To Shut Down Or Not to Shut Down
Every aircraft on which I have operated has had the same immediate actions. If a Fire Warning is illuminated, Shut down the affected engine with the Fire Handle/Switch after confirming Warning and Engine to be shutdown. Why, because the Engine Fire Handle actuates all the appropriate valves and electrical relays to isolate the engine in terms of fuel, hydraulics, bleed air, electrics etc. If the Engine Fire Warning persists after shutting down, fire the first bottle. If the warning extinguishes complete the Clean Up checks as per the Checklist. If the warning persists after firing the first bottle, fire the second. Engine fires are not always able to be seen, so you have to believe that the warning is valid and act accordingly. If you have an uncontrollable fire just pray and fly at a speed which will hopefully blow the fire out. Aircraft manufacturers put a lot of money, time and effort into designing procedures to suit their product. They know what is best I suggest. Follow their published procedures.