Long Before Boeing 737 Max Crash, Ethiopian Air Pilot Warned of Dangers
bloomberg.com
bloomberg.com
You can see from the graph that in the final minutes and seconds, the pilot put insane amounts of force on the control column (aka the yoke) to try to pull the plane out of the dive - to save the 189 people on board. But no, MCAS was overpowering and lacked the documentation for the pilot to try anything else.
Also interesting to see is the amount of times the pilots bring the nose up, only for MCAS to kick in and force the nose back down. 26 times.
All data from this Seattle Times article, which was written before the second crash occurred: [1] https://www.seattletimes.com/business/boeing-aerospace/black...
That is awful. I heard that MCAS kicks in for ten seconds and then goes off for five seconds. So that must have been terrifying, for the pilot to think he has it under control for the death wish of MCAS to try again, and again and again until it gets its own way.
When you look at how much has been invested in Homeland Security over the last seventeen years it is doubly tragic. It wasn't terrorists that we needed to fear, it was hasty management decisions at the FAA.
2) While this is certainly a tragic incident, it has nothing to do with homeland security existing or not. It's not like the autopilot suddenly decided to use planes as weapons. Apples and oranges.
Blaming Boeing is one thing but we know from our own coding work that you don't have the programmer test and deploy mission critical stuff, you get someone else to do it. It is a team effort. In code if you cut the people out that do all the testing and just ask the programmers to deploy stuff when they want to it goes wrong.
I am not cutting Boeing slack in this, if you go back to the programmer analogy, you still get your code written to best practice before you put it anywhere near the testing and deployment people.
Because of 2) obviously. All the money is gone. No budget for rigorous testing and validation of specs.
Not for budget reasons, but for "deregulation is good" reasons. The money isn't gone. We've just got people who'd like "a government so small they can drown it in a bathtub". Well, it's drowning alright.
[1] http://community.seattletimes.nwsource.com/archive/?date=199...
After flaps are retracted for the final time, the altitude seems to stabilize. So why the sudden drop before the crash? Why couldn't the pilots just keep on flying on the same level?
There must be a sudden behavioural change of the plane or the pilots right before it went down, but I never got it explained to me clearly why...
Second question: why did they retract the flaps? Wouldn't the wings generate more lift with flaps extended?
Sure, until they get ripped off at speed. Flaps aren't a magic "more lift plz" button.
Edit: here we go: Pilots have demonstrated in simulator that the trim wheels cannot be moved in severe mis-trim conditions combined with a high airspeed.[92][93] As the pilots on Flight 302 pulled on the yoke to raise the nose, the aerodynamic forces on the tail’s elevator would create an opposing force on the stabilizer trim jackscrew that would prevent the pilots from moving the trim wheel by hand.[86][91][94]
The resolution for this jammed trim issue is not part of Boeing's current 737 manual according to The Air Current.[90] The Seattle Times reports pilots on the 737-200 were trained for this failure, but latter models got so reliable, this procedure was no longer necessary.[91][90]
Just stolen from Wikipedia before I sleep: https://en.m.wikipedia.org/wiki/Ethiopian_Airlines_Flight_30...
They couldn't redeploy the flaps to shutdown MCAS because
A) they didn't know it would work, and it was not documented in any standard procedure
B) the plane was travelling too fast for safe flap deployment
C)Flap deployment decreases the critical AoA of the wing, meaning that pilots would have to be extremely careful during the recovery, and may in fact not have been able to pull out fast enough even if they fixed the mistrim.
Also, remember that a plane flying straight at the ground is still making lift as it barrels toward the earth. Lift isn't something magic that guarantees the plane stays away from the ground. The force vector will happily accelerate you 90° relative to your lifting surface's velocity vector through the fluid.
If for whatever reason you decide that that vector should no longer be parallel to the surface... Well... That's on you.
Or in this case, a computer programmed with an insufficiently robust algorithm for safely doing what it was actually meant to do. As the flight computer had no way of understanding that what its AoA sensor was telling it could possibly be wrong, and therefore alerting the pilots that they were flying on their own now.
So while the pilots knew what they wanted, the computer, not being programmed with the possibility of being wrong in mind, did exactly as it was designed to do.
And this, ladies and gentlemen, is how you kill 300 people without realizing that you're doing it.
> There must be a sudden behavioural change of the plane or the pilots right before it went down
The altitude was stable because the pilot valiantly countered the AND (aircraft nose down) trim input from MCAS with ANU trim (using the electric trim switch) again and again and again. And again.
From what I gather, he then handed the plane off to the copilot to look things up in the QRH (Quick reference handbook, checklists basically), and unfortunately the copilot did not trim up quite as stubbornly, allowing MCAS to trim down so much as to be unrecoverable with elevator control forces alone. Truly terrible.
> Second question: why did they retract the flaps? Wouldn't the wings generate more lift with flaps extended?
Standard operating procedure after the initial climb, you retract flaps. Yes, wing would generate more lift with flaps, but that’s not the problem if you’re pointing downward.
Having said that, deploying flaps would have inhibited MCAS and allowed them to control the plane, maybe, but they didn’t know that.
EDIT to add: I’m talking about the doomed Lion Air flight here (which the FDR data plot linked above pertains to, if I’m not mistaken).
