Type Ratings are a funny thing. If you get a Hawker HS-125 type rating you can fly everything from the Series 1 which first flew in 1962, through the current production Hawker 800XP which has the Collins Proline 21 glass cockpit. Through out this time there has been numerous changes to the engines (from straight turbojets to TFE-731 turbofans), fuel systems (wing tanks only, dorsal tank added, dorsal tank removed & ventral tank added), cockpit (old style gauges through the -700, Honeywell EFIS for the 800 and early 800XP, Collins Proline 21 in current production), APU (no APU in early models, Solar APU for gound use only in 800 and early 800XP, Garrett APU that can be used in flight in current model and retrofitted to some earlier aircraft) in addition the electrical system has changed and many cockpit controls changed locations.
During its 40+ years of production the aircraft has been stretched, the wings have grown is span and then been changed to an entirely different design and numerous other changes have taken place.
It is still legal to get type rated in the latest model and then jump into a 30 year old airplane which is in reality, a totally different aircraft. But to the FAA they are still all just a HS-125.
I have always wondered if the FAA has some list of all the type ratings and what you can fly if you have each one, but I have never heard of this being posted anywhere. It can get pretty confusing as to what rating you need to fly what jet. I know that if you get a CE-500 type rating for the Citation you can fly quite a few different models, but it would be nice to have a place to look which would list each one.
