ET302 crash taking off

[IAHM-COL]

https://amp.cnn.com/cnn/world/live-news ... index.html

[HJ1an]

This is ridiculous. Now I'm angry. As I've always said, new isn't better, it just means new unknowns. Now we have this unknown.

[D-73]

These two recent crashes of the 737-max happened both soon after takeoff. I wonder if that is a coincidense. Hope the investigators will find an answer to both of these crashes.

[IAHM-COL]

eerily, these two crashes are similar enough to be hair-rising.

In October, another Boeing 737-8 MAX plunged into the Java Sea just minutes after taking off from Jakarta, Indonesia's capital, killing all 189 people on board the plane Lion Air flight. The cockpit data recorder showed that the jet's airspeed indicator had malfunctioned on its last four flights, though Lion Air initially claimed that problems with the aircraft had been fixed.

Blackbox, I've read, has been found. Intriguing...
Multiple airlines currently grounding their B73X-MAXes.

[HJ1an]

eerily, these two crashes are similar enough to be hair-rising.

The main difference being that for JT610 Lion Air, they should have grounded that particular problem Max in the first place. Instead they continued on, and compounded the problem even though they went through the maintenance check. (Had they turned back and grounded that particular jet and asked Boeing to scrutinize the problem, it wouldn't have happened - *however*, would Boeing have cleared it for airworthiness without fixing the actual issue and then it would happen again? That's the unknown.)

It's like knowing your brand new car steering is loose, and you kept going to your destination anyway. Got someone to take a look at it, and say, oh it's just a loose nut, tightens it and then lets you go on your way without a test drive. That loose nut may only be the symptom to a bigger issue, virbations working it loose, wrong nut size, etc. etc. It happens again on another drive, by another driver, on a longer route... and it becomes catastrophic.

If I had a brand new crar and a critical component such as steering nut worked itself loose, I would take the car back and tell them swap out the part and inform the manufacturer and they test it until i'm fully satisfied. And then no long distance driving for a while until I'm sure the problem doesn't recurr.

The ET302 seemingly had no problems to begin with until its final flight, at least from the sources we can read off of.

[V12]

On Mar 12th 2019 Boeing issued following release with respect to MCAS, Lion Air Flight 610 and Ethiopian flight 302:

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.

Source :
http://avherald.com/h?article=4c534c4a&opt=7681

Why the hell is automatic system "stronger" than pilot's input ? Other words - why trim stabilizer has larger authority than elevators ?

[IAHM-COL]

Why the hell is automatic system "stronger" than pilot's input ?

The ages old question of whether the philosophy behind "fly-by-wire" or "die-by wire" technology is fundamentally sound, or not.

[HJ1an]

Why the hell is automatic system "stronger" than pilot's input ?

The ages old question of whether the philosophy behind "fly-by-wire" or "die-by wire" technology is fundamentally sound, or not.

Yes, whatever happened to pilot having the ultimate control? Boeing screwed up major there.

[HJ1an]

http://www.b737.org.uk/mcas.htm

This site offers some really technical details on MCAS.

I had assumed that the AoA source for MCAS was always the Captains AoA probe but the following explanation from an engineer suggests that it alternates between AoA probes each flight:

MCAS is implemented within the two Flight Control Computers (FCCs). The Left FCC uses the Left AOA sensor for MCAS and the Right FCC uses the Right AOA sensor for MCAS. Only one FCC operates at a time to provide MCAS commands. With electrical power to the FCCs maintained, the unit that provides MCAS changes between flights. In this manner, the AOA sensor that is used for MCAS changes with each flight.

[IAHM-COL]

even USA now grounded the MAXes?!
Wow, things are getting though for the Boeing...

President Trump grounded Boeing’s 737 Max planes Wednesday, following the lead of 51 other countries that have ordered an indefinite freeze on flying the model involved in two calamitous crashes.

The union for American’s pilots, the Allied Pilots Assn., said Tuesday that American’s 737 Max planes are unique because they are the only ones equipped with two displays, one for each pilot, related to the software in question. That provides “an extra layer of awareness and warning,” the union said.