Plain English Meaning

Switches that stop the wheels from folding up while the airplane's weight is sitting on them. When the airplane is on the ground, the switch is pressed in by the weight and locks the gear-up command out of the system.

Full Definition

Electrical switches built into the landing gear system that prevent the gear from being retracted while the airplane is on the ground. The most common type is a squat switch mounted on a main landing gear strut: when the strut is compressed by the airplane's weight, the switch opens the electrical circuit to the gear retraction system, blocking inadvertent retraction on the ground.

Context Anchor

Seen in discussions of retractable landing gear systems and the devices that help prevent accidental gear retraction on the ground.