Collision Avoidance vs. "See and Avoid" for GA
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Even TCAS equipment doesn't always spot other aircraft. Not infrequently I see other aircraft pass close by, whom I know full well are squawking mode S, and yet they don't appear on the TCAS. Make no assumptions, and don't let the equipment do the looking for you.
It's called "see and avoid" for a reason...not "monitor and avoid."
It's called "see and avoid" for a reason...not "monitor and avoid."
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I see other aircraft pass close by, whom I know full well are squawking mode S, and yet they don't appear on the TCAS
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Why? They should. IF they are actually squawking, and your installation is not masked by the airframe etc.
This isn't exactly an amature installation, and the condition in which I see traffic missed occur when I'm looking right at the traffic and it's the only traffic around. It happens, and I've seen it on a fairly wide variety of equipment, installations, and circumstances. Even the costliest and best installations still miss traffic. Go figure.
Point is that the law is see and avoid. This applies in IFR flight every bit as much as VFR. If you can possibly see it, you're responsible to be looking for it.
Use all the other equipment and gimmicks you like (and if they're available, you should)...but there's no substitute for the Mark 1 eyeball. See and avoid like your life depends on it.
Because it does.
Avoid imitations
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TCAS has never been a replacement for see and avoid and was never intended to be. I've never met a pilot who actually thinks that it is. Certainly, any pilot using it regularly soon discovers the limitations of the equipment and knows where to place the information it gives, as far as prioritites are concerned. I consider mine an extra pair of eyes, nothing more.
I wonder if those who say they don't want it at any cost would also object to anyone in the other seat pointing out other aircraft, similarly would they not bother with an ATC radar service because they would object to being advised of other traffic? Both of these also provide assistance to 'see and avoid' but similarly are not infallible.
TCAS I offers basic collision avoidance information to pilots as an aid to ‘see and avoid’. The main difference from TCAS II is that it does not generate 'Resolution Advisory' (RA) warnings. Because of this principle difference, TCAS I systems are less costly and smaller, making them attractive for those operating at low levels and/or outside controlled airspace where extra information to assist with ‘see and avoid’ is most welcome.
I wonder if those who say they don't want it at any cost would also object to anyone in the other seat pointing out other aircraft, similarly would they not bother with an ATC radar service because they would object to being advised of other traffic? Both of these also provide assistance to 'see and avoid' but similarly are not infallible.
TCAS I offers basic collision avoidance information to pilots as an aid to ‘see and avoid’. The main difference from TCAS II is that it does not generate 'Resolution Advisory' (RA) warnings. Because of this principle difference, TCAS I systems are less costly and smaller, making them attractive for those operating at low levels and/or outside controlled airspace where extra information to assist with ‘see and avoid’ is most welcome.
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but there's no substitute for the Mark 1 eyeball
Personally when cruising at 300kts and someone is coming at you at 300 kts, my eyes won't see them until it is too late
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Oh no, lets not start that debate again
Personally when cruising at 300kts and someone is coming at you at 300 kts, my eyes won't see them until it is too late
Personally when cruising at 300kts and someone is coming at you at 300 kts, my eyes won't see them until it is too late
You'll note that I previously correctly stated that one should use all the resources available to look for traffic, as well one should. None of them relieve one of the responsibility to be heads up and looking for traffic. Even at 600 knots closing speed.
TCAS has never been a replacement for see and avoid and was never intended to be. I've never met a pilot who actually thinks that it is.
Gimmicks don't replace the eyes. They supplment them, but don't replace the responsibility, requirement, and duty to stay eyes-peeled for traffic.
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Ask any glider pilot flying around in the Alps about the value of FLARM and you will get a unanimous answer. In a sport where mid-air collisions are one of the most popular ways to die, people gladly spend hundreds of pounds and make room on their panel and in the glider for the equipment and batteries.
