> and underscores the importance of pilots understanding severe runaway trim recovery procedures.
So we're back to blaming the pilots?
So we're back to blaming the pilots?
Pilots really should have extensive emergency training, but that doesn't mean it's ok for the manufacturer to Add a new failure case to a previously fine aircraft.
I totally misread/interpreted the comment I was replying to, and am entirely in agreement :D ]
In this case the "fix" is called the "roller coaster", but Boeing has removed the documentation regarding this from the manuals - specifically the Pilots could have 100% perfect recall of the entire 737-MAX documentation and it wouldn't have helped.
This is 100% Boeing's responsibility:
* They designed a system that overrode pilot control so that they could avoid a requirement to retrain pilots. MCAS existed specifically to maintain the perception of identical flight behaviour entirely to avoid the need for recertification and training. That is the only reason MCAS existed.
* They had minimal (no?) documentation indicating it existed
* They made a warning system to report that the system was faulty - literally they shipped a broken safety system: the warning was intended to be freely available, but it was incorrectly tied to a costly system, so even though it was meant to be a standard feature, it was not present.
* The recommended recovery technique from their documentation was not physically possible, even when you knew exactly what you were meant to do.
* The only technique to recover - the roller coaster - had been deliberately removed from the training and flight manuals. The pilots who managed to recover were only able to recover because they knew of the "solution" from old manuals that were published online after both crashes had occurred, by some non-Boeing website. Even then the pilots in the article said that they didn't believe it would be possible to recover once you got below 5000 feet.
Now, exactly how was this in any way the pilot's fault? They were fully trained, they had clearly read the manuals provided by Boeing (they knew they were mean to be using the manual wheel thing), the warning system was non-functional due to a construction/software error in Boeing's control software, etc.
From what I can make out MCAS points the plane at the ground, so it accelerates - I don’t know if it also increases thrust but if it’s meant to be anti-stall maybe it does?
The only way to reduce load once you’re at those speeds with a faulty plane (as far as I can understand it) is to keep pointing to the ground and move the trim control a bit, pull up again (which reintroduces the load) to gain altitude, then point down again and repeat until you’ve defeated the unsafe aircraft.
> under the circumstances the captain's decision to ditch into the Hudson River was the better choice, documents released Tuesday by a federal safety panel said
> He also would have had no way of knowing that he would be successful, and therefore would have been risking the possibility of a catastrophic crash in a densely populated area.
From Wikipedia:
> The NTSB used flight simulators to test the possibility that the flight could have returned safely to LaGuardia or diverted to Teterboro; only seven of the thirteen simulated returns to La Guardia succeeded, and only one of the two to Teterboro.
> Furthermore, the NTSB report called these simulations unrealistic: "The immediate turn made by the pilots during the simulations did not reflect or account for real-world considerations, such as the time delay required to recognize the bird strike and decide on a course of action." A further simulation, in which a 35-second delay was inserted to allow for those, crashed.
And you're criticising him for .... what, exactly?
Sully didn't do anything hard from a piloting standpoint. He made the right decision to ditch in the Hudson. Once that decision was made, it was just a long glide. Plenty of room. He had the full Airbus flight control system doing most of the work. Read "Fly By Wire", by Langewiesche, which goes into this in great detail.
The Ethiopian Air pilots faced a very tough problem. They were nosing down for an unknown reason, the standard recovery procedure didn't work, and they didn't have much altitude.
Don't underestimate the accumulated knowledge and experience that gives one the ability to make a series of very important decisions in an extreme stress situation.
Clearly, the condition is recoverable, with simulator training. Throw in a triple redundant AoA sensor on top of the training, plus the inclusion of MCAS implementation details in the training material, and things would likely have had a much higher chance of being dealt with without loss of life.
Would Boeing have had a harder sell? Yes. Would there have been a non-zero chance of losing out on the order? Yes.
Would 300+ people currently be pulp? I think not. I have a great deal of respect for the skill pilots develop. They are only human however, and are therefore subject to the same weakness of not being omniscient.
If MCAS was the bullet, Boeing's opaque communication, and refusal to not game aviation certification regulations was the gun. Of that, I'm fairly certain.
What plays the trigger pull in this sordid affair is the last thing that remains to be declared, but there are some seriously bright neon signs pointing at either somewhere in Chicago, or at the culture as a whole at Boeing.
Let the digging continue. Let's see how deep the rabbit hole goes.
I actually wonder whether anyone with access to the simulator has tried pulsing the trim switches in sub 4 second intervals. Which depending on how the trim switches work, (I.e. are they continuously coupled, or do they act by moving around a discrete set-point) might be able to fend off MCAS by constantly resetting the time until reactivation long enough to give the trim system time to neutralize.
If something like that were done, a recovery below 5000AGL may be possible.
It's not by a long shot the most intuitive approach out there, and it doesn't generalize well, but for the specific MCAS behavior that's been revealed it may work.
(If there's any 737 pilots out there with insight, I'd be giddy if you'd offer some perspective.)
Ignoring this learning opportunity for better general pilot education would be a mistake. Pilots being better trained is always a good thing.
Page 26 in Ethiopia's report: https://fearoflanding.com/files/2019/04/Preliminary-Report-B...