Systems and methods are disclosed herein for distributing cooling air in gas turbine engines. A tangential on board injector (“TOBI”) may supply cooling air to a turbine section of a gas turbine engine. The cooling air may be split into a first cooling air path and a second cooling air path. The first cooling air path may fluidly connect the TOBI and the interior of a first stage rotor blade. The second cooling air path may fluidly connect the TOBI and a cavity. The cavity may be located between a first disk and a second disk. The cooling air paths from a single cooling air source may thermally isolate portions of the turbine section.