The basic principles of an engine:
Suck, Sqeeze, Bang, Blow
(Intake, Compression, Combustion, Exhaust)
In the US for instrument currency:
Six Approaches
Holding
Intercepting
Tracking
within 6 months
In the US, required information for VOR check:
Dog Poop Bear !!!!
(Date, Place, Bearing Error, Signature)
Lok