IO540

You prove my point for me that some people are operating under a misconception. There are people out there who will use their ACAS system (which includes TCAS and everything else in the market) in the horizontal plane. The system is not designed for that and is not accurate enough in providing bearings. They could be up to 30 degrees out.

Turning to the right simply because your display says the traffic is head on could actually be turning you right in to the guy you are 'blindly' trying to avoid. ACAS is only accurate for vertical avoidance manouevres, that is how it is designed.

It is not an airborne radar or an accurate horizontal situation display. It can give you a clue as to where to look and you might sight the traffic involved (or you might not). You can then take appropriate horizontal avoiding action. If you don't sight the traffic and manouevre horizontally based on the picture being given to you by your kit, don't be too surprised if you get a nasty surprise on occasion.

I think you're also operating under a misconception, PPrune Radar, about the alternative to TCAS and TCAD. You're thinking like a controller.

There's no doubt that ACAS systems are unsuitable for traffic management. To have traffic jumping around the screen while trying to work a busy sector would be madness, and so the sorts of azimuthal accuracies that are obtainable with ACAS are orders of magntitude less than the requirements of radar.

But the pilot's situation is a little different. Imagine that, as usual, we're in a situation where, because of controller workload, traffic density, or both, a radar advisory service is unavailable or impractical. So some helpful controller is calling traffic under a RIS.

And he calls "G-CD, traffic 12 o'clock, 3 miles, opposite direction, height and type unknown". At a typical closing speed of 300 kt, we have a little over 30 seconds to the potential impact. So we look for a few seconds, in the 30 degree arc -- that's the resolution of the clock code too -- ahead of us. And we see nothing. "G-CD nothing seen, update please?" "G-CD say again please, I was on the landline..." "Update on the traffic you called for G-CD please?"

A number of possibilities now emerge:

"G-CD he's now in your 10 o'clock, half a mile, passing down your left hand side"
"G-CD he's now in your 2 o'clock, half a mile, passing down your right hand side"

In either of those, I hold course. I never saw the traffic and had no way to manoeuvre to increase separation. If I turn left in the first case, or right in the second case, I make matters worse.

"G-CD he's still in your 12 o'clock, half a mile, opposite direction"

Course of action now? Prayer, perhaps?

Now compare that to ACAS. I find an aircraft at 12 o'clock, 3 miles, no altitude indication. I look out, but see nothing. I look again at the display for a few seconds. The relative bearing is increasing, it's now at about 12.15, 2 miles.

What do I do? Turn to the guy next to me and say "well the azimuthal resolution of TCAS is only 30 degrees so let's just sit here and see what happens?" Of course I don't. I commence a gentle turn to the left to increase the separation, looking out all the time. And I do that because as a pilot I'm a safety manager, and for every occasion that the manoeuvre takes me closer to the other aircraft, there are 99 occasions when it really does increase the separation. Those are good odds. And without guaranteed separation from ATC, odds are all I have when the notoriously unreliable human eye fails me.

Compare

with

They are in effect the same thing, i.e sometimes the information will not be accurate in the horizontal plane, although you give a numerical value (backed up by a report somewhere I guess).

ACAS is nothing like a controller since they are trying to provide different things. A controller is trying to meet separation standards, which are large. ACAS is monitoring other traffic with a view to preventing a collision only. It won't care what your separation is, just as long as you manouevre out of the impending collision. It will also wait until an aircraft is potentially going to be much closer than a controller (in perfect circusmtances) would before giving a warning.

It is the last safety net you have left when ground based systems and your own eyes haven't worked. But it's still only designed for vertical resolutions. Being aware of the limitations is an essential part of the 'training' before using such kit in anger. But then no one insists on training apart from the large aircraft operators.

Yes. I wouldn't for a moment argue with your point that pilots need to understand the limitations of ACAS, and that's particularly relevant to using it to manoeuvre in the horizontal plane.

I think there are three reasons why ACAS uses the vertical plane for resolution:

1) greater precision of the measured value (and trend) of level vs azimuth
2) easier 1-dimensional deconfliction problem in calculating an advisory
3) ATC tends to use horizontal deconfliction (vectors) so it's less likely to contradict ATC

All of those are reasons for preferring a vertical manoeuvre if possible, even as a human-initiated response to a TA. If it's not possible, using the azimuthal trend information to increase separation make sense.