I agree, this is the main issue. In both cases if pilots had a clear option to just switch off MCAS we would have not lost over 500 lives.
In an emergency it has repeatedly been shown that pilots often forget complicated/rare recovery procedures. We need to stop relying on humans to perform at a superhuman level in these situations; better automation is the only way out.
Maybe the 737 Max is just too complex and relies too much on automation to fly correctly? I'm reminded of the Quantas QF32 flight, where pilots were nearly overwhelmed by the endless amount of errors and checklists they had to perform. [2]
[1] https://www.youtube.com/watch?v=lIusD6Z-3cU
[2] https://www.news.com.au/travel/travel-advice/flights/inside-...
And in the case of MCAS, physically unable to exert the effort to overcome the automated trim settings. (Posted above):
1. "they didn't even get as far as switching off the stab trim" means they were incompetent.
2. MCAS, obviously, was a bad design
3. there was a physical issue with the sensor, possibly due to a bird strike
Fix any one of those, and the flight wouldn't have crashed.
I thought a central part of this was that there was according to Boeing no need to train on this particular aircraft because it was so close operationally to the 737NG. But that in fact the correct response in the particular situation is vastly different. So yes, kinda "incompetence" but more "ignorant due to Boeing's assertions that training wasn't needed"; ie the blame should not primarily rest on the pilots.(?)
I'm ignorant on the details, but this sort of article seems convincing:
> It’s probably this counterintuitive characteristic, which goes against what has been trained many times in the simulator for unwanted autopilot trim or manual trim runaway, which has confused the pilots of JT610. They learned that holding against the trim stopped the nose down, and then they could take action, like counter-trimming or outright CUTOUT the trim servo. But it didn’t. After a 10 second trim to a 2.5° nose down stabilizer position, the trimming started again despite the Pilots pulling against it. The faulty high AOA signal was still present.
> How should they know that pulling on the Yoke didn’t stop the trim? It was described nowhere; neither in the aircraft’s manual, the AFM, nor in the Pilot’s manual, the FCOM. This has created strong reactions from airlines with the 737 MAX on the flight line and their Pilots. They have learned the NG and the MAX flies the same. They fly them interchangeably during the week.
> (https://leehamnews.com/2018/11/14/boeings-automatic-trim-for...) //
If a human is pulling back on the thing that says "plane needs to go UP" believe what they're requesting.
The problem here is nearly identical to the problems with self driving cars. The automation is capable of handling 95% of situations, but the 5% it's not capable of is not clear to either the operators or the software itself.
I firmly believe that both car and air travel need to be either 100% completely automated, or 100% under the control of the operators with well defined areas where the automation systems will ASSIST but always yield to the well trained (pilots) or poorly trained (car drivers) when requested. A human operator is able to think outside the box, and is not limited to what code has been conceived and written.
In any event, the situation where the humans aren't processing the data correctly and doing illogical things as a result would always lead to failure outcomes, until the point where we no longer allow humans to be pilots/operators at all.
Either way, as I understand, it wouldn't matter with the MCAS-related MAX aircraft crashes. The elevator trim is able to move the entire elevator (literally, the entire elevator moves in response to the jackscrew controlled by the trim system) to such an extent that, depending on CG, airspeed, and other factors, it cannot be overpowered by moving the control surface to its full deflection. So whether or not the MAX had boosted controls or fly-by-wire probably wouldn't have mattered in the case the aircraft were trimmed fully nose-down. The pilots would have been struggling to maintain control either way. That's why there's stabilizer trim cut-out switches and manual trim.
I'd highly recommend Mentour Pilot's videos on the subject, links below:
Runaway Stabilizer: How to stop MCAS - https://www.youtube.com/watch?v=xixM_cwSLcQ
Boeing 737 Unable to Trim! Cockpit video (full flight sim) - https://www.youtube.com/watch?v=aoNOVlxJmow
Five questions about the Boeing 737 MAX Answered - https://www.youtube.com/watch?v=CD0JabYjF3A
Start at 13:20 to skip straight to the relevant bit.
Much appreciated!
When did I say it has anything to do with it?
> The 737 does not have artificial feel in any case, as far as I know. There's a direct mechanical linkage from the yoke to the control surfaces, so no artificial feel is necessary.
Modern planes come with stick shaker-pusher systems: https://www.flyingmag.com/how-it-works-stick-shaker-pusher
That's what I was referring to. Also whilst the 737 does have mechanical linkages to the control surfaces, they are there primarily for redundancy so the plane is flyable in case of hydraulics/power failure. By definition any hydraulics assisted system requires artificial force feedback.
Hmm? You were talking about systems that mimic the yoke feel of an aircraft with manual controls. A stick shaker is an emergency warning system that would never once activate on a normal flight. It has no effect on the feel of the controls.
>When did I say it has anything to do with it?
In the comment I replied to:
"To give pilots this feedback, Boeing simulates it mechanically by exerting force on the yoke. Normally this is fine and dandy, until the critical AoA sensor malfunctions and makes the computer think the plane is in a different attitude than it actually is in."
The AoA sensor does not function on the ground, it's basically a windvane and with no air moving over it, it would move to whatever angle gravity dictates.
A certain air speed is required (to turn the weather vane, as it were).
