Posted for "Paul Nafziger" <naf@britevalley.com>:
Right at rotation this morning, I heard a thunk and heavy vibrations
started.  Elected to get airborne and think it over, since movie people were
using the normal runway and I was on a short one.  Brake application right
after leaving the ground stopped the vibration, so I figured it was a flat
tire or something.  A flyby with the gear hanging showed no problems.
Pretty heavy vibration on touchdown, which decreased with speed.  At taxi
speed I could hear it but couldn't really feel any more vibration, so I
taxied in.  Surprisingly, the right brake still worked pretty good.

Upon inspection, about 1/3 of the right brake rotor was missing.  Never saw
anything like that before!

Any ideas what could cause that other than simple material failure?

Naf
LNC2 N7PN