PCAS collision avoidance

[europaflyer]

I heard yesterday about the tragic collision between two RAF Tutors, killing two instructors and two young air cadets. I recall hearing about one or more midairs last year as well.

A large number of aircraft are now fitted with transponder equipment. Because of the number of ground stations and commercial air traffic, this equipment will be interrogated regularly. PCAS units (passive collision avoidance) would therefore function well if used sensibly by pilots.

Both the Tutors were fitted with thousands of pounds worth of transponding equipment, which was useless to them because they did not have a 300-pound gizmo fitted.

I would like to hazard a guess that in most airproxes between 2+ seat aircraft, at least 1 aircraft has a transponder. Therefore, the collision could be avoided with a simple, comparatively cheap unit which every pilot could carry - it runs on AA batteries.

The accepted position of GA on any cost related issue is to put its fingers in its ears and dig its heels in. Why, this time, don't we be proactive and invest in the technology which could have saved two young lives, and those of their pilots? Even, dare I say it, pressure the CAA in to making it mandatory, so if your aircraft has a transponder, then you know that everyone else will see you?

[IO540]

The problem with the £300 one is that it doesn't tell you the azimuth (heading) of the conflicting traffic.

To get the one which gives you some idea, it is the £1000 one.

But all these are - for paperwork / regulation reasons - portable cigar-lighter-plug type things which IMHO put a lot of people off because you end up with the power lead strung across messily the instrument panel.

If one could fit the £1000 one somewhere neatly, that would be something else, but there is no legal way to do it because it is not certified for a permanent installation (not in a G-reg, for sure).

A proper installed system starts at around £10k, but is rendered much less than useful by the number of planes whose pilots are exercising their free citizen's privileges and flying with transponders turned off.

[soay]

It brings it home to you how inadequate see and avoid is, when it fails so tragically for two experienced RAF pilots. I'd support any proposal to make mode C mandatory in all powered aircraft with electrical systems. That should encourage the take up of collision avoidance systems, and so reduce their prices.

[robin]

... but the problem remains PCAS only detects transponding aircraft. You may end up coming into conflict with a Luscombe (see AAIB Feb report) or Jodel without a power source for a Tx and PCAS - both power-hungry.

I tried the £300 one coming out of the PFA Rally some years ago. The sky was black with departing aircraft but not a squeak from the PCAS, which burned through the batteries in very short order.

When aircraft are outside CAS there is no requirement to be on radio or they might even have been talking to different operators. The Luscombe incident makes it clear that even if they had asked for a LARS service, it wasn't available.

Lookout isn't perfect by any manner of means, but often it's all we have.

[europaflyer]

Does anyone else have experience of how well the units work?

On the point of it not providing bearing info - I would hope that if a unit told you that there was traffic nearby then you would find it visually, regardless of what info it gave - and that range and altitude would be sufficient for this. If it is out of line of sight behind the aircraft, then odds on it won't be a threat in most cases, at it will either see you ahead, or have insufficient speed to catch up.

I have seen euipment on sale for installing in a panel and hooking up to the electrical supply for the 300-pound set.

In the case of the two Tutors yesterday, they would very probably have been in range of a ground station interrogating their transponders, and therefore the equipment would probably have prevented this tragic accident from happening.

[chrisN]

Flarm would also have almost certainly helped avoid this, but GA is apparently largely in ignorance of it or resolutely against fitting it, even though many GA pilots continually complain about gliders being a collision hazard, and UK gliders are getting Flarm in increasing numbers.

(Unlike PCAS, Flarm alerts when a collision is likely i.e. converging tracks, not just another unit in the vicinity which may not be a threat; and it shows the direction of the threat. It does not alert nearby but not converging track units.)

Same arguments as PCAS re wires etc., however – it would for most people be a portable piece of equipment, needing a battery supply or lead to a lighter socket or something.

As I have posted several times before, GA power/power collisions are more frequent than GA/CAT (civil air transport - thankfully none yet in the UK) or unrelated power/glider (only about 4 in the last 30 years).

Regarding wider use of FLARM, my personal opinion is that for the UK, use by gliders will increase slowly from a few per cent to a significant proportion, when the critical mass will be perceived as being large enough to encourage most glider pilots to use it. Unless something better comes along for powered GA, I think it quite possible that the same thing would happen, with the timing a few years later. I suspect that the middle phase, rapid increase in use once a critical mass is reached, will happen because those without will be shown how many more aircraft they can’t see that are in fact detectable. Just my opinion.

see Flarm - Homepage (http://www.flarm.com)

(No commercial relationship with Flarm, just a customer).

Chris N.

[Rod1]

I do not know what the cause of the RAF Tutors accident was, but there is a possibility they were formation flying so PCAS would have been irrelevant.

If you take the recent AAIB report on the Staffordshire mid air (See separate thread) then you get an interesting picture. The vintage aircraft spotted the Micro, took avoiding action and was collected by a turboprop. The vintage machine and the micro had no transponder and there was no radar service available in the area. If the turboprop had had PCAS it would have failed to see either of the other aircraft, but see and avoid avoided the potential conflict between the vintage machine and the micro.

I fly from the same strip and the vintage machine and about 80% of locally based flying machines are not transponder equipped. It if far more likely that I will fit FLARM than PCAS.

Rod1

[NorthSouth]

soay:It brings it home to you how inadequate see and avoid is, when it fails so tragically for two experienced RAF pilotsI presume like everyone else you don't actually know (a) what these aircraft were doing when they collided, (b) whether they knew of each other's presence, (c) whether the pilots were RAF (not all AEF pilots are) and (d) how experienced they were. So I think drawing conclusions about the efficacy of see and avoid may be a tad premature.
NS

[Slopey]

I do not know what the cause of the RAF Tutors accident was, but there is a possibility they were formation flying so PCAS would have been irrelevant.

Off topic I know, but on the BBC site but one of the eye witness did mention something along the lines that "she didn't think planes flew that close" and "for a couple of minutes". So in that case PCAS wouldn't help.

[RatherBeFlying]

Flarm is basically a 576 Euro TCAS box for us little guys.

Two bureaucratic obstacles to Flarm:
Not Invented Here as far as ICAO is concerned -- TCAS will have to be pried out of their dead fingers:}
The manufacturer refuses to sell in North America because of product liability issues

Were I ICAO dictator, I'd buy out Flarm, license it worldwide and mandate an appropriate version (extended detection distance) in airliners so that they could spot the little guys in good time.

Sure beats putting Mode S in everything that flies when radars and transponders are on their way to being superceded by ADSB:confused:

[europaflyer]

As to whether the Tutors were flying in formation, I would say almost certainly no - formation flying in AEF, due to the presence of civillians on board, is usually an absolute no-no.

[tdbristol]

I have had one of the £1,000 units (Zaon) for around 18 months and found it works very well. It gives approx range., approx heading and altitude w/altitude trend, plus an audible alert 'Traffic' in the headset if something is near.
It is a minor pain having to put it in the rental aircraft with wires each time, but there have been enough times it has alerted me to close traffic - which I have not seen before the alert - that I would not want to fly without it.
Of course, you look out as best you can but you are bound to not see some other aircraft.
Obviously it does not pick up everything - only those with transponder on - but I would rather be alerted to at least some of the other aircraft than none of those that my Mk1 eyeball has not spotted.

