What action is triggered by an increasing positive G force in the cockpit?

The increase in positive G force in the cockpit can significantly impact a pilot’s ability to maintain consciousness and operate the aircraft. When G forces rise, blood is pulled away from the brain due to inertia, which can lead to a loss of vision or consciousness. To counteract these effects, many cockpits are equipped with anti-G systems which utilize an anti-G valve.

The anti-G valve works by supplying additional air pressure to the pilot's anti-G suit, which helps to prevent blood pooling in the lower extremities and maintain blood flow to the brain. By opening the anti-G valve, the suit inflates, applying pressure to the body and counteracting the effects of the increased G forces. This is a crucial mechanism for ensuring that the pilot remains alert and responsive during flight maneuvers that impose high G loads.

The other choices do not directly address the need to counteract increasing G forces. For example, increasing oxygen intake or activating air conditioning might enhance comfort or performance but do not specifically counteract the physiological effects of G forces. Closing the safety outflow valve could potentially impede air circulation but would not provide the necessary support to combat the effects of high G forces in the cockpit.