While in flight, I often change the chart scale by zooming in or out, depending on what I'm looking at.

Is there a quick way of resetting to a preferred scale, say 1:500k

Back in the day, when I used a paper map, I could estimate distances and times very quickly by counting thumbjoints and multiplying by 9 to get miles, or 6 to get minutes.

With an arbitrary chart scale, this isn't possible, so I'd like to be able to quick set back to 1:500k.  In planning mode the Home button seems to achieve this but I can't see how in flight mode.

Is this possible?  I'm using SD for Android 3.15.3.22163 on a Galaxy Tab S.