What should be the first action after starting an aircraft engine?

• A. Shut down the engine and recheck all systems.
• B. Immediately set full rich mixture.
• C. Adjust for proper RPM and check for desired indications on the engine gauges.
• D. Advance the propeller to maximum pitch.

Answer: (C)

After starting, the priority is to confirm the engine is running normally by bringing the engine to a proper idle and watching the gauges. You want the tachometer to show the expected idle RPM, and the oil pressure should rise into its normal range within a few seconds. Other indicators—oil temperature, fuel pressure, electrical load, suction if applicable, and any temperature or pressure readings—should be within normal limits or showing a safe trend. If any indication is off, you address it before moving on; if everything looks good, you proceed with taxi and flight.

Shutting everything down to recheck would waste time and could be unsafe if the engine is actually performing correctly. Setting the mixture to full rich right after start isn’t the first action you take once the engine is already running—mixture and throttle are managed to bring the engine to a stable idle and then adjusted as needed. Advancing the propeller to maximum pitch after start isn’t a standard post-start step and can disrupt the engine’s idle and overall performance.