There aren't enough mid-air collisions in power planes to get people interested in collision avoidance. In my experience, power pilots are more worried about engine failures or crashing in to a hillside in bad weather, probably because that's the most popular way to die in a power plane. If you could make a box that helped prevent engine failures or CFIT people would be snapping them up in their thousands.
There aren't enough mid-air collisions in power planes to get people interested in collision avoidance. In my experience, power pilots are more worried about engine failures or crashing in to a hillside in bad weather, probably because that's the most popular way to die in a power plane. If you could make a box that helped prevent engine failures or CFIT people would be snapping them up in their thousands.
Avoid imitations
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I surely have. More often than not, when I hear someone alerted to traffic, the response on the radio is "Got 'em on TCAS." Not "Traffic in sight."
And they will "Get 'em on TCAS" before visually aquiring it, that's the whole point of the equipment, as an aid to lookout....
The equipment fitted to the aircraft I fly for a living works out to 20 miles. There is no way that the human eye will see other traffic at that range, no matter what the owner of the eye might claim and pre-warned is pre-pared.
Next time you ask for a radar information service, why not ask ATC to delay telling you about other traffic until just after you've seen it; perhaps giving you a heads up in good time is not sporting enough?
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Next time you ask for a radar information service, why not ask ATC to delay telling you about other traffic until just after you've seen it; perhaps giving you a heads up in good time is not sporting enough?
One uses all the tools at one's discretion. These tools never relieve one of the responsibility to see and avoid, however.
I know a lot of pilots who believe otherwise.
In the general aviation, lower altitude, more congested airspace arena where not only is more traffic, but ground clutter, reduced visibility, and other distractions to acquiring traffic a factor, the issue of seeing and avoiding is even more critical; far more so than what we may see at FL410.
For the general aviation pilot who relies upon a gimmick that may or may not work, may or may not see other traffic, and in which other general aviation airplanes may or may not be visibile or even equipped with an electrical system, a false sense of security may be imbued and may lead to a false sense of security. Add to that a device which doesn't report the whole picture or give an adequate pictorial display, and you may just have more of a distraction than it's worth.
Personally, I wouldn't own one. I use TCAS II, it's useful, but I couldn't afford to put it in my own aircraft, and wouldn't bother with TPAS or other cockpit gimmicks available today. My eyes work reasonably well, however. Your own mileage may vary.
Avoid imitations
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Now why introduce such stupidity into the conversation? Why not just turn off the TCAS for that matter?
These tools never relieve one of the responsibility to see and avoid, however. I know a lot of pilots who believe otherwise.
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Don't be surprised. Yes, the rules are clear. Never the less, just as the burgeoning generation of glass-and-gps trained pilots is leading to the inability to navigate between two blades of grass when the GPS is turned off, the use of equipment that is sold as having the ability to spot traffic has lead to even more lax use of the eyes in the cockpit.
"Got em' on TCAS" isn't simply a lazy response. Too often it's a report that marks the end of the effort to spot the traffic.
See and avoid applies under IFR just as VFR; the responsibility is never relieved.
TCAS is an excellent tool, with lesser versions becoming progressively less useful as the price tag and capability decreases, but it's never more than just that; a tool.
A few years ago I took a checkride in a King Air 200 with an FAA inspector. I had borrowed the airplane, which was well equipped. It included TCAS. When he climbed aboard, he saw the TCAS and groaned. We departed his home field, which was located in a heavy training area in a busy metropolitan city airspace, and immediately had a TCAS screen full of warnings, displays, and threats. Even with the threat ring reduced to a minimum, there was still a constant run of traffic alerts and warnings as we worked our way between multiple airports out to a "practice area" for air work. Even there we had more nuisance warnings than help, and the TCAS served as more of a distraction than an aid. It also called for attention often enough that the temptation to go heads down and look for it on the TCAS was a detriment to safety; the inspector turned it off.
We've used them extensively in airline service, charter, various government work, and in the fire service. I've seen them become a help, and not uncommonly, a hinderance which in some cases has compromised safety instead of enhancing it. Even in fairly hard-core visual operations, I've seen people fall victim to the tendency to let the TCAS spot traffic for them.
