What occurs when the pitch disconnect T handle is used?

When the pitch disconnect T handle is used, it separates the control wheels. This function is critical for situations requiring manual control of the aircraft, particularly in response to a malfunction or when piloting needs to take manual command of the aircraft's pitch control system. By disconnecting the control wheels, each pilot can operate their side independently, allowing for coordinated control during flight operations or in emergency scenarios.

This separation is particularly important in ensuring that one pilot can continue to operate the aircraft without interference from the other pilot's inputs, which can be vital in training environments or during challenging flying conditions. It enhances safety by allowing the pilots to have non-conflicting controls.

The other options focus on various systems of the aircraft, but they do not relate to the immediate and functional purpose of the pitch disconnect T handle. Specifically, disconnecting engine power, overriding autopilot controls, or resetting hydraulic systems would involve different controls and procedures that are not associated with the function of separating control wheels.