Originally Posted by PBL
Those crediting TCAS with all these "saves" need to explain why, before the advent of TCAS, there were a statistically-negligible number of collisions in the history of airline flying, and upon the introduction of TCAS there are suddenly almost 60 per year.
Originally Posted by Andu
The answer, as already given, is GPS and IRS
Really?
That might be a factor in explaining an increase in en-route near misses. Most TCAS activations occur in other phases of flight, off the airways, as far as I understand it, so your proposed factor wouldn't affect those statistics.
In any case, your factor wouldn't affect the *sudden* jump in apparent "saves" which occurred with the introduction of TCAS, since nav equipment precision has evolved, rather than jumping spontaneously and coincidentally with the mandate for TCAS.
PBL