What is the first steps of checking air way of a casualty?

The first step in checking the airway of a casualty is to ensure the scene is safe for both the rescuer and the victim. Then, gently tilt the casualty's head back by placing one hand on the forehead and using the other hand to lift the chin, which helps open the airway. Next, check for breathing by looking, listening, and feeling for any signs of breath for no more than 10 seconds. If the casualty is not breathing, initiate appropriate emergency response measures, such as calling for help and beginning CPR if trained to do so.