TCAS-I vs TCAS-II
 

What's the difference between TCAS-I and TCAS-II and what limitations does having only TCAS-I impose ?

see Traffic Collision Avoidance System - Wikipedia, the free encyclopedia

Collision Resolution Advisories are coordinated by TCAS II between platforms before vocalised instructions are issued to pilots.

II is the one to have.

I was speaking with a technical manager of one of the local charter companies and he said if they had TCAS-II on board they could operate some of their business jets above 45,000 ft ? With TCAS-I he was saying it was 35,000ft limitation. Is this correct ?

tcasII uses mode S transponders to give u RA's, ie an escape maneuver in the vertical plane, however if the other aircraft has mode C transponder you will not be getting any RA's, instead you get TA's ie traffic advisories, in TCAS I u can only get TA's

That is wrong. Of course you wll get RAs against Mode C equipped aircrafts as long as they report their altitude. It just won't be coordinated as that not only needs Mode S but another TCAS II as well.

You won't get RAs against aircrafts which do not report their altitude though, simply because TCAS doesn't know in which altitude said aircraft ist. TAs are still generated to improve crew awareness.

Thanks everyone for the replies

im sorry denti is correct,, looks like GSP is misleading

Has anyone any info on TCAS IV?

I read it also had lateral RAs but haven't seen a detailed spec yet.

and I still don't know what happened to TCAS III :confused:

Taken from the Eurocontrol ACAS FAQ:

TCAS I = warnings when collision situation arises
TCAS II = same with computer that calculates best escape path vertically (in cooperation with Mode S to talk to other a/c TCAS computer). Escape path displayed in cockpit + voice
TCAS III = same, but also horizontal escape paths. Most new computers have this ready to be implemented, but not activated. But e.g. tot test a modern TCAS processor, you have to align IRS's, this is to test the horizontal system, even if it is not installed yet. I don't know how far regulations are at TCAS III.