We need to wait for the investigation before we jump to conclusions.
I think that is a good point.
The 737 Max is the same type rating as all other 737. That means the pilots and crew switch back and forth between the Max and non-Max planes — despite the fact that they act very different in certain circumstances.
This was intentional, it saves airlines money to have fewer type ratings.
Besides, so soon after take off there’s very little time to recover when your plane is overriding you attempts to keep it from nose diving into the ground. It’s not as simple as flipping a single switch.
Did the pilots of the Lion Air flight and possibly the Ethiopian Air flight understand what was wrong in-flight and were unable to fix it due to an inability to override aircraft controls?
This is what I am getting out of the discussion so far but maybe I am gravely misunderstanding what's happening? So as a passenger without any knowledge of aviation systems my question is merely whether the pilot gets control over the aircraft when he demands it? Fly-by-wire should at least never lead to autopilot suicide, even if it has to ensure flight integrity to a certain degree due to the technical nature of large, modern aircraft.
Thanks for reading it :) . As you phrased it specifically, I can't disagree with you. But in these systems, the devil is in the details. For Boeing's MCAS, which is like an add-on piece of functionality to the core control system, it seems like an obvious piece which should have a manual override - and it does. The criticism, as I understand it based on Lion Air, is that the override functionality is not obvious and if you were previously a 737 pilot on non-Max variants, you might not know about this or have practiced its use.
However, consider safety systems such as Automatic Ground Collision Avoidance System ("Auto GCAS") or Automatic Air Collision Avoidance System ("Auto ACAS"). These systems are designed as reactions to multiple known cases of human error that have resulted in otherwise under-control aircraft being flown into the ground or other aircraft. They are specifically designed to override a mistaken human. Technically, it's not impossible that pathological failures or spoofing could trigger these automated systems, which would wrest control away from pilots. Should such systems be overridable at all times?
Resolving these kinds of issues does involve some judgment and adopting a philosophy prior to the implementation. Airbus and Boeing, for example, have historically differed in their philosophies, each with reasonable rationale.
I personally favor the approach Boeing has historically used, with AF447 and QF32 illustrating some of the pitfalls of Airbus' approach. For example, as pointed out by ggreer in https://news.ycombinator.com/item?id=19355402 , being susceptible to common mode faults.
However, I still fly on either manufacturer's aircraft without hesitation.
Except that's exactly what it is and then manually setting the trim. The NY times had an excellent article about the procedure:
> The crucial step, would be to reach across to the central console to a pair of switches, and flip the switches off. Those switches disable electric control of the motor that moves the stabilizers up and down, preventing the anti-stall system from exerting control over their position.
https://www.nytimes.com/interactive/2018/11/16/world/asia/li...
You really should watch this video just to get an idea of how catastrophic this error is:
The lion air pilots had 15 mins to disable the automatic trim system and simply set the trim manually. It's turning off a switch and spinning a wheel. Manually setting trim is second nature to student pilots.
They should also have read the log prior to departure and seen the previous four flights had this problem that did exactly this. Quite sure pilot error will be the outcome for lion air.
There's absolutely no difference in procedure here a normal 737. Unsure where you got that idea from.
The procedure to set the trim manually was the same, but I assume that in most flights the actual flywheel is never turned by hand (and thus rarely deactivated). I'm sure most pilots use the fly-by-wire systems or autopilot.
The procedure which was different was the automated MCAS system - pilots who have logged significant hours flying the previous model of 737 would be unprepared for this during an extremely busy phase of the flight.
Ultimately, yes, it was the pilots error when they didn't take the proper actions when the problem first occurred. Nevertheless, we must first take into account why the automated system failed to begin with, and why the pilots made the error (lack of training, sleep, preparation).
This isn't binary, and the fact Boeing is issuing a patch for the software systems as a direct result of Lion Air tells me there is more to the story than just "pilot error".
