OpenFLARM project

[bcw]

Has anyone any opinions on the OpenFLARM project?

OpenFLARM (http://www.openflarm.co.uk?s=pprune)

It is a £50 GPS and traffic receiver that can also pick up contacts carrying FLARM. It is fully open source and non-commercial and trying to break the closed monopoly we currently have in the light aircraft world and bring the cost of a traffic avoidance system within reach of all pilots.

Be interested to hear if anybody has seen it and/or has an opinion.

http://www.openflarm.co.uk/img/sd-resized.png?s=pprune

[Forfoxake]

This looks interesting and I applaud the fact that it is open source.
However, it looks of very limited value at the moment.
This is because it appears not to pick up transmissions of ADS-B or be visible to FLARM/PowerFLARM users. I am not even sure if it picks up all types of transponders either.
In my experience of using PowerFLARM portable over the last couple of years, the vast majority of light aircraft that I pick up are transponding Mode C/S and the airliners are transmitting ADS-B.
However, perhaps it will develop into the cheap universal electronic detection device that is needed.

PS I prefer a device that warns of imminent collision rather than providing a virtual radar display.

PPS Suggest you have a look at PilotAware- it seems to have been developed along the correct lines!

[znww5]

Looking at the link, it would appear that (at least at this stage of development) the system will do nothing other than detect other 'OpenFLARM' systems. It won't detect ADSB, FLARM, PilotAware or any other transmission. If the other aircraft isn't also carrying OpenFLARM, you simply won't see it.

I would be interested to know two things: does the GPS make use of the WAAS/EGNOS data; does it derive height purely from the GPS or does it also have a barometric sensor. It would appear that the GPS unit they use is GNSS only, so there is no access to other GPS constellations such as GLONASS.

Apart from the laudable open source approach, the strength of OpenFLARM must be the £50 price target, making it likely to be far more widely adopted than the competing systems. If collision warning is added, that would dramatically increase its appeal.

For me, a £50 unit with collision warnings would be worth the punt - until then I'll await developments.

[ChickenHouse]

The one idea is the good one - open source low cost. But, I doubt this initiative will be widely used. There are now so many Pi-based (some tinker) solutions out there doing ADS-B (Stratux, Openflightbox, Pilotaware with a similar system ...) jumping on the same and there are now the small Echo devices from uavionix.

My prognosis and a little hope, if politicians finally wake up - after all they will adopt UAT, if they stay that deaf and dump - we get our own European system in 20 years with 10 percent functionality of todays US infrastructure.

[bcw]

Looking at the link, it would appear that (at least at this stage of development) the system will do nothing other than detect other 'OpenFLARM' systems. It won't detect ADSB, FLARM, PilotAware or any other transmission. If the other aircraft isn't also carrying OpenFLARM, you simply won't see it.

It will detect FLARM.

ADSB is mentioned on the web page as not working.

PilotAware claims to be open but in fact does not publish it's protocol, hence leading people down the same terrible path as FLARM did.

I would be interested to know two things: does the GPS make use of the WAAS/EGNOS data; does it derive height purely from the GPS or does it also have a barometric sensor. It would appear that the GPS unit they use is GNSS only, so there is no access to other GPS constellations such as GLONASS.

I don't know about 'WAAS/EGNOS' but I can tell you (from the link to the GPS datasheet on the page) that the chipset supports GLONASS.

Apart from the laudable open source approach, the strength of OpenFLARM must be the £50 price target, making it likely to be far more widely adopted than the competing systems. If collision warning is added, that would dramatically increase its appeal.

For me, a £50 unit with collision warnings would be worth the punt - until then I'll await developments.

As far as I am aware, SkyDemon and the like calculate their own 'collision warnings' when fed with suitable data, and probably far more accurately given the processing power available to them over and above that in a conventional FLARM.

[PaulisHome]

We need yet another 'standard' for transmitting position like a hole in the head.

Let's think: Mode S. ADSB. Flarm. Pilot Aware. Now this. Too much confusion over standards merely leads to lower overall takeup - there's no point if people are flying around with different systems.

If they want to use something that is 'open' what's wrong with ADSB?

As far as I am aware, SkyDemon and the like calculate their own 'collision warnings' when fed with suitable data, and probably far more accurately given the processing power available to them over and above that in a conventional FLARM.

The point about the Flarm anti-collision algorithms (which are the patented bit of the system) is that they are designed for use in gliders, where close proximity is normal - it's only when an actual collision is imminent that there is a warning. It's quite different from, say, TCAS, which has quite a large bubble around it. It's not about processing power, it's about what you do with it.

Paul

[bcw]

Mode S. ADSB. Flarm. Pilot Aware. Now this. Too much confusion over standards merely leads to lower overall takeup....

I absolutely agree. Taking ADSB and Mode S out of the question for a minute, the problem we as an hobby and private aviation community is that we have had to opt for closed solutions because that was the only choice. I don't blame people for doing that, but their trailblazing is blindly leading the rest of the community down a dead end.

FLARM is completely closed. In fact they take active steps to both encrypt and obfuscate their traffic information in the hope that it will force us to buy their hardware at massively inflated costs. I understand that people have got to make a living, and that we as a community do tend to have reasonable budgets, but the level of cost vs RRP is far too large in my opinon.

PilotAware looked great at the start, a real solution to breaking the FLARM monopoly, but unfortunately their promise of making their protocol open has evaporated. They have never published it, and they ignore requests for information. In conclusion they are using the same predatory tactic as FLARM.

So as I said above, I quite agree that we don't need another protocol but instead an open protocol both in terms of anyone being free to implement it but also anyone being free to comment, expand or suggest changes to without having a manufacturer having ultimate veto. Unfortunately it seems that neither FLARM nor PA wish to take that step.

....there's no point if people are flying around with different systems.

The OpenFLARM system supports FLARM receive 'out of the box' ie doesn't need an £800 add on to make it work (like PA does). It will be receive only at the outset, purely because there are parts of the FLARM protocol that have not yet been reverse engineered and we do not wish to risk safety by transmitting data without understanding what it does.

We are quite happy to support PA's PI3 protocol if they wish to start talking to us. We are also quite happy to give them our information so that they can integrate with our system.

