Originally Posted by
victorpapa
From B787 FCOM
Range Selector (Outer)
Selects the desired ND nautical mile range scale:
• increment/decrement knob
• rotating clockwise/counter-clockwise increases/decreases ND range
respectively
• between 0.5nm to 1280nm
Havent found a 511 nm range
As extreme p has hinted at It’s the max value radius you can enter for range rings around any fixes in the FMC fix pages...it’s the same on the T7 so looks like it’s standard Boeing “thing”
no idea about the reason for the max runwa6 extension length.