[RTN11]

http://www.aaib.gov.uk/cms_resources...AY%2002-09.pdf (http://www.aaib.gov.uk/cms_resources...AY%2002-09.pdf)

from the AAIB report into the mid air collision in December 2007

"Following the accident to G-AKUI and ZK-KAY, AAIB investigators discussed mid-air collisions involving recreational aircraft, and electronic conspicuity, with staff at the CAA’s Directorate of Airspace Policy. The Directorate staff explained that, although they perceived a widespread concern about mid-air collisions amongst participants in recreational aviation, they were also aware of strong opposition from aircraft owners to mandatory requirements to fit transponders, on the grounds of complexity, cost, and weight. For these reasons, proposals to mandate widespread carriage of Mode S transponders had been withdrawn, and more limited proposals had been put forward for consultation. These proposals did not amount to an effort to reduce the collision risk between recreational aircraft, but only to protect aircraft operating inside controlled airspace from collision with recreational aircraft."

Whilst this is the mentality, there will always be collisions between recreational aircraft.

The human eyeball is simply not enough for collision avoidence

[Robin400]

Electronic conspicuity and collision prevention
Electronic conspicuity involves the carriage and operation of devices such as transponders and ‘FLARM’ (a device developed initially for gliders). These devices make aircraft ‘electronically conspicuous’ to other aircraft which are equipped with the means of detection of, or interaction with, the equipment on the subject aircraft. These systems require electric power and the fitting of wiring and antennae, which demand spare capacity from the aircraft’s power sources; they also add weight to the aircraft.
Aircraft owners may fit equipment such as TCAS, transponder proximity receivers, and FLARM, which assist their pilots in gaining awareness of other aircraft around them, and, in the case of TCAS, provide guidance to assist in avoiding collisions. Some lightweight devices are available, including some which carry their own battery power supplies.
TCAS is in very limited use in recreational aircraft, transponder proximity receivers are used by a small number of pilots, and FLARM, although gaining popularity amongst glider pilots, is finding less widespread acceptance outside gliding. It is widely accepted that the introduction of TCAS in commercial air transport aircraft has markedly reduced the probability of collision involving a TCAS-equipped aircraft and another transponding aircraft

[robin]

from the AAIB report into the mid air collision in December 2007

"Following the accident to G-AKUI and ZK-KAY, AAIB investigators discussed mid-air collisions involving recreational aircraft, and electronic conspicuity, with staff at the CAA’s Directorate of Airspace Policy. The Directorate staff explained that, although they perceived a widespread concern about mid-air collisions amongst participants in recreational aviation, they were also aware of strong opposition from aircraft owners to mandatory requirements to fit transponders, on the grounds of complexity, cost, and weight. For these reasons, proposals to mandate widespread carriage of Mode S transponders had been withdrawn, and more limited proposals had been put forward for consultation. These proposals did not amount to an effort to reduce the collision risk between recreational aircraft, but only to protect aircraft operating inside controlled airspace from collision with recreational aircraft."

Whilst this is the mentality, there will always be collisions between recreational aircraft.


Please don't take that comment at face value. There are genuine reasons why the recreational fleet has been contesting the Mode S hype from the CAA.

These include cost (up to £5k to fit a Mode S when the aircraft might be worth less than that) and practicality (no power source or battery life less than the length of a day's flying. There is little gain in safety except for the very short period when a commercial aircraft flies in areas where GA is prevalent - Class G. GA gets very little from that.

We were promised by the CAA a low-cost, low-powered Tx but this is years away. Add to that the cost of a PCAS and and that would wreck any idea of low-end aviation.

Don't ever think that we are hostile to appropriate use of technology - in the case of the Luscombe fatality, the pilot died, while the bigger aircraft landed successfully. It is likely to be the smaller aircraft that will come off worse.

But given that the ATSOCAS services are variable, carrying expensive kit will not give much in the way of safety. Look at the proposal for Jersey Zone, for example. In future when you ask for a Traffic Service it will be downgraded to a Basic Service - ie non-radar derived information.

[dublinpilot]

Look at the proposal for Jersey Zone, for example. In future when you ask for a Traffic Service it will be downgraded to a Basic Service - ie non-radar derived information.

I missed that. How can that be? All traffic in the Jersey Zone is special VFR, which means positive control (and seperation) by ATC. How could you get a traffice or basis service while ATC provides seperation?

Is the proposal to downgrade the class A?

I totally missed whatever it is you're refering to. A link would be much appreciated ;)

dp

[soay]

It brings it home to you how inadequate see and avoid is, when it fails so tragically for two experienced RAF pilots
I presume like everyone else you don't actually know (a) what these aircraft were doing when they collided, (b) whether they knew of each other's presence, (c) whether the pilots were RAF (not all AEF pilots are) and (d) how experienced they were. So I think drawing conclusions about the efficacy of see and avoid may be a tad premature.
From BBC News (http://news.bbc.co.uk/1/hi/wales/7885595.stm):

Flying Officer Hylton Price was a retired wing commander who was part of the RAF voluntary reserves and an experienced instructor. He was a former Tornado and Phantom jet pilot.

Flt Lt Andy Marsh, who had "excellent flying skills", was only promoted last week and was waiting to start advanced fast jet training at Raf Valley.

Gp Capt Andy Naismith said that there were "very strict rules" to ensure planes did not fly too close together.

Seems likely that they were better pilots than most of us, but still did not see each other.

This would not surprise anyone who's flown with TCAS, or a radar information service, because of the number of times you're warned of aircraft that you can't see - even though you've been informed where to look.

[ShyTorque]

This would not surprise anyone who's flown with TCAS, or a radar information service, because of the number of times you're warned of aircraft that you can't see - even though you've been informed where to look.

I agree, TCAS makes you more concerned about maintaining a good lookout because you realise how many you probably failed to see before you had use of it. Conversely, pilots not having had use of TCAS or similar systems probably have a false idea of how busy the sky actually is. Even in 8/8 blue conditions the human eye is not good at spotting fast moving targets which occupy the same part of the retina - i.e. are on a collision course.

[Fuji Abound]

I am surprised given past discussion on this issue some of the misconception here.

Zaon Pcas units are the ones we talk about. There are two versions. The difference is the more expensive one indicates the compass quarter in which to look.

Having used both units alongside Skyforce CAS I can report that their accuracy is outstanding.

Both units give a range and altitude difference. This means it is relatively easy to determine if traffic is getting closer and is at the same height. There maybe sound theoretical grounds for not reacting to traffic you cant see, however if the traffic is getting closer and is the same height adjusting to ensure vertical seperation has in my experience always avoided a conflict whether or not I could see the traffic.

It is interesting to note on how many occasions you never see the traffic or when you do just how close it is. Knowing the quarter in which to look to spot the traffic is a benefit but I am not convinced the benefit is as significant as you might believe.

The cheaper PCAS unit is self contained. It runs on two AA batteries for at least four hours. There are no trailing wires. It is easy to stick to almost anything. The more expensive unit does require an external power source but it is easy to connect a small battery pack.

