What is stick force gradient and why is it important for handling qualities?

Stick force gradient (dF/dg or dF/dn) is the change in control force required per unit change in load factor, typically expressed as lb/g or N/g. It provides the pilot with force feedback proportional to aircraft response. Requirements (MIL-F-8785): Minimum values ensure adequate force cues (prevent over-g), Maximum values prevent excessive pilot fatigue, Stick force per g should increase with speed. Typical values are 3-8 lb/g for center-stick fighters, higher for transport aircraft. Gradient depends on: Static margin (forward CG increases gradient), Control system design (bobweight, downspring, q-feel), and Irreversibility (powered controls need artificial feel). Proper gradient is critical for safe, comfortable handling.