Typhoons Need Midair Collision Avoidance System, Safety Officials Say
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So those who have flown with the system, how does it go with formation flying? The RHWR goes off enough with a/c in close, I can't imagine what manoeuvring formation jets in and out of close would do to TCAS. Then if you turn it off when in formation, for mil jets virtually all the time, what is the point? Also is the system keyed into the performance of the jet or is it generic thinking a typhoon is going to turn like an airliner trying to avoid spilling coffee?
My first thought is false positives would make it a pointless system.
My first thought is false positives would make it a pointless system.
Interesting views, I had a feeling this would not be considered a cut and dry "no brainer" decision by some here. As such it is questionable whether the MAA was right to go so public on this - now the scope for a debate on its importance has effectively been taken out of the decision makers hands and it has become a political/red top presentational issue.
Presumably they have done the numbers on risks and usefulness of something like ACAS and are confident that they have scored the trade off correctly.
I hope so.
Presumably they have done the numbers on risks and usefulness of something like ACAS and are confident that they have scored the trade off correctly.
I hope so.
I'd like to hear how your mini-cooper could smash into an airliner, Leon.
An airliner doesn't have to be in the air to crash into it...
You see the problem with TCASII - ie. The one that most jet airliners use is that they 'talk' to other TCAS II units to give resolution advisories (RAs). Typically, an RA will be issued 20-30 seconds from collision, so if you have a Typhoon climbing at 15,000ft/min and there is an airliner 7,500ft above it then it will alert even though the Typhoon can see the airliner, is going to stay outside the controlled airspace the airliner is flying in and is a perfectly safe manoeuvre. The airliner will get an RA to climb, or even descend, rapidly to break the collision in the vertical - now how safe is that? In the horizontal it can be just as bad, a jet flying at 500kts+ IAS near an airliner doing 300kts+ IAS can have a closure rate of 800kts+ at lower levels or over 1100kts at medium/high level - that is 18 nautical miles a minute of closure. So everytime the Typhoon flies within 9 miles of the centreline of the airway it could trigger an alert to the airliner; even though it will be no-where near a mid air collision if it is pulling 9g.
Fitting TCASI would only give traffic advisories and only really does the job that the Typhoon's RADAR/Interrogator/IRST/MIDS will do. An airliner's TCAS will see the Typhoon's Mode S or Mode 3/A and does not 'handshake' with other TCAS Is like the later and more capable TCASII (which we discussed above is unsuitable for FJ type performance in my opinion).
So, that is why we have been trying to develop an Airborne Collision Awareness System for the Tornado GR for the past 15 years or so. It was as easy as plopping in a TCAS into a high performance FJ then it would have been done years ago!
LJ
Sorry folks, but the advantages of TCAS are being ignored. The RAF has/(and had!) several types that easily integrate TCAS function into their operations. It is not beyond the wit of man to write SOP's that get the best from the system and avoid most of the pitfalls. 
OAP
OAP
Typhoons Need Midair Collision Avoidance System, Safety Officials Say
TCAS in the Hawk T2.
I started on the jet when it was still at a reasonably early stage of syllabus development in the RAF and the integration caused a few headaches.
Since the kit is in the jet it is very hard to justify ever turning it off. Formations in segregated airspace operating visually with each other would be one time this could be done.
It did create a few problems especially at times when you didn't want your student to know there was another jet coming (low level evasion for instance). It was also quite annoying that it would steal your left hand screen whenever it issued a warning.
I wasn't the biggest fan of it initially and was happy that I had a fairly effective lookout scan but with the best eyes in the world you can still miss things.
The bottom line is that since a couple of guys I knew died in the GR4 midair I believe it is getting harder to justify not fitting it to all FJs. TCAS II is not a perfect system and I would much rather see something that is optimised for FJ use but in the meantime I would just fit it anyway. It would be much easier to sleep at night for some folks. It almost certainly would have prevented the midair in question but who knows if it could prevent more in future. Once it's fitted you'll never know.
The problems it causes can be mitigated against and despite what I've said on previous threads I'd take the rough with the smooth personally.
