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Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

bbc.co.uk

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Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#91

Post by skrebbel »

jakecopp wrote: post #58
vfinn wrote: post #46

Every time I read about these plane accidents, I wonder why planes don't have any emergency features to save these people. Couldn't you build a plane that would eject the cabin as a parachute module or something. Yes, I'm sure this is naive, but why? Edit: My point is that almost anything is better than crashing down with the plane.

Hard engineering problem - where do you open up the fuselage to get the people out? It's a tube so you can't weaken it. You also can't open a hole at the back and let them slide out backwards, you'd need a cylindrical tube in a tube which can then slide out. That's a HUGE amount of extra weight and complexity. Planes are so so much safer than cars. Before we parachute people out of passenger planes we should be eject…

> Before we parachute people out of passenger planes we should be ejecting people out of the roofs of cars if an imminent collision is detected :)

I'd be "accidentally" driving into a lot of trees if cars had that. Sounds like major fun!

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#92

Post by Neil44 »

prmph wrote: post #61

Maybe this is a naive question, but why can't the automated controls on plane be designed such that: 1. They can be independently disabled? 2. For MCAS in particular, disabling it will automatically revert to the previous trim level before it shuts off? 3. They can rely on sensors that are kept in enclosed storage (thus much less likely to fail due to freezing, etc) and immediately deployed when there is a problem wi…

I guess it would be the complexity of the troubleshooting procedures involved if every feature had it's own disabler. You only have a short time under high pressure to resolve these issues so I can see that fewer, broader stroke options would be better.

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#93

Post by sundvor »

Tor3 wrote: post #68
cdolan wrote: post #51

Earlier quoted context omitted.

How can you say “no training” caused this second crash after reading the article? Did you read the article?

(Edited) They had training (and sundvor didn't say otherwise), but still, remember Boeing's decision that little or no re-training for the Max was needed for pilots already having 737 training. See e.g. https://edition.cnn.com/2019/03/22/politics/boeing-737-manua...

Thanks, that was what I was referring to. Cheers.

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#94

Post by tialaramex »

vfinn wrote: post #46

Every time I read about these plane accidents, I wonder why planes don't have any emergency features to save these people. Couldn't you build a plane that would eject the cabin as a parachute module or something. Yes, I'm sure this is naive, but why? Edit: My point is that almost anything is better than crashing down with the plane.

The mass involved is far too great to be practical for parachute descent. Also, when are you going to "eject" this parachute module? Most serious accidents happen in the phases of flight very close to the ground, take off and landing. But just deploying a parachute won't work when you're so close to the ground. Try it for yourself if you like, buy a parachute, attach it, and jump off a ten story building. Your corpse will be surrounded by as-yet undeployed parachute fabric at the bottom.

A fighter jet gets around the being too close to the ground problem by adding a rocket motor. When you "eject" the rocket shoots the pilot's entire seat into the sky first. If you want to eject the entire cabin you're going to need a very big rocket.

Not crashing the plane is better. The goal is to not crash the plane whereupon this is all irrelevant. If you're wondering why that wasn't enough for fighter jets the answer is that the other guy's fighter jet is trying to shoot yours out of the sky. Planes don't fly once you put enough bullets into them. How many is "enough"? Well it may be prudent to eject before getting a firm answer.

Small prop planes can fit parachutes that try to save the whole fuselage, these have been seen to work at least sometimes, but they're very much a last ditch, they are expensive and they're only "practical" (if that's even the right word for something so expensive and relatively ineffective) for small planes.

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#95

Post by sundvor »

cdolan wrote: post #51
sundvor wrote: post #23

Earlier quoted context omitted.

Yep, the issues started way earlier than the software. In fact the software is at the very end of the chain here, unless you also want to insert "no training". It all started when they wanted those big engines crammed into an airframe not designed to hold them, so as to try to quickly catch up to shifting market demands being met by Airbus.

How can you say “no training” caused this second crash after reading the article? Did you read the article?

I'm talking about a chain of causes here. There are clearly multiple factors at play.

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#96

Post by vfinn »

russdill wrote: post #65
vfinn wrote: post #46

Every time I read about these plane accidents, I wonder why planes don't have any emergency features to save these people. Couldn't you build a plane that would eject the cabin as a parachute module or something. Yes, I'm sure this is naive, but why? Edit: My point is that almost anything is better than crashing down with the plane.

Go look up some of the recent airliner incidents. It doesn't appear that parachutes would have helped very many, if any. To make matters worse, such a feature would greatly cut down on passenger numbers per plane, which means more flights, which means more accidents. https://en.wikipedia.org/wiki/List_of_accidents_and_incident...

True. Quite many incidents / accidents during the takeoff. Also, crashes into mountains seem common as well. Not sure what the reaction time is in those cases.

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#97

Post by qaq »

mhandley wrote: post #7

Will be interesting to see the details when the report is actually public. It does sound like the scenario that Mentourpilot explored in the simulator is close to what happened, namely: Bad AoA probe causes MCAS to trim down, and also to indicate IAS disagree. Pilots increase throttle as per non-normal checklist to reduce the risk of stalling due to unreliable airspeed. Pilots disable electric stabilizer trim, as per…

Why speculate here's memory item (pilot should know without looking at the manual) for all 737s for runaway stabilizer. Do you have any information they followed this. All published information we had was specifically that they did not follow the procedure:

CONTROL COLUMN - HOLD FIRMLY

AUTOPILOT (if engaged) - DISENGAGE

Do not re-engage the autopilot. Control airplane pitch attitude manually with control column and main electric trim as needed

If the Runaway Continues

STAB TRIM CUTOUT SWITCHES (both) - CUTOUT

If the Runaway Continues

STABILIZER TRIM WHEEL - GRASP and HOLD

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#99

Post by mhandley »

qaq wrote: post #97
mhandley wrote: post #7

Will be interesting to see the details when the report is actually public. It does sound like the scenario that Mentourpilot explored in the simulator is close to what happened, namely: Bad AoA probe causes MCAS to trim down, and also to indicate IAS disagree. Pilots increase throttle as per non-normal checklist to reduce the risk of stalling due to unreliable airspeed. Pilots disable electric stabilizer trim, as per…

Why speculate here's memory item (pilot should know without looking at the manual) for all 737s for runaway stabilizer. Do you have any information they followed this. All published information we had was specifically that they did not follow the procedure: CONTROL COLUMN - HOLD FIRMLY AUTOPILOT (if engaged) - DISENGAGE Do not re-engage the autopilot. Control airplane pitch attitude manually with control column and m…

From today's Ethiopian Airlines press release:

"The preliminary report clearly showed that the Ethiopian Airlines Pilots who were commanding FlightET 302/10 March have followed the Boeing recommended and FAA approved emergency procedures to handle the most difficult emergency situation created on the airplane. Despite their hard work and full compliance with the emergency procedures, it was very unfortunate that they could not recover the airplane from the persistence of nose diving. As the investigation continues with more detailed analysis, as usual we will continue with our full cooperation with the investigation team."

Edit: perhaps you're refering to the LionAir crash, where they didn't disable stabilzer trim?

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#100

Post by ajuc »

DanielBMarkham wrote: post #16

There you have it, folks, programmers killing people. No, it wasn't on-purpose, but that doesn't mean it didn't happen. This, of course, has been happening for a long time, it's just getting more and more obvious now. I feel strongly that AF 447 was an example. It's important to understand that this is the natural result of two trends. One, software/hardware systems continue to become more and more complex, many time…

> There you have it, folks, programmers killing people.

Programmers were killing people since before we had electronic computers.

IBM did punch-card system for mechanical computers for managing people in nazi death camps.

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