And just for the record, any OpenFLARM system can transmit and receive data from any other OpenFLARM, be that aircraft or ground station relay.

If they want to use something that is 'open' what's wrong with ADSB?

Yes, I also agree, having every aircraft running Mode S/ADSB would be a great solution. However as of today how many hobby and private pilots - the sort of people who would buy a FLARM or PA - actually carry the equipment to transmit it? In my experience, virtually none. The approval process to actually having transmit capability, ie to be seen yourself, is prohibitively expensive and those that can afford it are likely to be 'up high' and out of the way.

My conclusion therefore is that it is of limited use in the real (hobby and private) world at the moment, and that is the root of the problem. Any system needs critical mass, you end up playing 'chicken and egg', and when the cost of entry is so high it prevents that cycle being broken.

OpenFLARM on the other hand is a £50 punt, less than most of us pay for 0.5 hours I would expect, and just plugs in an goes. An external GPS receiver for your tablet costs more than that, so even without the collision avoidance it is a useful device.

Back on ADSB, the time I can actually see it being useful is in the vicinity of a large airfield where light aircraft are mixing it with bigger stuff. There is a solution for that built in to the OpenFLARM protocol where a ground station at the airfield can retransmit ADSB or Mode S data for this exact purpose and that data can be shared between devices in flight in order to increase range.

Also please take a look at the video on ADS-B linked from the OpenFLARM site. It is a of a presentation given at the DEFCON hacker convention which points out some massive security weaknesses in ADS-B. Quite scary stuff when you start thinking about it. I am actually split on my opinion on this. Part of me says hopefully the aviation community as a whole will wake up and fix these issues, either by extending the standard or replacing it altogether. The other part of me says that if that does happen it is likely to make the approval process even more difficult and put the technology even further out of reach.

[Jan Olieslagers]

having every aircraft running Mode S/ADSB would be a great solution. However as of today how many hobby and private pilots - the sort of people who would buy a FLARM or PA - actually carry the equipment to transmit it? In my experience, virtually none.

That may be true in the UK but it certainly isn't everywhere. In Germany, for one example, even many ultralights are carrying a mode S transponder. Myself will soon be installing a Trig transponder too, and mainly to be more visible to other pilots.

I might however be interested to add "something", preferrably open source, perhaps running on a RasPI or so, to display nearby ADSB transmitting planes. Flarm I will not touch even with a barge-pole - it is not under any formal norm or control, bases upon the cheapest consumer electronics, and is partially non-open.

Your bit about security holes in ADS-B is a bit disconcerting, though, I will have to look into that before proceeding any further. If substantial modifications to ADS-B are found to be in order, my transponder investment might loose a lot of its value, perhaps even all.

[PaulisHome]

I might however be interested to add "something", preferrably open source, perhaps running on a RasPI or so, to display nearby ADSB transmitting planes.

...Flarm I will not touch even with a barge-pole - it is not under any formal norm or control, bases upon the cheapest consumer electronics, and is partially non-open.

Make up your mind Jan, are you going with 'cheapest consumer electronics' or not? (Not that Flarm is, actually, that).

But more importantly, in the UK at least, probably 75% of gliders flying cross country carry Flarm. If you want to see them, that's what you need. You might wish they carried something different, but they don't.

Paul

[Jan Olieslagers]

A fair remark, Paul, still I'll stand my ground: for announcing where I am, I will use something decent. This is after all both towards ground stations (my main concern) and towards other pilots (a side benefit). On the receiving side, I might be less demanding, as I consider electronics only a help in detecting other traffic. Not wanting to redo the discussion on the Mk1 eyeball, though, that has been done to death.

As for gliders using Flarm: it must be quite general yes, on the continent too. Still we should not follow them in this abhorrence. At my homefield, the better equipped gliders carry both Flarm and ADS-B transmitters - if that isn't a waste of payload and of electric power!

[PaulisHome]

A fair remark, Paul, still I'll stand my ground: for announcing where I am, I will use something decent. This is after all both towards ground stations (my main concern) and towards other pilots (a side benefit). On the receiving side, I might be less demanding, as I consider electronics only a help in detecting other traffic. Not wanting to redo the discussion on the Mk1 eyeball, though, that has been done to death.

As for gliders using Flarm: it must be quite general yes, on the continent too. Still we should not follow them in this abhorrence. At my homefield, the better equipped gliders carry both Flarm and ADS-B transmitters - if that isn't a waste of payload and of electric power!

I think this whole thing is a tough problem, though I don't think anyone is suggesting that everyone should adopt Flarm. I can think of lots of cases where multiple technologies existed for a while before some sort of shake out. In this case though, there's a 'natural monopoly' in that having anti-collision systems which can't see each other kind of defeats the point.

A few thoughts:


There probably isn't a one size fits all solution. The requirements of functionality, reliability, size, cost and power consumption are different for different use cases (airliners in controlled airspace different from a glider outside etc).

Ability to encrypt / not spoof might be illusory. You can make it more difficult to break, but probably not more than that. See the huge amount of work that went into making DVDs and Blu Rays secure, and how far that got them. And Flarm's attempts at encryption.

I don't think the market can afford too many non-co-operative products. It means that none of them actually achieve their aim.

Regulation is probably actually getting in the way. In the UK there are some trials of ADSB with low cost GPSs, but they are moving awfully slowly.


So what to do? Personally I wish that the powers that be actually get on with a low cost ADSB and make it happen. Get some products out, remove the regulatory barriers. Gliders will probably continue with Flarm in the short to medium term, not least because of the anti-collision algorithms, but everybody gets to receive both.

[I carry a Flarm and a mode-S in my glider. The first helps me with gliders, the second keeps big things with a traffic service away from me. Neither helps me much with GA]

Paul

[bcw]

First off, thank you to the mods for reconsidering their decision to remove this thread. Glad we can continue to have a reasonable discussion on this matter.

Let me take a step back for a minute; as I understand it (and I don't claim to be an expert) the two main issues with ADS-B that were revealed in the DEFCON talks were essentially the following:

1. There is no mechanism to verify that a position report transmitted on ADS-B actually originated from the aircraft it claims to be from.

