TCAS and Fast Jets

[Icanseeclearly]

Just a quick question...

Towards the end of last year whilst on a flight over the north sea we had the great sight of what my FO claimed was a tornado.

Only snag was we got an RA on our TCAS and had to put the aircraft into a steep climb.

Am I right in assuming that miltary FJ's have no TCAS and ours was reacting purely to the other aircrafts mode C and was probably confused due to the speed of the FJ.?

What is the best way for us to let you know we are about (ATC told us about the other aircraft only after the event) if the weather radar is on will you pick it up on your ESM equipment and thereby know we are there and so avoid us or is that just wishful thinking?

Thanks in advance.

ICSC

[recceguy]

Weather radar might be an idea - provided the fighter has the appropriate equipment, fitted with the appropriate database....
Fighter jets cannot operate with TCAS, because from the beginning to the end of their flights, they are doing rejoin or intercept manoeuvres between themselves, or the tanker, or even some liner they are missioned to identify...
so their flights would be a nightmare of RAs from the beginning to the end
and even without that, just one of them pointing his nose towards you in a perfectly safe manner, miles away but at 450/500 kts, would generate enough RA and reports to spend one hour after each flight filling the reports...

Also space and weight are at a premium in a fighter jet (you already have to bargain for a 20 kg ECM device which will save the day out in operations)

Just remember that for the fighter, you are motionless in the sky -- so HE will avoid you- please do nothing...

[gashman]

not sure about the do nothing statement there. I'd say that doing nothing is reasonable advice only if you are in controlled airspace and you know why the RA is being generated. Fast jets work on a see and avoid principle, but you are right in saying that the speeds used and especially the very rapid rates of climb and descent available to FJ crews, are prone to setting off TCAS. We go to great lengths to minimize these alarms when operating around CAS, especially when we are climbing underneath airways. If you are outside of CAS though, and getting close to FJ operations, a high speed turn miles away from you may give enough of a vector to tickle the TCAS. That's why, where possible, we use MDAs to keep ourselves segregated from non military aircraft.

[PPRuNeUser0172]

No FJ do not have TCAS, the Tucano does plus the heavies but pointy types do not.

When you say "over the North Sea" do you mean under a RAS between NEW-ADN? or were you above one of the other danger areas 613/323 complex?

Just out of interest when you get an RA, are you mandated to file against mil types?

[Icanseeclearly]

Dirty Sanchez it was the ADN - NEW and under what was then a RAS.

We do by law have to obey all RA's and subsequently report them whoever is involved so the do nothing is not an option.

thanks for the answers

[PPRuNeUser0172]

No worries

Just as an insight, do you think it prudent to operate outside of CAS under a RAS/ traffic/deconfliction service in area where there are known to be many mil fast jets operating.

From our side of the house, we bend over backwards to accommodate the requests to stay out of your way, we never see you take a 20degree hdg change to stay out of our way.

It is only a matter of time before the the NEW-ADN becomes class A permanently and the incessant reporting of RAs that are non-events does not help. Clearly exercises and large force packages tend to use the MDAs under segregations but availability/sea state/ volume will often see many fast jet ac legitimately using OTA E (Northumberland east of scottish TMA) and I sometimes question the prudence of airliners transiting up and down under a RAS.

The difference is, I don't pay for my fuel and I guess this one will have to be a case of agree to disagree.

[TheInquisitor]

Action precipitated by an RA is mandatory and trumps any other ATC instruction - it has to be, otherwise you're kind of defeating the object of TCAS.

DS raises some valid points, which are only going to get worse with the ever-diminishing airspace available in and around the UK. Most other nations have dedicated Mil airspace that civ traffic does not fly through - at least routinely. Then again, most other nations have the space to do so!

One possible option here is for civ traffic operating OUTCAS is to operate in TA only - it would avoid the scenarios described above and doesn't present any real additional risk - after all, ALL players were operating in this fashion until only a few years ago. The TA mode would simply give you some additional SA that you didn't have before, and let you make the decision on whether avoiding action was warranted - which it generally wouldn't be.

Persuading your company to incorporate that into their SOPs may be the hardest part of that battle, though!

[Sentry Agitator]

ICSC

Were you IMC or VMC on the Link rte? I ask as I attended an airspace seminar at Durham some time back where a certain airline rep stated that his crews were mandated by the company to demand (request?) a RAS under any met condition. A RAS over Northumberland would have given you less flexibility to track progress on time without having to take ATC directed avoidance action or TCAS RAs.