BV
I started on the jet when it was still at a reasonably early stage of syllabus development in the RAF and the integration caused a few headaches.
Since the kit is in the jet it is very hard to justify ever turning it off. Formations in segregated airspace operating visually with each other would be one time this could be done.
It did create a few problems especially at times when you didn't want your student to know there was another jet coming (low level evasion for instance). It was also quite annoying that it would steal your left hand screen whenever it issued a warning.
I wasn't the biggest fan of it initially and was happy that I had a fairly effective lookout scan but with the best eyes in the world you can still miss things.
The bottom line is that since a couple of guys I knew died in the GR4 midair I believe it is getting harder to justify not fitting it to all FJs. TCAS II is not a perfect system and I would much rather see something that is optimised for FJ use but in the meantime I would just fit it anyway. It would be much easier to sleep at night for some folks. It almost certainly would have prevented the midair in question but who knows if it could prevent more in future. Once it's fitted you'll never know.
The problems it causes can be mitigated against and despite what I've said on previous threads I'd take the rough with the smooth personally.
BV
Typhoons Need Midair Collision Avoidance System, Safety Officials Say
We would always turn it on in controlled airspace and then select it off when exiting. Never had an RA to respond to though.
As an aside it always struck me as worrying that a TCAS RA could happily tell you to descend regardless of height. Unless I've misunderstood something.
BV
As an aside it always struck me as worrying that a TCAS RA could happily tell you to descend regardless of height. Unless I've misunderstood something.
BV
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Yes, though in an airliner the EGPWS would protect you in that circumstance.
No issue with turning it on in controlled airspace shared with civilian traffic.
Entering the MATZ is a different matter though.
As I remember it initially the brief was "ignore RA if positive visual ID"
This was then changed to "always obey an RA" which I strongly disagreed with.
The problem is that even a hawk has the ability to operate well outside the limits that TCAS was ever designed to cope with, so often the RA is just wrong.
It was designed for an airliner, not something that can produce rates or turn/climb like a fast jet.
It also has huge protection bubbles, and in my opinion a military pilot has to be comfortable in close proximity to other aircraft.
RAs are reasonably regular at Heathrow when a departing aircraft has a slightly high rate of climb on the SID. It sound like a big deal, but when you look at the separations involved very few would be worthy of comment or even notice in a MATZ.
No issue with turning it on in controlled airspace shared with civilian traffic.
Entering the MATZ is a different matter though.
As I remember it initially the brief was "ignore RA if positive visual ID"
This was then changed to "always obey an RA" which I strongly disagreed with.
The problem is that even a hawk has the ability to operate well outside the limits that TCAS was ever designed to cope with, so often the RA is just wrong.
It was designed for an airliner, not something that can produce rates or turn/climb like a fast jet.
It also has huge protection bubbles, and in my opinion a military pilot has to be comfortable in close proximity to other aircraft.
RAs are reasonably regular at Heathrow when a departing aircraft has a slightly high rate of climb on the SID. It sound like a big deal, but when you look at the separations involved very few would be worthy of comment or even notice in a MATZ.
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Of course a military pilot has to be comfortable in close proximity but that's hardly an argument against TCAS. I did acknowledge most of those limitations about ten posts ago. But are we really better off with nothing? Or are we holding out for a (not yet invented) catch-all "magic bullet" system which may not arrive for years, or in context of Tornado, ever?
PS Leon, airports these days are circled by barriers that are more robust than a mini-cooper... But I suppose you could drop one out of a herc!
PS Leon, airports these days are circled by barriers that are more robust than a mini-cooper... But I suppose you could drop one out of a herc!
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TCAS II is not a perfect system and I would much rather see something that is optimised for FJ use
In a reply to a recent written PQ on risk MoD declared that the Typhoon's overall risk to life is "0 in 1000", simply because no one has died, yet. This approach on risk assessment, within the MoD (which includes the MAA), has remained unchanged for years. How does this sit with the DG's report? Perhaps the DG has the Tornado FAI in mind, which appears to have gone from "Unlikely" to "Probable" over the last six months, and he is just trying to protect his back. If he wants to be really brave he should declare the risk of collision for Typhoon as not being ALARP.
