Originally Posted by
Vessbot
We’re talking about different things. You’re talking about normal usage of heading mode, which is setting headings for discrete lengths of time during which you intend to fly that heading (most often because of a vector). What I’m talking about comes up pretty rarely so maybe you haven’t seen it, in which case you should count yourself lucky.
But when you do, it’s eye-watering. Like there’s the LGA 31 expressway visual, an approach in the US where for a large segment of it you’re supposed to follow a road. Every once in a while I’ll fly with someone who isn’t comfortable flying and wants to “reduce the workload” and use the autopilot, and they’ll be virtually unable to take their hands off the heading knob having to make constant corrections for the initial overshoot, later overshoots from that overshoot (as inevitably the slow roll rate and overall response of the AP does not match up with the ground track he thought was gonna happen) wind changes, slight turns in the road, etc., all the meanwhile he’s trying to manage the VS as well.
There’s another control for that! And this is not what the autopilot was meant for.
Flying the
expressway visual in heading mode should be illegal. I've also flown with somebody who's insisted on doing the
river visual with the AP (albeit in NAV mode). What's the point?