Do you have a reference?

Systems such as the Avidyne 600 give you a reasonable azimuth reading, from what I have seen. Way better than nothing which is all we get most of the time it is most needed. Way better than an RIS under which the controller is not obliged to give you every contact because it is subject to controller workload.

The majority of traffic is not spotted visually even when you have a bearing (from TCAS or from RIS) even if you have four people in the cockpit all "knowing" where to look. A 30 degree turn or a climb/descent is easy enough to implement.

Don't knock a piece of technology just because it isn't perfect. One day it might be much better - when everybody is emitting GPS lat/long over Mode S 1090ES, just like airliners do already. But the altitude value will still be baro derived (instead of a precise GPS value) so it will be +/- 200ft, so if flying at 2400ft under the LTMA the smart choice will be to turn rather than a level change.

Interesting article TCAS Traffic Display

Of note: So if we go down the route above of a "TCAS type" system, but with TAs only, it will be hard to relate to TCAS where we are not allowed to manoeuvre based on a TA (only).

I am not 100% against such systems... but the implications of bringing such systems in would need to be very carefully evaluated / applied. As above, what do you do if your "system" advises you, or indicates such that you wish, to manouevre whilst under a Radar Service? Do you disobey ATC?

Even if you "relegate" the system to vertical avoidance only (as above, whilst TCAS is pretty good at bearing info, it is fallible, and can easily make a safe situation catastrophic if believed), without an RA "decision" process - it can again lead to problems... TCAS uses "crossing RAs", where an aircraft above you, but descending, might ask you to climb... so a GA system where a pilot seeing an aircraft "above" (but not appreciate / judge it's high RoD) might descend and now create a collision.

If the sole purpose of such devices is to "lead your eyes to the traffic", and then take action based on the resulting visual sighting, then it would seem a benefit (provided the accuracy is such that it does not have you looking in the wrong place :{ ). But a device that causes you to manoeuvre, based on it's information alone, is going to generate almost (?) as many problems as it solves IMHO...

NoD

Interesting article, NoD, but it relates to the pilot acting contrary to a radar control service such as one gets in CAS / airways.

The context here is GA, OCAS, where the only radar service under which the controller is legally permitted to suggest avoidance is a Radar Advisory Service. Very few pilots use RAS because ATC sends you all over the sky, often with 90/90/90 degree doglegs flown around nontransponding contacts which for anybody cares could be 5000ft below you. It's also not available most of the time you might want it, due to controller workload because the required separation is impossible to achieve in the actual traffic density OCAS.

So, with the kind of TCAS systems available to GA today, all one is going to get is other traffic azimuth/altitude information, and since ATC giving a Radar Information Service (the most common radar service one goes for, OCAS) aren't allowed to even suggest which way to turn, the pilot is never going to be acting in conflict with ATC.

I am afraid that in GA we are pretty well on our own and have to do our own "safety management".

When I fly airways, which I do occassionally, I fly FL100-FL190 and one doesn't need TCAS there because there ain't no traffic there anyway! CAT flies way above or way below, and the routings take one many miles away from any CAT climbing/descending in the busy terminal areas. Never flown a hold on ATC instructions, either. And other GA in the airways is rare as rocking horse s*** :)

“The majority of traffic is not spotted visually even when you have a bearing (from TCAS or from RIS) even if you have four people in the cockpit all "knowing" where to look.”

Glorious day for flying today. Turned the GPS and the Radio off (but the transponder on C). Got the map out and did a tour of Wales. Hit the waypoints +/- 1 min, spotted lots of other aircraft enjoying the weather (had to dodge a few gliders).

Maybe we should take a really good look at the biannual flight review. We could include some really accurate nav using the map, and check people are using a proper scan/lookout. Any pilots not to up to the job would have to fly with a competent companion for 12 months, they might learn something.:rolleyes:

Rod1

Rod1, but how close did you come to those other aircraft that you never saw today?

