TCAS + Mil Aviation

[Audax]

Does anyone have any knowledge as to why a lot (the majority?) of Military aircraft don't have TCAS? I really know very little about the system but surely anything that alerts you to the presence of another a/c has to be good value. Presumably it works at low level although the range will be limited.

I've been told the system is relativly cheap and easy to fit, so why not? Heaven help us if there is a mid-air and it was proved that TCAS could have alerted the crews, could the MoD be taken to court?

[BEagle]

As with many items of equipment which grown-ups are required to carry in their aircraft, such as 8.33 radio, then FM-immune navigation receivers, HM'sFC thought that it could get away with claiming 'state aircraft exemption'.......basically because the chair-polishers claimed that they hadn't known about the requirement and, you guessed it, 'there's no money for it'!
So even in European RVSM airspace, we don't have the level of safety required for the cheapest lager-lout toting charter operator. I don't know whether C-17 has it, but TriStar is getting it and C130J has it already. VC10 doesn't.
Perhaps when EASA takes over from the JAA, someone will be harder nosed with us, as we are now only a minority airspace user, and will tell us that either we comply or we stay out of European RVSM airspace. Already you hear queries on the N Atlantic asking why our aircraft don't show up on TCAS..... It took a fatal collision between a Tu154 and a C141 to convince other air forces of the need to fit TCAS - ours can't afford to pay for such safety, it would seem.

[Mowgli]

Audax

Having flown with it for 8 months now, I never want to fly without it. Apart from the obvious anti-collision properties, it gives excellent SA when there is a lot of traffic within 2000' of you (vertically) and within 15 miles. It's been fitted to ac because it can stop disasters, and with the airspace getting busier ALL ac should have it. Obviously the Red Arrows and tactical formation members would often need it to be suppressed for portions of the flight, but if only the Reds leader had it on with the wingmen in sby it could save the possibility of a lost sqwaker who didn't read the NOTAMS becoming an unwanted part of the famous routine. As for transport ac not having it - well "I don't believe it!!"

[Who's Ya Daddy]

Audax

The MoD are spending £80 million on the system and will have it installed on some aircraft soonish. For more info on it you need to cantact the Inspectorate of Flight Safety at RAF Bentley Priory. I was on a course there recently but I can't remember the exact detail of the info. Not surprisingly there are going to be difficulties for 9-ship tonka formations though (if they can all get airborne at the same time!)

[15/15 flex]

BEagle

Your a/c DO show up on TCAS, as I can bear witness to every time we enter the Brize zone, which as you know can be v busy on occasions.

As I'm sure you are aware, TCAS works best by interrogating other Mode S squawkers, and providing vertical conflict resoultions, thereby ensuring the two a/c don't both take the same avoiding action. It will also give traffic advisory on an a/c squawking Mode A, plus a height differential if you are also squawking mode C.

Having had a close-ish encounter of the 747 variety on the South Atlantic route a number of years ago, it was reassuring to know that the other a/c was fitted with TCAS - fortunately he was also listening on the discrete freq, heard our position report and acted accordingly. Now I feel naked if we dispatch without it, especially when in Africa, or the remote oceanic areas. How well it would work for low-level a/c I don't know, but every other fleet - especially those operating into high traffic density locations - should be fitted asap.

[BEagle]

15/15f - yes, we do show up on your TCAS! Which is nice. Out of curiosity, assuming that there is no proximity meriting a RA, what tells you on your display that the target ac isn't squawking Mode S?

[15/15 flex]

If squawking Mode we will get a height differential, but no indication that you do not have mode S. With mode A only, the system will assume that you are co-altitude.

[Firestreak]

Has anyone tried TCAS at low level? Is it useful or does it soak up mental capacity with spurious/excess info?

[15/15 flex]

TCAS change 7 has RA modes inhibited below 700' (I think) - ergo would not be much use at low level. However, comma, it can be used for flypasts etc and the TA mode is still functional.

[ 28 August 2001: Message edited by: 15/15 flex ]

[Marine]

From our perspective we initially were all for TCAS on all our fixed wing acft, better SA and an outstanding IVSI/altimeter combination.

The resistance from the aircrews started when we heard about the implementation. Integration questions with out modes 1,2, and 4 where we could have select one or all w/o selecting 3 or S.

The other problem was the fact that the directed installs had the aural commands 20% louder than any other (radio, threat warning/employment systems, ICS, malfunction warning system, etc.) aural communication device on a particular aircraft.

So we would have systems that if turned on anybody could interrogate mode 3 an/or S and at the same time the alerts would be louder than any other cockpit communication device!

Combine that with the currently installed systems that interrogate modes 1, 2, 3, and 4 but no altitude and to a better range spec. that won’t work with a TCAS system installed. I think it’s quite reasonable for us select the lack of TCAS as the best overall option.

[keepin it in trim]

TCAS is fairly common on police and air ambulance helo's who live mainly in the bottom 1000' of the atmosphere. All the guys I have spoken to who have used it in those roles swear by it. It may not be perfect for that but if it gives you 20 seconds warning of an aircraft on constant bearing, lurking behind the canopy arch, it gets my vote. If it's a nuisance in a hostile environment surely it isn't beyond the wit of man ( or MoD PE ) to specify an off switch?