All these systems rely on the other aircraft transponding. I am constantly surprised by how many are, particularly the higher you are and the worse the weather. You are inevitably most at risk low level on a sunny day!

In my view these systems significantly reduce the risk of a mid air. They are not a substiute for maintaining a good look out nor do they detract in any way from doing so.

[vihai]

Flarm would also have almost certainly helped avoid this

Until flarm stop having anticompetitive, locking-in, unethical business practices they can sell their stuff to themselves.

They have at least on death, a friend of mine, on their shoulders. Don't ask me for details, but if they weren't such a bunch of bastards, there is a chance he would be still alive.

...

[robin]

Quote:
Look at the proposal for Jersey Zone, for example. In future when you ask for a Traffic Service it will be downgraded to a Basic Service - ie non-radar derived information.
I missed that. How can that be? All traffic in the Jersey Zone is special VFR, which means positive control (and seperation) by ATC. How could you get a traffice or basis service while ATC provides seperation?

Is the proposal to downgrade the class A?

I totally missed whatever it is you're refering to. A link would be much appreciated

dp


http://www.pplir.org/images/stories/pplir_files/jerseyatsocas.pdf

[Sciolistes]

I used to use Zaon PCAS (the cheap and highly transportable one). It is good, but not the be and end all. If you rent aircraft then you may have issues with false alerts. The reason is that the unit makes assumptions about attenuation of the signal to determine range and sometimes thinks the host aircraft's transponder is a threat. Once you have figured out the best placement then it should be OK or else the host transponder is weak and needs a seeing to.

No issues in my cub though, no tranny :) I have to say by and large it didn't detect that many other aircraft that I wasn't aware of from R/T, in the time (albeit just a few months) I flew with it there weren't any significant threats. It was certainly reassuring when in IMC to get traffic information and then see it on the PCAS.

[europaflyer]

One of the major arguments against PCAS is that there is no way that all aircraft can be fitted with transponders, or that the unit will function reliably. I started this thread about PCAS, but how about now looking at the possibilities of FLARM? It is a low-power unit, which is quite cheap, and could certainly be installed in all aircraft - and provide a reliable traffic warning all the time. How about trying to get this made mandatory? If GA took the initiative on this one (it is, after all, mainly of benefit to us) then it would be ages before the next attempt by anyone to get us to fit expensive and useless equipment. FLARM may also be able to provide warnings in airliners. I certainly dont think we should base our opinion on the post from 'vihai', unless he gives us more reasons.

Surely FLARM is what we've been looking for?

[philipnz]

I use a Zaon XRX and swear by it but it does have it's limitations

Firstly of course it relys on other aircraft having their transponder on and it amazing how many GA aircraft you see in TM zones that don't and i'm not talking specials but cessna 172's etc

secondly it does pick up yourself when you alter course and sees you as a threat, that can get a little annoying but easily dismissed as it appears very close out of the blue......

......which means it is of limited use in the circuit. you just get too many warnings and convince yourself you have another or multiple aircraft within feet. It actually freaks me out.

It is fantastic though approaching an airport and transit lanes, high use areas.

[Rod1]

As I said in my previous post I am very keen on FLARM. It is far lower cost than a transponder and PCAS, it is portable, battery powered and light. Almost all flying machines could carry it today. It has limitations in terms of range, but it is proven to work in our environment. There are many other potential solutions, but right now this one appears to be the only likely one if we want high take up.

Rod1

[chrisN]

Vihai of Milano, Italy,

If you grieve for a friend, I am sorry; as you request that we don’t ask you for details, I won’t, but you can’t expect me to take any notice of your objection to Flarm either, when I don’t understand how intellectual property rights can cause a death.

I’m with Rod on this.

Chris N.

[dublinpilot]

Thanks Robin.

So it's only outside the Jersey Zone that is being effected. The zone stays class A, and SVF and full control & seperation service.

Outside, they will only offer a basic service. From memory, they always dumped me once outside the Zone anyway, so I never got a RIS from them.

dp

[europaflyer]

So what we've basically concluded is that PCAS is useful, but has limitations (lack of transponders in many aircraft, unreliability), but FLARM seems to work (in a limited range), the only obstacle being that the idea may never catch on to the extent that there is a point in having one installed.

So a rather contravertial idea - how about petitioning the CAA to make FLARM (or a similar system) mandatory? Midairs would become a thing of the past, and it would greatly improve the image of GA in many eyes. At 500 pounds a shot (or much less when demand picks up) this would seem to be a very real solution to this massive problem.

Who's with me?

[Rod1]

The problem with any system is that it can get you into trouble. In the case of the Staffs incident see and avoid worked, the vintage machine turned to miss the micro and that put it into the path of the turboprop. I think this could happen with any system. If you also consider formation mid airs and Gliders you will never get to zero. The FLARM system could offer valuable assistance, but why not try to get the various bodies to recommend it initially?

Rod1

[S-Works]

I use a Zaon XRX linked to a Garmin 496. Works well enough for my needs which is to give me alerts while I get from a private strip into the airways.

[Fuji Abound]

So a rather contravertial idea - how about petitioning the CAA to make FLARM (or a similar system) mandatory? Midairs would become a thing of the past, and it would greatly improve the image of GA in many eyes. At 500 pounds a shot (or much less when demand picks up) this would seem to be a very real solution to this massive problem.

As I understand the matter there is no generic FLARM. A regulatory authority should not approve FLARM for this reason alone.

It also cannot make sense to have two incompatible systems in use. Transponders are already so well established there is no possibility of FLARM becoming a widespread alternative.

I feel sure that eventually ADS-B or son of will eventually replace both.

[robin]

I feel sure that eventually ADS-B or son of will eventually replace both.

Only up to a point. Our dear friends at the CAA would only permit ADS-B when linked to a fully approved GPS - not a Skymap III/Garmin 196 etc. So although it might well be a good thing, the devil (and massive cost) is in the detail.

[Robin400]

Information from my sbs-1 shows how many modern aircraft do not transmit ads-b data. It seems strange that although equipped with mode s transponders, they are not fully configured.

[Rod1]

“Transponders are already so well established there is no possibility of FLARM becoming a widespread alternative.”

Do you think so? In aircraft which typically fly around below 5000ft VFR? I would have thought Transponders the exception. The Micros, LAA, Gliders etc have much bigger numbers and are mostly not Transponder equipped. The CAA tried to force Transponders on them and failed, this is a much better alternative, and you could of course have both in your IFR wonder ship…

Rod1

[Fitter2]

Information from my sbs-1 shows how many modern aircraft do not transmit ads-b data. It seems strange that although equipped with mode s transponders, they are not fully configured.

To feed 1090ES ADS-B info into a extended squitter capable Mode S transponder (most are capable, the Garmin 328 and Funkwerk TRT600 are exceptions) requires the position/vector information to supplied by a IFR certified unit.

The vast majority of GA aircraft don't have appropriate equipment, so won't have ADS-B data.

[421C]

“Transponders are already so well established there is no possibility of FLARM becoming a widespread alternative.”

Do you think so? In aircraft which typically fly around below 5000ft VFR? I would have thought Transponders the exception.


