this may be not that well known but there's a little chime that plays when a plane goes over 10k ft (i think it was added in the recent update?), i assume it's meant to mimic the seatbelt sign turning off.
the problem is it's way too quiet and often gets drowned out by engine sounds, it'd be nice to have it be more audible.
If you dunno what i'm referring to please watch the attached vid
~~ nvm