[Rob Humphries]

Having operated with this system for some time, there is no doubt that TCAS is good and having it with its inherent limitations is better than not having it. However, it is a system designed for use in airliners and as such is not ideal for military use (except when flying in airline mode to the next kebab and kokinelli fiesta). Most of the problems can be dealt with through cunning aircraft systems design - ie enable TAs with audio at low level when the gear is up (so it won't bleat on finals). However, the biggest drawback is the fact that it can only see other transponding aircraft - you don't have to have a transponder to fly a civi aircraft in the UKLFS. Until the CAA mandate the use of transponders for all air vehicles below 10 000 ft, TCAS is going to be a handy but flawed collision avoidance system for military use.

[fergineer]

Having flown with the system since getting out and having it save me and 800 more people from dying in a mid air I can thoroughly recommend it. If you want to see the model that the CAA built on the computer ask them, it frightened me when it happened and it sure didnt come any easier with the computer simulation. Any one flying airways should have it, its a nusience at times but I would rather put up with the few disadvantages than go without the system.

[Marine]

A good portion of the problem is the same people who came out with our GPWS systems were going to implement our TCAS. They were tired of being abused about the GPWS problems, to include the function test flight profiles, and just turning the system off.

If we could get a system that the audio could be de-selected with the rest of the system on and be able to select the individual modes we’d be very happy. It appeared that one of the manufacturer preferred our implementation scheme but the civilian (and a few in uniform) bureaucrats had a bad case of rough a** after taking very warranted abuse on other systems. The fact that TCAS is/was directed gave them a stick to beat the operators over the head with.

It would then be a very valuable system.

[NoseGunner]

Just a point that I think is being missed: for FJ I don't think its the low level that's a problem - it's the other formation members causing false alarms (no squawking stby allowed!). Not to mention it would make all bouncexs, intercepts and TOO completely pointless.

Interestingly, RAIDS has a system where you can define formation members, other players and non players all separately setting your own warnings for each group eg 5 secs to 1000' bubble or anything within 10nm and 5000' or whatever. Only works with people carrying a raids pod though!

The other portion of TCAS is of course the terrain bit which I believe most FJ are in the process of getting (GPWS)
:)

[Marco]

A RAF Tucano collided with a Police Helicopter in Sept '97 over Wookey near the Wells mast in Somerset. One would have thought this would persuaded the RAF to do something about it. But here we are 4 years later with nothing. I might add the Police Air Support Unit had a TCAS 1 fitted within 6 months. Having flown with it for some time I wouldn't be without it.

True it can only pick up transponding a/c but that has got to better than nothing as we all are aware that see & avoid doesn't work a lot of the time. The fast jet fraternity are well known for not talking to anyone or transponding when low level. This is what most of the emergency service aircraft are irrated about.

Ask joe public who he would prefer over his house!

[Blue Stuff]

Just to aid my understanding, the 'T' in TCAS stands for 'Terrain', does it? Triv question, I know - just trying to keep up! ;)

Blue.

[HugMonster]

Nope. It stands for "traffic".

[2 TWU]

:( Marco, I take exception to your comments that the fast jet fraternity are well known for not using IFF or the radio at low level, well known to whom? We do use the conspicuity code and we do talk to people, indeed in some areas it is mandatory.

Try putting your comments to some members of the civilian fratenity who amongst other things will enter a MATZ without talking: tell it to the civilian who had an airmiss at 250ft in a Scottish valley a couple of years ago and then claimed he was miles away; tell it to the glider pilot who landed on a very active military airfield unannounced and then demanded access for his tow truck.

Nobody is perect Marco, please don't throw accusations around as you did.

[ 01 September 2001: Message edited by: 2 TWU ]

[Marine]

As stated TCAS is Traffic avoidance. GPWS is Ground Proximity Warning System and GCAS is Ground Collision Avoidance System.

All three use active emitters. The last two use at least a radar altimeter and other sensors. Problem being radalts can be very effective missile and AAA magnets for shorter range systems.

On this side of the pond it is far more likely that a civilian will accidently wander into a live range that has mil. acft dropping things or popping into a LL route w/o checking than the other way around. Quite often the civilian can't even be raised on either VHF or UHF guard.

[Blue Stuff]

HM & Marine,

Ta!

Blue.

[RATBOY]

The other problem with installing TCAS in TACAIR aircraft is the lack of available real estate in the cockpit for another box. The TCAS systems that do exist are a fairly straightforward fit for cargo and similar aircraft but for TACAIR integration into the total avionics fit calls for lots of engineering labor hours (for labor hours read money).

Another collision avoidance system in existance is Automatic Dependent Surveillance. There are several flavors but the basic idea is that the airplane knows where it is (GPS, RNAV, inertial, whatever) and then transmits it to everyone or just some specific people on a data link. The receiver then knows where the transmiting aircraft is and through the miracle of electricity can but a blip on a screen or give a traffic alert at certain parameters etc. Problem is that like with TCAS unless everybody is equiped and operating you can't be sure you are going to be alerted to the presence of the oter aircraft.