2. There is no geographical protection to the receiver system; in other words a message could be received in the UK giving a position report in the US and the ADS-B network would propagate even though it is clearly not possible (if the plane was really in the US a UK receiver would not pick it up)

The latter could easily be fixed in software; in fact it probably already has been (I would certainly hope so!) but the former is a lot more complicated.

Certainly encryption is not the answer for the fundamental reason that in order to read the data every device must have they key to decrypt and once that key gets into the open suddenly your encryption is broken. This is what happened with DVD - someone managed to extract a decryption key and made it public. There are other reasons to encrypt of course, for example to make your traffic difficult or obscure (as FLARM does) but ultimately if you sell a device containing a decryption key (which any receiver would need to have) it will be a possible to recover that key and break the encryption.

What ADS-B needs is a way of signing a clear text message with a cryptographic system that proves that the message was sent from the aircraft it claims to be from. Something like an RSA signature (https://en.wikipedia.org/wiki/RSA_(cryptosystem)#Signing_messages) or a PGP signature (https://en.wikipedia.org/wiki/Pretty_Good_Privacy#Digital_signatures) on an email. Such systems are based on a public and private key.

Adding this signature to the ADS-B message is not a huge issue but the problem comes when you realise that in order to implement this a receiver would need to maintain a database of the public keys of all aircraft it is likely to come across. This is not a huge problem for modern electronic systems* but certainly beyond the scope of transponders as we know them. Maybe someone will come up with an add-on box that authenticates ADS-B transmissions - in fact I suspect that is quite likely - but really the powers that be in the aviation industry should be taking the opportunity to come up with a better solution that takes into account all users (ie not just the 'big boys') and solves the inherent issues with ADS-B.

However, like any technology this comes down to critical mass, and ADS-B certainly has that in the commercial aviation sector. As such we are unlikely to see changes any time soon, and given that fact an interim solution of allowing non-approved GPS units to be connected to ADS-B is probably a sensible step, if it ever happens of course.

Back on to FLARM and OpenFLARM, the question really is 'Why is everyone not carrying a FLARM?'. Personally I think the answer is that it is too expensive for what it actually achieves, and part of that lack of functionality is down to critical mass. If all light aircraft carried one (as well as all the gliders that already do) it would be a far more useful device.

The whole aim of the OpenFLARM project is to put the technology within the 'why wouldn't you?' price bracket therefore stimulating the market to achieve this critical mass.

Chris

*A quick Google brought up this article (http://www.telegraph.co.uk/travel/travel-truths/how-many-planes-are-there-in-the-world) which suggests a figure of 150,000 planes ever being produced. It's not clear whether that figure includes light aircraft, but it is sufficient for an order of magnitude. So let's say each aircraft needed a 64bit public key, that's 8 bytes x 150,000 keys = 1.1 megabytes. Even if we allowed for 100x that number it would still be a tiny amount of data in today's world.

[Forfoxake]

bcw wrote:
"We are quite happy to support PA's PI3 protocol if they wish to start talking to us. We are also quite happy to give them our information so that they can integrate with our system."

This strongly suggests that bcw is closely associated with the OpenFLARM project. If so, I am very disappointed that bcw did not declare an interest in OpenFLARM in the initial post. Perhaps that is why the moderators initially removed it.

Having said that, a very useful discussion has developed on a subject that has interested me for several years because Mark 1 eyeball is simply not good enough!

I came to the conclusion a couple of years ago that a low cost electronic anti-collision warning system would eventually be developed for GA, probably based on ADS-B.
However, I also came to the conclusion that it was several years away. In the meantime, imho PowerFLARM offered valuable safety benefits immediately.

That is why I bought PowerFLARM portable despite the cost. In any event it was/is a fraction of the cost of TCAS. Since then, I have found it very capable and useful but of course it is not perfect. The Mark 1 eyeball is still important because a lot of traffic still has no electronic signature. And amazingly, I have found that in a lot of Mode C equipped aircraft, the pilot does not even switch it on.

So you can wait for perfection or use what is already available and useful. I have done the latter. You pays your money and you takes your choice.

PS I have no commercial connection whatever with PowerFLARM or FLARM.

[bcw]

bcw wrote:
"We are quite happy to support PA's PI3 protocol if they wish to start talking to us. We are also quite happy to give them our information so that they can integrate with our system."

For the record, I am a volunteer developer on the project.

(I did write this in the thread which was removed, apologies if this was not clear)

[iRaven]

£50? Is that "all in"? Can it be run in conjunction with a Stratux or PilotAware? Can it be seen on the Open Glider Network receivers?

Yes, I'm interested but I would like the capability to see both ADS-B and those that have now got PilotAware.

iRaven

[bcw]

£50? Is that "all in"?

Yes, 'all in' in terms of it will be a box with an aerial on the back and a GPS puck. You pop it on the coaming, connect your iPad to the wifi network it transmits, and you are off.

Can it be run in conjunction with a Stratux or PilotAware?

The intention is that you use this device as an alternative to either of those or a FLARM

Can it be seen on the Open Glider Network receivers?

Probably not as things stand. I was in regular contact with Paweł from the OGN and even went to visit him at the University of Oxford. He has however stopped responding to my emails recently. I do hope however that he will change his mind and support the OpenFLARM protocol.

Yes, I'm interested but I would like the capability to see both ADS-B and those that have now got PilotAware.

As above, PA is an issue because they will not publish their protocol even though they originally said that they would. As with OGN, hopefully they will change their mind and either let us implement their protocol or, better, implement our protocol which will be fully open and published in full for anyone else to use in the future.

Direct ADS-B reception will not be possible on the version 1 units however you will be able to connect a unit on the ground to an ADS-B receiver (or Internet feed) and have it relay ADS-B contacts to aircraft in the vicinity. The idea here is that airfields with a mix of traffic can have one of these units to provide ADS-B coverage near to their field.

Chris

[Crash one]

So this OpenFlarm device cannot see ADSB, Mode C, Mode S, Flarm.
It can see other OpenFlarm.
Please can someone tell me the advantages over Pilot Aware which can see all of the above except Flarm.
And why is it called "OpenFlarm" which implies it can "open the encrypted Flarm signal" ?