I suspect you don't fly with a TCAS/TAS because if you did you would understand that my question isn't borne out of sarcasm. You didn't spot all the other aircraft out there, because no-one does.

PPRuNe Radar, what you say is basically correct but the limitations of TCAS/TAS equipment are outlined in the instruction handbooks and the Flight Manual.

I have to agree with IO540, sometimes pilots are obliged to make a captaincy decision based on insufficient information.

I understand the point in controlled airspace, but in class G following your TCAS procedures (which are being related as a rote set of prescribed actions) is even worse. You have no idea what the other aircraft is going to do, as without the other half of the system, the other pilot is just going to use his judgement on where he thinks you are and make some manoeuvre (or just hold his course relying on the big sky)

In real life controllers seem to worry a lot about some separation but none about others. On a busy hazy Saturday in the South there are lots and lots of light GA aircraft, sandwiched into a thin slice of air being asked in some cases to navigate with positional accuracy similar to PRNAV (i.e. the gap between Biggin and Gatwick airspace - which at its tightest is only 3/4 mile wide on each side of the M25) with the warm words of comfort - 'limited information service only due to high traffic density and poor radar performance'. I am not complaining, only pointing out that the GA traffic advisory concept needs to be evaluated in a world of separation expectations much reduced to those of IFR in controlled airspace - and where high quality radar information is only provided on an adhoc basis.

There are numerous posts where some GA pilot says 'I was on a RIS and someone crossed me 50 feet above me', controllers respond with 'well it is only information and you are supposed to be looking out!' (which of course is true). Having a bleeping things saying 'traffic closer and closer same level' is a huge step up from 'Sorry, was busy'.

Most of the arguments I have heard against GA traffic detection systems have been based around a logic that most things out there to hit aren't visible to these systems anyhow and having one may give a false sense of security. The fact that it is not as good as having TCAS, turbines, and Class A from the ground up is true but is not a good reason not to take the first step. (It reminds me a bit of the logic that GPS approaches are not perfect so we should stay with NDBs ;) )

You are joking aren't you? Follow the M25, or is that PRNAV?

Gliders have low cost ACAS
 

here is a link to a low cost collision avoidance system
Flarm - Homepage
It is only £400 and needs no maintenance. Gliders have fitted these in large numbers and it does work in aeroplanes or helicopters too. This week alone I have had numerous warnings of traffic approaching from my blind spot or out of sun.
I remember an Australian flying school that fitted a similar system (ADSB) to all its training aeroplanes years ago, should UK flying clubs do the same?

The advantages are that you don't need expensive transponders, or radar, or ATC. A complete stand alone low cost life saving device.
FLARM will also warn pilots of obstructions (masts and ski cables etc) in many parts of Europe

FLARM does not appear to have a future in mainstream European GA because it has no ICAO and thus national CAA backing.

ADS-B is "coming" but it will be implemented using the Mode S data channel, known as 1090MHz Extended Squitter.

So if you have say a GTX330 Mode S transponder, and connect it to a GPS, it will radiate your lat/long. This already happens on airliners' Mode S installations but the resulting system is classified as Enhanced Mode S which is a certification issue for GA which currently uses Elementary Mode S (which AIUI is not permitted to radiate any parameter at all).

Then you need an ADS-B receiver and I don't know how that will be done. Maybe a GTX330 can do that bit too?

ADS-B would work well because it uses the GPS position which is ultra precise, and won't need the complicated direction-sensing multiple-antenna and very expensive installations which present-day TCAS systems need. In principle, a cheap PDA fed from a 1090ES receiver could act as your "TCAS".

But it is all many years away, in Europe, and as always there will be exemptions for VFR which will make it to a large degree worthless.

