I have just read through this thread and am surprised to see no input from military Spey guys who worked on the Phantom. Yes, the CASC was indeed a mind boggling piece of kit to understand but the military Spey 202/203 had the additional joy of reheat complete with it's own fuel and oil systems. I had a fun time trying to change a CSDU for the first time when I found out about the oil outlet pipe which came out through the top of the unit and was near impossible to disconnect and reconnect. This was also the 'wrong ' engine for the F4 and took a team of five a full 8-10 hours to do an engine change as it didn't fit too well. Once it was in there though it was a truly impressive sight in full burner especially at night!