View Full Version : TCAS Kamikaze (version 8)

4th Nov 2003, 14:42
From the Asahi Shimbun
Pilots & Controllers to share Data

Air traffic controllers will soon be able to instantly access instructions relayed to pilots by their in-flight collision avoidance systems, an advance the transport ministry hopes will prevent crashes through information sharing.
The traffic alert and collision avoidance systems (TCASs) in airplane cockpits issue resolution advisories (RAs) to pilots to help them navigate and avoid accidents.
Under the new system, due to start in the high-traffic Kanto region Nov. 20 and the Kinki region in February, pilots and air traffic controllers will be able to share such advisories.
Officials hope the system will prevent incidents such as the near miss between two Japan Airlines Co. planes in 2001 over Shizuoka Prefecture.
An air traffic controller mistakenly ordered one of the planes to lower its altitude, though the TCAS had advised flying higher to avoid a crash.
When the pilot followed the controller's orders, the planes barely missed colliding.
After the incident, the Aircraft and Railway Accidents Investigation Commission urged that controllers be able to access RAs given to pilots.
At present, pilots update controllers in writing or by radio only after they have taken steps to avoid a collision.
If a crash is about to occur, meanwhile, controllers are sent warning signals triggered when anticipated flight paths stray too close. This warning system, however, is slow to adapt to changes in a plane's course.
Under the new system, all RAs will be beamed to a centralized air traffic control center, where controllers will be provided with the flight number, altitude and speed of the aircraft.
(IHT/Asahi: November 3,2003) (11/03)

from this link (http://www.asahi.com/english/politics/TKY200311030092.html)

a. Is this prospective development (above) to be just a Japanese "thing"? (starting 20 Nov 03??)

b. Does it accord with Honeywell thinking? Does it accord with the TCAS II designer's intent? Is it sympatico with the equipment (or is it just a Japanese add-on?). Will it just further confuse the issue? Is it an attempt by Japanese ATC to have the last word (or is it an exercise in ATC face-saving after the very near mid-air collision in Japan mentioned above?)

c. Does the JAA, ICAO, US FAA and NTSB agree with it and endorse it as a giant leap forward (or backwards)? Has the FAA and JAA harmonized on this?

d. What about foreign aircraft operating into that airspace? Will they be so equipped? (optionally/mandatorily?). What does ALPA, APA, CAPA think?

To me it sounds as though TCAS is about to become a bunfight. (Spy versus Spy). The last thing that you need to further distract your urgent reaction (overlaid upon an excitated language problem) is an ATC controller getting an RA and deciding to agree/disagree with it (or its "automated" resolution). The whole idea was that TCAS would take over only once ATC had failed the mission for one reason or another. It will be very interesting to see how this all "pans" (or maydays) out. Will it become version 8 (pilot versus pilot versus ATC versus "late appearing on scene" ATC supervisor)

Since TCAS II was first certified in the late 1980's, a number of needed improvements to the system have been identified. Soon, a software update, referred to as "Version 7," will be incorporated in all new TCAS II systems. This update will also be made available by the various manufacturers as a retrofit for all existing TCAS II systems.
Many of the TCAS manufacturers will provide the update free of charge on recently purchased TCAS systems. Older systems can be upgraded for a fee. A service bulletin on the Version 7 update from each respective manufacturer is expected later this fall.
Version 7 will contain solutions to 19 known problems and incorporate new requirements deemed necessary by the FAA as well as industry experts. Some of the improvements are related to performance features and others are a result of experience with the system as we continue to learn more about aircraft encounters around the world.
At this point, Version 7 only applies to TCAS II systems and is only required for FAR Part 121 operators. There will be a two-year timeline for mandatory updating released later this fall. For more information on Version 7, operators can contact a TCAS-authorized service center.

Kalium Chloride
4th Nov 2003, 15:34
It's not just a Japanese thing. Eurocontrol initiated an investigation into the possibility of downlinking TCAS advisories to air traffic controllers shortly after the Uberlingen mid-air collision.

But the jury is still out in Europe on whether such information would be genuinely useful. Personally I think all that's needed is a clearer TCAS policy.

4th Nov 2003, 16:39

I don't really understand your thinking. What we are trying to prevent is the scenario described in Japan. There have now been quite a few very serious incidents where ATC and TCAS avoiding action have been contradictory.

