The principle of the Mach indicator is based on the computation of the ratio:
Domanda 100, Aircraft General Knowledge - Instrumentation - ATPL - Airline Transport Pilot license
| (Pt - Ps)/Ps |
| (Pt + Ps)/Ps |
| (Pt - Ps)/Pt |
| Pt/Ps |
| (Pt - Ps)/Ps |
| (Pt + Ps)/Ps |
| (Pt - Ps)/Pt |
| Pt/Ps |