"Got 'em on TCAS" isn't an acceptable response to ATC. "Traffic in sight" is acceptable, as is "negative contact." But not "Got 'em on TCAS." That doesn't mean a lot to a controller, nor can the controller be assured of what you've "got" on TCAS.
"XXX traffic two o' clock and two miles, three thousand, opposite direction."
"XXX, got 'em on TCAS."
"Riiiiiiiiiight...turn left heading two seven zero, descend and maintain one thousand five hundred, report traffic in sight."
"Got em' on TCAS" isn't simply a lazy response. Too often it's a report that marks the end of the effort to spot the traffic.
See and avoid applies under IFR just as VFR; the responsibility is never relieved.
TCAS is an excellent tool, with lesser versions becoming progressively less useful as the price tag and capability decreases, but it's never more than just that; a tool.
A few years ago I took a checkride in a King Air 200 with an FAA inspector. I had borrowed the airplane, which was well equipped. It included TCAS. When he climbed aboard, he saw the TCAS and groaned. We departed his home field, which was located in a heavy training area in a busy metropolitan city airspace, and immediately had a TCAS screen full of warnings, displays, and threats. Even with the threat ring reduced to a minimum, there was still a constant run of traffic alerts and warnings as we worked our way between multiple airports out to a "practice area" for air work. Even there we had more nuisance warnings than help, and the TCAS served as more of a distraction than an aid. It also called for attention often enough that the temptation to go heads down and look for it on the TCAS was a detriment to safety; the inspector turned it off.
We've used them extensively in airline service, charter, various government work, and in the fire service. I've seen them become a help, and not uncommonly, a hinderance which in some cases has compromised safety instead of enhancing it. Even in fairly hard-core visual operations, I've seen people fall victim to the tendency to let the TCAS spot traffic for them.
"Got 'em on TCAS" isn't an acceptable response to ATC. "Traffic in sight" is acceptable, as is "negative contact." But not "Got 'em on TCAS." That doesn't mean a lot to a controller, nor can the controller be assured of what you've "got" on TCAS.
"XXX traffic two o' clock and two miles, three thousand, opposite direction."
"XXX, got 'em on TCAS."
"Riiiiiiiiiight...turn left heading two seven zero, descend and maintain one thousand five hundred, report traffic in sight."
Avoid imitations
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SNS, I think we might be separated by a common language here because this discussion seems to be going round in circles and I think we are mainly singing the same song.
In what capacity have you seen people 'fall vicitim'? I initially got the impression that you are an airline pilot; your profile doesn't mention in what capacity you operate or what licence you hold.
I have seen some pilots over-concentrate on spotting a TCAS 'target' that will not conflict, almost as if they try to prove to themselves how good their eyesight is. Meanwhile, they neglect the rest of the sky. Is this what you allude to? If so, I agree but this is a training issue, not a fault of the equipment. Just like over-concentrating on anything else inside the cockpit or getting distracted.
I've been flying TCAS 1 / TAS equipped aircraft for almost a decade, most of it outside controlled airspace, both single pilot and multi crew. I previously flew more than twenty years before that without it. All the instruction manuals I've read have stressed that avoiding action must NOT be taken on TCAS / TAS derived information alone, it is an aid to aquiring visual contact, no more. I repeat, TCAS must be used properly, it's a simple tool or aid to be used as part of a lookout scan, definitely not to be used as a replacement for lookout.
Every pilot I've met has been intelligent enough to realise that the equipment is far from infallible; i.e. if other aircraft aren't squawking they don't appear on TCAS. Similarly, an ATC service can only do so much, especially outside CAS. Some aircraft present a poor radar return and a controller may sometimes not be in a position to pass on timely advice on a 'late spot'.
Having said that, I would NEVER turn off something that might just save my neck and that of my passengers. I might turn down the audio warnings as low as they go via my headset control but would never turn off the box itself. A TCAS screen full of diamonds is not a distraction; it just reminds me to keep looking out of the windows.