I think you would find it easier to keep the peeps down the back happy with the G&Ts if you had utilized a RIS. Post CAP 774 the Traffic Service vice Deconfliction Service if you are VMC would be my recommendation.

However, if I could be so bold as to try and offer you a little bit of reassurance; most (not all) fast jet traffic operating tactically in the area will be getting an ATS from either SCATTC Mil, ASACS, AWACS, EGQL, Spadeadam or even EGPH/EGNT. The fighters will most likely be getting a traffic service and SHOULD/WILL be informed about you on the route. Those operating VFR will be VMC and using either radar to take their own sep or as already stated the see and avoid principle if non radar equipped. If the traffic is working in one of the MDAs then they will know about you should they egress the areas. Within Class C they should adhere to ROCD if they are likely to 'interact' with GAT to avoid unnecessary TCAS RAs.

Therefore, I believe that the airlines are restricting themselves unnecessarily and having to take avoidance action in Class G because they request an inappropriate service for the met condition. This then leads to more incident reports which results in a lack of flexibility in airspace utilization.

The blue suits don't set out to upset other airspace users but we do rely on the satisfactory application of the appropriate ATSOCAS by all airspace users.

SA

[US Herk]

Action precipitated by an RA is mandatory and trumps any other ATC instruction - it has to be, otherwise you're kind of defeating the object of TCAS.

It is mandatory and it is a sound policy to always follow RAs IF and only IF all aircraft have TCAS, otherwise, the aircraft w/o TCAS is an unpredictable entity and TCAS RAs are based on predictability (ie - the other aircraft either reacts to its own RA, or if not TCAS equipped, continues in its present manner). Add in the latency of updates (~1 sec ish?) and you have a challenging situation.

I always here about TCAS would've saved the day on the Russian/DHL midair back in '02 and the controller bungled the job. He was working two sectors simultaneously and gave the Russians instructions counter to their TCAS. However, remove TCAS and the controller had a plan to deconflict the traffic - no issue. The issue was TCAS was involved directing the DHL to do something and, in this case, if both aircraft equipped with TCAS followed their RAs, it would have saved the day. The Russians, by not following TCAS, became unpredictable - the same as if they didn't have it.

My only 3 RAs have all come from fast jets climbing rapidly through my altitude - in ALL cases, my TCAS gave me a climb RA which simply makes the matter worse. TCAS gives me a climb because the offending aircraft is below me. In all cases, I was VMC, twice above cloud where I could not initially identify the "intruder", but it was simple to deduce what it was. I ignored all 3 RAs because, as the Captain, I have the obligation and responsibility for the safe conduct of the flight - technology notwithstanding. Since VMC and able to VID the "conflict" TCAS identified, I simply did nothing. Nor did I report this to anyone, although I would have been well within bounds to report a near-miss/airprox/HATR.

I'm a huge fan of TA-only right now - at least until ALL aircraft are fitted. I love the SA the "fishfinder" gives me - for now, I shall also use lateral offset to avoid RAs, or to augment. Of course, when VMC, the Mk1 eyeball is primary, with a good radar backup (when avail). Until such time as all aircraft are TCAS (or ACAS) equipped, I simply do not know what the "intruder" is going to do or how he is going to react. In the overwhelming majority of the cases, the RA will work well, however, there is still that percentage...

[Jay Tyock]

DS is absolutely correct to point out the fact that the ADN-NEW 'airway' is not a true airway for most of the day. Of course we all know that it will become permanent eventually; apparently certain airlines consider that saving fuel is more important than getting their passengers safely to their destination. All the FJs in their way (doing their job in ever more constricted airspace) do their level best to get out of the way, I can assure you, but class F/G airspace is not an airway.

Bearing that in mind, again I back up DS' point of 'what are you thinking selecting RA outside of CAS'. I take it that this didn't happen during 'quiet hours'. My albeit limited understanding of TCAS in RA mode is that it is only effective if everyone is in the same mode. Unfortunately I don't recall the rules mentioning the difference. Maybe the rules assume a modicum of common sense.....

On the positive side, the mil FJ in that area of class F/G airspace are now required to try to get a service. This will be at the expense of their flexibility and effectiveness but is the best that can be done. They could just stay on the ground and not train......

I suggest that everyone recognises the freedoms of class F/G, which are essential to FJ ops, and either keep a good look out or pressure their companies to confine themselves to CAS for passenger flights, or at least stick to TA outside of CAS.

Pull out the pin and let it roll........