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HDG advice when conflict

Old 11th May 2010 | 06:03
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HDG advice when conflict

As far as I know ACARS does not have any heading advice when there is a traffic alert ,I have heard that new ACARS will have that function ,is that true ? If it is true what is the rule about giving the heading ? I think it is very complicated .
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Old 11th May 2010 | 11:28
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yes, ACARS is very complicated and TCAS even more!
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Old 11th May 2010 | 12:16
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I think you mean ACAS (Airborne Collision Avoidance System), not ACARS (Aircraft Communication Addressing and Reporting System)

ACAS is TCAS II version 7 (Traffic Collision Avoidance System).

Search Wikipedia for TCAS and you will get a description.
It also says that work on TCAS III has been suspended.

Hope this helps.
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Old 11th May 2010 | 14:15
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Sorry , I meant ACAS ,because we currently thinking about if we can make a rule about heading when two aircrafts are gonna to hit each other.
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Old 11th May 2010 | 14:34
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With a TCAS RA, keep it simple. The system is designed so you fly only a vertical escape manoeuvre. Turning at the same time may negate the good work done by the TCAS or worse, generate a secondary conflict with other aircraft, of which you were previously unaware.

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Old 11th May 2010 | 21:01
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Sorry , I meant ACAS ,because we currently thinking about if we can make a rule about heading when two aircrafts are gonna to hit each other.
No need to reinvent the wheel -- when to aircraft are on a converging (ie collision, or threat-of-collision) course, the aircraft that has the other aircraft to it's right, shall give way. When two aircraft are approaching head-on, both aircraft shall give way to the right. Let's not forget the basics!

(However, follow the RA and don't pull any stunts!)
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Old 12th May 2010 | 14:02
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Yes ,you are right ,but that is the basic rules ,sometimes that rule may not work .It seems that we need to establish a matmatics model and calculate the wind speed ,IAS etc ,then we can give a better resolution.
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Old 12th May 2010 | 15:29
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Think less and do as it says.... Disconnect climb or descend.

Even if a mathematical model was developed and added to the RA command IMHO it adds complexity that isn't required. Remember the more complex something is the more things can go wrong.
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Old 12th May 2010 | 15:46
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Heard some expert input that a heading resolution will never be implemented, TCAS II works well and there is not a necessity to further complicate a system that already is very efficient.
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Old 12th May 2010 | 15:55
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Yes ,you are right ,but that is the basic rules ,sometimes that rule may not work
Could you give an example?

It seems that we need to establish a matmatics model and calculate the wind speed ,IAS etc ,then we can give a better resolution.
Consider the fact that a given wind will affect two aircraft in close proximity, to virtually the same extent.

"If it ain't broken" comes to mind. And be very very very very careful about trying to outsmart TCAS. Others have done it before, and some of them are not here anymore.
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Old 12th May 2010 | 16:22
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Who's asking?

Originally Posted by caucatc
we currently thinking about if we can make a rule about heading
Who are 'we'?

Originally Posted by caucatc
It seems that we need to establish a matmatics model and calculate the wind speed ,IAS etc ,then we can give a better resolution.
Where does this need come from? And again, who are 'we'?
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Old 12th May 2010 | 16:50
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TCAS (the Rockwell Collins proprietary system which meets the ACAS standard) works on the basis that aircraft at different altitudes cannot collide. Aircraft on different headings can collide - depending on their relative positions. TCAS resolves the relative position of the target aircraft via radio direction finding, which simply isn't accurate enough to resolve the position of an aircraft to calculate an avoidance trajectory. (Watch a target aircraft jump around as it flies an ILS to see how rough the position finding is!)

Using an encoded GPS position via mode S transponder transmissions would require a new compulsory standard throughout the industry, and simply isn't necessary.
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Old 12th May 2010 | 16:52
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CAUCATC:
Does the answer on the other thread you started not tell you what you need?
http://www.pprune.org/atc-issues/414...d-traffic.html
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Old 13th May 2010 | 08:15
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Hi there,
I know Airbus has certified last year a new TCAS mode for the A380 (other models in a very near future), an implementation in the Auto Flight Computer consisting of "managed" vertical inputs able to solve a TCAS resolution advisory.
The lateral resolution concept (TCASIII and IV), was introduced with the coming of Mode-S datalink, able to transmit both GPS coordinates and altitude, used by TCAS to provide a lateral resolution. Needless to say that every aircraft involved in a conflict has to be equipped with DL-Mode S. Anyway can find all you need to know in the following document:

http://www.tc.faa.gov/its/worldpac/techrpt/tctn099.pdf

As far as I know, it hasn't been certified yet ...

Regards,
fredgrav

Last edited by fredgrav; 13th May 2010 at 15:10. Reason: check for link consistency
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Old 13th May 2010 | 14:16
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One Outsider
We means my workmates and I .
jackieofalltrades
I think I explained that again .
fredgrav
Thanks for your help ,I will check that .That is what I am intetested.
BTW ,can somebody tell me how to "Quote" ? I could not find quote button .
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Old 13th May 2010 | 14:18
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fredgrav
I could not open that link ,it said the file was broken or damaged.
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Old 13th May 2010 | 14:32
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cauatc:
I could not open that link ,it said the file was broken or damaged.
FWIW, the link worked fine for me.
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