FLARM is here now
 

With over 11,000 aircraft currently fitted with FLARM why should European GA wait for the local " Authorities on Civil Aviation" ?
It may not ( but probably could) meet certification, but it is here, now, working and saving lives.
If light aircraft pilots fit it this week end it could save them next week, not in 5 years time when full ADSB comes along. Light aeroplanes can use this now I believe and it does not need to be "certified".
Having said that, the risk of collision remains low. Over central UK yesterday there were hundreds of gliders and aeroplanes ( possibly 700+ and certainly 250 competition gliders alone) airborne within 50nm of Oxford between 1200 and 1700 amassing thousands of hours airborne without miss hap, and the vast majority without transponders or talking to ATC. How could that number of aircraft actually talk to one ATC centre and how could anyone separate all those contacts on radar? 700 aircraft 300 minutes! FLARM is actually designed to work in a high traffic density situation and could be the correct solution, but I am no expert. All I know is that it was worth me spending my hard earned money on.
I have given up on the light weight, low power transponder malarkey, I don't think it will ever happen.
bb

Just to check, your FLARM thing will only work against other FLARM equipped aircraft? And what % of GA aircraft are so equipped, in say, the UK?

Obviously if it works, and it gets over say 50% of aircraft equipped... it becomes useful and worth having. But there's rather a chicken and egg before that?

Gliders I'd rather leave out of it - they are somewhat unique in "congregating" in areas risking collisions, and a close community where establishing the critical mass may work (or already has?).

Do you have a breakdown by aircraft type for that figure?

IO540 You somewhat miss the point I was trying to make (no doubt poorly). TCAS gives an "indication" of bearing, but it is sometimes poor, and variable (tragets hop about in bearing but are of course unerringly accurate in range).

The article makes the point it is very easy, either by poor interpretation of, or poor accuracy of, the "bearing" to actually reduce the separation by taking action on it.

Take a head on target at 1NM when you wish to start avoidance, and a 5 degree "uncertainty" in bearing. If you are on opposing tracks, and 0 degrees off, then you would hit each other. If you are 5 degrees off you would be 500' apart - close, but you live. Trouble is, if that accuracy is misinterpreted / wroingly displayed, you may take the lateral action and cause the 500' to become nothing :confused: As was being implied by some (inappropriate) action taken in the article.

TCAS in fact can be 30 degrees out... what sort of accuracy can the GA systems out there guarantee? As you say and on an individual basis I can agree. Trouble is, for a manufacturer, or regulator, or indeed anyone, to encourage or mandate such systems causes the big "liability" word to enter the equation... where the consequences of it creating a collision outweigh leaving people to look out and bear the responsibility.

NoD

sorry I am not able to give a current breakdown but there was some information on the FLARM website.

Indeed FLARM only works against other FLARM equiped aircraft

Indeed, chicken and egg. What did the guy with the first phone do with it?

Probably made a few more as gifts for friends and family. :) Whilst it might be a good idea, I can't see the manufacturers giving them away free just so that we will all be persuaded to use them in the future. :hmm:

ICAO Annex 10 Volume IV is a good place to start. Surveillance and Collision Avoidance Systems Standards and Recommended Practices. My italic bolding added.

Never thought of FLARM, but if it s well under 1.000 Euros..., why would we not?

Are there GA plane in the UK that carry it? Such as one who frequently fly near glider sites? Experiences?

Nothing to stop anyone starting a condolences thread, which is the usual form if people want somewhere free from debate to record their rememberances and tributes.

No one has ... yet.

Yesplentyhourstogo
 

why the annoyance? I d never heard of FLARM and although it seems a one brand affair, if thousands have used it successfully in gliding, why should we not consider it?

Condolences is not what this forum is (only) about. It is about exchanging views in normal manner in the hope we can all learn from it.

I didn t know any of the crew(s), and i think it s sad. I feel for their families, but it seems pretty hollow to say that here. If i knew them i d have started a condolence register on an appropriate website.

To get back on subject: Any powered GA planes that use FLARM? Experiences?

Pprune Radar - that ICAO reference is again in CAT context, not GA.

Also nobody is suggesting making TCAS mandatory; for GA that would be silly. The only bit which could be mandatory is transponder usage, unless technically impossible.

FLARM was pushed very hard by the BGA in the 1st Mode S consultation. The CAA’s response to the consultation formally rejects it as an acceptable solution for a number of reasons.

I know some of you would love to a nice black box which will guarantee your collision avoidance with no pilot effort but it just is not going to happen. The CAA has stated that it will not mandate any form of transponder and most flying machines do not and probably never will have one. The CAA took its current position because it became convinced that it was not technically feasible to fit a transponder to most flying machines. No transponder = no warning = work on your look out. The same is also true of radios, most do not have one.

