HA
From memory the Shadin was a pretty accurate piece of gear.
But regardless, the old fuel in, gases out the exhausts (hopefully) fuel in check, is still the only way to verify for each flight.
As you say check, x check, double check and use every means at your disposal to monitor the health of those engines.
I have always said that pilots really should belong to the Engine drivers, Fettlers and Firemans Union .. EFFU....
Coz thats what they really get paid for.
