Metro man I explained it fully so people would understand it fully - and it is JUST as relevant to 'Modern jet transports with central air data computers' - I fly 777s and when I am crossing the Austrian Alps etc in winter I amend the Flight plan MORAs using that formula and a handy ATIS.
I do get weird looks when I do so
There is not an aircraft on the planet that corrects for ISA deviation altimeter errors.
Its all about the height of the 'column of air' the aircraft is sitting 'on'. When its cold the air is denser than when its hot.
You may not think it has have any real effect for MOST Baron/Chieftain pilots - what about those operating in Tas/Vic/SA in winter?
On the other hand how can you do a meaningful G/S check at the OM in ISA+20 unless you have done a quick calc to see what it
should say.
Sailing past the OM at say 1500' and noting the altimeter says 1400' and simply mouthing "OM 1500', Checked" when it DOESN'T say 1500' and you have no freaking idea why doesn't sound smart to me
