[ethbr1]

After watching the below video, it's the excess bearing play and thus no-longer-constrained force directions that would seem to be the issue.

With a proper tolerance bearing in place, the force is constrained so that other parts are only stressed in directions they're well suited to handle (because the bearing takes the load).

Once the bearing develops excess tolerance, you've got a bucking engine that (to your point) is directly loading other parts in unexpected ways/directions, eventually causing failure.

The fact that Boeing supposedly modeled this and came up with non-safety critical in the event of bearing breakage... curious how that will turn out.

[jacquesm]

> The fact that Boeing supposedly modeled this and came up with non-safety critical in the event of bearing breakage... curious how that will turn out.

They'd have to show at least one plane with a bearing gone that still flies as intended. I suggest we break one on purpose, put the full complement of Boeing execs on that plane to prove its safety given the alternative of retracting that statement.

[cbsks]

My company has a policy limiting the number of high level execs traveling on a plane at a time. I wonder if plane manufacturers have similar restrictions. It’d be an ironic to for them to simultaneously assert that their planes are safe for the general public, and also believe the risk is too high for a planeload of their execs to fly in one.

[tmp10423288442]

Controlled flight into terrain is a thing

[Someone]

> They'd have to show at least one plane with a bearing gone that still flies as intended.

That depends on the meaning of “safety of flight”. I don’t know what it means in aviation, but do not rule out that there is significant room between “flies as intended” and “result in a safety of flight condition”.

For example, if an engine were to complete drop off the plane, would that necessarily result in a safety of flight condition, or does “the plane will be able to continue take off and land again” mean safety of flight isn’t affected?

[ethbr1]

Some of it may be related to the 3-engine design, if Boeing had modeled that 2 engines still provided sufficient power in all scenarios.

But a takeoff does seem like the worst time to catastrophically lose 1/3 power, even without FOD intake by the central engine.

[foldr]

Certainly two engines would provide enough power in all scenarios, including take off. That’s a fundamental safety requirement that any airliner meets.

[i_am_jl]

Niki Lauda, eat your heart out

[LgWoodenBadger]

To see extreme examples of this, look at any wallowed-out/wallered-out through-bore in construction equipment (e.g. excavator buckets), particularly when a pin hasn't been greased, or is seized.

This same scenario combined with the amount of vibration and stresses caused by the engine, should scream "this is a catastrophe waiting to happen" for any engineer.