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by zaroth 2471 days ago
I like the brake pedal analogy. It's not perfect, but it makes the point well. To add insult to injury, when the driver flipped a cut-out switch to disable the cruise control, the brakes were useless, the manual brake adjustment lever failed, and the only documented procedure to fix them at that point (for that model plane, err, car) was to turn cruise control back on.
2 comments

As someone who's driven a lot of vehicles in various states of mechanical failure I don't. Once you stop treating a vehicle as a magical black box where everything affects everything the analogy falls apart.

Vehicles have predictable failure mode and systems that are integrated with each other in known and fairly standardized ways. Short of catastrophic mechanical failure (i. e the front fell off) someone with sufficient experience to recognize what is going on should be able to disable systems until some level of basic control is restored. Your brakes have nothing to do with cruise control other than having a little switch on them (usually two switches) to tell cruise control to turn off when you press them. I feel like airline pilots should in theory have that level of understanding of the systems in their aircraft since they are trained professionals and the stakes are very high so they need to be able to handle failures gracefully.

And before anyone puts words in my mouth I'm not saying Boeing isn't the most at fault party in all of this.

I feel like airline pilots should in theory have that level of understanding of the systems in their aircraft since they are trained professionals and the stakes are very high so they need to be able to handle failures gracefully.

I agree. But you need to knowe that a system exists in the first place.

Something the manufacturer failed to document to begin with.

If an analogy didn't fall down at a deep enough layer of inspection, it wouldn't be an analogy.

To someone who has no idea what "trim" is, let alone electric assist versus manual trim, MCAS, aerodynamic loading,... the brake pedal analogy gets the general point across of what it must have felt like to the pilots, to be fighting against the machine.

A more accurate car analogy may be a lane assist system with access to the steering system having an undocumented fire hydrant avoidance module added that causes a car to veer into a jersey barrier because it happened to have a truck loaded with fire hydrants pull in front of it and brake.

At least in terms of the pilot's POV. I can't quite torture anything else to sufficiently resemble what chain of business decisions Boeing made to end up having their process drive them into this error state. It'll just have to stand on it's own merit. Though I've commented on it many times with much greater detail this year.