although I rarely use them I check my instruments every flight.
the altimeter is set to airfield height by tweaking the QNH.
after a flight typically for an hour or more and altitudes up to 6000ft I return and land. the altimeter on the taxy back is reading the airfield height.
I'd say it was working satisfactorily.
occasionally I check my stall speed. 42 knots indicated. bang on the money every time. now I know that there is a 10 knot instrument setup error and I am actually stalling at 52 knots but that doesn't matter. I fly circuit speeds on the indicated speeds. in cruise I use a gps anyway. at 120 knots the error is 1 knot.
I never use my magnetic compass ever. I check it on the lineup every few months and if the leg is long and the air stable I compare it to the gps.
it hasn't been out in over 10 years.
to assume that aircraft are being flown with wildly inaccurate and never checked instruments is nonsense. they get checked all the time by pilots.
one of the things never mentioned in the race to deride old technology is that aircraft instruments are of the highest quality ever made. they are not shonky items. why would an instrument made to such quality go out of adjustment?
mine don't.
the wackett fatality had nothing to do with the compass in reality.
the pilot assumed that he would see the transcontinental railway line and be able to turn for forrest.
I took a photo on one of my flights in the position where he crossed the railway.
in the afternoon light, even when you know where the railway is, it is impossible to see it. a salutary warning for pilots flying pilotage in the gafa.
the gravel ballast is the same colour as the surrounds and the actual rails are only 4 inches wide. unless you get the shine on the rails they are invisible.