Next time you are in good VMC make a note every time you spot another flying machine and make a guess as to weather it has a transponder or not. I assume traditional group a has, LAA types 25%, and micros, gliders, hang gliders etc 0%. I think you will find that a very large % of the things out there have no transponder and are not likely ever to have.

Rod1

Lookout
 

Took a 45 min local flight out of Cov on Sat ( was due to go last Sun just before the tragic event).I have to say my lookout was keener than ever (sure my head rotated a full 360) and although Cov was giving it's usual excellent FIS I still never got visual with traffic mentioned:eek:.The most worrying aspect for me was the amount of 'heights unknown' I was getting about traffic.
I took matters into my own hands and gave regular position/height reports more for the benefit of other pilots than ATC.

Guess if this sad incident has provoked people into thinking harder about their flying ( me included) then their loss has not been totally in vain.

MM

Sorry, but you're wrong. The ICAO standards don't specify that they only apply to CAT, otherwise as a GA pilot you could ignore all the airspace classifications, rules of the air, RT phraseology, equipment specifications, international licencing rules, etc, etc. The standards are published so that States may meet an international standard and so that industries throughout the world can provide equipment which meets a common standard and not one which operates in isolation. States may file differences to ICAO reccomendations, but they should then appear in their AIP. I can't find one which says that Airborne Collision Avoidance System (ACAS) standards only apply to CAT in the UK ... but then that's because they don't.

Bear in mind ICAO does not say that TCAS is the only show in town for collision avoidance systems (generically known as ACAS). Any company could produce a collision avoidance system which is not TCAS, but if they want it certificated for airworthiness purposes, then they'll almost certainly have to meet the ICAO Standards since this is what most States in the world base their requirements on.

TCAS standards take the generic ICAO ones and apply more detail to specify a common standard for people who build the TCAS equipment and operate collision avoidance systems using TCAS as their tool. A group called the RTCA publish those but they will still meet the ICAO specifications as a minimum, and do. These standards don't say they apply to CAT only. Why would they ??

As others have said, there are other systems out there such as FLARM and TCAD. Others are on the way too, like ADS-B. They still all find their specifications coming down from ICAO, and then being further detailed in RTCA or EUROCAE documentation, regardless of what type of aircraft they will be fitted in.

I don't believe anyone here did say make TCAS mandatory ... or maybe I missed it.

Mandatory Mode S is currently the European administrators answer to everything. Many are still to be convinced, me included.

Rod, you keep banging on about this, but when you say "most" you are obviously counting all those parachutists with a lawn mower strapped on their back.

The vast majority of "flying machines" which actually pose a risk to what I would call a normal GA pilot (flying a powered plane at normal non kerb crawling levels, making proper use of available vertical space) can most certainly be transponder equipped.

Gliders pose a risk to normal GA but statistics suggest it is extremely small - even smaller than then very tiny risk of a GA-on-GA midair.

IO540

Ever flown near to the Malverns on a thermic day? or try flying west to east when Popham or Sandown have a microlight day?

For my type of flying, these are the big risks - that and pilots who don't look out the window. This summer I've lost count of the times I have had right of way and have had to change course and put on my landing lights to avoid a dozy pilot who never made the slightest attempt to change course as required under the Rules of the Air.

Obviously I can't know why they didn't see me, but lit up like a Christmas tree I would guess looking out wasn't their prime concern.

I cant help feeling there is some lack of understanding of TCAS in light aircraft.

I would like to set out my experience.

The last few days round trip was to and from the west country - a couple of hundred miles in each direction.

About 80% of the flight was with a RIS, 100% with TCAS on the MFD. The outbound route was all low level - not above 3,500 feet and coming back about half above FL75 and half low level.

TCAS was set to display all traffic - the options are above and below with or without a height buffer and unlimited. The traffic appears as the usual diamond on the moving map with altitude if the traffic is transponding mode C or S and an arrow to indicate the altitude trend.

Over the total route there was one primary contact identified by AT which was not transponding but presented a "threat". Of course it was not displayed by TCAS. The position and altitude of all other traffic, and there was a lot outbound, coincided with that reported by AT.

