# Key Takeaways # Details # Additional Resources - ## FAA Definition ***Definition*** :: The forward [[force]] produced by the [[Engine|powerplant]]/[[propeller]] or [[rotor]]. It opposes or overcomes the force of [[Drag 1]]. As a general rule, it acts parallel to the [[longitudinal axis]]. However, this is not always the case. ***Source*** :: [[PHAK Ch5]] #glossary #four-forces #concept