Ray, if the accident occurred shortly after takeoff i.e in the initial 15-20 minutes of flight I would have expected the engine parameters and performance to have been closely monitored. Had your Dad had the opportunity to continue the air test he would probably have climbed to altitude, closed down the subject engine, checked the feathering and re-started it. I don't know what else would be involved. I did go as a joy-rider on one of our Vikings that was having an air test and that was what I observed. Regards Tom.