Correct, without Mode-S TCAS is not fully functional and that is a 3 day repair period item if you fly within german or french airspace. In other european countries it is 10 days.
However, several european countries require mandatory mode s carriage and for a jet (IFR traffic with more than 5,7t MTOW, 250kts or more cruise speed) that would be the enhanced surveillance version. Namely germany, france and the UK require mode s equipment, netherlands and belgium above FL245. If you want to fly through the airspace of any of those countries you need an exemption from the relevant CAA for each country. Best to get in touch with your governing CAA and talk with them about it, get it repaired asap in any case.
Last edited by Denti; 18th May 2012 at 09:15.