Originally Posted by
ANAJASJAL008
Hello all,
When I fly using VNAV, the target speed on CDU ECON CRZ page is always shown in Mach speed.
But I think it should be displayed in IAS below 26,000ft.
Because MCP speed window is automatic changeover at approximately FL260.
I hope you will be able to provide the information.
What are you saying, that the ECON CRZ is in Mach when the CRZ ALT is below 260, or when you're below 260?
Why do you think it should be IAS below 260 - just because that's what the MCP does? Conversion isn't an altitude, it happens when your climb Mach reaches your desired climb/cruise Mach - something the FMC calculates. The MCP on the other hand is a dumb mode: if you kept 300kts up to FL390 you'd be supersonic. So to be on the safe side I'm guessing they've given it an arbitrary changover altitude? I'm not a 737 pilot so I might be talking bollocks of course...