|Quoting Connies4ever (Reply 2):
Yes, Soyuz TMA can carry three people, but someone has to pilot up and down, and that person isn't going to be ISS crew.
Yes, that person is. Yurchikhin was pilot of the last Soyuz launch (in April) and is now commander of ISS. He replaced another Russian pilot who launched last October and flew home in April.
Each Soyuz and its crew of three remains at ISS for six months at a time, although sometimes the third person rides up on the new Soyuz and leaves on the old Soyuz a week later. Generally that's because the third ISS crewmember will be replaced by someone on an upcoming Shuttle flight. Technically, Soyuz doesn't need a pilot (Progress flies to ISS remotely operated or autonomously all the time, a few have even made safely landings autonomously too) but hell will freeze over before Russia launches a Soyuz without at least one Russian pilot on board (and I don't begrudge them that.)
The ISS crew will probably be two pilot-types and four scientist-types after Node 3 arrives. The two pilots will probably also be trained in Station operations (as they are now), and two scientists will probably also have cursory training on Soyuz operations (as they do now), enough to know which switches to throw and when for an automatic re-entry in case a pilot gets appendicitis or something.
Edit: Kotov was the Soyuz pilot, not Yurchikhin.
[Edited 2007-06-11 20:12:20]