scurvy
yes I can see your point regarding upset and RVSM...more details willhelp clarify.
CHECKERS, regarding TCAS, our TCAS system was very advanced and not just one that issued alerts. to those who dont' know, some TCAS sytems can display planes farther out than the minimum required by technical order...indeed some TCAS can and will only show alert traffic and resolution advisory...not other planes.
eventually the DC10 mentioned did show itself as we went to one side of centerline...aparently empenage was blocking transponder signal. cargo planes at one time did not need TCAS and did not need to have more advanced transponder antenna mountings on both top and bottom
And what if either of these brand new planes had tansponder antenna wiring faults not previously noted...as on top of the plane...ATC would probably work fine on bottom. who else would know?