What must vehicles with daytime running lights do when parked on the airfield?

The correct choice emphasizes the importance of ensuring safety and compliance on the airfield. Vehicles parked on the airfield must be turned off with the ignition switched to off, the parking brake engaged, and emergency flashers off. This procedure is critical for several reasons.

Firstly, turning off the ignition prevents the vehicle from accidentally moving, which is essential in an area with high traffic and numerous hazards, thus ensuring the safety of personnel and equipment around. Engaging the parking brake adds an additional layer of precaution to keep the vehicle stationary.

Keeping the emergency flashers off is equally important as they can create confusion or misinterpretation among other drivers and operators on the airfield about the vehicle's status. Emergency flashers are typically used to signal a breakdown or other urgent issues, which is not applicable in a stationary vehicle that is parked properly.

Maintaining strict control over parked vehicles helps promote a safe driving environment, reducing the risk of accidents that might occur due to interference from improperly parked or active vehicles.