No way. Transponders are the norm in VFR under 5000', not the exception. You do tend to mythologise sport aircraft (gliders, micros etc) as dominating private aviation and I think this simply isn't true. Whatever the number of aircraft is by category, the sporty ones must simply fly less. I don't ever recall a flight in which the majority of other movements I encountered were non-transponder. I am sure there are bubbles of airspace around in which this is the case, but no way are transponders an "exception".

I understand the issue with gliders, but I am confused about micros and LAA. You are always extolling the virtues of these aircraft compared to "spamcans" that will be resigned to history's dustbin. Suddenly a "spamcan" able to carry a transponder and supply it with power becomes a "wonder-ship". Which is it? Are Micros and LAA types able to carry sensible loads and useful avionics, or not?

The CAA was wrong to over gold-plate the transponder requirement with mandatory Mode S for everything. FLARM sounds useful for the hot spots of sport aviation, but a certified technology is the only universal solution. Just squawking Mode C is massively useful to all the TCAS, TAS, PCAS fitted aircraft and ATC SSR and should be encouraged for anyone who can fit one.

brgds
421C

[europaflyer]

So, the bottom line...

Is there a system superior to the FLARM-type system, which A) does not require a power source other than battery, B) costs as little as the FLARM and C) is always effective in alerting to nearby traffic?

If there is, then tell us about it. However, I havn't seen one - transponders and their receiving equipment are costly (particularly the active receiving boxes - 10,000-pounds) and consume a lot of power. ADS-B and ADS-B receivers will probably be similarly expensive and power-hungry. Neither, as far as I can see, could form a system capable of being fitted in all light aircraft at a low enough cost.

There will always be some new 'wonder unit' just around the corner. But some time, we need to take the plunge and settle on one type of unit. I understand that there are a number of companies producing FLARM-compatible equipment, so there is no monopoly problem. Maybe making them mandatory is a bit radical, but strongly encouraging their use by various means, perhaps followed by making them mandatory, would seem to be a good idea. They seem to be proven in the gliding community.

Any thoughts?

[IO540]

Of course there is no such box but you knew that :)

The point here is that technologies exist which are a lot better than the traditionalist-favourite Mk1 eyeball.

If people who can have transponders (the great majority of planes that actually fly for real, and I don't mean the 1-in-a-million Thruster pilot/adventurer who flew all the way to Kahtmandu) put in a straight Mode C unit, we would get

- a meaningful RIS, without the useless "level unknown" majority of reports

- TCAS activation in commercial aircraft, protecting GA's interests against the regulators

- TCAS activation in private aircraft whose owners have chosen to spend the money

- less resistance to CAS transits

- less resistance to CAS expansion (to a large degree because non-mode-C traffic flying under CAS has to be assumed to be OCAS, and thus far the luck in that daft assumption has held up, despite the hundreds of known CAS busts each year...)

As 421C says, it is completely misleading to suggest that non-powered ultralights or whatever make up the majority of GA. They do occassionally bust some piece of airspace as a group of 20+, all flying together, but that isn't quite the same thing :)

[Fuji Abound]

Trig TT21 Transponder (http://www.trig-avionics.com/tt21.html)

Very small, and compact, minimal power with battery power only around the corner. Combine the new generation of mode S units with PCAS and a TAS system is a reality. Price is still a factor and FLARM clearly has more than the edge in this respect, but sadly aviation was never cheap - but you knew that anyway.

[bookworm]

Is there a system superior to the FLARM-type system, which A) does not require a power source other than battery, B) costs as little as the FLARM and C) is always effective in alerting to nearby traffic?

FLARM has low power consumption because it transmits at low power and is therefore low range. It costs less than a transponder because it does not meet a certified standard. If you mandate FLARM, and therefore require certification, and increase its power to something more generally useful, you end up with something that is as expensive and power hungry as Mode S.

What we need is a low power, uncertified system that works over 1090ES and is therefore compatible with the vast installed base of Mode S and TCAS.

[Rod1]

421C

“No way. Transponders are the norm in VFR under 5000', not the exception. You do tend to mythologise sport aircraft (gliders, micros etc) as dominating private aviation and I think this simply isn't true.”

The last time I looked at this, which is some time ago, the single engine C of A fleet was about ½ the size of the Micro / LAA / Glider fleet. If you get even lighter then the numbers get even bigger. Do you have more up to date info?

“I understand the issue with gliders”

Good.

“but I am confused about micros and LAA”

I have explained this is very simple terms, so if you can use the search feature you should be ok

“You are always extolling the virtues of these aircraft compared to "spamcans" that will be resigned to history's dustbin. Suddenly a "spamcan" able to carry a transponder and supply it with power becomes a "wonder-ship". Which is it? Are Micros and LAA types able to carry sensible loads and useful avionics, or not?”

I “extol the virtues” of the type of aircraft I fly, which is a modern LAA VLA. It has modern glass which can have all types of collision avoidance interfaced into it and it already has a mode c transponder, navcom, advanced GPS etc and exceptional visibility. This is a type of aircraft, which is growing in number, but it represents a very small % of the total LAA fleet. The vast majority of micros and well over 50% of LAA types do not have a transponder, and even if they did they would also need more kit to detect other aircraft. The CAA has accepted that mandatory transponders will not happen. FLARM is the only tec I know of which could help us all out, but if you would rather carry on as we are, at least acknowledge that some of us are trying to be constructive.:ugh:

Rod1

[Rod1]

“FLARM has low power consumption because it transmits at low power and is therefore low range. It costs less than a transponder because it does not meet a certified standard. If you mandate FLARM, and therefore require certification, and increase its power to something more generally useful, you end up with something that is as expensive and power hungry as Mode S.”

Parts of the world mandate PLB’s which, are hand held, battery powered and save lives. FLARM could be done in the same way, is affordable, and would save lives.

OK guys, I give up. I have put my credit card away and will give my canopy an extra polish before I get airborne next.

Rod1
PS perhaps we could get AOPA / LAA to run a course on getting the best from see and avoid. Looks like it will be the only game in town for the foreseeable future.

[RTN11]

Alongside the technology discussion, we should also consider what can be done to help aircraft be spotted visually.

It is now being understood that bright aircraft, white in particular, are harder to spot. Such as the RAF tutors involved in the mid air this week.

Whereas darker colours, particularly black, are easier to spot.

Why not paint all aircraft darker colours, to give the eyeball a fighting chance?

[bookworm]

Parts of the world mandate PLB’s which, are hand held, battery powered and save lives.

...and transmit on a frequency in the ISM band requiring a special receiver to detect? I think not. Mine transmits on 121.5 and 406, like an ELT, so that the SAR aircraft with standard detection equipment can come and get me.

[philipnz]

You shouldn't paint composite aircraft dark colours if used in warm climates

[421C]

The last time I looked at this, which is some time ago, the single engine C of A fleet was about ½ the size of the Micro / LAA / Glider fleet. If you get even lighter then the numbers get even bigger. Do you have more up to date info?

No, I based my comment on the mid-air collision risk being related to aircraft actually in the air. Do you have any info on hours flown by the Micro/LAA/Glider fleet?


at least acknowledge that some of us are trying to be constructive

We all are. The constructive comment some of us are trying to make is that, attractive as FLARM seems to you, it is not a universal solution - simply because it is limited and uncertified and therefore not suitable for many aircraft that operate in uncontrolled airspace, and who already carry Mode C/S.

