A380 Engine Blowout

A few days ago, one of Airbus' A380 superjumbo jets had yet another technical issue with their monstrous aircraft.  This time the engine failed, spewing debris across the wing and damaging the aircraft to the extent that it was forced to make an emergency landing.

Airbus A380 wing ripped apart by engine pieces

Judging from the picture of the damage, the first thought that came into my mind was that the engine "threw" a turbine blade.  How does this happen, you ask?  Well, let me refer to a schematic of a turbofan jet engine:

As you can see the engine is composed of several rows of blades that are arranged into various sizes of fan patterns throughout the entirety of the engine.  The most destructive and catastrophic failure that a jet engine can undergo is that of either severe over-pressurization in the combustion chamber or failure of a compressor or turbine blade.

I suspect that the engine on the Qantas suffered a high- or low-pressure turbine blade failure.  This is caused when a turbine blade comes loose either due to over-stressing it or by fatigue.  The blade that comes loose then is imparted with enormous velocity, courtesy of the high rate of rotation of the turbine fan.  Depending on exactly when it breaks, it can fly off in any direction orthogonal to the axis of rotation of the turbine fan.  Below is an image of a turbine blade missing from the fan, and is probably similar to what mechanics found inside of the this A380 Rolls-Royce engine upon return.

Missing blade from a turbine fan.

The passengers of this Qantas flight were fortunate that it didn't come loose a few nanoseconds prior, or it might have flown through the cabin of the aircraft.

The only question that remains is what exactly caused the turbine blade to come loose?  Hard to say without more information...