Barkingmad, several years ago I was involved in a high speed turboprop, using those highly swept 'banana' blades (no, not the 7J7, this one actually had a flying prototype).
At any rate, we were told to treat anything that could cause a blade failure as catastrophic (i.e. less than 10-9/hr probability). Reason was that if a blade failed at power, the resultant imbalance and vibration would structurally fail the wing
I know very little about the F27 (ah, I did fly on an F28 a few times, does that count?
) But looking at some of the photos of what remained of the gearbox, it makes me wonder if it wasn't designed to fail. That is, if it lost a prop blade, I wonder if the gearbox was designed to fail and let the prop separate from the engine to protect the wing structure from the vibrations.