For example this, thankfully non-fatal, accident, which could have been avoided by the glider pilot turning the transponder on...
mindensoaringclub.com - Glider pilot survives mid-air collision with jet (http://www.mindensoaringclub.com/int2/index.php?option=com_content&task=view&id=90&Itemid=1)

The fact the CAA's mandatory Mode S was defeated (a good thing) doesn't mean that people shouldn't be (constructively) encouraged to fit Mode C. I still stand by my guess that the majority of hours flown VFR below 5000' are in types that carry Mode C (or S).

FLARM is simply not going to happen, except in bubbles of airspace where users congregate. Fitting Mode C brings benefits to other aircraft and ATC, and you have the option of adding a PCAS box.

[Fujiflyer]

I flew with a PCAS unit (XRX) this afternoon, it was its first use by me. I was surprised by how many (non urgent) alerts it warned me of. On my flight to LFAT it was generally quiet once I was above FL55, East of SFD, but nearer Shoreham (returning), below FL45, on my return, it was almost constantly showing other traffic, usually within 1000' vertical and less than 3nm range. Of some concern was that I only spotted two of these visually, these were about where it "said." It must have warned of about 20 - 30 ones which I didn't see, either because I couldn't or did not have time to concentrate on looking for them,

I was squawking mode "S" throughout.

Rich

[dublinpilot]

Are you sure that it wasn't seeing your own transponder? Many other people have reported this, when they have not calibrated it in accordance with it's instructions.

Once calibrated, this problem seems to go away. At least that's the reports that I've heard.

dp

[Fuji Abound]

There was indeed a reasonable amount of traffic arround today as might be expected given the good weather. On TAS I was never short of three or four contacts and sometimes quite a few more. I guess I saw two non transponding. You can always tell, when Farnborough is too busy to give a RIS.

[vee-tail-1]

It all seems a bit hit or miss...oh my god did I say that.
But seriously I might fit flarm and be hit by someone with mode C. And with mode C fitted I might be hit by someone without a transponder. Or I may hit a glider, or someone not looking out might hit me...etc etc.

Surely there is some hope that the new high intensity LED strobes may increase our chances of see and be seen?

[Fuji Abound]

It all seems a bit hit or miss

Unfortunately it is.

That is why there is such a storm over it because the authorities are increasingly concerned that emotionally it is difficult to justify aircraft without collision avoidance. God forbid a CAT and light aircraft collide - the press would have a field day. Everyone believes all aircraft are under radar control ALL the time and have TAS.

Those in the know beat the authorites with the "big sky" stick to which the authorities havent got a convincing answer.

FLARM has its advanatges but is just too late on the scene. It will never be widely adopted.

I have changed my view, and now think all flying machines should be fitted with a transponder. Prices have fallen, I dont think weight is any longer an issue, (see my earlier link) and battery portable units are around the corner. However, I accept cost is an issue, although I think you will get a mode S fitted in a homebuilt for less than £2K.

Although PCAS will never be certified, not only does it work but the technology could be developed further, and the cost would fall significantly if there was greater uptake. I could imagine the vast majoirty of light aircraft having a directional PCAS unit for less than £500. This would provide as good as it gets solution for GA and gliders short of a fully certified Skyforce system.

[Droopystop]

I definitely think something needs to be done. Transponders/TCAS1 (VFR only as I understand it), full blown TCAS2 or FLARM..... there needs to be something to aid the mk1 eyeball. Fitting a fully certified IFR system for Private flying would be prohibitively expensive and would need some form of pilot training. FLARM would be ok if it is as great as it is made out (at what stage would the system become saturated?). TCAS1 is not terribly accurate and requires a visual contact before being able to manouevre to avoid.

But the big issue here is the military. They have been invovled in a significant number of mid airs with civvy machines, but they will never fit FLARM and if they do have mode S they often don't seem to use it. And if they do have fancy target tracking radar, they don't use it for avoiding other aircraft.

[DavidHoul52]

The recent collision of two satellites reduces the credibility of the big sky theory somewhat?

Yet given that most GA aircraft don't use TCAS and we are told we don't see most of the other aircraft flying nearby, the number of mid-air collisions are surprisingly few. Not really surprising as the chances of another aircraft flying in another light aircraft's path within 10 or so feet of the same altitude outside of an ATZ must be statistically very small. (Why are encouraged at as students to fly cross-country at only 2000 feet?)

I recently tried an experiment on FS using FS Recorder Module which allows one to replay multiple previous flights simultaneously with the current one. I arranged for up to 20 "Cessnas" to fly up and down at lease twice at 2000 feet over a 5 mile stretch motorway having taking off at 15 second or so intervals. Although some of the aircraft came alarmingly close there were no "collisions" and only occasional avoidance manoeuvring was required.

On the other hand, if TCAS is available and it helps to give vital information, why are we not all using it? If it was a legal requirement to have one then all the rental aircraft would have them fitted. Most if not all already have transponders.

[Fuji Abound]

(Why are encouraged at as students to fly cross-country at only 2000 feet?)

Reverse engineering - everyone has been told for so long NOT to fly at 2,000 feet that you are now better doing so because no one else is. :confused:

Who knows?

Perhaps we need a survey - who does / does not fly at 2,000 feet?

[bookworm]

On the other hand, if TCAS is available and it helps to give vital information, why are we not all using it?

The 5 or 6 digit price tag? Or do you mean passive systems like PCAS?

[DavidHoul52]

I meant PCAS.

By the way, I see the cheap XRX unit has velcro stick-on mounts. How well does this work when having to mount on different aircraft?

Also when working with a LARS - is PCAS going to give you any information that the FIS is not going to give you anyway?

[IO540]

I think the short answer is that the collision risk is only at low levels, say below 1500ft, but

- many of these people are nontransponding (can't or deliberately won't)

- in the circuit, any form of TCAS is not as useful as it could be anyway

If one flies just a bit higher than the UK GA average, the traffic density is very low and it gets very hard to justify the cost of the fitted system (above £10k) and the portable gadgets are messy because for legal reasons they have to appear to be temporary (removable) installations.

[Rod1]

“No, I based my comment on the mid-air collision risk being related to aircraft actually in the air. Do you have any info on hours flown by the Micro/LAA/Glider fleet?”

On a poor day, mid week, you are right, most aircraft will have transponders. On a good Saturday in June I would guess the balance would be at least 3 non to 1 with. If hours at my strip v local licensed airfield are typical then LAA / Micros would be flying more than C of A machines. The exception would be the 1% IFR guys who would manage a lot of hours but are very few in number.

If we want a GA/GA anti collision system right now we can have;

A Transponder with a LARS service (IF you can fit it £1600 - £5000 to fit)

Most of the UK is a LARS free zone at the weekends, which is when most GA flying takes place. A Transponder on its own has no GA/GA collision avoidance benefit, as PCAS equipment is not at all common. If we could get everyone a RIS at the W/E this would be an interesting option. Many aircraft cannot fit a Transponder for legal or technical reasons, a fact now accepted by the CAA.

