PCAS collision avoidance

[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.

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

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.

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.