"one day, you'll put in the inputs to recover the spin and it won't recover as you expect, don't start £$%"£$"£ about with it, stick with it and it will drop out" It did it once and completed another rotation and then dropped out. I don't know why, but it did.
This is the key. That warning should be plaquered on the instrument panel. Sometimes the Firefly doesn't react the way it should.
It's like ghosts, you don't believe in them until you see one yourself.
Was this a right-hand spin? The Edwards test flight guys found the aircraft recovered quicker from left-hand spins. They speculated it was due to prop wash making the rudder more effective. The fatal Academy intentional spin crash hit the ground in a right-hand spin. The Apr 2016 crash looks to be right-hand too.
We should also take note that many of the T67 crashes resulted from stalls, some at low level, some that progressed into spins. In the
T67 stall + rudder = aggressive wing drop. That should be plaquered too.