A Transponder and a PCAS (IF you can fit it £2600 - £6000)

This will detect others with transponders. I would think that in the area around say Biggin, you would have a high % of transponding traffic, in the location I fly I consider 80% non transponder equipped at the weekend, which is when I do most of my 90 hours a year. Many aircraft cannot fit a Transponder for legal or technical reasons, a fact now accepted by the CAA

A FLARM system (£500)

(average value of a micro / LAA aircraft is around £10,000)

This would require GA to carry a portable battery powered unit, which can be used in all GA aircraft. No certification issues as it is totally portable.

Now lets look at what will actually happen in practice. Nothing at all! The CAA are not going to revisit the transponder issue as after many years it has realised it is not possible to get what it wanted. The “heavy” end of GA has invested in Mode S and will not accept a simple low cost solution. The “light” end of GA can only go FLARM, and will not do that unless there is a realistic chance of it reaching critical mass. Better brush up on you see and avoid, it is the only game in town for the time being

Rod1

[Fuji Abound]

Better brush up on you see and avoid, it is the only game in town for the time being


I think that is a little widesweeping, although I understand "where you are coming from".

Although I use TAS most of the time (which is hellishly expensive) I also have used PCAS for many hundreds of hours. In reality both "see" a lot of aircraft that you would not see with mark 1 eyes.

In fact whilst I note your view on the ratio of transponding to non transponding traffic I am constantly surprised how little traffic is reported when receiving a RIS that is not apparent on TAS. Perhaps, as you suggest, the ratio changes dramatically at the weekend and is dependant where you fly.

Never the less combine your eyes with PCAS or TAS and you have a better chance of avoiding other aircraft. Moreover, the nearest collision I had was between me (in a twin) and another twin. At these speeds the time to see and avoid becomes unpleasantly short, BUT the faster the traffic the more likely it WILL be transponding. The threat (to some degree) is proportional to speed.

In short, do not dismiss safety aids of this sort so readily. they may not be a panacea, but I believe they are a significant aid.

[IO540]

The “heavy” end of GA has invested in Mode S and will not accept a simple low cost solution.

Hardly. It is simply that when I have a Mode S transponder installed (and it was obvious c. 2005 - FOUR years ago - that this battle was lost for anybody actually going anywhere for real in Europe) which cost me £2500, minus the $1500 I got for the old Mode C unit on U.S. Ebay, I am not going to have yet another gizmo in the cockpit stuck to the dash with a piece of self adhesive velcro, with the power lead dangling across the instrument panel down to the cigar lighter socket, which I have to push in every 5 minutes (because cigar lighter plugs are pretty crap and work loose) and if I fly above about 1500ft then I am statistically speaking higher than almost any mid-air in recent decades.

[Fuji Abound]

IO540

you know I hate trailing wires as well but the cheaper PCAS runs of two self contained AA batteries and the whole unit is about the size of a big matchbox. It is hardly a nuisance on the glare shield. True, you do have to replace the batteries every four hours but that is not the end of the world.

The more expensive unit does require an external power source but if you will, replace the cigarette lighter connector with a BNC and wire a fused supply into the top of the panel - technically removable and not a risk in any event.

[Robin400]

oh dear, we are in a mess!!!!!!!:ugh:

[IO540]

The smaller one doesn't give azimuth info, which is IMHO as much use as a chocolate teapot :)

One could climb/descend I suppose...

oh dear, we are in a mess!!

why?

[Robin400]

we did this subject to death a few months ago.

[Fuji Abound]

The smaller one doesn't give azimuth info, which is IMHO as much use as a chocolate teapot


I can understand why you would say that, but I dont agree. Have you tried it?

You will get an alert at five miles, and a seperation level. A thousand feet above or below and its not a threat. However, if it is at the same level keep out an even more careful eye. If the traffic is a significant threat the distance will close - at MOST GA speeds, even head on, not too quickly. Within one mile, you will get an urgent alert - my that concentrates the mind, particularly when, as is quite frequently the case, you STILL have not spotted the traffic. You may well have elected before to have built in some vertical seperation. In fact in some ways the azimuth information can be a distraction. Without azimuth you fall back on a 180 scan, never forgetting that something else might be closing from the other azimuth that is not transponding.

All I can add is that I have used the "system" for hundreds of hours. I have not yet had an urgent alert without eventually seeing the traffic and my vertical seperation has always ensured there wasnt a risk of collision. I know there is an inherant risk that TAS in any form is not completely accuraye in either veritcal or horizontal reporting but I feel a great deal happier with it than without it.

If you havent tried it, it is well worth a go, you have very little to loose with the cheap as chips unit and perhaps something to gain.

It is worth a thought that it almost certainly will never happen to you, but it has only got to happen once. In a few thousand hours I have had three that were close and one way way to close for comfort.

[Captain Kirk]

Wow, I am genuinely shocked by some of the replies on this thread, many of which appear to be complacent as to the limitiations of see and avoid, if not completely deluded. My lookout is excellent (!) but I am fully aware of how inadequate it is - airframe blanking, time inevitably consumed by in-cockpit tasks, inability to look in more than one direction at once, empty-field myopia, lack of relative movement against constant-bearing traffic, etc, mean that it is impossible to reliably detect all possible conflicts. Fact.

Anything that assists you in this critical task has to be taken seriously, such as the economic use of the radio to gain SA on local traffic, for example. I have only just learned about these PCAS devices but I am amazed that there is so much ill-informed comment and reluctance to even try it! The MRX model looks like an absolute no-brainer for the cost - even without azimuth, what a great cue to STOP whatever else you are doing and look out NOW! Even it it only alerts you to squawking traffic, at least you can look for that traffic and, having found it and/or resolved any conflict, continue looking for other traffic with a better mental model of the airspace around you. With good, 3D situation awareness (asking a lot, I know), you can even reslove conflicts without seeing the traffic - you can only have a mid-air at YOUR altitude! As to being an in-cockpit distraction, what rubbish - no more so than the altimeter!

Flying IS inherently dangerous AND it is terribly unforgiving of any carelessness, incapacity or neglect.

...with apologies to Captain A. G. Lamplugh!

[Rod1]

I just spoke to the main reseller in the UK for this kit. The numbers sold since 2006 are very small indeed, with a 1/3 (smaller one) 2/3 split. We are talking about 278 units!!! Plans to develop a panel mounted version have been recently abandoned, so perhaps the idea has come and failed?

Rod1

[Cirrostratuss]

I bought a XRX a few months ago and finally had a chance last weekend to take it for a cross country flight. On my way back home, my second to last waypoint, was over a smaller uncontrolled airfield. I was in a low wing plane, cruising at 3000 inside and talking to the TMA controller.

A mile or two before crossing over the small airfield, my PCAS made a small blip and displayed traffic 12 o'clock and -2500 below. The traffic was right below my nose, probably just took off from the field. There was no way for me to see it with my eyes because it was below me but the Zaon was telling it was there. It then showed it climbing up to 1300 feet or -1700 relative to my altitude but parallel to my direction. It was persistently right below me.

We continued forward and about 5 miles further the TMA controller told me to descend to 2000 and that there was VFR traffic below me, a mile to my right at 2 o'clock. I tried looking but just couldnt spot the bugger, the PCAS was showing it but my eyes were not picking it up. This got me nervous so I did a 45 degree bank to the left and made ample room between the two of us. After this I was able to spot him below my right wing, it was a high wing Cessna. He was flying in uncontrolled airspace, below me to my right, and probably completely oblivious to my presence above him.

