T achometer
O oil pressure gauge
M anifold pressure gauge for each atmosphere engine
A irspeed indicator
T emperature gauge for each liquid cooled engine
O il temperature gauge

F uel level gauge
L anding gear position indicator
A ltimeter
M agnetic heading indicator
E mergency locator transmitter (ELT)
S eat belts

And, of course, for night:

F uses
L anding lights
A nticollision lamps
P position indicator lamps
S ource of power

ELT Rules & Inspections