So I’m in a long haul right now to Copenhagen on a Singapore A380. Been at cruise through the night, woke up and realized that my ground speed has been consistently dropping. When I went to bed I was at M.85 and traveling about 500kts, now I’m about 456kts but my engines are set to M.89.
So long story short tell me what I’m missing that is causing this to happen.
Mach speed does not represent a specific ground speed. It resprestents the percent of the speed of sound at the current altitude, temperature, winds, etc… All of those factors will effect the ground speed shown. I believe it effects all aircraft the exact same.