[bcw]

So this OpenFlarm device cannot see ADSB, Mode C, Mode S, Flarm.
It can see other OpenFlarm.


At the risk of repeating myself...

It can see FLARM users, FLARM cannot see it. FLARM appears to be the incumbent standard for small aircraft ie the number of units deployed in the kind of aircraft that private and hobby are likely to come during normal operation. What I mean by this is that of the small aircraft that carry collision avoidance technology the largest proportion of these are using FLARM and it is therefore the one you are most likely to come across in normal operations.

It cannot see ADSB (and the related technologies you mention) directly but can via a ground station, the intention being that these can be deployed in areas where small aircraft are likely to be mixing it with larger ones carrying ADSB transmission equipment. The reason for not including this functionality is that only a tiny minority of small aircraft carry ADS-B transmit capability (Pilot Aware only receives) and it is therefore of limited use to small aircraft pilots at this time.

It can see other OpenFLARM units.

We hope it will be able to see other PA units in the future but this is subject to their cooperation.

Please can someone tell me the advantages over Pilot Aware which can see all of the above except Flarm.

It is significantly cheaper than a FLARM setup of the same functionality (ie that can link to a tablet via wifi)

It is cheaper and far less complicated than a Pilot Aware and does not require any DIY. If you factor the cost of adding FLARM capability to Pilot Aware the cost is also significantly less.

The advantage to the community as a whole is that it promotes a collision avoidance technology that is both open (as in ADS-B) and does not require expensive (due to heavy certification requirements) equipment. None of the standards current available tick both of these boxes.

And why is it called "OpenFlarm" which implies it can "open the encrypted Flarm signal" ?

It is 'Open' as in 'Open Source' That means that the protocol, software and hardware are going to be released to the public (the latter already has).

As such, any manufacturer can build they own device either based on our hardware and software design or their own. Market pressures will decide whether Pilot Aware and/or FLARM make their units compatible with this protocol. As a community it should be obvious that it would be a good thing to promote an open standard instead of the closed shop we have now and we as individuals and potential customers should therefore be pushing the manufacturers down this road. Up to now though there has been no viable alternative and therefore no way to develop the critical mass to force the manufacturers to wake up. The sole driver behind coming up with a device that is priced at such a level that it becomes a must-have item and achieves this critical mass.

[Crash one]

Ok my mistake, it can detect Flarm.
But it can't detect a transponder nor Open Glider network nor Pilot aware.
It uses a wifi connection to the iPad.
How many separate wifi connections can an iPad handle at one time?
I'm not very computer literate so that may be irrelevant.
Can SkyDemons and their various other flavours use multiple GPS signals from Pilot Aware and Open Flarm?
I don't want to knock it but it seems there are still a number of different systems out there that are each limited to being able to see "some" other systems but not all of them.
Could this device be used in conjunction with Pilot Aware instead of the Flarm mouse at £££ ?
Flarm may be extremely numerous but I'm under the impression that it is a short range device, designed to keep gliders separated.
How many of the numerous Flarm units are used by GA?
How many GA aircraft have a transponder?
How many gliders have a transponder?
If gliders fitted with expensive Flarm units also fit a Pilot aware in order to see/be seen by GA, gradually the take up of Flarm alone will diminish.
The cost difference between Pilot Aware and Open Flarm of times four is not really significant if the coverage is considered.
The cost of Flarm would put it out of consideration now that other systems are available.

[crablab]

Ok my mistake, it can detect Flarm.
But it can't detect a transponder nor Open Glider network nor Pilot aware.
It uses a wifi connection to the iPad.
How many separate wifi connections can an iPad handle at one time?
I'm not very computer literate so that may be irrelevant.
Can SkyDemons and their various other flavours use multiple GPS signals from Pilot Aware and Open Flarm?
I don't want to knock it but it seems there are still a number of different systems out there that are each limited to being able to see "some" other systems but not all of them.
Could this device be used in conjunction with Pilot Aware instead of the Flarm mouse at £££ ?
Flarm may be extremely numerous but I'm under the impression that it is a short range device, designed to keep gliders separated.
How many of the numerous Flarm units are used by GA?
How many GA aircraft have a transponder?
How many gliders have a transponder?
If gliders fitted with expensive Flarm units also fit a Pilot aware in order to see/be seen by GA, gradually the take up of Flarm alone will diminish.
The cost difference between Pilot Aware and Open Flarm of times four is not really significant if the coverage is considered.
The cost of Flarm would put it out of consideration now that other systems are available.

A device can only support one connection per antenna.
They can indeed.
The multitude of systems is indeed the problem, hence why I suggest things like Stratux that use the industry standard (ADS-B and Mode S)
There would be no advantage to doing that
That is exactly what FLARM was designed for
Most now. How many have Mode S and ADS-B is less clear...
Few
Yes, particularly as FLARM have not published their protocol
Indeed.

The other *massive* advantage of PilotAware that has not been mentioned as far as I can see, is that with a Mode S transponder it can be configured to make ADS-B broadcasts - along the open standard, that all the controllers and commercial traffic use. Surely this is better than FLARM etc? It is certainly cheaper than the £2.5k needed for the "official" unit and before people ask, yes it is allowed and has been "approved" by the CAA.

Disclaimer: I'm a software engineer but not affiliated with any of these projects.

[bcw]

The other *massive* advantage of PilotAware that has not been mentioned as far as I can see, is that with a Mode S transponder it can be configured to make ADS-B broadcasts - along the open standard, that all the controllers and commercial traffic use. Surely this is better than FLARM etc? It is certainly cheaper than the £2.5k needed for the "official" unit and before people ask, yes it is allowed and has been "approved" by the CAA.


That would be a massive advantage, but as far as I am aware it is not the case. Yes it can do it technically, but the regulations state that an approved and certified GPS source must be used. Pilot Aware is neither and therefore you would be breaking the law if you connected it to your transponder.

This was also mentioned above by PaulisHome:

Regulation is probably actually getting in the way. In the UK there are some trials of ADSB with low cost GPSs, but they are moving awfully slowly.

