Boeing Halts 777X Flight Tests over Damage Found in Engine Mount

Also not an airplane expert...

Agreed that finding issues is (often) good (it means you are human and you also found your errors).

But of course such testing, certification, is costly and uneconomical, and if you aren't allowed to fail, then you can't do the correct testing either...

I suspect the issue is two-fold: Firstly, Boeing can't afford to fail, and hence can't test. Secondly, it is driven primarily by profit, not safety, which is part of why it can't afford to fail. Profit drives/motivates new features, efficiencies, and ultimately complex systems, which require exponentially more time to thoroughly test than simple, inefficient, easily verifiable systems.

Falling apart because they are no longer profitable may not be a good thing either - sure, something could "rise from the ashes", but that thing will be in all likelihood, immature, poorly tested, and mostly incompatible with existing systems.

The best bet would be to simplify, as much as possible, all systems, suppliers, etc, and to double, quadruple, perhaps even expand by an order of magnitude the testing effort(s). Perhaps even some sort of new New Deal could come about...

This seems to be a certification test (https://www.seattletimes.com/business/boeing-aerospace/boein...), aka the "make-or-break, 0-failures allowed test before we get final approval to sell this aircraft, and we are 99.999% sure this test is going to go flawlessly".

Failing is a pretty big deal. This should have been found far sooner in the process.

This is not quite the same. This is finding a failed part that should not have failed, as it should have been designed to -at least- pass the flight test requirements it was designed to fulfil.

And what this article failed to mention was that similar structural issues were found on 2 other test aircrafts.

What they are saying here is that the component was designed to X, but, not manufactured to those specifications.

Depending on who made that actual component, this is either a failure of Boeing directly or a failure of Boeing to ensure that their suppliers have adequate processes in place to capture these kinds of problems.

This is actually a much more serious failure than a design failure because the problem can't easily be systemically addressed, there is no single component they need to address now. Boeing can not simply say "we checked the other engine mounts in production and they are fine". Even saying that they addressed the issue with the production of that component is insufficient. The real root cause here is why any component which did not meet design specifications was accepted and allowed to be installed on the aircraft. Boeing will need to do a huge review to understand this and may need to inspect and replace huge numbers of other, seemingly unrelated, components.

But I also wonder if we aren't pushing the limits of what's reasonable for a 2-engine passenger airliner. I get that the more people you can put on a flight the more money the airlines make from that flight, but there's a practical limit somewhere.

That points to major structural issues. Or better said, yet an other structural issue on an aircraft type that is already 5 years late.

Well, they had the opportunity to sign for an other aircraft, and "unexpectedly" jumped ship at the last moment, so that's on them.

And of course all the apaches, globemasters, ospreys, super hornets..

They are definitely too big to fail.

Much of the issues Boeing has are as a result of government involvement.

Just look at the entire starliner debacle, in any truly free market Boeing would have been fired as a vendor years ago. They were (and are) way behind schedule, their unmanned demo flight was a failure, they still went forward with a manned flight which has been an abject failure -- the crew is on month three of what was supposed to be a 3 hour^W^W9 day tour. They might not be coming home till February. I hope they have someone watering their plants.

It really shows that it was designed in this century. The focus on type certificates/training is really holding the industry back (as well as causing the terrible MCAS crashes).

I’m not sure how the relative straightforwardness of that approach maps to a company that basically has two main supply chains (737 in Renton and everything else in Everett with North Charleston as a satellite.)

I'm not quite certain. Airbus is possibly quite happy to have a stumbling giant occupying that space and tripping over its own feet. It's a lot more comfortable than having to compete against a heavily subsided Chinese company, like what is happening in the EV market. (Not that they are a threat at the moment)

I plopped that filter text in, and... BOOM. Problem eliminated! Thanks man.

as the aircraft was beginning its takeoff rotation, engine number one (the left engine) separated from the left wing, flipping over the top of the wing and landing on the runway. As the engine separated from the aircraft, it severed hydraulic lines that lock the wing's leading-edge slats in place and damaged a 3-foot (1 m) section of the left wing's leading edge. Aerodynamic forces acting on the wing resulted in an uncommanded retraction of the outboard slats. As the aircraft began to climb, the damaged left wing produced far less lift than the right wing, which had its slats still deployed and its engine providing full takeoff thrust. The disrupted and unbalanced aerodynamics of the aircraft caused it to roll abruptly to the left until it was partially inverted, reaching a bank angle of 112°, before crashing in an open field by a trailer park near the end of the runway. The engine separation was attributed to damage to the pylon structure holding the engine to the wing, caused by improper maintenance procedures at American Airlines.

https://en.wikipedia.org/wiki/American_Airlines_Flight_191

It is a safe-life part, so yes, it is a single point of failure part for that engine. And, if something fails unexpectedly, it could significantly damage the wing too, as has happened in the past with deadly consequences.

The problem being encountered on two other test planes, makes it a lot more problematic, as the probability of the second engine shearing off then becomes a lot, lot higher.

Once one mounting point fails, the other ones will fail as well. The mounting points are engineered to try to minimise wing damage when that happens.