Question id 354 - Aircraft General Knowledge - Airframe, Systems, Powerplant - ATPL - Airline Transport Pilot license

A Guard On The Selector Switch Which Cannot Be Moved Until The Aircraft Is Airborne.
The electrical control system being routed through the weight on wheels switch.
A pneumatic interlock which disables the hydraulic up selector.
Any Attempt To Select The Landing Gear Up Will Result In A Flashing Warning Light And A Loud Horn.