While in ground effect, the air flow is different from the airflow in flight (away from the ground), so apparently a certain altitude above ground is required for the indication to be considered reliable.
However, I believe that it should be possible to recognise a sufficiently defective AoA sensor during the take off roll, and possibly in time to abort the take off. However, not sure whether pilots are briefed to do so, as that is a risky manoeuvre in itself, and a missing AoA sensor should not be any problem per se (in the absence of MCAS that is trying to kill you).
Not seeing much discussion of the guy who called it right and is losing his job because of it. I'm not sure if there's a way to know if he's being forced out or choosing to avoid some backlash, but it seems sad that the one person in the story who made the right call pays a hefty price, as opposed to being kept, protected, and/or promoted. Same thing has happened to many people trying to do the right thing, Roger Boisjoly would be a super famous example, one of the engineers who predicted the Challenger disaster.
Are there examples of people being rewarded for their efforts after a large scale accident, rather than punished?
You likely don't hear about this, because for these cases the oversight works and it's just people doing their jobs.
I'm just curious if there are any well-known cases of companies doing right by the people who tried to avert the accident, of companies admitting it was a management mistake as opposed to letting their fears / liability concerns / embarrassment steamroll the only people who did the right thing.
I really wish the media wouldn't leave out important context when making statements like this.
If you aren't a pilot or an aviation enthusiast, you'd think leaving the thrust high was a mistake, but an on the fritz AoA sensor means you're in an airspeed unreliable condition, which calls for maintaining appropriate power for the desired flight regime, which in this case was TO/ascent, a regime generally flown at higher power.
https://www.skybrary.aero/index.php/Unreliable_Airspeed_Indi...
Or, how leaving the airspeed issue unresolved until the more pressing issue, the plane being continually put out of trim, is a triage call akin to what a medical professional would be expected to make in a condition where there were more problems to solve than hands or brains to resolve them.
Or how Boeing intentionally changed the functionality of the console stabilizer trim cutout switches in such a way as to prevent pilots from being able to shut out the flight computer's capability to command trim adjustments with the trim motor, but maintaining the pilots' ability to leverage the trim motor to neutralize trim against aerodynamic load through their trim switches on the yoke.
https://www.seattletimes.com/business/boeing-aerospace/boein...
This is one of those cases where we need the layman to be accurately informed at all costs. There is no room for weasel legal maneuvering that we as a society can afford when this comes to trial. The courts have no authority over physics.
But the memory item calls for 75% N1 and 4deg pitch up. Not leaving it at 94% N1
The important takeaway is that no matter which way you look at it, this "you don't need to know" item absolutely needed to be known since new error cases altered the process of "walking the fault tree" had been substantially.
Calling them on the throttle is a bit like blaming a blindfolded man for walking off a cliff with his shoe untied.
Yes, the untied shoe may have tripped him up, but the culprit is still pretty damn clear.
We don't know if MCAS is the only thing keeping the planes in the air, and if it is easily disabled by faulty sensors in their new software update, we don't know how unsafe those planes are.
The MCAS system was known about after the Lion Air crash, and it baffles me why pilots wouldn't have known about successful corrective action taken on the previous flight. After all, I read about this in the newspaper. It wasn't a secret.
It's hard to tell from the newspaper accounts, which often leave off crucial details, but it seems the electric trim switches (on the control column) override the MCAS commands. So the way to recover is to set the electric trim switches to nose up, turn the trim system on at the cutoff switches, wait until it's trimmed out properly, then turn it off via the cutoff switches and let go of the electric trim switches.
Check out the altitude graphic here [1]. It must have been absolutely terrifying, I doubt many of us have the nerves of steel to react so quickly and correctly in such a situation.
[1] https://graphics.reuters.com/ETHIOPIA-AIRPLANE/0100911Q1DX/i...
1. set the electric trim switches to nose up
2. enable the trim via the cutoff switches
3. wait until correct trim is established
4. cut off the trim via the cutoff switches
> I doubt many of us have the nerves of steel to react so quickly and correctly in such a situation
Indeed. That's why, if I was an MCAS pilot, I would have carefully read the reports on what went wrong, what went right with the previous LA flight, how the trim system worked, and what I needed to do if it happened to me.
It's my own life at stake. I don't understand not doing this.
My father used to do acrobatic formation flying with the Air Force. The idea for everyone but the lead is to concentrate on the wingtip of the adjacent airplane and track it. There were incidents where the lead would fly into the ground and the rest of the formation would fly in, too.
Against orders, my dad said he'd be damned if the lead would fly him into the ground, and would keep one eye on the wingtip and the other on the ground. He died as a very old man.
You might also want to read Chuck Yeager's biography. In it he makes a point of not just following checklists, but learning how the airplane systems worked. Saved his life many times. Yeager's still alive, and has buried many of his colleagues who took shortcuts.
The pilots could have also had this reflex training on the effected systems, but Boeing and the regulators decided not to bother with training, and the training they did have was inadequate because Boeing's system was fatally flawed.
> They didn't need to manually trim it:
This procedure you outlined goes directly in the face of Boeing's guidance to 'follow the procedure for runaway trim'. Since the system wasn't documented at all, I assume people would trust that the procedure should work. It's not until the plane is diving into the ground due to uncorrectable trim did they discover the procedure was going to get them killed.