[crablab]

That would be a massive advantage, but as far as I am aware it is not the case. Yes it can do it technically, but the regulations state that an approved and certified GPS source must be used. Pilot Aware is neither and therefore you would be breaking the law if you connected it to your transponder.


Did you read my last sentence?
You can do it, legally, with PilotAware, without a certified GPS.

Read here
(http://www.pilotaware.com/wp-content/uploads/2016/09/160902-Connecting-to-a-transponder-.pdf)

[FullWings]

It’s great that people are developing cheaper and (hopefully) less proprietary electronic conspicuity systems but interoperability appears to be slipping down the priority list.

Barely a week or two goes by in UK airspace where there isn’t some form of near get-together that could have been prevented by devices (and people) talking to each other. VHF/UHF, XPDR, FLARM, PilotAware, ADSB, SSR... The information needed to prevent collisions is mostly out there and has been for some time but the multiplicity of formats seems to be preventing an effective one-stop solution.

I am much reminded of:

https://imgs.xkcd.com/comics/standards.png

[crablab]

FullWings: entirely agree. But ADS-B IS the standard, isn't it? the FAA mandate it and it's being pushed by EASA. FLARM, OpenFLARM, P3i etc. have just sprung up of their own accord as a "distraction" from the main problem: ADS-B has been too expensive in the past to install. Now, it's getting slightly cheaper to have certified GPS etc. but the cheapest option still seems to be uncertified GPS with PAW, giving you both ADS-B in and out. The equivalent panel transponder from Garmin that does that is about £5k.

[FullWings]

True. I don’t understand enough about the technicalities of ADS-B to know if you could get FLARM-equivalent performance from ADS-B data. If that works, then great.

For instance, this year there will be 100+ gliders and light aircraft in the immediate vicinity of Lasham before the tasks start at the European Championships this August. If they were all squawking, it would be a mess but FLARM seems to be able to cope as they all carry it.

[ChickenHouse]

ADS-B In/Out could serve perfectly, if not better, than Flarm, BUT physics comes right at the corner. The US already had to introduce UAT to free available bandwidth from 1090ES and if we really would all go for an ADS-B 1090ES solution, the gibberish of all that stations will congest the air. Flarm did overcome some of the restrictions by reducing power, so making the area covered "fit for purpose of the gliders". Now with the new PowerFlarm the advantage gets less ... Same trouble as with radios, as long as we all had 3 to 5 Watts of power, we could reach the next airport and traffic control, now we blow our stumbling with 16 Watts from final in Birmingham to the Orkneys.

[bcw]

Did you read my last sentence?

I did. Did you read my post before you quoted it?

That would be a massive advantage, but as far as I am aware it is not the case.

I was not aware when I wrote that post that the law had changed. Thank you for providing the link; this is something I will read up on.

[Forfoxake]

ADS-B In/Out could serve perfectly, if not better, than Flarm, BUT physics comes right at the corner. The US already had to introduce UAT to free available bandwidth from 1090ES and if we really would all go for an ADS-B 1090ES solution, the gibberish of all that stations will congest the air. Flarm did overcome some of the restrictions by reducing power, so making the area covered "fit for purpose of the gliders". Now with the new PowerFlarm the advantage gets less ... Same trouble as with radios, as long as we all had 3 to 5 Watts of power, we could reach the next airport and traffic control, now we blow our stumbling with 16 Watts from final in Birmingham to the Orkneys.



Take your point about ADS-B in/out do not think this would be much of a problem as long as the system used mainly warns of imminent collision, which is thankfully very rare. That is why I much prefer some sort of audible warning of a potential collision rather than the virtual radar display being promoted by many. You really do not need to know about all the aircraft near you- only about the ones that are likely to hit you!


PowerFLARM does this with ADS-B and other FLARM/PowerFLARM transmitters but only indicates the close presence of Transponder equipped aircraft (if transponder switched on!). Not sure about PilotAware.


So ADS-B in/out would be much better but is still pretty expensive (and not widely adopted by light aircraft).


In the meantime, I think PowerFLARM is the best solution (or possibly PilotAware), despite the cost. What price do you put on reducing the risk of a probably fatal mid-air collision?


PS Any system that detects ADS-B is better than nothing because nearly all airliners have it. Can you imagine the consequences for GA in the UK if a light aircraft, microlight, gyro, helicopter or glider were to pile into an airliner?

[cotterpot]

Barely a week or two goes by in UK airspace where there isn’t some form of near get-together

I don't see that at all. Any recent evidence?

[abgd]

Any system that detects ADS-B is better than nothing because nearly all airliners have it. Can you imagine the consequences for GA in the UK if a light aircraft, microlight, gyro, helicopter or glider were to pile into an airliner?

How does one pile into an airliner? How does one avoid an airliner? I suspect with considerable difficulty, as it's more likely to be the airliner that does the piling-in. In my hang-gliding days my instructor's advice was that if a military jet came along, one should turn to show them your wing... the thinking being that the speed differential was such that there was nothing you could do to avoid a jet, but if they knew you were there, they might just be able to avoid you.

I imagine a transponder is a more useful tool for avoiding meeting airliners. Even in class-G, someone can usually see you on radar and separate you.

Not saying a system that shows you the airliners is useless... but I doubt it's a panacea either.

[abgd]

I don't see that at all. Any recent evidence? Ditto. The Kitfox/Cessna 177 accident is the last one I can think of. En-route midairs cause a very small proportion of aviation fatalities. I share the concern re. the risks to GA if someone were to bring down an airliner but mid-air collisions with other small aircraft are fairly low on my list of concerns - well below the weather, carb-icing and all of that.

[Forfoxake]

How does one pile into an airliner? How does one avoid an airliner? I suspect with considerable difficulty, as it's more likely to be the airliner that does the piling-in. In my hang-gliding days my instructor's advice was that if a military jet came along, one should turn to show them your wing... the thinking being that the speed differential was such that there was nothing you could do to avoid a jet, but if they knew you were there, they might just be able to avoid you.

I imagine a transponder is a more useful tool for avoiding meeting airliners. Even in class-G, someone can usually see you on radar and separate you.

