Why flying BVLOS isn't a good idea . . .

[GFields]

This morning I was flying around an old Cadillac Stamping plant to photograph its demolition--1/2 mile south of the Detroit City Airport runway. I'd asked Drone Zone for 50' (less than the height of the building) and they gave me 100'. I'd talked to the Tower and they knew I was there. Nevertheless, here comes a single engine private pilot on final approach--just barely clearing the building. I was at 95' when I saw it, and had plenty of time to descend to a safe level below the building. I'd been especially alert because I knew I was near the airport, but still, it was a lesson about what can happen if you're not paying attention.

Very true

 

[Dbez1]

If you had good direct FPV visibility of an aircraft approaching then the appropriate evasive action would probably not be too hard to figure out, but that's not generally going to happen - hence the VLOS requirement. But even with VLOS it is often going to be difficult to determine relative flight paths and altitude in order to decide whether to go up/down, left/right etc. Hopefully Airsense and RID will provide an extra layer of assurance, even though they are certainly not going to be infallible due to lack of ADS-B out on some manned aircraft.

My experience has been the majority of small aircraft don’t have ADS-B.

 

[cgmaxed]

Here is scenario: Your drone is behind but above a 200 ft building. You see a plane coming at 250ft, so you descend to 150ft behind the building. But, oh no, oops, you lose connection to the drone because of the building. It then goes into RTH and begins gaining altitude which you set at 300ft so it wouldn't hit the building on its way home, while the manned airplane is maintaining 250ft. You can't get your signal back. You can't abort your drone's RTH procedure. Are they gonna impact? Yeah, I know this scenario is a billion to one. I just thought it would be interesting to think about it. Congrats, you just won the crash lottery.

 

[sar104]

Here is scenario: Your drone is behind but above a 200 ft building. You see a plane coming at 250ft, so you descend to 150ft behind the building. But, oh no, oops, you lose connection to the drone because of the building. It then goes into RTH and begins gaining altitude which you set at 300ft so it wouldn't hit the building on its way home, while the manned airplane is maintaining 250ft. You can't get your signal back. You can't abort your drone's RTH procedure. Are they gonna impact? Yeah, I know this scenario is a billion to one. I just thought it would be interesting to think about it. Congrats, you just won the crash lottery.

And here's the answer - plan for that kind of issue before you fly. Don't set an RTH height that will either take you above your approved maximum or into the path of traffic that you might need to avoid.

And stop looking for scenarios where it is somehow not your fault if your drone collides with an aircraft, because short of actual firmware or hardware failure inducing an uncontrolled flyaway, there are none.

 

[sar104]

My experience has been the majority of small aircraft don’t have ADS-B.

I think it depends somewhat on where they are based and where they typically fly.

 

[rnwinn]

For those who say, "If an airplane/helicopter is flying less than 400' AGL they have problems on their hands and should never be flying in "My Area" that low" you're WRONG!

Take a look at a picture snapped right here in western NC yesterday from someone's front deck (This is not a drone/aerial pic). This C-130 (and the other 3 shortly there after) were flying legally at about 200' AGL.

View attachment 129011

If you can't See & Avoid you shouldn't be flying at all . . .

I live in Denver and we had one of those flying Yesterday at about as low as your picture shows. So, yes aircraft do fly very low at times.

 

[cgmaxed]

And stop looking for scenarios where it is somehow not your fault if your drone collides with an aircraft, because short of actual firmware or hardware failure inducing an uncontrolled flyaway, there are none.

I wasn't looking for a "not your fault" scenario. I agree it would have been the drone operators fault obviously. I'm just throwing things out into the wind, to see what people may say about it. I rather liked my scenario. But it would be my fault if I was stupid enough to set myself up for a situation like that. Anyway, as I said it's a billion to one scenario, and a multitrillion to one shot, that there would actually be a collision.

 

[Rich QR]

Helicopters are limited to 200-500 agl.

They're not always limited to any particular altitude.

91.119 has some guidelines for minimum safe altitudes, but they don't apply during takeoff/landing. Helicopters can and do land off-airport. Sometimes they land in unusual spots for emergencies (medevac) sometimes for other reasons.

Even when not taking off or landing, 91.119(c) says that, over open water or a sparsely populated area, there is no minimum altitude required, just 500' from any person, vessel, vehicle, or structure. That rule allows any aircraft, fixed wing or helicopter, to legally fly down in "our" airspace below 400' AGL (but only over open water or sparsely populated areas).

