Posted on 04/03/2019 7:18:49 AM PDT by WhoisAlanGreenspan?
Pilots at the controls of the Boeing Co. 737 MAX that crashed in March in Ethiopia initially followed emergency procedures laid out by the plane maker but still failed to recover control of the jet, according to people briefed on the probe’s preliminary findings.
After turning off a flight-control system that was automatically pushing down the plane’s nose shortly after takeoff March 10, these people said, the crew couldn’t get the aircraft to climb and ended up turning it back on and relying on other steps before the final plunge killed all 157 people on board.
The sequence of events, still subject to further evaluation by investigators, calls into question assertions by Boeing BA, -1.56% and the U.S. Federal Aviation Administration over the past five months that by simply following established procedures to turn off the suspect stall-prevention feature, called MCAS, pilots could overcome a misfire of the system and avoid ending in a crash.
(Excerpt) Read more at marketwatch.com ...
We're supposed to get some more info this week, but if true that they did disengage the MCAS and still couldn't recover in time... Wow.
… according to people briefed on the probe’s preliminary findings. …Right, and the common denominator of Mahometanism had absolutely nothing to do with it. “(A)ccording to people briefed on the probe’s preliminary findings.” Yup.
Turn off the MCAS, Hal.........
I’m sorry, I can’t do that, Dave..................
Article states that the aircrew re-engaged the MCAS. If MCAS led to a runaway trim condition, there are two switches located between the pilots that can disengage the automatic trim allowing for manual trim inputs. The flight data recorder would indicate if the trim was disengaged.
I think part of this story (yet to unfold) is the altitude/timing that was given to the aircrew. Maybe if they’d had another 5,000 feet, it would have made a difference in recover time.
EETimes assessment of the problems with 737 Max.
Written by engineers, for engineers.
They feel it is a airframe design flaw caused by moving new engines forward.
https://www.eetimes.com/document.asp?doc_id=1334482
After turning off a flight-control system that was automatically pushing down the plane’s nose shortly after takeoff March 10, these people said, the crew couldn’t get the aircraft to climb and ended up turning it back on and relying on other steps before the final plunge killed all 157 people on board.
...
The trim wheels can take some strength to turn manually, but both pilots can work together to do it. Some FReepers are allowing themselves to be mislead by the media on this story.
I’d rather go with the opinion of a 737 pilot.
https://www.youtube.com/channel/UCwpHKudUkP5tNgmMdexB3ow
Does ANYONE have numbers on the 737 Max?
How many were in service?
Total number of successful TO’s and landings.
How many times did this same problem occur?
I understand ONE crash is too many if it is a systemic issue. I just want to know if these were 2 in a 100 flights, 2 in a 1000 flights, 2 in 10,000 flights, or 2 in 100,000 flights.
How great was the risk Boeing subjected passengers to?
My hypothesis is neither one of them knew much about flying the aircraft manually, and had no idea the trim had been adjusted to put the nose down.
A pilot would have to be really bad not to notice the trim moving automatically. The wheels are large, right next to the arms of both pilots, and make noise when they turn.
I had heard something about this. The idea is that you should be able to basically balance an airplane (front to back) at a point on the fuselage around the center of the main wings. If they moved that point farther forward, it almost suggests the plane needed the addition of a canard wing to compensate.
Trying to save money to avoid all the testing, etc. by making it a different airplane, they may have pushed the “modifications to an existing airframe” envelope too far on this one.
If they moved that point farther forward = farther BACKWARD.
i.e. it sounds like the plane is nose heavy, and the programming may not have accounted for it properly.
You have to hand crank the manual trim wheel. It takes many many turns to accomplish what a click of the trim button will do.If they have never done it maybe they didn’t understand how hard it is. When they turned the auto system back on they sealed their fate. I put it down to a combination of panic and poor training. (30,000 + hours, most of it in Boeings)
This is why Boeing is working with the FAA (and likely EASA) on a fix. That fix is currently (probably) “base tested” on the 737 MAX 7 prototype and will soon be expected to be tested on the 737 MAX 8 and 737 MAX 9 planes.
“i.e. it sounds like the plane is nose heavy, and the programming may not have accounted for it properly.”
You can come out of your cave, now.
is there no such thing as unassisted positive pilot control of an aircraft of this type? it would seem (to me a layman) that there ought to be a way to turn off all the automated systems in an emergency.
You can come out of your cave, now.
Exactly. Probably programmed to override the pilots.
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