Is the 111 still flying? 580 is prop, right?
both very old, too...
Yep. Basically the same airframe as the CV-240/340/440 series, but either converted to or built as turboprop. The company I used to work for had (probably still has) one for conducting flight tests of various electronic systems. I participated in a series of data collection flights to prove some new (to us anyway) radar signal processing technologies. I started out as the "navigator". I had written a program to calculate an IP and "fly to point" given our altitude, airspeed and wind speed and direction, that would result in our pointing the fixed radar at the desired target area. Originally they were going to implement the algorithm on the test equipments computer, but instead I ended up running it on a laptop sitting in a passenger type seat just behind the cockpit. The nav system operator would read me the winds from the last pass, I'd run the program (which I'd pre loaded with other parameters, and I'd read off the IP and fly-to for the flight crew to input into their separate (but FAA certified) nav system.
Due to other folks getting pulled off for higher priority tasks, I ended up as the flight test engineer on the later flights. Didn't mean anything, the techs knew what they were doing without me telling them. This was all about 10 or 12 years ago.