What is one example of an "on the ground" safety feature in military aircraft?

Safety pins serve as a critical "on the ground" safety feature in military aircraft. They are used to prevent accidental deployment or activation of various systems and mechanisms while the aircraft is stationary and on the ground. For example, safety pins can be installed in weapons systems or in the ejection seat to ensure that they cannot be inadvertently triggered during maintenance or pre-flight checks. This is crucial for maintaining safety for ground crew and personnel working near the aircraft, helping to prevent accidents and injuries that might occur from unexpected system activations.

In contrast, the other options describe safety features that are either relevant during flight operations or do not specifically address ground safety concerns. Emergency ejection seats are pertinent during flight, enabling pilots to escape in emergencies. Fire suppression systems are vital during operations but often focused on mitigating in-flight risks. Landing gear indicators, while important for flight operations, are primarily used to communicate the status of landing gear during takeoff and landing rather than addressing ground safety directly.