I've seen people fall victim to the tendency to let the TCAS spot traffic for them.
I have seen some pilots over-concentrate on spotting a TCAS 'target' that will not conflict, almost as if they try to prove to themselves how good their eyesight is. Meanwhile, they neglect the rest of the sky. Is this what you allude to? If so, I agree but this is a training issue, not a fault of the equipment. Just like over-concentrating on anything else inside the cockpit or getting distracted.
I've been flying TCAS 1 / TAS equipped aircraft for almost a decade, most of it outside controlled airspace, both single pilot and multi crew. I previously flew more than twenty years before that without it. All the instruction manuals I've read have stressed that avoiding action must NOT be taken on TCAS / TAS derived information alone, it is an aid to aquiring visual contact, no more. I repeat, TCAS must be used properly, it's a simple tool or aid to be used as part of a lookout scan, definitely not to be used as a replacement for lookout.
Every pilot I've met has been intelligent enough to realise that the equipment is far from infallible; i.e. if other aircraft aren't squawking they don't appear on TCAS. Similarly, an ATC service can only do so much, especially outside CAS. Some aircraft present a poor radar return and a controller may sometimes not be in a position to pass on timely advice on a 'late spot'.
Having said that, I would NEVER turn off something that might just save my neck and that of my passengers. I might turn down the audio warnings as low as they go via my headset control but would never turn off the box itself. A TCAS screen full of diamonds is not a distraction; it just reminds me to keep looking out of the windows.
"Got 'em on TCAS" isn't an acceptable response to ATC. "Traffic in sight" is acceptable, as is "negative contact." But not "Got 'em on TCAS." That doesn't mean a lot to a controller, nor can the controller be assured of what you've "got" on TCAS.
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All, Thanks for these replies it is showing some interesting themes...
I think the main point that is coming out is that these are all equipment and should be used as aids and information sources to assist the pilot - but do not replace a good lookout.
Also I think comment regarding FLARM in the alps raises an interesting issue. In the Alps people are flying closer together, there have been more incidents of aircraft occupying the same bit of airspace at the same time and therefore people choose to install this technology. But because of the terrain etc. more aircraft carry FLARM that don't therefore the solution works. However there is no mandate to carry it, it is purely an example of how the flying population recognise a danger and take their own approach to do it.
In the 'congested' skies over the UK, (I put that term in inverted commas because can you argue that the UK skies are as congested as a valley in the Alps?) there is, maybe, not the collision risk that is present in the Alps and therefore people feel that they get no benefit from installation in skies such as the UK.
Please keep the replies coming... it is good stuff.
I think there is enough for me to throw my 2 pence in the ring: -
1) Do you know what it is? - Yes
2) Do you have it? - No
3) Would you buy/fit it? - No
4) If so, why, if not, why not.
I think there are other alternatives already available that if used correctly can help and have minimal cost, for example actually using the ATC services available, ensuring the aircraft is flown properly (e.g. in trim etc) allows more time for look out, taking a friend flying and asking them to assist with the lookout (also alleviates boredom), thinking about the altitude and where you are flying (everyone fliew at 2,500 and 3,000 feet for example, so fly at 2750; if you are above the transition altitude use the correct FL even if VFR and if you are flying along a line feature, even if you are not using that feature to navigate recognise the fact that other pilots will... fly on the correct side etc. Doing your downwind checks before you fly the circuit, then all you need to do is look out while you're in the circuit (Don;t forget the Reds, Greens, Blues on Final tho)
Anyway, my 2 pence worth!
As I said keep 'em coming this is a really good debate!
I think the main point that is coming out is that these are all equipment and should be used as aids and information sources to assist the pilot - but do not replace a good lookout.
