Is Vne a true airspeed or a indicated airspeed?

[Flysher]

Turbine aircraft don't have a yellow arc. I think this is mostly FAR 23/25 or what ever it is that lists what must take place.

Yea I know I fly one, Im just curious as to why the yellow arc doesnt appear on their airspeed indicators. If i remember right on the piston planes it has something to do with the airspeeds at which an FAA defined "gust" could damage the airplane or something like that...

 

[ReportCanoa]

VNE is derived from EAS. EAS is where it's at in the performance world. There isn't a real compressibility issue until you're flying above 300 TAS and whether or not every manufacturer has taken into consideration compressibilty effect, I'm not sure. It probably depends on how high and fast the airplane is designed to travel. If they have NOT taken into account compressibility, then VNE is derived from TAS and not EAS.

Bottom line- any "V" or "M" speed is intended as a limitation based on the indicator in the cockpit. Good luck.