Facts :
this is a high pressure rotor element of a jet engine
the diameter of the housing is not much bigger than the diameter of this rotor,
most of the witnesses heared a sound that they describe as the sound of a military aircraft (highly pitched and strident), not the sound of an airliner.
Conclusion :
this piece and the streamlining behind don't come from the engine of a modern airliner, like a 757, which has a high bypass ratio and low pressure fans of much larger size than the high pressure rotors, so that the streamlinings are much larger than the diameters of the high pressure rotors.
The engines of this plane have low diameter low pressure fans or don't have them at all : they are military engines, for which noise is not a problem, or engines from an old airliner (with low bypass ratio)
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