Eeyore writes:

Eh ?

Exactly.

Doctors can't perform surgery on simulated human beings, at least not yet.
Therefore the first surgery is a "revenue flight": a real surgical procedure
on a real person, not a practice run. This is quite unlike many forms of
aviation, which can be practiced in simulation, or even in real aircraft on
practice flights (with no passengers, and thus "non-revenue").

--
Transpose mxsmanic and gmail to reach me by e-mail.