Hi, just a very quick and I hope simple question. On the stock Citation primary flight display, immediately below the airspeed ribbon, I see a small yellow “M” followed by three green digits. Could anyone enlighten me as to what this number represents? Many thanks Fred

That is the speed in mach (the mach number)

Citation PFD mysterious (to me!) number

MikeB54331 March 29, 2023, 5:39pm 5

You’re not high enough and not fast enough. I believe it will show up once you get up around FL270.