When a lightning warning is in effect within 5NM, what must all aircraft do?

In the event of a lightning warning being issued within 5 nautical miles, the appropriate response for all aircraft is to cease all ground operations. This is a crucial safety measure because lightning poses a significant threat during ground operations, especially when aircraft are on the taxiway, runway, or parked on the ramp.

Ceasing all ground operations means that the aircraft will stop taxiing, and any personnel will take shelter in safe areas away from open spaces or metal structures. This action helps to safeguard both the crew and passengers on board as well as ground personnel from the dangers of lightning strikes and associated hazards.

Continuing taxiing to parking or changing to an alternate parking area could expose aircraft and personnel to unnecessary risks. Taking off immediately is typically not an option during such warnings, as ensuring safety on the ground takes precedence before considering airborne operations. Thus, halting all ground activities is the mandated protocol in order to mitigate the hazards associated with lightning activity.