What is the first action item to be taken in the event of braking loss or asymmetry?

In the situation of braking loss or asymmetry, the first action item is to release the wheel brakes momentarily. This step is crucial because keeping the brakes applied during a loss of braking effectiveness can exacerbate the problem and potentially lead to further loss of control. By momentarily releasing the brakes, you allow the wheels to rotate freely, which can help regain some braking authority and assist in stabilizing the aircraft.

This tactical response aims to mitigate the asymmetrical braking forces that may be acting on the aircraft, allowing for better control. Once the brakes have been released, the flight crew can assess the situation and take appropriate subsequent actions, such as reapplying the brakes if needed or activating other measures.

Other choices involve actions that may not be immediately appropriate for addressing the initial symptom of braking loss. For example, applying maximum reverse thrust or reapplying wheel brakes without first assessing the state of the brakes might lead to further complications. Setting the ANTI-SKID to OFF would not be advisable without understanding the braking system's current status, as this could also lead to a loss of effective braking. Hence, the momentary release of the brakes stands out as the most prudent first step.