The object of this disclosure is to cool the brakes of the landing gear of an aircraft. For this, it uses the air of the same air conditioning system of the airplane. The supply to the air conditioning system of the airplane can receive pre-conditioned air from outside by an air inlet in the lower part of the fuselage of the airplane to which an external equipment is connected. This air inlet has a non-return valve inside, which prevents the air from going outside. In order to extract the air from the air conditioning system of the airplane while it is on the ground, it is necessary to overpass the air valve. For this purpose, a tool that overpasses that valve from outside has been designed, and in this way, extracting and directing the air through connectors and tubes to the brakes, cooling them for a new takeoff.