the need for spotters in FPV or Collision avoidance systems?


I fly FPV as do most of you Here at DIY Drones, and I will admit that I have flown at times without the use of a Spotter. Yes I know it’s a bad Idea to do so, however I also know I’m not alone. Lots of you do This I know I have seen The videos, But I don’t want to talk about this other than to raise the point that a spotter is not always available at times or necessary, If you are way out in the sticks, and under 400 feet no Biggie in my book. Others will I am sure disagree but that is a discussion for another Blog.

The big problem is that the requirement for a spotter comes from aviation law / rules / advisories that define a remote-controlled aircraft to be a vehicle flown via unaided visual contact. In order to meet this requirement, a spotter that has visual contact to the aircraft and possibility to take over control is needed. The visual line of sight rule comes from another section of aviation law, which dictates that people participating in the airspace must be able to "see and avoid" at all times.

My question or idea is why not have a Collision Avoidance System in conjunction with an autopilot?

It seems simple to me, and yes I know The FAA  is not fond of autopilots on our aircraft, however we fly in a very artificial environment to say the least. And we use all manner of electronic devices to give us Air Speed, Altitude, Heading, and more, so why not add a collision avoidance system to what we currently use to help be that extra set of eyes we need. Add an auto pilot that could take control in the event of a loss of signal or other mishap, and it would make flying FPV a lot safer for all.  No it won’t replace a human but it would help with”see and avoid”, even pilots of full size aircraft have trouble with this in crowded airspace which is why systems like these exists in the first place.

I recently went looking for a small affordable system and I found one, I am sure there are others.

The Zanon flight Systems PCAS MRX is a tiny system that is as small as the radar detector you might have in your Car, yet it can monitor your location, altitude, and heading, and will let you know if any other aircraft are in your area,  that and many other features. Yes those other  aircraft need to be broadcasting a transponder signal, however the FAA requires most all small aircraft to do so, except for ultra lights, para gliders, and the like, and I think they would like even them to do so. I would think this should be very valuable information to those of us flying FPV. Some of the units ability's are: Digital range, scalable from 5NM to 1NM, Relative altitude, scalable from ±2500 ft to ±500 ft, with ascending/descending indicator, A built-in altimeter for real-time accuracy, Displays the local squawk code and altitude, Audio alerts for threats and advisories. Not bad for its size and price, it sells for about $550.00. Until we can put a radar system on our planes and multi copters this might be the way to go. I think it should be possible to adapt this device, or one like it, to work with our OSD systems and auto pilots and give us that extra bit of real time safety that a spotter allows. The website for this device is here at

Just food for thought I don’t have any Idea how hard it would be to add this to an OSD/ auto pilot, however I think our hobby is getting to the point where we will need something like this soon. And with all the talk about new regulations for drones coming soon I think it would make pilots of commercial and privet planes feel a lot safer to know we can see them and we are listening to FAA control and advisories for the airspace we are sharing with them. Please Let me know your thoughts about this idea, and thanks for your time reading my ramblings


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Comment by MarcS on December 27, 2011 at 5:41am

Hi Daniel,

the idea of a collision avoidance is nice. In europe, the most common system for gliders is FLARM ( Several thousand in use and probably saved many lifes in crowded thermals...

PowerFlarm adds Transponder reception.

These systems are widely discussed in manned aviaton. I think especially in the US general aviation pilots want to keep the right of flying without electronics (even radio). You could search, I just read it here and there...

So as long as no system is mandatory for manned AC, you still need to be able to react to "incooperative systems" leading to visual sense and avoid. There are ideas to also solve this electronically but not very good, yet.

So, in short: Integration of such collision warning systems to an AP is easy, have worked with FLARM for another project... BUT as long as not every plane has to have one, you have to look at the sky yourself.

Using such a system (even ground based) today could show that you are a responsible flyer, anyway.

Comment by David Kovar on December 27, 2011 at 9:06am


I'm a rated fixed and rotor pilot and also have time in gliders and under parachute. I'm also a low time RC pilot and very new FPV pilot.

The manned aircraft pilot in me would really prefer a human in the "see and avoid" loop, particularly with the industry in its infancy. And, as @MarcS pointed out, there are a lot of aircraft in the US airspace that would not be detected by an automated collision avoidance system. Many of those aircraft tend to avoid built up airspace, and thus are likely to be sharing the airspace we're flying in.

The sUAV entrepreneur in me wants something done that will allow us to start flying legally without requiring $50K and up aircraft. I fear that the military UAV vendors are pressuring the FAA to impose major restrictions in the interests of safety that will hamper or completely choke off the small business opportunities for sales, service, training, support and services.


