Speeds - Mohsen Hamedi

Maximum Speeds

Maximum Operating Limit Speed $\pmb{V_{MO}/M_{MO}}$ . The speeds that may not be deliberately exceeded in any regime of flight.
Flap Extended Speeds $\pmb{V_{FE}}$ . The speed cannot exceed the design flap speed.
Landing Gear Speeds $\pmb{V_{LO}/V_{LE}}$ . $V_{LO}$ is the maximum speed at which it is safe both to extend and retract the landing gear, and $V_{LE}$ is the maximum speed at which it is safe to fly with the landing gear secured is the fully extended position.

Minimum Speeds

Control Speed on the Ground $\pmb{V_{MCG}}$ . The minimum calibrated airspeed during the take-off run in case the critical engine fails, so that it is safe to maintain control of the aircraft with the use of the primary surfaces.
Minimum Control Speed in the Air $\pmb{V_{MCA}}$ . The minimum calibrated airspeed in case the critical engine fails, so that it is safe to maintain straight flight with an angle of bank less than $5$ degrees.
Minimum Control Speed during Approach and Landing $\pmb{V_{MCL}}$ . The minimum calibrated airspeed during approach and landing in case the critical engine fails, so that it is safe to maintain straight flight with an angle of bank less than $5$ degrees.
Minimum Unstick Speed $\pmb{V_{MU}}$ . The minimum calibrated airspeed at and above which the aircraft can safely lift off the ground and continue the take off.
Stall Speed. When the angle of attack increases above a certain value, the lift coefficient drops drastically.