Some pilots call the yellow arc “the caution range” but a better name is ‘smooth air range’. Basically you should not fly in the yellow arc if there is any turbulence including light chop, or “bumpy” as some call it. The rational is that most airframes are “older” and more fragile than newer vintage airframes and anything above light turbulence risks structural failure even in the lower range of the yellow arc.
So, can we fly in the yellow if light turbulence is encountered and an emergency descent is required? The simple answer is NO! The “smooth air” range is not the “smooth air except in an emergency” range!
Definitely enjoy the higher speeds in the yellow arc, but only in smooth air and with caution. Be ready to yank the throttle back to idle if unexpected turbulence develops.
Fly safe friends