DV
Last edited by Distant Voice; 16th Jan 2015 at 10:46.
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I fail to see how TCAS can be very useful in a military aircraft in terms of safety.
In controlled airspace the risk of collision is already very low and TCAS RA could be selected without any real problems, but it is a solution without a problem in controlled airspace.
In the open FIR, jets cause all kinds of problems for current TCAS equipped aircraft with RA selected, so I fail to see how fitting it to jets would help.
If left in TA mode it can be quite useful at times, but as anyone who has used it knows it is very rough and ready as a kind of map view. Not convinced the time spent looking at it wouldn't be best spent looking out.
I found it most useful for spotting reaper/pred in their orbits at medium level. Tricky things to spot visually, but I would mention that they can take a long while to find. longer than you would have steaming through at speed.
In controlled airspace the risk of collision is already very low and TCAS RA could be selected without any real problems, but it is a solution without a problem in controlled airspace.
In the open FIR, jets cause all kinds of problems for current TCAS equipped aircraft with RA selected, so I fail to see how fitting it to jets would help.
If left in TA mode it can be quite useful at times, but as anyone who has used it knows it is very rough and ready as a kind of map view. Not convinced the time spent looking at it wouldn't be best spent looking out.
I found it most useful for spotting reaper/pred in their orbits at medium level. Tricky things to spot visually, but I would mention that they can take a long while to find. longer than you would have steaming through at speed.
The HMS Liverpool Lynx, which had encroached into the CCZ, was radiating in the sense her radar was working as was her I Band transponder.
Typhoon TCAS
If Typhoon or Lightning II need TCAS to achieve SA, we the taxpayers have been duped.
If there is a current front-line Typhoon driver who would rather have TCAS than improved operational sensors (and fusion) then let him/her speak up and I'll get back in my box.
Tonkas, trainers & truckies? Well that's a different story.
If there is a current front-line Typhoon driver who would rather have TCAS than improved operational sensors (and fusion) then let him/her speak up and I'll get back in my box.
Tonkas, trainers & truckies? Well that's a different story.
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Minnie Burner, you say;
What would you prefer when driving at night, a better Satnav, or headlights? With all due respect to Typhoon "drivers", I do not think they have all the facts in order to carry out a meaningful risk assessment. The guys on Ninrod XV230 believed that their aircraft was safe.
Beware of adopting the same mentality as MoD of no deaths, so no risk; so lets ignore all the near misses and keep going until something goes wrong.
DV
If there is a current front-line Typhoon driver who would rather have TCAS than improved operational sensors (and fusion) then let him/her speak up and I'll get back in my box.
Beware of adopting the same mentality as MoD of no deaths, so no risk; so lets ignore all the near misses and keep going until something goes wrong.
DV
Last edited by Distant Voice; 17th Jan 2015 at 09:47.
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DV
I think you are being unreasonable.
Do you imagine for a moment that the Typhoon drivers are likely to be unaware of TCAS?
It is a spectacularly simple system which is why the idea is very clever and very effective in the environment it is designed for, ie unmaneuverable aircraft that proceed in a stately manner about the skys operating in a system designed to ensure that they never get close to each other.
That does not really describe a modern military aircraft.
I think you are being unreasonable.
Do you imagine for a moment that the Typhoon drivers are likely to be unaware of TCAS?
It is a spectacularly simple system which is why the idea is very clever and very effective in the environment it is designed for, ie unmaneuverable aircraft that proceed in a stately manner about the skys operating in a system designed to ensure that they never get close to each other.
That does not really describe a modern military aircraft.
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The bit where you said that they were not in possession of the facts perhaps?
Since the relative safety advantages of TCAS or operational sensors was what was being discussed, the only facts I could see you might think they were not aware of was the usefulness or otherwise of TCAS.
Since the relative safety advantages of TCAS or operational sensors was what was being discussed, the only facts I could see you might think they were not aware of was the usefulness or otherwise of TCAS.