If you ever get the chance to see an ATC radar recording and a TCAS RA recording at the same time the time difference between displaying the same event is quite unnerving because of time lag.

It is not going to be any spy vs spy system because, certainly in the UK, ATC are clearly instructed that when a pilot announces RA action we give no more instructions. What this might do is -

1. Stop the contradictory avoiding action instructions.
2. Allow ATC to be aware of the RA and give relevent traffic information (not all aircraft are SSR never mind TCAS equipped)
3. Allow ATC to try to stop the "domino" effect of TCAS RA setting of more TCAS RAs, by seeing the RA instruction and trying to move potential 3rd party conflictions out of the way so they do not become involved.

The only possible drawback to this is the speed at which it can be displayed to ATC and the time taken assimilate the information and act upon it, possibly in a busy ATC environment. At worst it should merely add to the information available to all parties.

Chippie Chappie
4th Nov 2003, 17:16
What about some new ATC instruction like "Follow priority TCAS or descend/climb FLXXX"?

Ivan Taclue
4th Nov 2003, 17:25
By the time he has said it, it's too late.
Conflict gone or..................xxxxx

4th Nov 2003, 18:24
'TCAS would take over only once ATC had failed the mission'

Oh really,I think you'll find it covers a lot more than that UNCTUOUS.
It's probably me,but the article talks about sharing/accessing TCAS info,you seem to have assumed that the ATCO will have the ability to override TCAS,not sure that is the reason at all,FINDO's points,show some of the current shortfalls that might be helped by such air/ground sharing of info.

Capt Homesick
4th Nov 2003, 23:08
I agree with Findo that an alert to ATC of TCAS RAs is a good idea. An extra factor in his point 1 and 2 is that the frequency gets a little quieter- not only for the aircraft involved, but for everyone else. Most of the time, not being able to get a word in on freq is frustrating- occasionally, it gives you some very tense moments...

Chippie Chappie
5th Nov 2003, 00:00
Ivan Taclue - Agreed that crew should not wait for ATC to issue an instruction if they get an RA. What I'm saying is that the RA takes priority. What happens if ATC issue an instruction to an aircraft 5 seconds before a TA/RA occurs? Will there be any doubt in the mind of the pilot? Maybe it's redundent as most seem to agree that TCAS instructions take priority of ATC instructions (on this forum anyway) but the brain can be confused from time to time but giving it conflicting information. Just a thought...



5th Nov 2003, 03:32

The only possible drawback to this is the speed at which it can be displayed to ATC and the time taken assimilate the information and act upon it, possibly in a busy ATC environment. At worst it should merely add to the information available to all parties.

But it may even crank up the overtransmitting that usually occurs.... and totally negates any R/T inputs.

I also disagree that ATC-monitored ground radar (AMASS or Whatever) can ever overcome the similar problem of undoing a runway incursion that's already happened (or is in process of happening). There comes a point in every fiasco where the pilot enters survival mode. With runway incursion it's via Dreadle (search Google if you don't read ASW). With acute loss of separation, it's the TCAS RA response (by the numbers) - and not via the voice of authority over the Russian pilot's shoulder.

ATC Watcher
5th Nov 2003, 03:56
The subject of downlinking RAs is highly debated in some circles.
IFATCA is against it on time the info will take to be displayed , the info might no be correct any longer , and on legal issues. ( as a controller is not supposed to do anything anymore once he knows an RA is in progress ).
IFALPA is for ( they even presented a paper to the last ICAO ANC on it ) arguing that it is complementatry to R/T.
The Japanese intiative is purely a domestic Public relations issue.
Their near mid air near Tokyo in 2001 was due , in great part , to one of the pilots electing not to follow the RA, so dowlinking the RA to the controller would have confused the issue even more.
The Ueberlingen collision last year , the clearance was issued BEFORE the RA , and no more instructions were given after the RAs started. so downlinking would not have changed anything procedurally. And by the way, downlinking an RA to ATC will mean an RA has been triggered by a TCAS not that the pilot actually is following the RA ( in Europe, 40% of pilots still do not follow RAs according a 2000 -2001 Eurocontrol Bretigny survey ) so little use for controllers.

The only solution for me to the TCAS / ATC interface is a procedural one. ICAO will issue later this month clear guidelines for pilots that should go a long way in clarifying the situation.
Downlinking RAs will not resolve the problem.( especially since the Japanese "trial" will apparently not downlink the sense of the RA, just than an RA is triggerred )