blueloo, yes - no - maybe...
I understand die Lufthansa SOP is as you describe and that it is based on
JAR-OPS 1.872 Equipment for operation in RVSM....
(4) A secondary surveillance radar (SSR) transponder with altitude reporting system that can be connected to the altitude measurement system in use for altitude keeping.
Hovewer,
"can" is just an option, or?
(we also did this topic in
http://www.pprune.org/forums/showthread.php?t=284493)
BTW,
Gvendur_Bjalla, the ASA is monitoring all 3 systems. Even a C RA failure in FL 430 will trigger an NO LAND 3 announciation - no "hidden" systems here.