United flight 328 - Denver to Honolulu

[Maple Leaf]

7 minutes ago, Sharpie said:

 The only time my car leaves the ground is when the auto repair shop puts it on the lift.   So with all that testing how does what happened happen.

 

The fan blades are made of titanium, one of the strongest metals available.  Nevertheless, metal fatigue can still happen.

[trotter]

41 minutes ago, Sharpie said:

 The only time my car leaves the ground is when the auto repair shop puts it on the lift.   So with all that testing how does what happened happen.

 

33 minutes ago, Maple Leaf said:

 

The fan blades are made of titanium, one of the strongest metals available.  Nevertheless, metal fatigue can still happen.

Modern jet engines (at least RR ones) use a high nickel alloy instead of titanium as it works better at extreme temperatures. In general the hotter the engine runs, the more efficient it is. 

 

The fabrication of those fan blades (especially the ones in the hot part of the engine) is an art in and of itself. Google 'directional solidification' for more details. Most of them are actually hollow and have tiny little holes and channels to allow air to pass through them and keep them cool. 

 

Unfortunately even in this day and age, microscopic defects at the molecular level can make it past the QA/QC and subsequent in-service inspection processes. There is even the possibility that a defect has occurred over time on an otherwise perfectly built engine. Engine failures do happen from time to time, that's why commercial planes must have at least two. The worrying bit for me is that the engine cowling has come off. That is specifically designed so that in the event of a disintegrating engine, it contains all the bits and pieces and prevents them from puncturing the wings or fuselage. This clearly hasn't happened in this case. 

Edited February 22, 2021 by trotter