As a civil operator I have run across low level routes that happened to be in use even when NOTAMs didn't say they were, and in any case when there are NOTAMs most times they are useless because it gives a route and a day, so I guess all civil aircraft should stay out of that airspace for the day...particularly galling on weekends, when the reserves do a lot of practice.

[T_Handle]

TCAS on the C130-J works and it is great!!!
It actually creates more lookout and SA.
Worth every penny as the fleet has had to use it in anger on several occasions already.
8.33 - no probs, now just waiting for the RVSM calibration (oh yes and the FM stuff!!!)

"happiness is 70 tons and a HUD!"

[BEagle]

WHAT?? Are you really saying that the C130Joke came without FM-immunity compliant VHF communications and navigation receivers?? Even though it was well know that AWN84 was going to make them mandatory?

[ 07 September 2001: Message edited by: BEagle ]

[T_Handle]

You got it!!!!
Our lords and masters (and contract writers) turned it down - i am led to believe.
You know the story about upgrades rather than replacements!
Anyway we probably payed extra to have it taken out!!!!

Just as well the gulf has nice weather coz we are there all the time.

[4 of 7]

Having flown with TCAS regularly, you'll never want to fly without it again. You feel naked. Its bloody good. A bit like SKE but there's a damn sight more a/c with the transponders.

Hi Fergi, how are you doin'? Husband of VP/HR.

[Albert on Tour]

Does this answer your question Crashondeck?

[Bertie Thruster]

A reminder to everyone at low level. TCAS is not generally fitted to any of the charity funded HEMS helos in the UK. Especially those helos operating in the fast jet region. Most HEMS sorties are short and generally involve a landing and takeoff through a fast jet route.

In 2 years flying in this area I've seen lots of you in time. I just hope you see me!

[Crashondeck]

Thanks Albert - I feel embarassed now for not taking the time to search it out myself.

Bertie T - I agree. I've seen loads too and heard as many on uniform and never seen them.

It worries me that TDAs seem to get busted and HEMS/Police operators seem to have their necks on the line too.

Now I know why SAR birds are painted that rather baby pooh shade of yellow.

My question to the grown ups in the MOD would be if TCAS saved the loss of one Tornado/Tucano/Harrier/Hawk...+ crew would that not pay for TCAS in all their a/c.

Reminds me of a story of a pilot long lining in a forest, took off and found himself in formation (briefly) with the red arrows.

[2 TWU]

Light at the end of the tunnel? I hear a trial fit is going into the Tucano.

[contact_tower]

This january i experienced the following scenario while working our radar position: One of the a/c on the freq, a RoNoAF Bell-412SP flying VFR night L/L on goggels (below TMA, G airspace), I had no other reported traffic and informed the pilot of that when he req FIS. I allso had an FPL on a USAF MC-130 enroute L/L from Alta/ENAT. Suddenly the helo pilot cried out that a blacked out Herc had just passed below him, and that he himself was at 300ft AGL. (Everyone that have visited us know the limited radar coverage L/L btw :cool: )

The Herc checked in about 5 mins later, he had not seen a thing.

TCAS...... why bother..... :rolleyes:

[West Coast]

TCAS, why bother..You got to be kidding?

I would rather give up an engine than the metal detector flying in and out of GA crazy places like S. California.

[contact_tower]

You got to be kidding?

Affirm! :D

[West Coast]

Sit in the pointy end for awhile and I assure you you won't ever want to give TCAS up.

[Lima Juliet]

There is no TCAS fitted to any current fast jets (FJs) in the world. Even F22, F35, M2000-5, Rafale, Gripen and Typhoon aren't toted to be fitted with it - Question recently asked to all the manufacturers at Farnboro' and Paris.

Why? - It doesn't work! With the 30,000' per minute climb rates, high speeds and quick changes of direction by FJs, the TCAS would false alarm a lot. Hence, the UK Airprox Board is often troubled with TCAS RAs and TAs from airliners with FJs working in close proximity - but never in danger of colliding! (Plus the heroic TCAS obviously saves them!). The formation issue is also valid. The GR4 is being trialled with CWS (Collision Warning System) but I believe that QinetiQ/BAES are having problems with it.

If anyone knows of a working FJ TCAS then please let the MOD know!

LJ:ok:

[Chris Kebab]

That'll be a good one QinetiQ clearing CWS. How do they propose to test that then?!

Probably get MAR reccs about the same time that GR4 hits the scrapheap.

[slingsby]

Excuse my ignorance to equipment on fast jets, but as a civvie driver, I was wondering if your (as you term it) one or two seat FJs have radar intercept capabilities, surely that would avoid most if not all TA/RA incidents with us. If you have it, use it. I know you guys like sneaking around as covertly as possible, but in the advent of near misses and incidents, prudence should demand that your radar system should pick up civilian a/c and allow your drivers to maintain separation based on the information available to you. I may be completely wrong. (don't bite my head off, I'm just asking)
I for one am glad you are up here sharing the airspace, I don't mind seeing you guys passing us with your hair on fire anyday.