Cruising..1 lower than set mach

Anyone know why when cruising in the A350(sometimes other planes but mainly this one) cruise at 0.1 lower than the mach speed set in the autopilot panel?

I think this is because when you set the speed to let’s say 318 knots to go .85, it’s close to both .85 and .84 so you’ll see it’s set as .85 in the autopilot and indicates .84 but is close to .85.

From my experience, there’s two ways to fix this. You can either set full throttle for around 3 seconds and then set the mach number or you can set 0.1 mach over the speed you want.


Personally, I don’t activate the speed portion of autopilot until I reach cruise. I pitch for speed. I’ve noticed that doing that has helped me keep my speeds consistent to what they’re set to. This is because Mach Speeds have a high range. I can see if I just entered .85 or if I’m at the upper bounds of it.


True, I do the same. Still, the A220 nearly always ends up a ,77 when I set it to ,78 once at cruise level.
The other aircrafts I use rarely do it. It seems to be a typical trait of the 350 and 220.
No big deal.

I love found that you have to work with the autopilot on that. If you just tap speed mode, it will cut the throttle and then raise back up. Reduce power and then click on speed mode (be at higher range of Mach)

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Yes, it works, but as I do short hauls only, I let the plane decide for me if it wants ,77 or ,78! 😉

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