At GA speeds, (and in this case a cruising speed of around 175 knots) even with the traffic closing from ahead, it is simple to adjust the track and height to "ensure" separation. Moreover in almost every case it is reasonably straightforward to "work out" if the traffic is en route or manoeuvring.

The system may not be perfect but with the autopilot engaged and TCAS turned on your situational awareness of other aircraft and your ability to give them a wide berth is a million miles apart from working the same task visually. Moreover it enables your eyes to be outside hoping to pick up anything the "automatics" have missed.

What’s my point. Well TCAS is not a panacea anymore than FLARM. However both systems provide a very significant improvement on the mark 1 eyeball. Most en route traffic above 3,000 or 4,000 (on this trip at any rate) would seem to have been transponding and TCAS appeared to identify the traffic accurately 100% of the time. For me I am a great deal more comfortable having TCAS in the cockpit. I realise it is not a guarantee that I wont have a close encounter but it stacks the odds by another significant margin in my favour.

I felt I should make this post because I am not sure from some of the other posters whether they write from the perspective of having used TCAS in the cockpit. I recognise that I am privileged to fly an aircraft fitted with this system however as the price of modern avionics is driven down, glass cockpits become more common and less expensive alternatives become available (such as PCAS which I have found to be very reliable and already with the ability to link to a moving map display) I think we should not under estimate the safety enhancement these systems bring to general aviation. I made the decision some while back never to fly without a least a PCAS - it cost me a few hours flying but I reckon it was one of my best buys.

Finally, as I said before, I sense there is that brigade who are all too ready to chip away at TCAS or PCAS by inferring it is yet another excuse to fly the aircraft on instruments in VMC. If you allow it to be, then I guess they would be right. However, I flown with plenty of pilots who have a cockpit of steam gauges without a GPS in sight that fly on instruments in VMC. TCAS and PCAS do not encourage you to be head down any more than any other instrument and used properly they free up time to maintain an effective scan.

Sure, as another poster commented, there are plenty of aircraft not transponding but look at it this way, if I can identify all those that are, at least I have narrowed the odds in my favour. Maybe by a bigger margin that you might think because if it is fast its probably transponding and I reckon anything I am closing at 400 knots or more I am not going to do a very good job of spotting.

Ahh - so that was why the b*st*rds didn't try to avoid me - they were probably on autopilot. Thanks

Objectively, how close did they actually get?

I don't take avoiding action unless required. Some pilots get nervous of a contact passing one mile away - pointless.

Fuji...

Just to check, are you describing a full ICAO standard "TCAS" system?

Please assure me you do not adjust your track based on the TCAS display, but only after you acquire the traffic visually? And if you fail to acquire the traffic visually, you maintain track and height (or V/S) as and until you get an RA? Please :ugh:

NoD

Objectively? Difficult to say but in one case I saw the approaching aircraft about 30 seconds away and watched it closing on me. It was clear he hadn't seen me even though I'd switched all the lights on and my aircraft is quite brightly coloured. Being a coward I'd started to move out of his way and there wasn't a problem in the end. However, if I had taken the view, that some express, that I had right of way, then who knows.

My general view now is that I don't trust anyone to see me - be it on TCAS or using Mk1 eyeball - so will move out of their way.

NigelOnDraft

Skywatch has some limitations.

It will issue a traffic alert but it will not provide an RA.

The operating manual warns that the sytem should be used to visually acquire the traffic and then adjust track and height to ensure seperation.

AOPA conclude that pilots are far more likely to be able to acquire traffic with TCAS, than without.

You raise an interesting question.

In the event it has not proved possible to acquire the traffic what should the pilot do? With a system that initiates an audible RA is it not the case the pilot is expected to recognise and enact the RA within 5 seconds whether or not he has acquired the traffic? Response to a further RA is expected within 2.5 seconds. Of course TCAS have been developed primarily around the needs of commercial operators in a CAS. Examples outside CAS therefore seem to be rare. I have read the report of the incident between a Boeing 737 and a Tobago outside CAS in 2003. In this case the Boeing had the advantage of dual crew. The co-pilot was the handling pilot. The commander was solely concerned with "see and avoid". TCAS indicated traffic below and the descent was arrested (although the traffic had not at that time been visually acquired). Subsequently TCAS issued an RA to climb. The commander took over and complied. At no time did either crew members visually acquire the traffic. The Tobago pilot saw the traffic which he said appeared to be crossing his track but he thought this was probably an illusion and did not take further action.