But 91.119(d) allows helicopters, powered parachutes, and weight-shift-control aircraft to fly below the limits otherwise prescribed in 91.119. To take advantage of this paragraph, Helicopters must be operated in compliance with any routes and altitudes prescribed for helicopters by the FAA. But powered parachutes and weight-shift-control aircraft can fly pretty much as low as they want pretty much wherever they want.

Finally, even if a manned aircraft is being operated illegally at a low altitude, that doesn't relieve a drone pilot of the duty to see and avoid it. It's like when we're driving a car and a pedestrian jaywalks in front of us, we'd still better swerve and/or hit the brakes.

 

[tlswift58]

For those who say, "If an airplane/helicopter is flying less than 400' AGL they have problems on their hands and should never be flying in "My Area" that low" you're WRONG!

Take a look at a picture snapped right here in western NC yesterday from someone's front deck (This is not a drone/aerial pic). This C-130 (and the other 3 shortly there after) were flying legally at about 200' AGL.

View attachment 129011

If you can't See & Avoid you shouldn't be flying at all . . .

There was also a 3 state LAANC out a few weeks ago covering 3-4 days. We get them mainly flying over in evening or at night - but also in day time.

Duke Power also has permission (in NC) to fly at treetop level when out maintaining their power lines and cutting trees with same helicopter and that dangling saw contraption they use.

 

[NLOL]

I think something is wrong here. If the military/other wants to fly below 500 feet there needs to be some adequate pre-notice of it. Forget unmanned aircraft for a minute and look at small manned aircraft - what notice do they get? Back to unmanned - Suppose the unmanned operator is hard of hearing - or in a noisy location - the operator may very well not have adequate leadtime to 'duck' before his lil uav is impacted. Anyone, in any circumstance, that thinks the right of way is their's and intends to take it come hell or high water is acting unsafely.

Simply saying UAV operators must do so safely is missing some of the reducible risks. That being the case, an avoidable collision is inevitable. The risk requires comprehensive and shared discussion.

 

[sar104]

I think something is wrong here. If the military/other wants to fly below 500 feet there needs to be some adequate pre-notice of it. Forget unmanned aircraft for a minute and look at small manned aircraft - what notice do they get? Back to unmanned - Suppose the unmanned operator is hard of hearing - or in a noisy location - the operator may very well not have adequate leadtime to 'duck' before his lil uav is impacted. Anyone, in any circumstance, that thinks the right of way is their's and intends to take it come hell or high water is acting unsafely.

Simply saying UAV operators must do so safely is missing some of the reducible risks. That being the case, an avoidable collision is inevitable. The risk requires comprehensive and shared discussion.

Manned aircraft are assumed to be large enough for other low-flying traffic to see and avoid - that's how VFR works. That's not true of sUAS however.

 

[D-Wreck BXNY]

If you are no where near any airport (1 million miles away) AND you are over water. (No people, fish are swimming low).

Is it then safe to fly?

 

[Rich QR]

If you are no where near any airport (1 million miles away) AND you are over water. (No people, fish are swimming low).

Is it then safe that I could fly?

Those are precisely the conditions under which manned aircraft may legally fly as low as they please.

So you must watch for those planes and helicopters. If you do so, it should be safe.

The only place where I think I can safely assume no manned aircraft will be is indoors or under a thick canopy of trees.

 

[passedpawn]

Oh man I was in the north/northwest and almost got smacked by low-flying aircraft. Quite unnerving. Had to lower my M2P quickly. Not as bad as my experience at Mt Rushmore.

[edit] got a quick pic while retrieving my drone.

 

[Camino Ken]

This problem intrigued me so I ran a few quick numbers. Hopefully, the math comes out correct. If I am flying my M2P at 400ft it will take me 40sec to get it on the ground. A C-130 minimum operating speed is about 200ft/sec (1.2 X stall speed of 100 knts) and would transverse about 1.5 miles (2.4km) in this time. To be fairly safe I would need a visibility equal to this distance In all directions. If the aircraft is traveling faster than this I would need even more. Edit: This is if you are flying directly overhead, if you are off in the distance the visibility requirement is obviously more.