Not saying a system that shows you the airliners is useless... but I doubt it's a panacea either.


I agree that a Mode C/Mode S transponder (if switched on!) is a better tool at the moment for avoiding a close encounter with an airliner but only because it detects YOU with TCAS and airliners normally operate in a known traffic environment.

However, personally, despite my comments about virtual radar, I find it very reassuring that PowerFLARM confirms that a collision with a nearby airliner is not imminent because of the potential for large loss of life if a collision occurs and the probable resulting massive restrictions on GA in this country. Not that I would probably have to worry about the latter myself!

As you suggest, because of the higher closing speeds involved with jets, an electronic warning system is even more likely to be effective than the Mark 1 eyeball. However, I said that ADS-B detection was "better than nothing" not a panacea.

[Forfoxake]

Ditto. The Kitfox/Cessna 177 accident is the last one I can think of. En-route midairs cause a very small proportion of aviation fatalities. I share the concern re. the risks to GA if someone were to bring down an airliner but mid-air collisions with other small aircraft are fairly low on my list of concerns - well below the weather, carb-icing and all of that.

As I said earlier, imminent (mid-air) collisions are thankfully very rare but the results are almost always fatal, unlike many other incidents involving light aircraft.

Since I fly a Kitfox, it was probably the Kitfox/Cessna 177 accident that concentrated my mind on this issue, plus a few close encounters of my own. I think that most GA pilots who have done a reasonable number of hours in uncontrolled airspace will, if pressed, admit that they have come too close for comfort to another aircraft which they did not spot until very late.
And of course, you do not see the one that hits you!

I hate to say this but I came to the conclusion some time ago that "see and be seen" is largely a myth. Because of the natural limitations of the eye, the main reason that there are so few mid-air collisions is because the air is such a big place and there are, relatively, so few aircraft flying in it.

Electronic warning systems have been available for many years (what happened to the strobe detection system being trialled some years ago?) but have not been widely adopted in GA. I think it is about time we got our act together.

[FullWings]

I don't see that at all. Any recent evidence?
UKAB Reports ("https://www.airproxboard.org.uk/Reports-and-analysis/Monthly-summaries/Monthly-Airprox-reviews/“)

There are many instances of aircraft getting close enough to “cause concern” to the pilots or ATC. Often, they have some form of electronic conspicuity and/or are talking/listening on the radio but although there is enough data in retrospect to prevent the near-miss, it wasn’t available to assist at the time, e.g. a controller can see two dots converging on his screen (and maybe gets a STCA) but the aircraft aren’t on his frequency; one has FLARM, one has a XPDR; one is on an en-route frequency, the other on SafetyCom and so on.

That’s one of the frustrations: there is a lot of “here I am!” going on but because of the diversity of position reporting and receiving equipment on smaller aircraft, there are many cases of the data to prevent a near miss or collision being available but not collated/interpreted in real-enough time to help...

The Kitfox/Cessna 177 accident is the last one I can think of. En-route midairs cause a very small proportion of aviation fatalities. I share the concern re. the risks to GA if someone were to bring down an airliner but mid-air collisions with other small aircraft are fairly low on my list of concerns - well below the weather, carb-icing and all of that.
There were c.50 Airprox reports in 2016 that were graded at the highest risk category, “A”, in that the separation was small enough it was purely down to luck that the aircraft didn’t collide. Remember this is just from pilot & ATC reports - those that “pass in the night” are not recorded.

There were multiple fatal midairs in 2016, I haven’t researched the exact number but it was significant.

[Forfoxake]

Interestingly, the latest (2015) annual report by the UK Airprox Board states:

GA-GA incidents nearly doubled in 2014 compared to 2013, and only abated slightly in 2015. Depending on one’s perspective, this overall step-increase in GA-GA incidents over the last 2 years is either cause for concern in that GA are having more Airprox or, on the other hand, may be cause to rejoice in the fact that our engagement strategy over the last couple of years is bearing fruit through a greater awareness and willingness to report Airprox. However, notwithstanding the latter perspective, such a marked increase seems intuitively to indicate an underlying issue.

The equivalent AAIB Annual Safety Review for 2015 states:

"Nine of the AAIB’s reported field investigations were into accidents involving fatal injuries. Of these fatal accidents, eight were as a result of Loss of Control inflight (LOC-I) and one due to Controlled Flight Into Terrain (CFIT). Other factors recorded were one accident was a mid-air collision (MAC), one had a powerplant failure (SCF-PP) and one related to fuel (FUEL). Two of the fatal accidents suffered post crash fires (F-POST)."

Also very revealing, from the GASCo Flight Safety Extra:

"Avoiding collisions – a monthly update from Director UK Airprox Board giving some learning themes for recreational pilots.

The Airprox Board assessed 23 incidents during the January 2017 meeting, 7 of these were drone/UAV reports and 16 were aircraft-to-aircraft incidents. Of the aircraft-to-aircraft incidents, a definite risk of collision was assessed to exist for 5 events (1 x Category A and 4 x Category B). Two of these risk-bearing incidents involved aircraft joining the visual circuit (see comments below and the Airprox of the Month) which reinforces the need to fully understand the various join types, adhere to procedures, and watch out for others joining the circuit who you may not have heard on the radio. The other main themes discussed this month were: poor airmanship decisions in 9 incidents; late-sightings/non-sightings in 5 events; and 3 miscellaneous incidents involving simple conflicts where neither pilot was fully aware of the other.

As for the 2 incidents involving aircraft joining the visual circuit, both of these involved a combination of pilots pressing on when uncertain of the position of the other aircraft; assuming another pilot would do something he did not in the end do; pilots not following join procedures (thereby denying others situational awareness of where they might be); and confusion over radio calls that were either missed, or not representative of what the pilot was actually doing. As we have seen before, and especially at airfields with air-ground only, the visual circuit relies heavily on people being predictable (or clearly stating their intentions if they cannot be); robust lookout at all times; thinking about potential conflict points (and especially with respect to non-radio or radio-fail aircraft); and clear communication of intentions.

