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by twtw 2695 days ago
I do not think this is a good analogy.

Firstly, there is no single equivalent to "slamming on the brakes" for uncommanded nose-down. This could be caused by a variety of faults, and pilots are trained to respond in a fashion that will be effective for even those in which the first thing to try doesn't work. There is a standard procedure in place to use in this type of situation - arguing that the pilots should only be expected to do one thing with increasing desperation is essentially arguing that they will not be able to respond to a whole host of emergencies causing uncommanded nose-down.

Second,

> Information from the flight data recorder shows that the plane’s nose was pitched down more than two dozen times during the brief flight, resisting efforts by the pilots to keep it flying level ... The standard checklist for dealing with that sort of emergency on the previous version of the 737 focuses on flipping the stabilizer trim cutout switches and using the manual wheels to adjust the stabilizers. [emph mine]

your argument essentially hinges on the assumption that pulling hard back on the stick is a sufficient solution for all the problems that may happen with a plane with the exception of a fault with MCAS (the new system). I don't think that is accurate. Even prior to the the 737 max! It sounds there were a lot of things that would require further action that pulling back on the stick.

4 comments

Their response would have worked to return to level flight in non-MAX variants of the plane, though. Regardless of what the manual or checklist says, they had years of experience flying 737s that behaved in a specific way, they developed an unconscious/intuitive mental model of the plane based on those behaviors (that is faster and quicker to react than consulting checklists), and then a significant and deadly change was made to those behaviors and not communicated to them for cost-cutting reasons.

There's clearly a problem on Boeing's end here.

From the article:

"Older 737s had another way of addressing certain problems with the stabilizers: Pulling back on the yoke, or control column, one of which sits immediately in front of both the captain and the first officer, would cut off electronic control of the stabilizers, allowing the pilots to control them manually.

That feature was disabled on the Max when M.C.A.S. was activated — another change that pilots were unlikely to have been aware of. After the crash, Boeing told airlines that when M.C.A.S. is activated, as it appeared to have been on the Lion Air flight, pulling back on the control column will not stop so-called stabilizer runaway."

If the above is true, it's near criminal that Boeing didn't notify pilots about the change. It's also not just about following checklists but understanding the systems of the aircraft.

There's a Faustian bargain made by accepting so much abstraction from the true nature of an airplane by using software, and yet also that abstraction is not absolute. Pilots are made responsible for knowing all of the aircraft's behaviors, with full abstraction (normal mode), as well as partial abstractions (error and failure modes, of which there can be quite a few for a specific made/model, many of which must be inferred rather than being clearly displayed). If pilots get confused, however complicated and unintuitive the system behavior, they are blamed.

The more "piloting" computers are doing, it seems appropriate that they will be increasingly, properly, accused of the equivalent of "pilot error". And yet here is Boeing, taking more and more piloting responsibility, while still blaming the pilots when that doesn't work out. It's a deification of engineering: when things go properly and safely, praise engineering; when things fail, blame the pilots.

The point is that their response may have worked for this particular fault, but would not have worked in general. There is a reason that there are more procedures than "pull back on the stick" - pilots do not know what the fault is.

> they developed an unconscious/intuitive mental model of the plane

If the plane has a fault, it's frequently not going to behave like their unconscious model says it should. In the happy case, rely on your intuition. In the unhappy case, when things are working as they should, follow the emergency procedure.

Sorr, but this is a little like saying "follow standard procedure to put the landing gear down. If that procedure doesn't work, repeat your intuitive action over and over until hopefully the landing gear goes down." No - follow the emergency procedure in place for landing gear fails to descend.

> not communicated to them for cost-cutting reasons

Take it up with the FAA and the airlines?

> Take it up with the FAA and the airlines?

Sure. It's not just Boeings fault. I believe the FAA will course correct from this and probably all changes to flight controls will need to be reported to pilots. More lessons written in blood.

It's still more Boeing's fault than anyone else's though. They were the ones who made this change and then tried to hide it to the fullest extent possible, so that it wouldn't trigger mandatory retraining.
> and then tried to hide it to the fullest extent possible

I haven't seen any evidence of this. It's definitely not supported by this NYTimes article.

Do you have a source?

>Firstly, there is no single equivalent to "slamming on the brakes" for uncommanded nose-down.

Actually in the "old" version, there is.

From TFA:

Older 737s had another way of addressing certain problems with the stabilizers: Pulling back on the yoke, or control column, one of which sits immediately in front of both the captain and the first officer, would cut off electronic control of the stabilizers, allowing the pilots to control them manually.

Which makes the car analogy apt.

Indeed, any pilot will respond to nose down with ,pulling back on the yoke, or on the joystick, in other and older aircraft. This is a basic flying control, as basic as steering wheel and brakes, making this an excellent analogy. Any system that complicates this in the way described is a terrible system, for the reasons explained above.
Drivers aren't trained to follow checklists and usually don't have dozens of seconds to respond to mechanical emergencies. Cars also don't fall out of the sky if they break down. It's not a great metaphor.
> have dozens of seconds to respond

12 minutes, in this case.

Yeah, I figured it's usually many minutes but didn't want to underplay the stress and difficulty of following a checklist in an extreme emergency. In contrast, car major mechanical failures generally resolve themselves extremely quickly.
And yet the pilots of the previous flight flipped the cutout switches.

EDIT: ... Presumably because it's literally the second thing on the list of things to do in the case of a runaway stabilizer.

I strongly agree. I've read most of the other comments here, and as an armature pilot myself, I think most of the responses to you are missing the point.

Its extremely unfortunate, but these pilots had ~10 minutes of flight time between their request to return to the airport noting aircraft control issues, and their crash, during which they completely failed to follow their checklists. Lion Air put those under-trained (if we're being generous) pilots into that cockpit and they are the only ones who carry responsibility for this crash.

Its anecdotal, but most of my older flight instructors have been lamenting the loss of critical pilot skills in the industry, and this appears to be just another example of that.

>your argument essentially hinges on the assumption that pulling hard back on the stick is a sufficient solution for all the problems that may happen with a plane with the exception of a fault with MCAS (the new system).

I don't read it that way. To me, it's specifically based on removal (without notice to pilots) of a function that would absolutely have terminated a trim runaway condition.

In other words, Boeing eliminated one well-known and trained-on trim runaway fix, and didn't tell the pilots. This is different from saying that stick pullback is a universal solution.