In flight mechanics, the parasite drag coefficient () refers to a dimensionless parameter that quantifies the contribution of various non-lift-producing components and factors to the overall drag experienced by an aircraft in steady, level flight. Parasite drag is the form of drag that arises from sources other than the production of lift, and it includes factors such as skin friction, pressure drag, and interference drag.
- : This represents the parasite drag experienced by the aircraft due to its initial weight and configuration.
- : This represents the additional drag experienced due to the change in drag coefficient caused by the maneuver.
- : This represents the additional drag experienced due to the change in weight of the aircraft during the maneuver.