Also I think comment regarding FLARM in the alps raises an interesting issue. In the Alps people are flying closer together, there have been more incidents of aircraft occupying the same bit of airspace at the same time and therefore people choose to install this technology. But because of the terrain etc. more aircraft carry FLARM that don't therefore the solution works. However there is no mandate to carry it, it is purely an example of how the flying population recognise a danger and take their own approach to do it.
In the 'congested' skies over the UK, (I put that term in inverted commas because can you argue that the UK skies are as congested as a valley in the Alps?) there is, maybe, not the collision risk that is present in the Alps and therefore people feel that they get no benefit from installation in skies such as the UK.
Please keep the replies coming... it is good stuff.
I think there is enough for me to throw my 2 pence in the ring: -
1) Do you know what it is? - Yes
2) Do you have it? - No
3) Would you buy/fit it? - No
4) If so, why, if not, why not.
I think there are other alternatives already available that if used correctly can help and have minimal cost, for example actually using the ATC services available, ensuring the aircraft is flown properly (e.g. in trim etc) allows more time for look out, taking a friend flying and asking them to assist with the lookout (also alleviates boredom), thinking about the altitude and where you are flying (everyone fliew at 2,500 and 3,000 feet for example, so fly at 2750; if you are above the transition altitude use the correct FL even if VFR and if you are flying along a line feature, even if you are not using that feature to navigate recognise the fact that other pilots will... fly on the correct side etc. Doing your downwind checks before you fly the circuit, then all you need to do is look out while you're in the circuit (Don;t forget the Reds, Greens, Blues on Final tho)
Anyway, my 2 pence worth!
As I said keep 'em coming this is a really good debate!
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Italianjon, in UK class G airspace, it seems to be the case that most GA power typically cruises at 1000 to 2500 feet, and most glider cross country flying is in weather conditions where gliders will normally be higher than that. Statistics show that glider/glider collisions are one of the three big fatal collision causes, accounting for typically one fatality a year. Glider/other GA collisions happen at far lower rates – about four in the last 30 years, not all fatal. So, FLARM for gliders in class G in the UK make sense to me, and is making sense to growing numbers of glider pilots, and we are fitting them voluntarily. So far, in small but growing numbers. Worldwide, I understand that over 9000 units have been sold.
In terms of risk analysis, and bang for the buck, I believe it is the right place for us to spend money. I believe that widespread adoption of FLARM for gliders will save more lives than the equivalent amount of money spent on mode S. Not only that, but as I and others have repeatedly pointed out, FLARM is physically achievable in most gliders, whereas mode S Power and space requirements preclude it for many, as well as there being few EASA-approved installation schemes.
For some gliders, transponders may have worth while benefits for their cost. I am planning to fit one, partly because I fly close to controlled airspace where it is a choke point for GA traffic to skirt round Stansted, and partly because sometimes I want to penetrate controlled airspace myself. I have solved the power problem in my glider, but not the EASA-approved installation.
I have a simple response to airline or GA power pilots who think we should have interoperability between gliders and the rest. If they think it worth spending money on, they can spend it, by fitting FLARM. It is the only thing in the foreseeable future which will assist in detecting most gliders. If they don’t think it worth the money for them, why should anyone think it’s worth only some glider pilots spending far higher costs on mode S, for the limited number of gliders where it is actually practicable?
If they don’t want an extra piece of equipment in the cockpit, which gives no interoperability with transponder equipped aircraft but does with the low threat of glider collisions, why do they think gliders should fit transponders which give no interoperability with other gliders, although that is where the biggest threat of glider collisions remains?
By the way, I totally agree that any of these electronic aids must be used to aid, and not replace, “see” and avoid. I also agree with those who recognize that the eyeball on its own is a very imperfect collision avoidance tool. We can never overcome blindspots with eyeball alone, and human beings seem incapable of perfect lookout even where blindspots are not a factor. I saw a safety presentation which showed that most collisions involving gliders are from behind one of them. Only one pair of eyes, and sometimes not even that, had the chance of seeing and avoiding. Collision geometry such as the rearmost higher glider catching up lower glider in front can result in blindspots for both pilots. Whatever the cause, certainly that has happened.
