‘Mach number’ means the ratio of true air speed to the speed of sound.
 
‘Main rotor(s)’ means the rotor or rotors that supply the principal lift to a rotorcraft. 
 
‘Maximum Continuous Power and/or Thrust’ means the power and/or thrust identified in the performance data for use during periods of unrestricted duration.
 
‘Maximum Continuous Power and/or Thrust Rating’ means the minimum test bed acceptance power and/or thrust, as stated in the engine type certificate data sheet, of series and newly overhauled engines when running at the specified conditions and within the appropriate acceptance limitations.  
 
‘Maximum Engine Over-speed’ means the maximum rotational speed of a mechanically independent main rotating system of an engine, inadvertent occurrence of which for periods of up to 20 seconds, has been agreed not to require rejection of the engine from service or maintenance action (other than to correct the cause).
 
‘Maximum Engine Over-torque’ means (applicable only to turbo-propeller and turbo-shaft engines incorporating free power-turbines) the maximum torque of the free power-turbine, inadvertent occurrence of which for periods of up to 20 seconds, has been agreed not to require rejection of the engine from service or maintenance action (other than to correct the cause).
 
‘Maximum Exhaust Gas Over-temperature’ means (turbine engines) the maximum engine exhaust gas temperature, inadvertent use of which for periods of up to 20 seconds, , has been agreed not to require rejection of the engine from service or maintenance action (other than to correct the cause). This is not to be confused with maximum temperatures established for use during starting operations.