 

[brett8883]

Manned aircraft are assumed to be large enough for other low-flying traffic to see and avoid - that's how VFR works. That's not true of sUAS however.

Right so why don’t they change the assumption? I’m just using this as an example but how about if you are going to be flying lower than 500 ft except during take off and landing you need to be going a speed that gives both the manned aircraft pilot and the drone pilot some chance of avoiding each other. I’ll leave what the actual speed is open for comment but it would be slow enough that it effectively bans fixed wing aircraft from flying below 500ft AGL except for take off and landing.

Flying at 200 ft AGL for a fixed wing aircraft should be considered so dangerous that any collision is on the pilot of the fixed wing aircraft. There is no way you are going to see something traveling that fast that low in time to avoid it. Honestly the only way I’ve found you can avoid manned aircraft is by hearing them first. By the time I see them, even though I know they are coming and I’m looking for them, it would have been too late if I was in their path.

Honestly, except for military operations what do they really need to be flying that low for? If it’s for crop dusting or something then maybe there will be an exception but can only fly that low over private property you control or something.

I think you are hearing some frustration that the safety of manned aviation has been put completely on the shoulders of drone pilots and that doesn’t seem fair.

 

[sar104]

Right so why don’t they change the assumption?

The assumption that manned aircraft can see and avoid each other while manned aircraft cannot be expected to watch for tiny sUAS in their flight paths? They don't change it because it is a good assumption.

I’m just using this as an example but how about if you are going to be flying lower than 500 ft except during take off and landing you need to be going a speed that gives both the manned aircraft pilot and the drone pilot some chance of avoiding each other. I’ll leave what the actual speed is open for comment but it would be slow enough that it effectively bans fixed wing aircraft from flying below 500ft AGL except for take off and landing.

Precisely. Which is why that's not an option.

Flying at 200 ft AGL for a fixed wing aircraft should be considered so dangerous that any collision is on the pilot of the fixed wing aircraft. There is no way you are going to see something traveling that fast that low in time to avoid it. Honestly the only way I’ve found you can avoid manned aircraft is by hearing them first. By the time I see them, even though I know they are coming and I’m looking for them, it would have been too late if I was in their path.

So it should be considered dangerous because you want to make it dangerous by flying your drone, and then want to put the safety responsibility on the pilot of the manned aircraft?

Honestly, except for military operations what do they really need to be flying that low for? If it’s for crop dusting or something then maybe there will be an exception but can only fly that low over private property you control or something.

Why? In addition to your examples of military training and crop dusting, that would include Inspection work, LE operations, public safety operations, search and rescue operations, etc.

I think you are hearing some frustration that the safety of manned aviation has been put completely on the shoulders of drone pilots and that doesn’t seem fair.

It's fair because you, flying your drone, don't risk your own injury or death in colliding with a manned aircraft. And you should have a much better chance of seeing and hearing the approach of a manned aircraft than the pilot of that aircraft has of being able to see and avoid your drone.

 

[brett8883]

The assumption that manned aircraft can see and avoid each other while manned aircraft cannot be expected to watch for tiny sUAS in their flight paths? They don't change it because it is a good assumption.

You just said it wasn’t true for sUAS so it doesn’t seem like a good assumption.

Precisely. Which is why that's not an option.

Manned aircraft are plenty capable of flying above 500 ft so why isn’t it an option?

So it should be considered dangerous because you want to make it dangerous by flying your drone, and then want to put the safety responsibility on the pilot of the manned aircraft?

Why am I responsible for someone else’s safety if they want to do something that is dangerous to them? It’s like saying it’s my fault a driver crashed into my house and killed himself because if my house wasn’t there they would have been fine. Completely unreasonable.

Why? In addition to your examples of military training and crop dusting, that would include Inspection work, LE operations, public safety operations, search and rescue operations, etc.

Well maybe drones should do that kind of work instead leaving no reason for manned aircraft to need to fly that low except in designated areas or during take off and landing.

It's fair because you, flying your drone, don't risk your own injury or death in colliding with a manned aircraft. And you should have a much better chance of seeing and hearing the approach of a manned aircraft than the pilot of that aircraft has of being able to see and avoid your drone.

Fine then you know what would be helpful If ALL manned aircraft had to have ADS-B turned on at all times so I could at least know they were coming in enough time to avoid them. Is that such a big ask?