Chris N.
[edited - few, not necessarily no, EASA-approved glider installation schemes]
In terms of risk analysis, and bang for the buck, I believe it is the right place for us to spend money. I believe that widespread adoption of FLARM for gliders will save more lives than the equivalent amount of money spent on mode S. Not only that, but as I and others have repeatedly pointed out, FLARM is physically achievable in most gliders, whereas mode S Power and space requirements preclude it for many, as well as there being few EASA-approved installation schemes.
For some gliders, transponders may have worth while benefits for their cost. I am planning to fit one, partly because I fly close to controlled airspace where it is a choke point for GA traffic to skirt round Stansted, and partly because sometimes I want to penetrate controlled airspace myself. I have solved the power problem in my glider, but not the EASA-approved installation.
I have a simple response to airline or GA power pilots who think we should have interoperability between gliders and the rest. If they think it worth spending money on, they can spend it, by fitting FLARM. It is the only thing in the foreseeable future which will assist in detecting most gliders. If they don’t think it worth the money for them, why should anyone think it’s worth only some glider pilots spending far higher costs on mode S, for the limited number of gliders where it is actually practicable?
If they don’t want an extra piece of equipment in the cockpit, which gives no interoperability with transponder equipped aircraft but does with the low threat of glider collisions, why do they think gliders should fit transponders which give no interoperability with other gliders, although that is where the biggest threat of glider collisions remains?
By the way, I totally agree that any of these electronic aids must be used to aid, and not replace, “see” and avoid. I also agree with those who recognize that the eyeball on its own is a very imperfect collision avoidance tool. We can never overcome blindspots with eyeball alone, and human beings seem incapable of perfect lookout even where blindspots are not a factor. I saw a safety presentation which showed that most collisions involving gliders are from behind one of them. Only one pair of eyes, and sometimes not even that, had the chance of seeing and avoiding. Collision geometry such as the rearmost higher glider catching up lower glider in front can result in blindspots for both pilots. Whatever the cause, certainly that has happened.
Chris N.
[edited - few, not necessarily no, EASA-approved glider installation schemes]
Last edited by chrisN; 23rd Jul 2008 at 11:18.
In terms of risk analysis, and bang for the buck, I believe it is the right place for us to spend money. I believe that widespread adoption of FLARM for gliders will save more lives than the equivalent amount of money spent on mode S. Not only that, but as I and others have repeatedly pointed out, FLARM is physically achievable in most gliders, whereas mode S Power and space requirements preclude it for many, as well as there being no EASA-approved installation schemes.
I have a simple response to airline or GA power pilots who think we should have interoperability between gliders and the rest.
I wonder if synergy is possible at the level of the receiver? Can we make a FLARM receiver that decodes and displays 1090ES (ADS-B out or Mode S responses) or a system of the sort that italianjon describes that can also receive FLARM output?
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Everything helps
As mentioned in ‘another place’ where the same question was posed, I use the small Zaon unit. With all its limitations, it is better than nothing. I fly a relatively slow aircraft (the sort that gets bird strikes on the trailing edge of the wings), most other traffic overtakes me, so there is even less chance of me seeing them, although I hope they see me. When my unit starts to display, it reminds me to increase my look out. When it starts to beep too much, say in the circuit, I mute it.
I suspect the answer to the original question is that anything that helps awareness of other traffic is good. It’s a case of Mk1 Eyeball + LARS etc. + TCAS or cheaper equivalent + FLARM all the things that you can afford, power and use without too much distraction from the job in hand. My 2.5p’s worth (old money).
Safe Flying,
Richard W.
I suspect the answer to the original question is that anything that helps awareness of other traffic is good. It’s a case of Mk1 Eyeball + LARS etc. + TCAS or cheaper equivalent + FLARM all the things that you can afford, power and use without too much distraction from the job in hand. My 2.5p’s worth (old money).
Safe Flying,
Richard W.