something forcing my student to keep his hand on the gear leaver untill he gets three green....... a big wad of aviation grade masking tape or something
realistically there is probaby very little you will be able to do in the way of aviation safety in the cockpit that has not already been looked over millions of times. Something to stop paralax error when teaching co-ordination.. well if an instructor cannot tell if the aircraft is in balance without the balance ball something is going amiss.
I think the most useful thing that could be developed CHEAPER for the GA market is the TCAS system. They are quite expensive and operating out of the bussiest airport in the southern hemiphere they could save alot of lives if they were made cheaper for general use. See and avoid is just a way to remove the responsibility from ATC.
can't really think of anything else. There is to much of a mentality in the industry to not cause a fus and go AS IT IS of SHE'LL BE RIGHT