Collision Risks?

[shortstripper]

Monocock - You attitude to flight safely is astounding........and frankly frightening. I'm not going to waste my time addressing your inane rantings.
However with an attitude like that I'm sure it won't be long before I get to read your autobiography entitled "AAIB bulliten 08/2007"

Monocock .... Your answer says it all

[Tarq57]

It Happens... http://www.pprune.org/forums/showthread.php?t=210323

[Bravo73]

And here... http://www.pprune.org/forums/showthread.php?t=202743

[gasax]

I also am of the opinion that brooke23 is either someone who desparately wants gold braid on his sleeve or is simply a troll.

I love the condesencion about there being no traffic in the Scottish FIR. a lot of the time that is true, but when (or if) you fly up here remember most people are flying the same routes, passes etc, that includes a substantial amount of military hardware, all of this occurs in class D to G with no radar. so make sure your lookout is up to scratch.

However I fly quite a bit up and down the east coast to and from the continent, the service from the LARS units is highly variable and will not stop collisions.

If you think people are being irresponsible in not switching on the transponder in their "highly equipped club aircraft" fine, its a view you're welcome to. But it is completely irrelevant in any real terms.

Happy trolling

[slim_slag]

EnglishAl,

Just read about that horrible accident. There is little doubt that had they had a traffic info system - which would have worked there - it is less likely that this accident would have happened.

I suspect they were in a radar blind spot, so TIS would have dropped out. It's quite hilly around there and SOCAL cannot see you when close to the ground (used this once when I bust miramar Class B, suddenly decided to land at Ramona, this was before it had a tower - filed the NASA form of course )

[egbt]

I find myself in a quandary on this one, for preference I would prefer to do my own thing but is this reckless of my own safety and, perhaps more importantly, of others? Probably not, but why not take simple precautions to minimise the risk for everyone?

A while ago I had a very close airprox (Official and category A) and I can tell you it was very, very frightening being < 1 second away from disaster (we both estimated the same distance). Me keeping a better look out would probably not have helped as the other a/c was climbing and hidden from view (but I don’t fly wings level for very long now!). Having “I had right of way” or similar on the tomb stone would also not have been much consolation for anyone, except perhaps the insurance company.

Now, the precautions we are talking about would not (did not) help in this case as I was not close to a honey pot (and neither of us were going to/from the nearest one), was in class G airspace, in contact with an A/G station and I did have the transponder on (with height)- but even though I was at 2,000 agl in the south of England it subsequently could not be tracked properly from the tapes so would have been no use to a radar unit.

So happens, we all have to recognise that, but IMHO we should take reasonable precautions. For me that means putting the transponder on outside of the circuit (although in my current steed it does not provide height info), keeping at least a listening watch on appropriate frequencies and taking a FIS or RIS when there is a lot of Military activity or when flying through choke points such as Cottesmore / East Midlands and Odiham / Southampton.

I guess what I am saying is that none of us are invulnerable, keeping a good look out is essential but not a complete answer, so lets go and have fun taking resonable precautions but without tying our-selves in knots and overwhelming the ATC units.

[OpenCirrus619]

Mono - What you said

gasax - Ditto

booke23 - You get what you pays for. If you want someone else to guarantee separation / you don't trust yourself to look out then get an IR and always fly in Class A. If you want the freedom of F and G then stop complaining.
You're the sort who would insist a 40yr old gilder with NO electrics at all (in case this is not clear: no radio, GPS, torch, battery, ....) has a transponder so that it's not your fault when YOU cut them up.

OC619

Edited to add:
Take a look at page 5 of: http://www.caa.co.uk/docs/64/DAP_ACD_VFR_Guide.pdf to see who (supposedly) keeps who away from whom in what airspace.

[IO540]

CAS is no guarantee of separation; anyone can bimble into it. And if that "anyone" is not transponding Mode C, ATC has no idea if he is in it, or below it.

All you get by flying in CAS is a reduced probability of hitting somebody. You can achieve a similar improvement by flying high; flying at 5000ft in Class G is far far better than at 2000ft in Class G. There is almost nobody above 3000ft, relatively speaking.

