[boeinggggg]

I don't know. Maybe an expert can chime in but I think it is a hard problem because of ice etc. I think the 737Max has the problem where AoA matters more because you can get into a stall you can't get out of.

Whereas maybe before on older planes you get in a stall and you nose down to reduce AoA. You don't need a sensor to know this look at altitude etc.

So now you need perfect ten nines of reliability AoA sensors. Their use case has gone from a data point to mission critical, but the sensor is the same.

[imoverclocked]

You never want to get into a stall in a large commercial jet. Private pilots are taught stall and maybe spin recovery techniques for small GA aircraft. ATP rated pilots are taught stall/spin avoidance.

Chances are, if your AoA is anywhere near the critical AoA, a competent pilot is likely aware of it. The sensors are just another safety factor on top of that to help ensure situational awareness.

[K0balt]

Or, in the case of the 737Max, to trigger a chain of events that proved lethal to hundreds to people. That’s the secondary use of the AOA sensor in combination with the FC software that they implemented. It would have been relatively easy to integrate the AOA input with other sensors to eliminate this problem, but it would have invited a deeper look at the hazards of their design decisions.

Bean counters bathing in blood, all the way down.

[robocat]

> Bean counters bathing in blood, all the way down.

No resource is infinite and money is an important constraint in any engineering project. Engineering is all about making compromises. Good engineering is making the right compromises: especially when life and death decisions are being made.

Casually blaming "bean counters" is a distracting fantasy available to anyone that doesn't have to make real-world decisions. Understanding the causes of how Boeing systematically screwed up requires a bit more maturity than you appear to show. "Bean-counters" particularly comes across as childish name-calling to me, and clichés don't help either.

The fact that the MAX has been cleared to fly again shows that the design decisions were not utterly flawed.

[K0balt]

The design decisions were acceptable, if they had admitted the fact that the new design necessitated significant new training for the pilots, who were now flying a version of the 737 that could lose positive stability in some corners of its flight envelope….a fact they buried to reduce scrutiny (or facilitate deniability) from regulators and to make it an easier sell to airlines.

Bean counters bathing in blood, all the way down.

The forward mounting of the engine nacelles could have been countered with a small adjustment of the sweep or the surface area of the horizontal stabiliser, instead of the faulty flight control software solution, keeping the aircraft an aerodynamically safe aircraft as had been earlier generations. But that would have been a de-facto admission that the fundamental aerodynamic characteristics of the aircraft as certified were changed by the forward mounted nacelles.

They chose to monkeypatch the flight control system instead of making a minor change that would have produced the inherently safe aerodynamic characteristics that the aircraft was certified with.

They did this to avoid the delay and cost that would have resulted if they had been required to prove the aircraft design was still airworthy. There’s a reason that new designs must be certified to be used in passenger transport. They tried to work around the fact that the 737 max is a substantially new aircraft by monkeypatching the FCS to compensate for a potentially dangerous aerodynamic flaw that was introduced by the new location of the engines.

They chose to produce a more profitable but potentially dangerous aircraft instead of letting the engineers do their job and make the aircraft stable with the new engines. Regulators were also complicit in the regulatory evasion. Hundreds died as a direct result of this malfeasance.

Bean counters bathing in blood, all the way down.

[robocat]

The accountants are part of the engineering on large engineering projects.

> instead of letting the engineers do their job

This is your central point - that you imply engineers are infalliable and therefore it most be someone else's fault.

A problem due to systematic effects. As you point out the mistakes have obvious fixes if you have perfect 20/20 hindsight.

[K0balt]

There was significant debate within Boeing about aerodynamic fixes for the forward mounted nacelles. The aerodynamic fix was rejected because it would result in additional regulatory requirements for flight testing and certification. The FCS was certifiable with a pen.

You are correct in saying that the accountants are a critical part of the company and the engineering, it’s the MBAs in leadership that I’m referring to derisively.

[imtringued]

Except anyone who has read up on this topic knows that Boeing got fined for several billion dollars by the FAA and that the FAA has increased the training requirements and that Boeing has lost 20 billion dollars from aircraft groundings and cancelled orders.

Clearly, it doesn't look like Boeing was hurting for money whatsoever. Bean counters allocate money to billion dollar fines but they won't allocate it to safety and good engineering.

There aren't any deep or hidden truths behind the crashes. Turn off the MCAS and you don't get autopiloted into a crash, but telling pilots to turn off the MCAS would defeat its purpose, which is to save money on recertification and pilot training precisely by keeping it a secret.