But the FAA can’t bother even with this one tiny requirement. They go so far as to ban drones from having ADS-B out. It almost makes you think the FAA doesn’t really think drones are a threat to manned aircraft.

I know as you say that if drones had ADS-B out it would overwhelm the system but they could make it so drones could be filtered out of detection when the manned aircraft are above 500 ft. Plus if they are really a threat you’d think manned pilots would want to know about them.

Drone pilots seeing manned aircraft on radar, manned aircraft seeing drones on radar. Isn’t that the ideal solution?

 

[sar104]

You just said it wasn’t true for sUAS so it doesn’t seem like a good assumption.

Then you misunderstood what looks like a very clear statement.

Manned aircraft are plenty capable of flying above 500 ft so why isn’t it an option?

Because while the can fly above 500 ft, there are many cases, and I gave examples, where they need to fly below 500 ft.

Why am I responsible for someone else’s safety if they want to do something that is dangerous to them? It’s like saying it’s my fault a driver crashed into my house and killed himself because if my house wasn’t there they would have been fine. Completely unreasonable.

Your hard-to-see drone is what is causing the hazard to long-established manned aircraft operations. A more accurate analogy would be "why is it my fault if I place a hazard in the middle of the road and a driver crashes into it?"

Well maybe drones should do that kind of work instead leaving no reason for manned aircraft to need to fly that low except in designated areas or during take off and landing.

I look forward to seeing drones take over the operations that I listed previously. How exactly do you envisage Medivac drones working, just as an example?

Fine then you know what would be helpful If ALL manned aircraft had to have ADS-B turned on at all times so I could at least know they were coming in enough time to avoid them. Is that such a big ask?

No - that's a reasonable request, but it is imposing a significant burden on general aviation that will take time to fully implement. And of course there are also military and LE operations that really don't want to broadcast their position to the general public, which will need some figuring out.

But the FAA can’t bother even with this one tiny requirement. They go so far as to ban drones from having ADS-B out. It almost makes you think the FAA doesn’t really think drones are a threat to manned aircraft.

I know as you say that if drones had ADS-B out it would overwhelm the system but they could make it so drones could be filtered out of detection when the manned aircraft are above 500 ft. Plus if they are really a threat you’d think manned pilots would want to know about them.

You don't understand how ADS-B works. The problem is not screen clutter or notification overload. It's an asynchronous broadcast system. Too many aircraft broadcasting and they just continuously step on each others transmissions and the system fails at the source.

Drone pilots seeing manned aircraft on radar, manned aircraft seeing drones on radar. Isn’t that the ideal solution?

Yes. That's the goal of RID.

 

[Rich QR]

Fine then you know what would be helpful If ALL manned aircraft had to have ADS-B turned on at all times so I could at least know they were coming in enough time to avoid them. Is that such a big ask?

But the FAA can’t bother even with this one tiny requirement. They go so far as to ban drones from having ADS-B out. It almost makes you think the FAA doesn’t really think drones are a threat to manned aircraft.

I know as you say that if drones had ADS-B out it would overwhelm the system but they could make it so drones could be filtered out of detection when the manned aircraft are above 500 ft. Plus if they are really a threat you’d think manned pilots would want to know about them.

ADS-B transmitters are much more expensive than receivers. Check out the prices from Sporty's

ADS-B Out

The pricetag is a major part of why they don't insist on all aircraft having them. Someone flying a VFR Piper Cub with no electrical system in uncontrolled central Kansas airspace probably doesn't want or need the expense.

The size weight, and electrical power requirements make ADS-B impractical for drones. But there's a more important reason they're prohibited on drones: There are only two available radio frequencies. If multiple position reports are being transmitted on the same frequency by different aircraft simultaneously, they'll interfere with each other, and the position reports won't be received. If the signal strengths are widely different, maybe the stronger one will cover up the weaker one, but if the two signals are comparable, neither one will be received. This radio frequency congestion issue is a fundamental problem that can't be solved by masking out drone reports on a display, because the mere fact that the drone is transmitting at the same time as the passing 747 will cause interference.

Naturally, one would expect the interference from drones to be worst in built-up urban areas where there are lots of people. This also happens to be the area where there are likely to be high densities of medium-altitude traffic approaching and departing airports, and high potential for conflicts among the big airplanes. They rightly want to keep the ADS-B frequencies clear enough that the big airplanes can avoid each other.