Re: India:747/Tu154 collision +TCAS

Date:         13 Nov 96 02:41:21 
From:         "David G. Davidson" <gerhard@onramp.net>
Organization: http://rampages.onramp.net/~gerhard/tristar
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Karl Swartz wrote:

> >I forget...do -both- a/c need TCAS to make it effective?
>
> I *think* the other aircraft need only have a (mode C?) transponder.

With a MODE C Xpndr on the other aircraft only a Traffic Advisory (TA)
would be issued. To get a Resolution Advisory (RA) the other aircraft
would have to have a MODE S Xpndr.

So in this case, if the Saudia AC had an operating TCAS and the TU 154
had an operating Mode C Xpndr, the Saudia AC should have received a TA
from TCAS.