What does DR ABC mean in first aid?

This is a 5 point plan used to approach a casualty in a first air situation.

D = Danger, Check for danger to self, others and casualty.

R = Response, Is the casualty conscious?

A = Airway, Check the casualty's airway is clear.

B = Breathing, Is the casualty breathing?

C = Circulation, Do they have a pulse?