If somebody wrote

"won't be long before I get to read your autobiography entitled "AAIB bulliten 08/2007"

on my tombstone I would be very disappointed; I would have expected it to be spelt correctly

The only thing which has the potential to protect against mid-airs is TCAS. This comes at a cost, £10k-25k, plus everybody else using Mode C, or (in the far future) ADS-B with broadcast of GPS position (which would be much more accurate and probably much cheaper to buy and install).

[chevvron]

IO 540: Flying at 5000ft is all very well during the week, but at weekends, you'll find the sky close to UAS's full of Tutors between 4000ft and FL80 (roughly), and when Tutors fly at weekends, you often find it's without radar from the home airfield eg Boscombe and Benson, so no-ones going to warn them of your presence. Otherwise I agree; fly as high as you can without entering controlled airspace.

[Jo Cover]

I have been an uncontributing observer of Pprune for some time and have only just felt the need to register.

I cannot believe the lack of professionalism shown by some of the posters on this thread. Some of the comments are down right irresponsible.

If the a/c is equipped with transponder and radio then use them. They are there to assist you and others. You might think you are invincible but I can assure you you are NOT!

The transponder isn't difficult to use. You all know how they work. Normally one switch and it's on. Simple as that. Maybe with a few changes to squawk, if you actually use it correctly but it isn't dificult is it?

The radio might be something which frightens you and I know some grown men and women can be intimidated by speaking over an open channel for all to hear, BUT, don't forget that the radio is there to be used to assist you and others.

Remember the section regarding relaying a Pan or Mayday call in the R/T practical? Would you like it on your consience, if you ignored a fellow aviator in trouble, just because you couldn't be bothered to switch on and listen in to others in distress? And maybe, just maybe, make the difference and save someones life by alerting the appropriate emergency services, to the scene of either a crash or other potential life threatening situation? Would you like the idea someone else equipped with radio ignore your calls for help because they couldn't be bothered to switch on and monitor their radio?

Do you think that when the time comes for you to call for help when it all goes wrong, you will be able to enter the correct frequency, select the correct radio box and make the correct transmission when all is going wrong?

Maybe you are of the 'it won't happen to me brigade'. Maybe you never practise PFL's or EFATO's or other vital emergency action drills. Will you remember what to do when the need arises? The simple answer is a big NO! Of course, you don't need to because it's not going to happen to you is it...

May I suggest some of you re-think your posts, get out of your ivory towers and act as professionals. After all, this is the Professional Pilots Rumour Network is it not?

[booke23]

Here Here Jo Covers.

I was beginning to resign myself to the fact that alot of Private Pilots are in fact clowns, calling themselves "Bobo" who go flying on sunny weekends wearing oversize shoes and huge trousers.

I am however encouraged by the few posts of a positive nature......including yours.

I remain astonished at the level of hostility generated by a simple observation, one which I made only to highlight what is unnessary bad airmanship.

And before all you guys with no transponders/electrics start jumping up and down again, I suggest you read my initial post again......I never mentioned aviators in those groups....only people who hire well equipped aircraft who fail to use the transponder.....

...so kindly remove the chips from your anti establishment shoulders, leave your Ego at the door and be a bit more grown up about debating aviation safely matters.

[englishal]

Slim, you are probably right. I had "pop up" traffic appear below directly below me when IFR in that region which caused the controller to issue a traffic alert, and as you say TIS wouldn't have seen it either.

The problem with a FIS it is not a reliable source of traffic information and may lead to a false sense of security, so is worthless other than to give altimeter settings IMO. A RIS is valuable but if you're just going for a jolly, say to practice a bit of upper airwork, don't really know where you're going, other than South, and don't know what time you'll be back then it is unlikely a RIS would be given on a gin clear day, or it would be terminated pretty quickly if they are busy.

