When an aviation pilot boards an aircraft, the first thing they typically do is perform a pre-flight inspection. This involves a thorough check of the aircraft's systems and controls, including the engines, fuel system, landing gear, brakes, and navigation instruments. The pilot will also review the aircraft's maintenance records and check the weather conditions and flight plan before takeoff. Once the pre-flight inspection is complete and any necessary adjustments or repairs have been made, the pilot will start the engines and begin the process of taxiing to the runway for takeoff.