What type of G force triggers the anti-G valve in the cockpit during maneuvers?

The anti-G valve in the cockpit is designed to counteract the effects of high positive G forces experienced during maneuvers, such as tight turns or abrupt climbs. During these situations, pilots experience an increase in G force, which can lead to a phenomenon known as G-induced Loss of Consciousness (GLOC) if the forces are too high and the pilot cannot maintain blood flow to the brain.

The anti-G valve works by allowing the pilot to access compressed air, which helps to counteract the increased blood pooling in the lower extremities during high G maneuvers. This mechanism is crucial in maintaining pilot consciousness and performance, allowing them to effectively handle the aircraft under high G conditions.

This understanding helps situate the anti-G valve's function: it is specifically the increasing positive G forces during maneuvers that trigger its operation. This ensures that pilots can sustain their necessary physiological responses and remain operationally effective during demanding flying scenarios.