Here’s how you secure the bay.
Metal door, and frame.
Random number generator in secure location on the ground.
Require 2 flight officers to give unique, and secret codes to get the number.
If an incorrect number is input 3 times, the computer takes over and flies to the destination, or until correct code is input.
You can’t be 100% safe, and if the Captain wants to crash the plane, well, Prayer is pretty much your only option at that point.
ping