A turn to a heading is flown at more or less only one bank angle, and you'll always expect to see it start rolling out at something like to 5 to 15 degrees before it's reached. And it's very obvious when it begins reducing the bank.
Climb rates prior to an altitude capture can be anywhere from a few hundred to a few thousand FPM, and which would lead to capture initialization anywhere from 50 feet prior to the selected altitude, to more than a thousand. Moreover, pitch/VS changes are much more subtle for a given change, and much more easily hidden inside turbulence, AP chasing speed, and things like that. In short, harder to see. Therefore it's more valuable for the airplane to explicitly tell you that it's begun capturing. So if I'm climbing at 3000+ FPM toward a leveloff, it's 800 feet to go, it's subtly pitching down, I don't have to ask myself "is it doing it?" (since it can also be subtly pitching down for the other reasons I stated). "For this climb rate should it have started already? Or should I give it another couple of seconds?" Etc.
Also, heading mode is extremely simple logic and basically the same across every plane with a heading bug and an autopilot. But as far as leveling off, not all planes will necessarily level off at the selected altitude. Some, you need to push a separate button to arm that behavior. So that raises the potential for confusion through misapplication of old habits, so I appreciate the airplane telling me explicitly what it's doing instead of forcing me to infer it from assumptions.
Last edited by Vessbot; 27th March 2018 at 21:01.