My Airprox of the month was one of these joining incidents. Airprox 2016210 was a Category A incident involving a PA30 and an RV9 that were both joining runway 27LH at Shobden. The RV9 pilot was joining from the south and conducted an overhead join as he stated on the radio. The PA30 initially wanted to join effectively crosswind from the north but agreed also to conduct an overhead join when requested by the AFISO. Unfortunately, the PA30 pilot then subsequently reverted to a crosswind join rather than flying through the overhead, and the 2 aircraft came into proximity near the upwind threshold. The PA30 pilot was of course perfectly entitled to join crosswind, but should have made his revised intention to do so clear to all, and should have avoided the RV9. The full report can be found on the UKAB website at (Welcome to the UK Airprox Board | UK Airprox Board (http://www.airproxboard.org.uk)) in the ‘Airprox Reports and Analysis’ section within the appropriate year in the ‘Individual Airprox reports’ tab."

[bcw]

I think we are going a little off-topic here! :)

[abgd]

It's nonsensical to talk about solutions if discussion of the problems is off-topic.


I hate to say this but I came to the conclusion some time ago that "see and be seen" is largely a myth. Because of the natural limitations of the eye, the main reason that there are so few mid-air collisions is because the air is such a big place and there are, relatively, so few aircraft flying in itThis is true; as you probably know there's been a lot of proper research done that confirms your view. Theoretical studies. Practical experiments with 2 aircraft where they sit a pilot as a passenger, and fly the second aircraft around and ask the pilot-passengers to record when they see it. All of it confirms what you say: a good lookout only slightly reduces your chance of a midair collision because you don't see most traffic.

My own view is that a good lookout remains helpful around airfields where you can predict - more or less - what paths the aircraft are going to take. That means you can focus your attention on the most dangerous regions.

As for the number of near-misses - I'm not particularly impressed. As the numbers of mid-air collisions are low, anybody trying to study them will do well to look at near-misses, which are more frequent. For example, if there were to be lots of near-misses in the Luton/Stanstead corridor this would be a good indicator that something ought to be done to prevent a future accident. However, if you say 'it's true that over a period of X years, mid-air collisions make up only Y percent of fatal accidents - but look how common near misses are', this doesn't make mid-air collisions any more of a risk.

It's true that midair accidents are often fatal when they happen, but even then they are infrequent enough to be rare causes of fatalities. The issue with yet another box of tricks is that it's potentially yet another thing to distract our attention from the important things in aviation.

This isn't to say that I'm against the idea. If the signal to noise ratio is low enough - i.e. it only distracts you when evasive action is actually required - then why not? And in the future I think we will need tools to enable us to share airspace with drones.

I think part of the reason mid-airs capture our imagination so much is that psychologically we like to think we can handle emergencies such as an engine failure or inadvertent IMC - even when this may not be the case. The idea of colliding with another aircraft then being a passenger all the way down though, is horrifying.

[crablab]

I think mid-airs with drones are more frequent than other aircraft at the moment!
Although saying that there was the PA-28 collision in the London vicinity which only serves to reinforce the requirement for especially good lookout under the LTMA.

Only one had Mode S and although that doesn't necessarily provide ADS-B most have ES which does broadcast on 1090Mhz albeit with only altitude information. Report here (https://www.airproxboard.org.uk/uploadedFiles/Content/Standard_content/Airprox_report_files/2016/New_assessed_reports/Airprox%20Report%202016201.pdf)

[Forfoxake]

It's nonsensical to talk about solutions if discussion of the problems is off-topic.

This is true; as you probably know there's been a lot of proper research done that confirms your view. Theoretical studies. Practical experiments with 2 aircraft where they sit a pilot as a passenger, and fly the second aircraft around and ask the pilot-passengers to record when they see it. All of it confirms what you say: a good lookout only slightly reduces your chance of a midair collision because you don't see most traffic.

My own view is that a good lookout remains helpful around airfields where you can predict - more or less - what paths the aircraft are going to take. That means you can focus your attention on the most dangerous regions.

As for the number of near-misses - I'm not particularly impressed. As the numbers of mid-air collisions are low, anybody trying to study them will do well to look at near-misses, which are more frequent. For example, if there were to be lots of near-misses in the Luton/Stanstead corridor this would be a good indicator that something ought to be done to prevent a future accident. However, if you say 'it's true that over a period of X years, mid-air collisions make up only Y percent of fatal accidents - but look how common near misses are', this doesn't make mid-air collisions any more of a risk.

It's true that midair accidents are often fatal when they happen, but even then they are infrequent enough to be rare causes of fatalities. The issue with yet another box of tricks is that it's potentially yet another thing to distract our attention from the important things in aviation.

This isn't to say that I'm against the idea. If the signal to noise ratio is low enough - i.e. it only distracts you when evasive action is actually required - then why not? And in the future I think we will need tools to enable us to share airspace with drones.

I think part of the reason mid-airs capture our imagination so much is that psychologically we like to think we can handle emergencies such as an engine failure or inadvertent IMC - even when this may not be the case. The idea of colliding with another aircraft then being a passenger all the way down though, is horrifying.

Your point about drones is important. You have virtually no chance of spotting a small drone with your eyes if it is going to hit you. However, I fear that even if electronic conspicuity is made mandatory for drones soon, there will still be lots of illegal ones (*) around so we will have to depend again on the air being such a big space.

Your point about another distraction (in the cockpit) is also well made. That is why I dislike a sophisticated virtual radar display. A simple display that can be included in the visual scan plus some sort of special warning (for example an increasingly urgent audible tone into your headset in a powered aircraft) of an imminent collision is much better imho.

(*) The BBC website reports today that "A passenger plane had a near-miss with a drone at 10,000ft as it approached Heathrow Airport.....Large drones are not permitted to fly above 400ft (121m) or within proximity of airports or airfields. It happened on 11 November 2016, so quickly the Airbus A320 pilots said they had "no time to react"..... It was one of four near misses between aircraft and drones in the latest UKAB monthly report, and brings the total in the past 12 months to 59."

[Forfoxake]

PS Why do most people persist in calling such incidents a near-miss.
A near-hit would be much more accurate!

[crablab]

Distractions are an important point.

