ToD and RVSM questions

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I was watching an aviation video on the 767-300 making a flight from EGKK to Orlando, Florida. Most of the time ATC could not be heard on the video so perhaps, as the viewer, I didn't hear for their clearance to descend. I know the route programmed into the computer will compute the ToD and even update it for higher flight levels and altitude restrictions so my question is this: do you start your descent (as per FMS info) or must you wait for a clearance to descend? Interestingly, the crew on the video decided to descend a bit early to be "kinder to the engines" and I think this is what prompted my question. Perhaps ATC gave him clearance at his discretion?

Also, I am curious where the transition between RVSM and ICAO airspace is located in North America. I have some charts but the lines are hard to follow (bad copy). It appears that the transition line is slightly above N50 or N51. If anyone could point out some clearer charts I would appreciate it.

Cheers!

[Gary Lager]

The FMS is an aid to planning the descent profile, but you absolutely cannot change Flight Level/Altitude without ATC clearance.

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Thanks Gary. I always assumed that was the case but was confused when the pilot just "decided" to descend.

Cheers!

[Capt Claret]

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In Oz, 99% of the time we'll be given a clearance to descend when ready. This cleartance will be issued anything up to 10min before it's required and it's rare that one arrives at or approached TOPD without a clearance.

However, as Gary has said, one doesn't descend without a clearance. Except in an emergency.