During maneuvers, the anti-G valve on the left side console is opened by which force?

The anti-G system in the T-6B is designed to counteract the effects of increasing positive G forces experienced during high-performance maneuvers. When an aircraft maneuvers aggressively, the pilot can experience increased positive G forces, which can lead to the risk of G-induced Loss of Consciousness (GLOC) if those forces become excessive.

The anti-G valve serves to increase the pressure in the suit worn by the pilot, which helps to prevent blood pooling in the lower extremities and maintains blood flow to the brain. When the positive G forces increase, the anti-G valve opens under the influence of these forces, allowing air pressure to fill the G-suit. This additional pressure helps counteract the physiological effects of G forces on the pilot.

Thus, the correct answer indicates that the anti-G valve opens in response to the increasing positive G force, directly aligning with its purpose of enhancing pilot endurance and performance during maneuvers when G forces are elevated.