Ideally, if everyone has ADS-B you would see, during your scan that there is someone ahead, similar altitude and heading your way. So you take some avoiding action and try and get visual.

What actually happens at the moment is, there isn't a mandatory requirement in EASA land so not everyone has the device and there is a lot of complacence around that - just because YOU have ADS-B in Class G doesn't mean everyone else does and doesn't mean the magic tablet is gonna always get you out of a sticky situation. So, we end up with more heads down in the cockpit. The other problem is what happens if everyone has ADS-B? Well, in some areas you're going to end up with a big yellow blob on your screen - fat lot of good for anyone! As the Dutch found out at Schipol when they made Mode S mandatory, more isn't always better in the context of radar clutter ;)

Drones? There needs to be some kind of proper certification for them and training. I don't like to be a spoilsport but it is stating to get silly the no. of drone related airprox. All it's going to take is for one to get ingested, then the large lithium "bomb" will go bang and you'll have an engine failure/fire/dismembering of turbine.

[Crash one]

Why are we still off topic?
When will we get a little box that can receive and re-transmit a GPS position signal sent to every GPS receiver?
Everyone and his dog now has some flavour of SkyDemon.

[crablab]

You can get that. It's called a Mode S transponder with Extended Squitter and a certified GPS. About £5k from Garmin I believe for ADS-B In and Out and should work with SkyDemon.

[Crash one]

No. That is not what I mean.
No doubt the tech is there if you are prepared to pay through the nose for the commercial varieties. No doubt the military have got something that would do the job, probably called radar or some such.
I mean a box that will detect any GPS receiver, including iPads, smart phones, tablets of all flavours etc. And with the capability to squelch out the ground based morons texting each other or car satnavs. Without the need for a transponder, certified dedicated kit etc. And certainly not at some stupid price.

[crablab]

I mean a box that will detect any GPS receiver, including iPads, smart phones, tablets of all flavours etc. And with the capability to squelch out the ground based morons texting each other or car satnavs. Without the need for a transponder, certified dedicated kit etc. And certainly not at some stupid price.

That doesn't exist and wouldn't work technically with consumer hardware as GPS is "passive". It is conceivably possible using ACARS to send your position up to Immarsat's server who then calculate aircraft in proximity and set data down ACARS to your aircraft. But that would require an ACARS datalink and subscription which would cost a pretty penny... (plus it doesn't exist)

There are a couple of "open" protocols - P3I and OpenFlarm that broadcast your position on an unregulated frequency - essentially an unregulated "version" of ADS-B. But that leads to a load more individual protocols as has been pointed out previously...

[Forfoxake]

I still think a cheaper ADS-B in/out system is probably the answer. However, what if the pilot and/or passenger had a smartphone with internal GPS switched on. Would it be possible and accurate enough to give collision warning to/from other similarly equipped aircraft through the 3G or 4G networks? I doubt it but just a thought!

[Jan Olieslagers]

a box that will detect any GPS receiver

That's a good one to offer on April 1st. Receivers are not that easy to detect electronically - to say the least.

[bcw]

Why are we still off topic?
When will we get a little box that can receive and re-transmit a GPS position signal sent to every GPS receiver?
Everyone and his dog now has some flavour of SkyDemon.

That is pretty much what OpenFLARM is, for £50. Ok it can't pick up any "GPS receivers" but it does make you visible on Sky Demon to anyone else who has one as well as showing you FLARM contacts and other traffic in certain areas.

[homeuser2003]

Dear all,

it´s very interesting to read this and this discussion seems to reveal more details than the actual OpenFLARM homepage. I´m a Pilotaware user flying a Mooney and I´d be very interested in having the FLARM reception inegrated to PAW. Till now I understood that FLARM reception may technically be possible but illegal. Could anybody connected to the OpenFLARM project indicate why their method of reception is legal and how it technically works? I guess if this is with good reasoning and given the fact that OpenFLARM is really "open", PAW developers could probably use the same method to integrate this into PAW.

Not that I would not apprechiate the effort that OpenFLARM developers invest, but I´ll not put two non-certified devices into my plane and in my view PAW is already noticable steps ahead...

Again: I´m just a user with no connection to any of the providers/developers. I´m just happy with what PAW does already and the only thing I´m missing there is FLARM reception. I actually don´t care much about the lack of FLARM Tx since it´ll in any case be me to divert to avoid a collision. Thus it´s far more important that I know where the glider is then vice versa...

Thanks

[Prop swinger]

What makes you think that Flarm reception would be illegal?

[Crash one]

What makes you think that Flarm reception would be illegal?

I thought it involved cracking the encrypted (copyright?) protocol that PAW are not going to do illegally.

[Prop swinger]

The standard way to get Flarm into a PAW is to use a Flarm as the gps source, nothing illegal about that.

[crablab]

What makes you think that Flarm reception would be illegal?

Technically, if you are breaking any encryption that means you are gaining unauthorised access to data/a system which is illegal under the Computer Misuse Act.

I don't know whether FLARM data is actually encrypted but it is certainly not in a standard format hence, why we have OpenFLARM.

[Prop swinger]

I doubt that. There are hundreds of receivers across Europe, I've never heard of anyone being prosecuted & it's not some underground network either, they are very open about who they are & where they are.

All of which is irrelevant, if you want to receive Flarm on a PAW, hook it up to a Flarm unit. It cannot possibly be illegal to use a Flarm to receive Flarm signals.

[crablab]

It cannot possibly be illegal to use a Flarm to receive Flarm signals.

Indeed not, because it's a FLARM device. If it's not a FLARM device and, for the sake of hypothesis, you're using a non-FLARM device and breaking encryption then it would be illegal.

[homeuser2003]

I may not have made myself clear: Of course I could link a pricey original Flarmmouse to my PAW but with OPENflarm not being a licensed genuine Flarm product, claiming to be legally receiving and using Flarm information, I thought there would be a way without paying the fortune to Flarm...

[xyray]

Anyway, my best wishes are with the team not to stall but to make further progress. It would be fine to listen to FLARM traffic and talk the own position (ADS-B-out via transponder, if necessary).
I would be happy if I could get a PCB and materials list to fire up my soldering iron ;-)


Richard