All this metallurgy discussion is fine, but John Sharp's article disputing Bailey's report is interesting to me. He disputes the "engine overheating" theory, fine. He then admits the the prop only sheared off after the crew cut off the fuel to the engine. Now maybe they didn't cut off the fuel due to engine overheating, but they certainly did cut off the fuel. Why? According to the PAN call: "uncommanded engine operations and then our propeller has just sheared off."
So something, observable to the pilots, happened prior to the prop shear, which was enough to prompt a shutdown. Were these "uncommanded engine operations" the cause of the prop shear? Or perhaps merely a symptom of the prop partially shearing prior to completely shearing? Is the gearbox still ok?
Last edited by Derfred; 15th Apr 2017 at 18:28.