However, with increasing air traffic and the assignment of distinct flight levels to specific flights, airways, and directions of flight, it is no longer safe to climb continuously in this way, and so most flights compromise by climbing in distinct steps—a step climb—with air traffic control (ATC) approval, in order to ensure that the aircraft is always at an appropriate altitude for traffic control.
However, as air traffic increases and each flight is assigned unique flight levels, it is no longer safe to ascend continuously in this manner. Consequently, most flights compromise by ascending in distinct stages—a step climb—with the approval of air traffic control (ATC), ensuring that the aircraft remains at an appropriate altitude for ATC.