Comment by Daniel Hibben on December 27, 2011 at 9:28am

that is interesting i have not herd of that system but i am not a privet pilot nor do i fly in Europe but it sounds like it would be a good thing to have i a crowded thermal the videos of that i have seen i am amazed that they don't have accidents i will check it out thanks

you are right about not all aircraft having a transponder and i agree a lot of pilots would love to keep it electronics free. my thinking for this is not a system to solve the problem completely, only to add an extra layer of visibility to the whole process, because if we are looking for transponder signals it stands to reason we would be broadcasting one as well, so they could use there systems of this type to see us, and since it would monitor alerts i would think if an FAA controller started to tell us to clear out we would at least know about it and be able to react to there instructions i dont know if a system like this one has that level of capability but i see it has the ability to send "alerts" what this means exactly for the user i don't know i will have to check, but it would be nice to let them know "hey a drone is over hear and i am aware of all the aircraft around me with transponders"

ah well i dream a lot which is where this idea came from. i can't see the FAA controllers being excited to add a lot of small aircraft to the airspace. i guess i see lots of heavy regulation coming soon and i would love to dodge the bullet. maybe someone will read this and have a brain storm and come up with an idea that will solve the problem, like i said i dream a lot

take care

Comment by Daniel Hibben on December 27, 2011 at 9:38am

i just read your post David and i agree with you completely especialy about the regs coming and i would love to find a way for us to look around us like you can in a full scale aircraft  i fly with a wide view lens and 3d camera to help with distance, and once you use this any other 2d system is just scary to fly with i dont see how people land with out depth perception, so maybe we need to be looking at a camera system that allows us to look around better. head trackers are a start but not very reliable. ideas? 

Comment by Gary Mortimer on December 27, 2011 at 9:56am

The research currently being undertaken in Europe is to prove just how good the man in the sense and avoid part is. Make a number from which to make further UAS rules. Very quickly they have shown how poor the man is. A vision based system has been used and it works much better than the man!

Red Bull type aircraft were flown at a Seneca I think it was thats fitted with a vision based system. From all sorts of angles it saw the aircraft deliberately flying at it well before the human. 

So it will happen.

SSR based systems won't for a while as all aircraft don't have them fitted.

In the briefing I was at birds lifting could be filtered out, or shown. So sUAS are easily detected.

The roadblock for detect sense and avoid in the USA is just nonsense.

Plenty of collect can happen within VLOS and below 400' Even that is illegal in the USA.

David is exactly right as to whats happening. We will have more at sUAS News soon about some things.

But until potential users in the USA catch a wake up and actually bother to look at whats coming there is little hope.

The drum has been banged for several years and heads are stuck firmly in the sand.

Comment by Daniel Hibben on December 27, 2011 at 10:20am

that is very interesting Gary. it is always worth getting your input thank you.

i have not herd of this system or the tests i will look into it, i would agree that the right system would no doubt be better then the mk1 eyeball. it will be interesting to see what the future holds I think about the capability of something like the APM2.0, 10 years back pure sci-fi, we may wind up as just passengers on our UAV's instead of pilots

Comment by David Kovar on December 27, 2011 at 11:28am


If the FAA requires sUAVs to include a transponder we'll take a huge weight penalty for the hardware plus the power to run it. Also, the transponder will add little to no value below 600', or even higher in many cases.

Strobes would probably be more useful for "see and avoid" than a transponder, but would still have a pretty significant weight penalty.

Strobes plus transponder plus FLARM would require a military grade UAV and price us right out of business. 


Comment by David Kovar on December 27, 2011 at 11:31am


As a starting point, not that the FAA would go this route, a rural below 400 feet sUAV exemption would do wonders for the fledgling US industry.

I'm very awake, have a track record for doing successful startups in several roles, have a strong interest in supporting sUAS small business ventures, and am very frustrated. My best hope seems to be to move to Canada, which wouldn't do my family or the US economy any good.


Comment by MarcS on December 27, 2011 at 12:08pm

@Gary: It´s true and research shows that human pilots are not a good sense and avoid system... But who believes any regulation will lower the bar from what is already there please raise now :-(

@David: I guess there will be two sorts of regulations in the beginning. LOS flying rules without the need of complex systems (because you got manual override for SAA and System failure) and BLOS/NAS flying rules demanding full licences and certifications for systems and staff. There will be a gap in the middle for small BLOS systems which will probably filled later with emerging systems and experience, but I don´t hope for that soon. Since the "big solution" is the playing field of the big players and they guard it, small companies only have the small range option, which still offers lot´s of possibilities.

Comment by Gary Mortimer on December 27, 2011 at 12:41pm

I think they want to sell the box for GA aircraft, its gives a basic TCAS type alert.

The bottom line is that the restrictions in the USA at the minute are just plain silly and commercial VLOS should be allowed. You should have to show some basic understanding of the airspace system and promise not to hit anyone and thats it.

Perhaps its not about lowering the bar, but understanding the risk.


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