I,m told that the USAF getting rid of the T67 has more to do with the fact that slingsby could not get there act together and supply the spare parts and so could not get the use out of the aircraft.
As for the engine stopping in the spin the USAF have taken the aircraft to 24 turns in the spin without problems so i think that the court ruling is just a face saver for the USAF who dont want to admit that they delt with a company that was unable to support its (very good)product to the required standard.