I have mode C and transpond every time. I have a radio and maintain a listening watch to the relavent ATC unit, but don't always bother to call them unless enroute somewhere....otherwise my call would be along the lines of "GABCD is out of blah, local flight, dunno what altitude, probably going south for a bit, may be about an hour, request RIS"....

[shortstripper]

booke23,

With all due respect, I have re-read your original post and whilst you don't specifically refer to non transponder/radio aircraft, you certainly wrote it in a way that came across as all encompassing. To add to this, you flamed Monocock when he pointed this out and took the mickey out of your stating of a few obvious facts ... as if we don't all know that a middair will most likely result in death How do you turn such a post as his into the assumption that he is reckless and irresponsible? OK, if you are transponder equipped, and have a radio, then sure, turn them on, keep a listening watch and perhaps let people know you're about. Nothing in Mono's (or anyone else's) post suggested otherwise? Ithink you (and Jo Cover) seem to have missed the point that most are making; that is, that these things will not gaurantee your safety!

The time I personally worry the most about a middair is the 2000' overhead join. Here I may well be known to ATC and others, but have often been there, knowing there are three of four others joining, and I can't see one!

SS

[Monocock]

shortstripper -

I wouldn't be surprised if our friend and Jo Cover are the same people. Thanks for seeing my post as it was intended. Its content was not a "flaming" as you pointed out, just a different end of the scale to booke23's view.

Maybe you never practise PFL's or EFATO's or other vital emergency action drills. Will you remember what to do when the need arises? The simple answer is a big NO! Of course, you don't need to because it's not going to happen to you is it...

Would love to run you through my EFATO Jo. I'm just damn lucky I was flying the aircraft when it happened and not buggering about with a transponder as I wouldn't be here now if I had been

[Fuji Abound]

I think the poster is simply naive.

There is a misconception that the radio and transponder in some way prevents collisions in open FIR. That misconception can only arise from failing to understand how they work.

As others have said a transponder is of no use at all in collision avoidance (unless you have TCAS fitted, which is hardly anyone), or are receiving a RIS or RAS (which is most unlikely in open FIR).

Radio calls informing everyone of your position and height may be of some small help, in that other alert pilots may realise there is a potential conflict or adjust their height to ensure one does not arise. The problem is that on busy days when collisions are more likely it is often difficult or impossible to make frequent position reports. Moreover, pilots are likely to be talking to different stations - are they with London or working a local ATZ. They are also unlikely to know the local area well enough to know when a pilot calls overhead XXX that they are in the same area.

As I posted on another thread there are a number of ways in IMC you can reduce the risk of collision in open FIR. These ways apply equally in VMC with some additions.

1. Avoid overflying choke points - VORs, NDBs and VRPs

2. Avoid tracking close to the edge of CZ

3. Fly above 3,000 feet if possible, most GA pilots don’t like getting to high

4. Avoid gliding sites and any airfields

5. Avoid following line features - I suspect most GA pilots have forgotten the rules about line features and simply follow them regardless of which side they should be on

6. Fly at 2,000 feet (if you cant get high). Slightly tongue in cheek but everyone is told don’t fly at 2,000 feet and seem to have got to grips with that one, so now everyone is at some other height and 2,000 feet is presumably pretty conflict free

7. Never fly in a straight line, make small and frequent course changes

[benhurr]

Just to add to Fuji's list.

8. Fly at the correct quadrantal level/altitude whenever possible. Obviously noone would fly under controlled airspace or a nav route on QFE in the UK so I don't need to add quadrantal height to please the pedants.

I appreciate that at times then this can be difficult when controlled airspace is low.

I think point 7 is also particularly applicable in these GPS days. The accuracy of GPS is a wonderful thing but it also introduces another problem of raising the possibility of 2 aircraft on reciprocal headings between two points routing through exactly the same piece of sky.

I see nothing wrong with people flying in the open FIR with no radios and no transponders in most areas. However I would suggest, for purposes of self preservation, then this might not be wise through Coventry or Doncaster's final approaches.

Good airmanship involves a large degree of common sense - my main rule in whatever I am flying is that I don't want to die in any circumstances, even if I am in the right.