I suspect that will be a crucial point in the NTSB's report.
Your assessment about pilots not being ordered to their deaths is incorrect. My father served as a navigator on B-17s in WW2. He was ordered to fly 30 missions. At the time, the 30 mission survival rate was 20%, as bad as any beach assault.
The aircrews knew this, and it put a terrible strain on them. But they went anyway. My father told me he was convinced he was going to die, made peace with it, and simply decided to do the best job he could before he bought it.
The Luftwaffe pilots had it even worse. There was no 30 mission maximum. It was fly until you die. Not many survived.
I've wondered the same thing. My assumption is that the MCAS disables the input of the trim switches used by the pilots when it's active. We know that MCAS resets itself after certain conditions and 'forgets' what it did previously to override it's intended maximum authority. It's also be stated that the MCAS is 'reset' when the pilot uses the trim switches, but I would think that this would have been abundantly apparent as well: press switch, nose stops going down, unless they just did not notice the trim being activated in the first place (which based on other people's accounts, that would be hard to miss due to a giant wheel).
> Your assessment about pilots not being ordered to their deaths is incorrect. My father served as a navigator on B-17s in WW2. He was ordered to fly 30 missions. At the time, the 30 mission survival rate was 20%, as bad as any beach assault.
Fair enough, that does sound pretty brutal. My point was more about the reflexive training to overcome fear to function. It might be impossible to think critically in such a moment for most people, thus the goal is to put people on 'autopilot' when they encounter a specific scenario.
But, WW2 was USAAF, USAF didn't exist yet, so no way for me to get that context ;)
I can give you a good hunch as to why.
Because the absolute last thing a pilot wants to do with a plane load of people is experiment. That's what a simulator is for.
I stumbled across the "suppress MCAS by trim switch spamming" within the first few seconds after I read a complete description of the system's functionality.
It took a complete description of the problem, and a background in programming/systems design, engineering, and an enthusiast+ level of aviation familiarity to come to that course of action in that amount of time, under ideal information processing conditions, with the initial information uptake immediately prior to the advent of reasoning.
Airline pilots had how to fly, and no information initially that there were dragons there, and even once they knew, they had no way to try to build new situational reflexes due to the lack of availability of accurate MAX simulators, because Boeing fought tooth and nail to get the regulator to agree that they weren't necessary.
They had to manually fault inject on an NG simulator to even get an understanding of the conditions involved.
Military pilot training, from my understamding, bypasses the simulator, and dumps you into the seat of some of the most disagreeable aircraft ever designed, with an instructor who sabotages you regularly, leaving you in a spin, and you have 30 seconds to recover please. Begin.
In that case, it's you, and the a-hole who just put you in a flat spin. Experiment away. Not 100+ innocent civilians depending on your ability to reason through what this damn plane is doing.
Point being, information about the airframe was withheld due to an absolutely crushing need by Boeing for the aircraft to not require even the smallest degree of retraining.
The pilots were absolutely not at fault for not being able or willing to experiment at the drop of a hat with a system they suddenly realized they had no way to understand.
Putting them in that position in the first place is undeniably Boeing's fault.
Indeed. Pilot training should attempt to wash out those people.
There's an audiotape of a test pilot who's airplane went into an uncontrollable spin at high altitude. He was in conversation with the ground, and methodically tried one thing after another, all the way down, voice even and calm to the end. It's astonishing.
I am pretty sure that most if not all pilots are following these things very carefully. As you know well, Boeing has been way too slow to divulge the information necessary for “learning how the airplane systems worked”.
The Lion Air pilots didn’t know how the system works because they could not know. The Ethiopian Airlines pilots did cut out Stab Trim, and later switched it back on, possibly because they know more about the system than you do, and it made sense to them to deviate from the checklist (just the way you advocate, incidentally) - consider the two switches on the NG and undisclosed change in functionality on the MAX. Or maybe it was a CRM mistake, maybe one pilot thought the other one would hold the etrim switch pressed ANU.
We don’t know yet. But it is rather annoying to read from you how you’d have saved the plane so and so, because you followed the story in the newspaper and value your life and all. But, yeah, keep telling pilots to read the newspapers and inform them that they’ll die if their airplane crashes, maybe then we won’t have any accidents anymore.
That graph is based on faulty FlightAware data. According to the preliminary report they were at 7,000 feet AGL and climbing when they re-enabled the electric trim.
This is what I mean when the newspaper articles constantly leave out crucial details. You have to read many articles to get an idea of the complete picture.
It doesn't matter that a third pilot figured out what was wrong and what the corrective action should be. Because after he did it, it was known and all the pilots should have known.
https://theaircurrent.com/wp-content/uploads/2018/11/B737-MA...
You know how else to make it known to pilots? By making it a part of their training materials. But Boeing had significant financial interest in not doing so.
"Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTOUT switches to CUTOUT."
...but not if you follow the procedure set out by Boeing and reiterated in an FAR published after the Lion Air crash. The ET302 pilots recognized that they were dealing with MCAS failure, and followed the procedure, including toggling the trim cutout switches. On 737 NGs, one could turn off trim automation while allowing electrical control from the yoke, but on the Max, the latter was also disabled when these switches were toggled [1]. I don't think this way in which the Max differs from the NG came out until later.
