sentences:  The top of climb may be calculated manually with considerable effort.Alternatively, when manual planning and monitoring a VFR flight, TOC (top of climb) is an elegant and efficient way for a pilot to eliminate all the vaguery and variability of departing any airport (the turns assigned, changes of runway the pilot cannot control).TOC establishes a "starting gate" for the en route portion of a flight to allow timing and tracking along the course.