Hi,
In my book, 500 above max elevation doesn't determine a "MSA"
My reasoning is that max elevation on a chart is just that, an elevation. BUT
(there's always a 'but'!) the charts don't show structures (typically masts) that are below a height of 300'
As such, you need to add at least 800' (500 for rule 5 and 300 for the unmarked mast
I was flying around the Devon moors. There is a sector that has a max elevation of approx 1970' but there is a mast there unmarked
In my experience, we taught "add 1000' onto max elevation 5nm either side of track (ifr rules) unless the max
Elevation is a spot-height in which case add a further 300
It's quite safe to fly below this point if remaining vmc but if flying into difficulty, get yourself to this MSA. This
Could mean climb, but usually descend but if you are
Forced to
Go below that, turn back/divert
Bb