What is a 'runup' check in aviation?

A 'runup' check in aviation specifically refers to an engine check conducted before takeoff to verify that the engine is functioning properly. This procedure typically involves running the engine at various power settings to ensure that it operates smoothly and that systems like magnetos and the carburetor are functioning as intended. Pilots assess engine parameters such as RPM, oil pressure, and temperatures during this check to confirm that everything is within normal operating limits before proceeding with the flight.

This check is critical because it helps to identify any potential issues with the engine prior to takeoff, ensuring that the aircraft is in a safe condition for flight. It is a proactive step in flight safety, allowing pilots to address any discrepancies before they become serious during the critical phase of flight immediately after takeoff.

The other options listed relate to different aspects of flight preparation or safety, such as fuel checks, passenger safety equipment, and external inspections, but they do not capture the specific mechanics and importance of the runup check for engine functionality.