In one of the "Air Crash Investigation" episodes one of the investigators said they internationally do not watch any kind of news before examining the crash siteYes the fake news media would pollute any investigation.
safty critical with one sensor? ouch! idealy you want 3 so you know who to trust.
For the past several months and in the aftermath of Lion Air Flight 610, Boeing has been developing a flight control software enhancement for the 737 MAX, designed to make an already safe aircraft even safer. This includes updates to the Maneuvering Characteristics Augmentation System (MCAS) flight control law, pilot displays, operation manuals and crew training. The enhanced flight control law incorporates angle of attack (AOA) inputs, limits stabilizer trim commands in response to an erroneous angle of attack reading, and provides a limit to the stabilizer command in order to retain elevator authority.
[...]
From the video at #376:
"[...] The software fix is going to require this flight control system to rely on data from TWO sensors, it previously was only dependent on one [...]"
Really? The MCAS is reading only one sensor? That seems unbelievable to me. The engineers at Boeing no more no less, should have known better.
I think the idea will be to cross-check the two sensors for agreement, if they disagree then disable MCAS and issue a warning to the pilots.
• IAS DISAGREE alert.
• ALT DISAGREE alert.
• AOA DISAGREE alert (if the option is installed).
• FEEL DIFF PRESS light.
I think the idea will be to cross-check the two sensors for agreement, if they disagree then disable MCAS and issue a warning to the pilots.
From reply #339:Quote• IAS DISAGREE alert.
• ALT DISAGREE alert.
• AOA DISAGREE alert (if the option is installed).
• FEEL DIFF PRESS light.
AoA DISAGREE is (was?) an option!
But then, the second AoA what for was there? For decoration?
^ I don't get how this is even a cost issue. It seems much more like an oversight.
Boeing have been working on a software modification to MCAS since the Lion Air accident. Unfortunately although originally due for release in January it has still not been released due to both engineering challenges and differences of opinion among some federal and company safety experts over how extensive the changes should be. Apparently there have been discussions about potentially adding enhanced pilot training and possibly mandatory cockpit alerts to the package. There also has been consideration of more-sweeping design changes that would prevent faulty signals from a single sensor from touching off the automated stall-prevention system.
Somebody remind me why MCAS is even needed?
This 737 max 8 is presumably empty, but none the less, wow an impressive climb.
ET302 took off like a bat out of hell, hard vertical climb for the first few seconds after takeoff so I wonder if a sensor was not working right from the start.
On the horizon i can see a large number of relatives preparing to sue Boing.QuoteBoeing have been working on a software modification to MCAS since the Lion Air accident. Unfortunately although originally due for release in January it has still not been released due to both engineering challenges and differences of opinion among some federal and company safety experts over how extensive the changes should be. Apparently there have been discussions about potentially adding enhanced pilot training and possibly mandatory cockpit alerts to the package. There also has been consideration of more-sweeping design changes that would prevent faulty signals from a single sensor from touching off the automated stall-prevention system.
Somebody remind me why MCAS is even needed?
This 737 max 8 is presumably empty, but none the less, wow an impressive climb.
Read this Twitter thread for an interesting take on the root causes. Fuel prices/economic considerations led to a cascde of band aid design and sytems changes each one an attempt to compensate for problems introduced by the prior. The “software patch” is just the latest.
I won’t be surpised to see more of these kind of economics/complexity/systems problems in socierty going forward as there is more and more pressure on engineers to provide technology fixes to underlying economics/resource problems.
I suspect that in reality, Boeing will implement some fixes and there will be some training, and the MAX will ultimately become a safe airplane like the rest of the 737's.
Actually, the MCAS was needed in part *because* of those powerful engines. They are more powerful and mounted farther forward than the engines on other 737s, so their power generates a higher turning moment that wants to push the nose up, so the danger of a stall is increased. Furthermore, once you the AOA very high, the nacelles themselves generate some lift (again, with a large moment because of the forward placement relative to the center of rotation), and that pushes for an even higher AOA. This is really only a problem once you are already at high AOA, but essentially the engines themselves become a destabilizing force once you get out of the safe zone.
Read this Twitter thread for an interesting take on the root causes.
I'm struggling with this description. It makes it seem like the new engine placement has a tendency to push the nose of the plane up, and that is the main reason for MCAS.