Final answer:
Acceleration should be started on VMC takeoff with IMC transition when the aircraft has reached a safe speed and altitude for the transition.
Step-by-step explanation:
Acceleration should be started on VMC (Visual Meteorological Conditions) takeoff with IMC (Instrument Meteorological Conditions) transition when the aircraft has reached a safe speed and altitude for the transition. The transition from VMC to IMC typically occurs when the aircraft has climbed above any visual references and needs to rely solely on instruments for navigation and control. This transition should be done carefully and in accordance with the aircraft's operating procedures to ensure the safety of the flight.