I sincerely hope that everyone here shares that view.

Edited to please

[Tarq57]

Fuji Abound

all good points, especially#7. This is one thing you can easily do to a) make yourself more visible and (b) increase by quite a lot the chances of seeing another aircraft that was on a collision course.

Realistically, transponder on in D or G airspace will improve things in an area of radar cover, where a controller is providing a radar service to an IFR flight, you will likely be called as traffic information if a threat (ie likely to pass within 3nm). The more likely hazard is from VFR aircraft that happen to be on a "line of constant bearing" (read=collision course) and don't move across the windscreen. Very hard to spot. Especially gliders. This is why turns are useful.

Benhur, absolutely. Anything that increases the time you have to spot closing traffic has to improve the odds.

2 Cessnas collided over Milford Sound a few years ago on a tourist scenic. They were almost parallel but slightly converging. (This is a high density area) The report found that although one of the passengers could see the other aircraft approaching, and even photographed it, it was unlikely the PIC would have seen it without some unusual contortion. The other pilot's view was likely to be obscured by the wing.
So, yeah, big sky, but hey! In my opinion this is one area of flight safety where the unexpected will kill you. (mind you, I'm an ATCO, hence -in part-that opinion). Engine failure? Rare, and trained for. Fire? Very rare. Bad weather? Too common, but you have the answer in your own hands. Structural failure? Horrid but extremely rare. Stall? Too common, but still, trained for. Collision? Ride it down.
Keep things turning. (heads and aircraft.)

[bookworm]

Originally Posted by Gertrude the Wombat

Oh, you've done the sums have you? What's the mean free path then? - I didn't know anyone had actually done the arithmetic!

Well let's have a go. Mean free path is 1/nA where n is the concentration and A is the collision cross-section.

I'd assess A as between 100 and 500 m^2 for a typical B737 sort of thing. If they were all smaller aircraft, it might be more like 50 m^2, but let's use the larger number because the big ones are out there too.

For n, let's say 2000 flights simultaneously airborne across a 600 x 400 km rectangle of the UK. The distribution of levels is non-uniform, probably bimodal, but let's say 4000 m deep. That's about 10^15 m^3 so n is about 2 x 10^-12 m^-3.

So the mean free path is about 1 x 10^9 m, or about 500,000 nautical miles. So for a typical light aircraft, in a random environment you'll find yourself on a true collision course about one in a 5000 hour flying career.

The estimates above are fairly conservative, so I wouldn't be surprised if it were once every 100,000 flying hours for the average space in which light aircraft move.

Of course traffic density isn't constant, and so the mean free path will be much more than that in a high level cruise over Scotland, and much less than that around busy airports.

[Tarq57]

P.S. A tip: When I was checking out in Cessnas, one of my instructors recommended before turning, to lift the wing a few degrees first, and have a wee look round. This 'coz in the 172 (and similar) it's hard to see your flight path, especially in a left turn (or right if flying from that seat).

[Jo Cover]

Ooh this looks like handbags at dawn!!

Glad to see that some posters are explaining their posts in a more positive way. Some unfortunately, want to stay with the 'wont happen to me brigade'. Nevermind, I'll enjoy listening to their 'Near Miss' and 'how I heroically avoided disaster' stories at the airfields I visit or reading their obituaries in the press.

Of course, a Transponder and Radio won't make you invincible by any means. That wasn't my suggestion but they will increase your chances of survival if used correctly. They are there to assist in flight safety, why oh why is that so difficult for some to see??

Ask for a FIS, RIS or RAS and if the controller can give you the service, they will. If you dont ask you won't get it but if you have asked, they might just assist in making the skies a safer place to be.


Fly the correct quadrantal level? We are assuming here that everyone flies a FL not on QFE or regional QNH?


Mono, correct me if I am wrong but shouldnt the transponder be set as part of your pre take off checks?? Presuming that you bother with those of course...

Anyhow, glad to see that you were able to handle the EFATO. Well done!!