Although it´s "silent boat" in this thread since 5 days I´d rather like to "bang" the door one more time. We have worked through the case fairly well, I think. However, why do we stop close to the point where "Pandoras Box" is pulled open ? I like to refer to Turbine D´s list posted in Nr. 1888
Quote:
One way to look at it is this way: (A) leads to (B), (B) leads to (C), (C) leads to (D) and (E) leads to failure. This is the classical failure methodology of a complex system. Looking at engine #2's failure,
(A) = Unknown
(B) = Unknown
(C) = Unknown
(D) = Stub pipe
(E) = IPT Disc burst/major engine failure/damage to aircraft
The trick is to identify (C), (B) and (A), (A) being the root cause.[/quote]
Rolling down that list reversal way I´d like to start at
(E) : IPT Disc burst/major engine failure/damage to the aircraft - symptom caused by "D" through "A"
(D) : Stub pipe fracture /oil spill - probable contributional cause ? sympton
caused by "B" or "C" or "A" ??
(C) : vibration - light on LP and IP shaft, severe on HP shaft - sympton caused
by "B" or "A" ??
(B) : rising oil temperature, wear of bearing ?? - sympton caused by "A" ?????
(A) : the real start and cause of the desaster, this one triggered all the other
recorded events.
I believe there is something technically that I can not cover with my knowledge about sophisticated jet engines, but that engineers might know of. There fore this as my last try to get a logical answer to what went wrong in that Qantas engine.