PCAS collision avoidance
Joined: May 2001
Posts: 4,631
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From: UK
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.
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.
Joined: May 2001
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From: UK
The smaller one doesn't give azimuth info, which is IMHO as much use as a chocolate teapot
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.
Joined: Oct 1999
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From: Lincs
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!
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!
Joined: Apr 2003
Posts: 2,359
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From: Midlands
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
Rod1
Joined: May 2008
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From: KLZU
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.
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.
Some more money for Capt PPRuNe
Joined: Jan 2002
Posts: 271
Likes: 1
From: Ici
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???
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???
Joined: Aug 2003
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From: Not a million miles from EGTF
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???
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.
Joined: Aug 2003
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From: Surrey
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.
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.
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.
Joined: Aug 2003
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From: Not a million miles from EGTF
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.
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.
Some more money for Capt PPRuNe
Joined: Jan 2002
Posts: 271
Likes: 1
From: Ici
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...
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...
Joined: Aug 2003
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From: Not a million miles from EGTF
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.....
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.....
Joined: Oct 1999
Posts: 203
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From: Lincs
A blast from the past...
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
(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/2BE26...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.
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
(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/2BE26...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.
Joined: Sep 2006
Posts: 1,631
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From: Los Angeles, USA
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.
Joined: Apr 2003
Posts: 2,359
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From: Midlands
“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
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