This created a second problem - the trim wheels are very hard to turn manually under the load created by using the elevator to counteract the mis-trim. The procedure in this case is to unload the stabilizer jack-screw by pitching down, but the airplane was not high enough for that.
This might have been apparent if pilots had trained for an MCAS failure, which brings us to a question I had in another thread: Were there any simulators that realistically simulated MCAS failure, or were the simulator manufacturers and operators as much in the dark about MCAS as were pilots and airlines?
[1] https://www.seattletimes.com/business/boeing-aerospace/boein...
I read about this in the newspaper, it wasn't a secret. I do not have inside information.
Again, if I was an MCAS pilot I'd be very interested in following what happened with the Lion Air crash, to ensure it wouldn't happen to me. I'd still follow the procedures set out by Boeing - but when they didn't work I'd do what did work.
It's a little hard to discern from the erratic newspaper reports, but during the time the pilots were fighting the MCAS they were using the trim switches and surely would have noticed that those switches overrode the MCAS.
The reason we have pilots, and not a fully automated airplane, is we need them to think outside of the procedures when the procedures aren't working. This is not impossible as the pilots in the flight prior to the LA crash did have MCAS runaway and did successfully deal with it.
While we certainly hope that pilots will be able to extemporize a solution to a situation, even if that involves going beyond or against the documented procedure, and while it is certainly possible that there was a course of action that could have saved ET302 (though the success of the Lion Air pilots does not necessarily prove that, as there were differences), I do not accept the implication that if such a course of action existed, there is nothing to be concerned about. Reliance on pilots' problem-solving skills should be a last resort, not a planned-for solution, and those skills certainly are not helped by withholding information about aircraft systems.
> I do not accept the implication that if such a course of action existed, there is nothing to be concerned about.
I did not suggest that. Nearly all crashes are the result of a string of failures, including these crashes, and each point needs to be corrected.
> and those skills certainly are not helped by withholding information about aircraft systems.
After the LA crash, that was no longer the case. I reiterate that my information comes from the newspaper. If I was a MAX pilot you bet I'd be much more diligent in finding things out, if only just to save my own hide.
I further find it very strange that after the prior LA flight successfully dealt with the MCAS failure, that the airplane was still deemed flight-worthy and nobody even bothered to inform the next flight crew?
There's plenty of failure that needs to be dealt with all around with those accidents.
Maybe the crew of the earlier Lion Air flight were lucky and had the airplane temporarily back in trim at the point where the deadheading pilot recognized that they had an ongoing trim runaway situation, for which toggling the trim cutout switches was the documented response [1].
I think it is unreasonable to suggest that the EL302 pilots were negligently unprepared. After using the trim cutout switches to disable MCAS, they found they were unable to correct the trim manually, so they did exactly what you suggested in your first post: they re-engaged the electric trim and attempted, unsuccessfully, to re-trim the airplane before it crashed. This suggests a familiarity with the AD issued after the Lion Air inquiry. Maybe if they had not switched the trim off initially, they would have prevailed, but the message from Boeing after the Lion Air crash was that its pilots were at fault because they failed to use the cutout switches.
Given that Boeing was still holding to the line that MCAS failure should be handled as if it were just another case of trim runaway, and that the procedure for that was the same as on previous variants, the pilots could reasonably consider themselves to be well-prepared for the situation - they now knew about the problem, and they had trained for recovering from trim runaway on NG simulators. The AD issued after the Lion Air inquiry says "Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTOUT switches to CUTOUT. Manual stabilizer trim can be used before and after the STAB TRIM CUTOUT switches are moved to CUTOUT", but it says nothing about this differing from the NG, where one can disable faulty inputs while retaining trim-switch control. It also says "If relaxing the control column causes the trim to move, set stabilizer trim switches to CUTOUT" - and it seems quite possible that, in the case of MCAS runaway, relaxing the control column could coincide with the trim continuing to move (and the crew is not in a position to determine causation), at which point, using the cutout switches is prescribed. Finally, this checklist [1] says "If the runaway continues after the autopilot is disengaged: STAB TRIM CUTOUT switches (both) [to] CUTOUT." None of this says anything directly about getting the airplane back in trim before toggling the cutout switches, if that is what is necessary to regain control if this happens close to the surface.
[1] https://www.washingtonpost.com/the-boeing-737-max-8-aircraft...
The critical question here would be would be did they use the electric trim switches, and did they cut off the trim after re-trimming the stabilizer?
> None of this says anything directly about getting the airplane back in trim before toggling the cutout switches,
The FAD did say that directly, and you quoted that part.
> if that is what is necessary to regain control if this happens close to the surface.
It obviously was necessary. It's why they re-engaged the trim system.
Pilots are not robots blindly following procedures - if they were, we wouldn't have pilots on the airplanes, it would be run be a computer. Pilots are expected to have understanding of what the switches do and how to use them.
The wording of the FAD could be improved, but it is not that hard to understand. The electric trim switches override any other inputs to the stab trim, and the cutoff switches prevent powered movement of the stabilizer. Those two facts are all one needs to know to regain control.
