you? You resort back to VISUAL flight or you scream Fly Away and demand malfunction!! Which do you resort to?

For longer flights or more risky flights I employ VO or multiple VO.

For sure, with a total failure of any sort of feedback or controller information, firstly DJI consumer drone pilots are almost totally falling back on failsafe RTH.
While this is good to have, and from what I've gathered it works in the great majority of times, it's probably always going to carry some higher than normal risk.

If you've lost visual on your device screen, but still have control, then you can use manual RTH to gain direction to home point, then either let it do it's thing, or fly back in sports etc with fell forward stick.
Or you can follow the numbers on controllers with distance value, and aim for increasing countdown speed with slow yaw.

Using VO/s would need some level of practice I imagine, using some set feedback between the pilot and VO.
VO would need some directional guide for the pilot, most likely simply knowing the pilot is 'over that way, lets get him to turn close to that direction' is probably enough most times.

Ah, saw your post 26 on the linked thread above, of course they only keep an eye on the drone while you might be doing something else requiring eyes off the bird.

In a sister site there is an excellent discussion which I would invite all to read:

Visual line of sight ?

Many interesting issues are brought up and discussed.

A couple of posts really stuck out on the linked thread, implying the importance of keeping close enough to react . . . posts 9 and 21.

And the comment that drives it home . . . post 37.

"DJI drones move pretty slow, if a plane comes out over the treeline low I don't know how much avoidance I'm going to able to do."
 
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