AP,
Also, though not wishing to pour cold water on your rant, how come you didn't see him earlier? Being on the same freq doesn't prevent an airprox. Good lookout does.
Not always.
Good lookout helps, but it does b*gger all for you if something bigger and faster comes down just past your nose from above and behind as happened to me just outside Luton zone about a year ago ... and funnily enough, that was a Cessna twin as well, although I'd have said a 340, not a 421. I reported his position to ATC, but there was no secondary trace, so TCAS would not have helped either.
FF