On first reading, I also thought the quoted passage from the AD was an instruction to use the yoke switch to re-trim before cutting out the stabilizer trim, but the following sentence (also quoted above) makes it clear that it is not: it is actually part of a statement about what options are available to adjust the trim before and after the switches are set to cutout. I feel sure you will try to argue this point, but I am pretty confident that this is the correct reading, because the checklist has no mention of delaying trim cutout. This is very significant, because the checklist is what pilots are trained and expected to follow (and, furthermore, I believe this checklist is a 'memory item' - one of the procedures that pilots are required to be able to perform from memory.) Nothing in a checklist should be incomplete or ambiguous, nothing of consequence should be taken as read, and if anything is, it is a more serious matter than poor wording.
And the checklist is unambiguous about what to do: if the problem persists after the autopilot is disengaged, use the trim cutout, and thereafter, trim manually - this is what the crew experienced, and this is what the crew did.
It is quite clear from the documentation that the manual trim wheels were regarded as an adequate means of adjusting the trim if the electric trim was cut out. Once the pilots found that this wasn't working, they did extemporize - they re-enabled the electric trim - showing that, contrary to what you insinuate, they did understand what the switches do.
You have set up a false dichotomy between pilots acting as robots and being able to extemporize a solution to every problem from first principles. The reality is that aviation has achieved its unprecedented level of safety by, in part, by considering a great many things that could go wrong and figuring out the optimal responses, taking into account that these responses must be made in a stressful and often degraded (informationally, functionally, physiologically) situation. Pilots are trained, and expected, to execute the documented procedures promptly, and only deviate when the situation demands: extemporize on a check ride, and you are likely to fail. This is not mindless bureaucracy at work: it is the rigorous application of hard-learned lessons. At the same time, they are also expected to know their airplanes thoroughly so that they can respond to unanticipated problems, and this is precisely why they were annoyed at not being told about MCAS.
So, to summarize: 1) by their actions, the crew demonstrated that they were up-to-date on the procedures that nominally incorporated the lessons from JT610; 2) by their responses to a problem with this procedure, they demonstrated that they did understand what the switches did and how to use them. Undoubtedly they did not figure out what they needed to do as rapidly as you would have in their place, but it is unreasonable to fault them for that.
I recently learned that, prior to the Max, the trim wheels were so rarely needed that their use was no longer part of simulator training, and the diameter of the wheels was reduced on the Max, yet here we have an AD saying you can use these wheels to trim the airplane when the electrical mechanism is cut out, and item 6 on the checklist explicitly says to do so. Elsewhere in the AFM it notes that the trim wheels can be hard to move in some circumstances, but if you are going to fault the pilots for not connecting the dots, then it applies doubly so for the people at Boeing and the FAA tasked with writing and certifying the procedures for handling an MCAS failure, who all apparently overlooked something that was obvious to you just from reading some newspaper articles.
At this point, the more you argue that an effective procedure for dealing with MCAS runaway was obvious following the JT610 inquiry, the more you indict Boeing and the FAA for not making it explicit in their response.
[1] https://www.businessinsider.com/ethiopian-airlines-et302-boe...
You would have to pulse the switch in sub-5 second increments depending on the way the switch works.
If it's a direct switch, I.e. switch held down->motor moves, then they'd have to hold it down until trim was neutralized, then cut it out.
If it's a discrete toggle, I.e. each toggle increments/decrements a set point the motor then follows; a pilot would have to be very conscious of their timing on the switches, and how much the stabilizer had actually managed to travel.
Both of these would constitute new, MAX specific skills, that Boeing cannot show any acknowledgement or foreknowledge of without opening a massive can of worms.
That's why I suggested in this thread to activate the cutoff switches when the trim is in the correct position.
The electric trim switches are a hold down => motor moves. It's not a MAX specific skill. Neither are the cutoff switches.
Neat!
>It's not a MAX specific skill. Neither are the cutoff switches.
Well, the cutoff switches functionality was changed according to the Seattle Times, so while the procedure may be shared, the semantic significance of the switches did, in fact, change for MAX.
https://www.seattletimes.com/business/boeing-aerospace/boein...
It remains crazy how much this procedure would have required the pilots to do. It's utterly senseless how bad cockpit automation remains in 2019. If Boeing was going to add a bunch of code to the cockpit, they should have made flying the plane in an emergency easier, not harder.
But would "the procedure" actually have saved the plane? I don't believe so. WalterBright is arguing that the pilots should have known better than "the procedure" and done something different from what the checklists and memory items proscribed. I can't comment on doing so — as I'm not an airline pilot — but to put blame on pilots in this sort of situation without acknowledging Boeing's actions is beyond tasteless.
IMHO Boeing is 100% responsible for the deaths.
I said "pick on" the pilots, not "blame" them. There were a lot of bad things that added up. In the case of the Lion Air flight, the maintenance staff signed off on the plane even though they were aware the angle-of-attack sensors were completely broken, which had nearly caused a crash on the previous flight. The previous flights' pilots also either didn't report this incident, or their report was disregarded. Then when the emergency occurred, the pilots didn't know what to do. There are many reasons that that any plane's trim system could have malfunctioned, and the black box data suggests the pilots would have been unable to manage any of them. So the plane was taking off in an non-airworthy state with pilots who didn't know how to deal with a common system failure and weren't told that a system had just malfunctioned hours previously on this exact aircraft. The MCAS failure was a match thrown into a kindling box of bad circumstances.
