I frequently fly a 1.30 hour sector in a 747-400. On occasion we go to FL430
The Honkong-Manila flight was around 1.50. I think usually the last 2 hours of a 74X flight is flown near to the ceiling - obviously dependant on load.
When I was on the 742F, one of the Captains did mention that he had requested FL450 near the end of one of his flights just so he could see what it was like.
No one believes him