We were able to keep visual separation all the way home but it got me thinking. If I hadnt had the PCAS, I would not have known of him until the controller told me about it. The controller did not say the direction of flight for my traffic, so I wouldnt had a clue if the traffic was still there a few moments later. The controller told me to descend, practically straight towards the traffic. Again, I was in a low wing, the other guy was in a high wing. At that moment, I was happy to have the PCAS, I knew it was paying back the investment in a very meaningful way. The Zaon does not relieve you from doing a proper scan, but in situations like these, its a priceless tool.

[Fujiflyer]

I flew, this afternoon. The weather wasn't particularly great but I wanted to test my new EFIS module (electronic AI, for backup purposes), the conditions were good enough though, for my abilities.

As per normal, I had the PCAS unit running. On the return to Shoreham (from the SFD area) it picked up several transponding a/c, most of which I was then able to locate visually, based on its information. I suspect that without it I may have not seen many of them (due to not knowing where / when to look). The local visibilty was variable but generally poor at the time.


One part of the flight concerned me though. After leaving Shm, on an Eastern track (for SFD), an a/c passed me about 100ft (barely) below on a reciprocal heading. The PCAS picked up nothing (before or after), suggesting that the other a/c was not transponding. It was a reasonably sized 4 seater a/c.

I find it a bit irritating that such an a/c which could probably have been able to squark mode "C" did not do so???

[robin]

I find it a bit irritating that such an a/c which could probably have been able to squark mode "C" did not do so???

Hmm

Don't bite me but there are any numbers of reasons why you didn't pick up a squawk from him and not all would be due to an inconsiderate pilot.

What irritates me are people carrying PCAS (a minority of GA pilots) criticising other pilots for not squawking Mode C (a majority of GA pilots).

Yes, it would be nice if everyone did, but the reality is that the majority can't at the moment.

[mm_flynn]

Hmm

Don't bite me but there are any numbers of reasons why you didn't pick up a squawk from him and not all would be due to an inconsiderate pilot.

What irritates me are people carrying PCAS (a minority of GA pilots) criticising other pilots for not squawking Mode C (a majority of GA pilots).

Yes, it would be nice if everyone did, but the reality is that the majority can't at the moment.

There are two very different groups of pilots not squawking mode-C, those who can't for technical reasons (breaches empty weight, no electric system, etc.) and those who won't for philosophical reason. I have plenty of understanding for the first group and (at the moment) none for the second group.

Is there any reason an aircraft with an electrical system and no empty weight limit should not be squawking Mode C (other than in a close formation or other occasion when instructed by ATC not to squawk mode-c)? With the forced move of the IFR fleet to Mode-S, there must be quite a number of used transponders available and altitude encoding is a few hundred pounds to add to an existing transponder - so money shouldn't be an issue.

[robin]

mm_flynn

Quite agree.

I've flown recently with 2 other pilot owners. One owns a C172 and the other a PA28.

They have transponders that have problematic Mode C's but are OK in Mode A. As it isn't mandatory to carry one, they consider it is way down their lists of priorities, especially given the bills they have had to pay for the ARC renewals this year.

As mine is going through its annual now, and the bills are stacking up nicely, my plan to upgrade my radios has just been abandoned.

[Fujiflyer]

robin, I guess the point I was trying to make (maybe not sufficiently clearly) was that the reciprocal direction traffic was of a type that would be expected to have a decent (ie mode C) transponder. As you say though (and so does mm_flynn) this may have been an unreasonable assumption, in its own right. That said,I do get the impression that there are a sizeable (minority) of pilots that don't use "C" if it is not mandatory, I think that this is a shame as it is a level of (potential) protection wasted.

As for PCAS and related equipment, I think this is a bit of a controversial topic not least because the earlier units were not so good. However I find my present unit very good (ZAON XRS) – it often detects traffic I never get to see but are subsequently able to verify that the traffic actually does exist from the radio conversations. I certainly would not ignore a warning from it.

(Slight) change of subject: With the availability of lightweight, high power density Li batteries (I use some myself which weigh a few 100's grammes and provide around 100Wh), how valid really is the argument that some a/c cannot use a transponder due to no elec' system? I stand to be corrected but I seem to recall that the average input power into a transponder is less than 20W...

[robin]

I agree that technology is making the issue of transponder carriage easier.

But gliders would have difficulty in powering a tx for a 4 hour flight, microlights, similar. Add to that the Mode A equipped C172s/PA28s etc or those where the transponder output is weak and given the numbers of these aircraft which may total around 10,000 of the 20-odd-k GA craft expecting transponder-equipped aircraft to alert you on your PCAS is playing Russian Roulette.

So you PCAS-equipped owners, don't whinge at people disappearing under your wings without warning - you can expect over 50% of traffic not to alert your expensive PCAS/TCAS. You can even hit squawking traffic.

That happened to me a few weeks back in the Elstree 'circuit'. A PA28R routing from Stapleford towards Wycombe came straight at me. Although I was squawking Mode C and had right of way, he never made the slightest attempt to change course, Sitting there in bovine mode he didn't even notice my flashing my lights or my diving out of his way.

Being on Elstree's frequency I was positioning for arrival at Elstree. He was clipping the ATZ and probably on Farnborough North's frequency (or listening to his iPod).

Having a PCAS or squawking perhaps can give a false sense of security.

So for your own (and our) safety, please look out the window from time to time.....;)

[tristan1]

A good video review. Off to buy a MRX.

Aviation Consumer Aircraft Traffic Display Demo - YouTube

:D

[Captain Kirk]

I see that this thread is still going.

To those that think their lookout is unassailable, read this Accident Report - a redacted version of the full report is available online here:

[ARCHIVED CONTENT] Page not found (http://www.mod.uk/DefenceInternet/AboutDefence/CorporatePublications/BoardsOfInquiry/ServiceInquiryInvestigatingTheAccidentToTutorAircraftGbyutAn dGbyvn.htm)
(it is there - no idea why this error message appears?)

Part 1.4 of the report (Findings) includes Human Factors and, specifically, addresses the ability to ‘see’ at paragraph 2. b. For convenience, this link will take you directly to Part 1.4:

http://www.mod.uk/NR/rdonlyres/2BE26B7A-BA7F-4522-9781-264FEA9B54AD/0/ServiceInquiry_TutorAircraft_Part_1_4_Findings.pdf

Incidentally, since my last post I have flown many sorties with the MRX - it is invaluable. Not infallible, but invaluable nevertheless. Buy a TCAS. I don't care which one, but if you are serious about aviation and safety then you cannot possibly overlook the contribution that these make to safety.

[AdamFrisch]

The MRX is already integrating with the iPad with one software and showing graphical TCAS targets. Expect more to include this feature soon. Until it's integrated with Foreflight, I will hold off. I want a graphical display, not numbers. It's a bit like having the early GPS's that gives you lat and long only. Not very practical.

[stickandrudderman]

More and more GA aeroplanes are being fitted with glass cockpits now but there doesn't seem to be much on the market that enables traffic.
Why is this?