The LionAir crash was a tragedy. The Ethiopian Airlines crash was not just a tragedy; it was a complete systemic failure to appropriately react.
> tasteless
When you're trying to make airplanes safe, matters of taste, politics, emotions and legal culpability have nothing to do with it. The NTSB has a very good track record of dispassionately sticking to the facts, and I am looking forward to reading their report.
Here's the deal, though: this wasn't just one crash. It was two. The failure mode of the second was indeed different than the first: it was a failure of Boeing and the aviation authorities to appropriately respond to the first disaster.
To propose that pilots should have willy-nilly flipped MCAS on and off based on your reading of the news is just staggering. What if there was another bug where turning on MCAS when there was an AoA disagree led to an instant plunge, regardless of etrim inputs? I'd bet you'd be critiquing those dead pilots for not following the checklist — and keeping MCAS off — in such a case.
It's not willy-nilly nor staggering. The EAD (referenced in another post here) indeed talks about using the electric trim to fix the nose down problem, and then cutting off power to the system.
My point is that it's easy to armchair quarterback the pilots whether they followed the checklist or went off checklist to do something better or worse. The problem started long before they got in the cockpit, though, and had been made evident once before at the cost of 189 lives. To continue to focus on pilots' actions at this point is missing the elephant for the flea.
The EA pilots already had gone off the checklist when they turned the stab trim back on.
So add in the part where you can’t actually trust what your instruments are telling you, and the plane is flying like a demon has possessed it.
In the moment you are wondering, is the plane stalling? Is my airspeed actually what is being displayed? Why is trim not responding? My heart is beating 200bpm. Is that whooshing the blood in my ears or the wind?
The answers to these questions is obvious in hindsight. In that moment the flight had entered mortal peril. The question is not why didn’t the pilots recover from mortal peril with perfect hindsight. The question is how did this flight get into mortal peril in the first place?
One thing to keep in mind: it’s not like there’s a big sign popping up saying “hey, AoA is faulty, MCAS is trimming down the nose, unless you set Stab Trim switches to cutout. What do you want to do?”
Instead, you have stick shaker activation during climb out, EICAS warnings, chaos, and you struggle to bring things under control by putting the plane into a stable, manual, mode (autopilot off, flaps up, ...), and then MCAS kicks in surreptitiously, more or less (you have the trim wheels turning, but a lot of other stuff is going on), and trims your nose down.
> it baffles me why pilots wouldn't have known about successful corrective action
They did, and they flipped the stab trim switches to cutout, but they didn’t manage to overcome the required forces on the trim wheel to trim properly, and switched the stab trim back on. Now, there was the other issue with there being two stab trim switches on the NG with different function, which, if I understand correctly, would allow you to reenable the electric trim switch on the yoke while keeping the automatic stab trim disabled - but on the MAX apparently those two switches are identical, without that having been mentioned, to avoid recertification (I haven’t seen any proper elucidation of that yet - if you have two identical off switches, do you need to set them both to off, or only one, to turn it off?). I wonder (and again, haven’t seen anything about that yet) whether they flipped one of the switches back on, to get the electric trim support, deeming themselves safe from MCAS as the other one was still cut out, only to be foiled by the aircraft.
Edit: It's likely true, but surely nearly every airline had a pilot 'warn of dangers'. But why is this a news story being promoted?
I'm not seeing how this is beneficial for Boeing.
In both crashes, one of the two Angle of Attack sensors was incorrect. Boeing only use one AoA sensor per flight (alternating for some bewildering reason), and in this particular flight it was constantly incorrectly stating the plane was nearing a stall. So MCAS would continually kick in until the Pilot could no longer keep the plane in the air.
That tendency also exists on Classic and NG 737's, and is something pilots are trained to compensate for. The issue with the MAX is the degree of this tendency changed. MCAS was meant to emulate the old (less severe) behavior.
https://www.wsj.com/articles/faa-saw-737-max-flight-control-...
In that particular emergency, the control surfaces prevent it from gliding. You can even have issues on a Cessna - loss of elevator is not fun.[1]
It's not about "denying physics", it's about having insufficient redundancy[2] and improper amount of control from MCAS - 3 times more than the FAA approved: [3]
No plane is 100% safe. Boeing made this one worse for the sake of saving money - the physics work out just fine, and gliding ability is not really impacted. (But I don't think it'd be a normal response - I can't imagine a pilot thinking "oh, I'm getting a stall warning with nose down at 4,000 feet, I know, I'll cut power and glide".)
[1] https://airfactsjournal.com/2018/12/elevator-failure-at-4500...
[2] https://www.seattletimes.com/business/boeing-aerospace/a-lac...
[3] https://www.seattletimes.com/business/boeing-aerospace/faile...
[1] https://www.seattletimes.com/business/boeing-aerospace/u-s-p...
> Jon Weaks, president of the Southwest Airlines Pilots Association, said Monday the airline and the pilots “were kept in the dark.”
“We do not like the fact that a new system was put on the aircraft and wasn’t disclosed to anyone or put in the manuals,” he said in an interview. What’s more, he noted, Boeing and the Federal Aviation Administration have now warned “that the system may not be performing as it should.”
