It’s an intriguing idea.
Things to think about:
Can all of the cockpit functions that you want to control be mapped to a keyboard key? Some things can’t be.
Does the keyboard you intend to use have accessible copper contacts under the keys to solder a wire to? Keyboards are wired using a matrix. So you would have to be able to connect directly to those pads.
Make sure you have a fairly good soldering iron and practice soldering before doing the keyboard.