[liam548]

I use re chargeable lithium ion batteries and get at least 4 to 5 hours from the MRX...


http://img32.imageshack.us/img32/9545/20120330122817.jpg (http://imageshack.us/photo/my-images/32/20120330122817.jpg/)

[Rod1]

“More and more GA aeroplanes are being fitted with glass cockpits now but there doesn't seem to be much on the market that enables traffic.”

Pcas
Flarm
Power Flarm
TM250 Traffic Monitor
Gerrecht ADS-B + Flarm
Trig TA60

Three tecs, some of which are combined into single unit. ADS-B, transponder detection and Flarm. If you do a search this has been covered more recently than this thread. If you have a copy of my article in Flyer some time ago it also covers a test of PCAS, Flarm and talks about ADS-B. There will be an update to this in a few months.

A recent analysis of collisions going back 37 years showed that the risk in the cruse was quite low but the risk joining for a busy fly in are much more significant. A screen display showing 37 threats is probably of little value, but a device saying this aircraft is predicted to hit you in 19sec probably is.

Rod1

[Captain Kirk]

"It's a bit like having the early GPS's that gives you lat and long only. Not very practical."

Adam - you are deluding yourself.

A PCAS that had only a light bulb that came on to warn that an aircraft is within 1 nm would be an improvement over unaided see-and avoid!

Knowing WHEN to look (i.e. STOP whatever else you are doing and lookout in earnest) is valuable.

Sometimes see-and-avoid is all we have and I encourage everyone to develop a thorough and efficient lookout scan - it is difficult to maintain a good lookout and it takes training, practice and discipline.

Be under no illusion though...

- We cannot see through solid objects.

- We can only look in one direction at once.

- We have to attend to in-cockpit tasks and, occassionally at least, look at the instruments!

- The human visual system was designed for sneaking up on antelopes (and it is very good at this) and not for detecting a target on a constant bearing closing at 200 kts (it is rubbish at this)!

For those that think that their lookout is infallible... the aircraft you see most of the time were never going to hit you anyway and you remain oblivious to how many you never see.

I am reasonably confident that my lookout is as good as anyone else's on this forum, if not better, and I have a PCAS (MRX, with lithium ion batteries - works great).

I say again - if you are serious about your flying, and about safety, buy a PCAS!

[soay]

I say again - if you are serious about your flying, and about safety, buy a PCAS!

I'll second that, but it's a useless defence against non-transponding aircraft. If your aircraft has a transponder, please squawk mode C, to help those of us who've invested in PCAS keep out of your way!

[BackPacker]

I say again - if you are serious about your flying, and about safety, buy a PCAS!

If money is no issue, I agree. But between PCAS, Flarm, GPS, PLB and the spare Icomm you can easily spend half your PPL costs on electronic safety-enhancing gadgets alone. Alternatively, you can spend that money on advanced training such as aeros or an IMC.

I don't have statistics to hand, but I don't think mid-air collisions are very high on the scale of hazards in light GA. Loss of control (usually in IMC, plus departure stalls and stall/spin accidents on final), or controlled flight into terrain (usually in IMC as well) seem to be killing more pilots than midairs.

But gliders would have difficulty in powering a tx for a 4 hour flight, microlights, similar.

Actually, virtually all gliders in the Netherlands are now equipped with Mode-S transponders. Where I regularly fly they're not operated properly, in the sense that they're set to "Alt" as soon as the first pilot connects up the battery and performs the A-check, and are only switched off when the battery is disconnected for recharging at the end of the day. So they're running all day on the same battery that was previously only used to power the radio - which weighs approximately a kilo. So the electrical demands of a transponder are not that hard to meet.

What is a bigger problem, is installing the transponder antenna in a modern carbon-fiber glider. Since it has to be outside the hull, and causes drag.

[peterh337]

Best thing is to fly above 2000ft.

Most of GA thinks that you get a nosebleed at 2000ft so they don't go there :)

[Captain Kirk]

BP - I concede that money is, of course, an issue for many - and I certainly do not mean to imply that it is irresponsible for those who cannot afford a PCAS to fly without one. However, that is a very different consideration from those who can easily afford one and yet consider that they either do not need it - or else do not understand the contribution it can make to their safety - and the safety of others of course!

And neither GPS nor PLBs will not stop you from hitting someone else. GPS is great, but old-fashioned map and stop-watch navigation will teach more valuable basic skills and I would personally recommend investing in a PCAS before a GPS - subject to each individual's specific needs and circumstances of course. Certainly, acquiring a GPS too soon will provide little incentive to master the basics, and leaves one poorly placed when the GPS fails!

Peter - actually, I would recommend flying at 1900 ft, or 1800 ft - anything other than the nice even numbers that everyone else invariably flies at!!

[peterh337]

I meant above 2000. At say 3000 there is very little traffic.

But yet, always fly at funny numbers like 2300, 2700, 3300, 3700.

I would personally recommend investing in a PCAS before a GPS

That however is turning aviation safety on its head. You are extremely unlikely to hit somebody anywhere/anytime, but you are extremely likely to get disastrously lost if you make a nav error.

[liam548]

The GPS/PLB/PCAS all cost a fair amount of money but now I have them the investment is over.

Following on from Peters comments it was a breeze flying up to Scotland recently between 4 and 6 thousand feet, the only two aircraft I was told about by ATC were a Airbus A319 and a Fokker going into Newcastle.


The rest of the aircraft I saw all looked lke they were skimming the fields below.
I realise it is not always possible to fly at such levels due to airspace but I always try and get as high as poss.

[bookworm]

A PCAS that had only a light bulb that came on to warn that an aircraft is within 1 nm would be an improvement over unaided see-and avoid!

Knowing WHEN to look (i.e. STOP whatever else you are doing and lookout in earnest) is valuable.

But, unless every potential threat is co-operative, it won't tell you "when to look". Currently, you have to look all the time. As the percentage of equipage increases, you might eventually find that such a binary detector gave a useful discrimination between times you need to look and times you don't.

Andrews's experiments at the Lincoln Labs that showed an 8-fold increase in visual detection efficacy with traffic alerting were based on TCAS, with azimuthal information on the threats. My experience, albeit a long time ago, with a detector that had no azimuthal information was that the distraction wasn't worth the information.

[peterh337]

The rest of the aircraft I saw all looked lke they were skimming the fields below.

You seen to have discovered the joys of flying higher than the rest :)

That is indeed what one finds. Almost every plane you spot is way way down below. That is also why you won't spot the majority of "level unknown" contacts given to you by a traffic service.

[Captain Kirk]

Bookworm - do you really lookout ALL of the time? Of course not - it is not possible.

Yes, PCAS only alerts you to cooperative threats but having an alert against, say, half the threats is a 50% greater chance that you will not hit someone. I have already said that PCAS is not an infallible aid - it is about stacking the odds in one's favour.

And I certainly did not say that you ONLY lookout when PCAS alerts - in fact I specifically highlighted the importance of a good, disciplined scan - but the PCAS gives you an added cue to STOP any in-cockpit task and lookout like a demon.

Too many of the responses regarding PCAS resemble the 'Ostrich' approach to threats - if I can't see it then it can't hurt me!