[2] https://theaircurrent.com/aviation-safety/what-is-the-boeing...
> "Since it operates in situations where the aircraft is under relatively high g load and near stall, a pilot should never see the operation of MCAS. As such, Boeing did not include an MCAS description in its FCOM. The explainer continues: "In this case, MCAS will trim nose as designed to assist the pilot during recover, likely going unnoticed by the pilot."
There is another explanation, according to a Tuesday report in The Wall Street Journal: "One high-ranking Boeing official said the company had decided against disclosing more details to cockpit crews due to concerns about inundating average pilots with too much information - and significantly more technical data - than they needed or could digest."
This is not simply a case of regulatory capture, the FAA simply doesn't have the expertise and in-depth knowledge to perform completely independent verification. Requiring the FAA to do so might be prohibitively expensive, so this arrangement is the result of pragmatic realism more than regulatory capture. It does require a great amount of trust between all partners though, and it seems to me Boeing has been more than happy to skirt their responsibility in this case.
Perhaps the airplane manufacturer and certifier should be separate manufacturers?
How is the NHTSA able to certify crash tests for every make and model vehicle sold each year?
[1] https://www.seattletimes.com/business/boeing-aerospace/faile...
This completely missing the point of independent certification, validation, and acting as a proxy for the "customer of first resort" is the entire point of a regulator. If you can't sell an independently staffed regulator on your design, flying their own test regime, you shouldn't be making planes period. The new regime basically relegated the FAA to the role of paperwork auditor; a reactive instead of proactive regulatory process.
There’s a separate system of punishment for them involving their children hating them and acquired learning disabilities from cognitive dissonance. (Not a joke these are actually the primary mechanism by which America holds that class in check).
See for example the Theranos board. Living as a CEO/power broker type can lead to debilitating dementia in middle age.
This is one of the reasons we so rarely see middle managers drop back down into individual contributor roles. Early dementia literally inhibits the clear thinking required for production work. In a leadership role they can rely on the management hierarchy for executive function, but lose the ability to do it alone.
Bravo!
Even if you don't have academic sources, that greatly crystallized many anecdotal observations I've collected!
EDIT: What? I'm not even being sarcastic or tongue in cheek. I've seen the aftermath of what the poster has described many times in my career in terms of cognitive shift occurring in certain roles.
I'm not being judgemental even, one way or another, but I've run into a phenomena similar when trying to get something across to organizational leaders, to the point of having to conduct meetings behind closed doors and refusing to end the meeting until the point can be successfully communicated from all involved.
As to whether it is a learning disability or not, no comment, but there is definitely an effect on capability to reconcile organizational reality with physical reality.
If you haven't run into it, I suppose I must just be either the luckiest or unluckiest fellow on the planet. I'm still not sure whether or not there is an unwritten acknowledgement or tacit agreement to not call out or discuss the phenomena, because it never seems to make anyone comfortable. Whereas I find the idea liberating, because it means there is at least a reason for communication difficulties that is possible to overcome, even if it isn't terribly fun for everyone involved.
It's one thing to disagree, or to not have access to certain information to reason on.
It's another completely to know, and knowingly deceive, feign ignorance, or go out of your way to avoid having to come to terms with something.
And yes, I understand my view does not make me super popular in some circles, where fast and loose with the truth is more the norm.
"What were they doing flying our planes if they didn't want to crash?"
[1] https://www.seattletimes.com/business/boeing-aerospace/u-s-p...
> Jon Weaks, president of the Southwest Airlines Pilots Association, said Monday the airline and the pilots “were kept in the dark.”
“We do not like the fact that a new system was put on the aircraft and wasn’t disclosed to anyone or put in the manuals,” he said in an interview. What’s more, he noted, Boeing and the Federal Aviation Administration have now warned “that the system may not be performing as it should.”
[2] https://theaircurrent.com/aviation-safety/what-is-the-boeing...
> "Since it operates in situations where the aircraft is under relatively high g load and near stall, a pilot should never see the operation of MCAS. As such, Boeing did not include an MCAS description in its FCOM. The explainer continues: "In this case, MCAS will trim nose as designed to assist the pilot during recover, likely going unnoticed by the pilot."
There is another explanation, according to a Tuesday report in The Wall Street Journal: "One high-ranking Boeing official said the company had decided against disclosing more details to cockpit crews due to concerns about inundating average pilots with too much information - and significantly more technical data - than they needed or could digest."
Now, clearly that didn’t work very well, and there are many other problems, but I wouldn’t call Boeing’s initial attitude there “lies” or “extremely patronising”.
There's another issue raised here: what sort of training was available? By withholding the existence of MCAS, did Boeing create a situation where there were no simulators with the capability to train pilots in handling an MCAS failure?
It smells like a classic case of under-engineering. In a properly engineered system someone would have asked "What if an AoA sensor fails during flight?" and forced the MCAS to be redesigned. This question would have been asked about every single part of the system before it was deemed ready for production.
But unreflective ill-informed hostile accusations sometimes seen here (“lies”, “care only about profits”, etc.) is certainly neither appropriate nor helpful in avoiding a repeat of the problem.
https://www.youtube.com/watch?v=Pn0WdJx-Wkw
How oblivious and callous do you have to be?