So given the limitations of the Skywatch system a fast contact is approaching you from directly behind. (you might just as well be descending with traffic below as in the example above). The only way you are going to visually acquire the traffic is to turn away from the traffic. What action would you suggest? If you do nothing at best a few seconds before the collision you will get "traffic, traffic, traffic" - you will never get an RA. If you turn away from the traffic you acted before visual acquisition. If you turned away and climbed or descended you have also acted without visually acquiring the traffic as did the boeing crew.

We can debate the risks involved in operating light aircraft in IMC outside CAS. The fact of the matter is that pilots do, and the law permits such operations. Often no RIS is available. Once again the pilot is never going to visually acquire the traffic but Skywatch will for sure paint the traffic on the MFD. As the risk of a collision increases in the event no avoiding action is taken no RA will be issued other than "traffic, traffic traffic". Please assure me in such circumstances you will do something to avoid the traffic before you visually acquire the traffic.

Systems such as Skywatch are being used in a far less controlled enviroment than I suspect their manufacturers in the States may have envisaged. It maybe I need to give a deal of thought to how such sytems are best used. In these examples I find it difficult to rationalise the traditional wisdom that no action should be taken until the target is visually acquired or an RA is issued when the sytem is incapable of providing an RA.

I don't know why anyone would argue against traffic info in the cockpit. The world would be a safer place if everyone had a transponder / some method of broadcasting their position, and then those that wanted to could have a system to display conflicting traffic?

The TIS systems I have used in the USA are NOT TCAS but they have brought to my attention numerous targets which I wouldn't have otherwise seen - as displayed here. If nothing else as long as your altitude is different, a collision won't occur. You can also see altitude trends so if they are climbing or descending.....

I believe FLARM costs aout £500. If everyone in the UK or indeed Euroland decided to fit FLARM the cost would probably drop by half. They already offer discounts of 20% I think to 15 units or more, which I'm sure could be negotiable if someone decided to order several hundred or thousand.....

http://www.digital-reality.co.uk/traffic.jpg
http://www.digital-reality.co.uk/traffic2.jpg

Hear hear Al.

You would think that your average PPL'r would be able to afford a £500 investment in flight safety, never mind a snip at £250 if more followed suit. But then again, we still see rich PPL'rs arriving at Guernsey on almost dry tanks just to save £30 on a fill up! :rolleyes:

VFE.

If the CAA were to give a real (non political, rational, sensible) recommendation to something like FLARM then we would see a real take up. And largely from the traffic types who need it. The problem is that these people (CAA) are part of the 'system' and unless it has a serious price tag and industry lobbying and all the expensive things which provide the gravvy train they have no interest.

I'd buy FLARM if 40% of other aircraft were likely to have it. I have Mode C - and the only real benefit I get is easier transits - which is a bit marginal.

Mode S - a complete and utter waste of money unless if comes with TIS. Mode C - well hopefully nothing over 5750 kgs will bump into me, something of an investment. Could I get something similar to alert the gray pointy things? Unfortunately not but maybe coming.

And yet tomorrow we could all go and buy FLARM - and with a bit of promotion I'm sure many of us would. But it offers no international conferences, no expenses paid jaunts and so the people who are supposed to have a real, rational view of risk management ignore it.........

My guess is that one problem with FLARM is that it is not available in a certified form, and there is a limit to how much velcro-attached electronics, powered from the cigar lighter, the owner of a nice plane is going to put in.

Even fitting proper aircraft power connectors for portable devices is a bit of a grey area...

The £1000+ ZAON unit which gives you some kind of directional information is a pretty tacky installation, with the cigar lighter lead running right across your instrument panel.

A saleable FLARM unit would need to interface to panel mounted MFDs or whatever. And then it wouldn't be £500 but £5000, plus aerials, plus installation, plus certification.........

i hope the CAA read this forum