Yes, the B777-300 has a Vmo of 0.89M
Aerodynamically I don't see how 777-200ER can be certified to different speeds, having the same body and wing. Nominally 330/0.87M
I have always heard the 747-400 making 0.86M at FL280 too at ISA >+15. Wonder what kind of IAS these work out to be.
Can those guys really make it at FL280 .84/.86 for the B777-200ER and B747-400 respectively.
Might be a case of lie first,get the clearance and sort it out later, maybe a tad slower, no worries.
Another factor is the weight too.
Typo edit
[ 28 November 2001: Message edited by: 7times7 ]