After the Airfrance airbus incident they also introduced a "patch" to protect the aircraft from erroneous pilot actions leading to stalls when indicators are incorrect, those fixes were certainly not indicative of guilt but just another layer to stop pilots making mistakes.
To put it bluntly only a fool is going to start flipping switches willy nilly. Boeing has a procedure out to handle runaway stabilizer trim, and that's to flip the switches, but the Lion Air pilots did not encounter a runaway stabilizer so why would they go down that checklist and potentially add to their troubles? In the case of the cutout switches, those switches do different things on the NG and MAX (and are thus labeled differently) which potentially adds to the confusion and reduces the incentive to experiment. You're talking about counteracting a system that Boeing hid from pilots — hardly pilot error.
In fact if you look at the FDR data you'll see that the pilots were able to temporarily disable MCAS with the trim buttons on the yoke. Every time MCAS trimmed down, the pilot trimmed up and was able to maintain appropriate trim. That worked, and it seemed like the plane was largely under control (until it wasn't).
Meanwhile the unreliable airspeed indicators were illuminated and one of the stick shakers was going off, and there was probably an EICAS message about the elevator feel system but no actual indication of the underlying problem with AoA was given because Boeing charges extra for that. So, with the assumption that you had the stabilizer trim under control, why would you add to the significant workload by disabling the electrical control of the stabilizer?
I'm struggling to see how you think having to make manual adjustments every 30 seconds is "under control". Check the flight profile, it was never under control.
> the Lion Air pilots did not encounter a runaway stabilizer
What did the pilots on the four previous flights encounter? Did they not follow procedure correctly by overriding it? The trim stabiliser had to be adjusted 23 times during the the fatal flight, this is a solid fact. After a few times it should have been very apparent that there was a problem related to the automatic trim system and switched to manual.
Manual trim would only get adjusted a only few times during a regular flight, it's a very basic skill and the trim wheel itself takes up a huge amount of real estate in modern cockpits.
Sorry but you've written a lot of terribly inaccurate stuff here. Let's see what the report says.
There are dozens of design flaws in modern aircraft, a miniscule amount are unrecoverable following procedure.
The process to manually override trim on a 737 that should have been followed:
https://www.nytimes.com/interactive/2018/11/16/world/asia/li...
Every time MCAS trimmed down, the pilot trimmed up which resulted in two things: MCAS stopped trimming down, and the stabilizer was adjusted up. That's not a runaway situation.
What did the pilots on the four previous flights encounter?
The previous pilots ran into MCAS trimming the stabilizer down inappropriately. They wrote it up as a speed trim (STS) failure. The crew on the fatal flight read STS and was probably thinking STS when they crashed. Unlike the undocumented MCAS inputs, STS can be disabled by moving the control column.
Did they not follow procedure correctly by overriding it?
There was no procedure, MCAS was undocumented.
Manual trim would only get adjusted a only few times during a regular flight
You're almost never going to crank the trim wheels by hand but an NG pilot may be used to having to add input to counter STS.
The process to manually override trim on a 737 that should have been followed:
The pilots were presented with more than just uncommanded trim adjustments, they were presented with multiple, seemingly unrelated, failures. The failed AoA measurement meant they had no idea how fast they were going (new behavior on the MAX, see the repeated queries they made to the ATC), one of the stick shakers was going off (unsure if plane is going to stall and fall out of the sky), and there was probably a warning about the "elevator feel" system on EICAS like on the previous flight.
When faced only with uncommanded trim, sure, they probably would've thought STS because that's the only system Boeing bothered to document. In an ideal world the pilots would've recognized that this wasn't STS. In reality the pilots were busy triaging a variety of symptoms because Boeing did not make appropriate warning / status indications standard equipment on the MAX nor did Boeing actually document that MCAS exists (except in Brazil).
The only error that the Lion Air crew made was in not being clairvoyant.
Dissemination of information about a risk is an entirely separate issue from creating a solution to the underlying flaw.