25.1505—Maximum operating limit speed.
The maximum operating limit speed (V
MO /M
MO airspeed or Mach Number, whichever is critical at a particular altitude) is a speed that may not be deliberately exceeded in any regime of flight (climb, cruise, or descent), unless a higher speed is authorized for flight test or pilot training operations. V
MO /M
MO must be established so that it is not greater than the design cruising speed V
C and so that it is sufficiently below V
D /M
D or V
DF /M
DF, to make it highly improbable that the latter speeds will be inadvertently exceeded in operations. The speed margin between V
MO /M
MO and V
D /M
D or V
DF
M/
DF may not be less than that determined under § 25.335(b) or found necessary during the flight tests conducted under § 25.253.