Ethiopian air lines flight goes down all killed

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Originally Posted by JDNSW

According to what has been published, the speed at the time was 360 ->380kts. The trim from full nose down to neutral is 125 turns. I think slowing down was not possible in the circumstances - at that speed even if the elevators were sufficiently powerful, which I gather they are not, the control load would have been impossible for one pilot (the other on the trim).

It seems to me that they were in a virtually unrecoverable situation before they realised it was a serious problem.

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Hi John,
What I'm suggesting is twofold: To slow down from such a high speed (without any control input at all) would move the CP forward (reducing the pitch-down tendency from mach tuck). Remember the elevator only provides part of the total pitch force with a fully trimmable stabiliser. Nevertheless, if they did have difficulty with manual trim, slowing down may have made trimming easier (see my last para).

Part of the checklist requires the autothrottle to be disengaged. This probably happened after acceleration altitude when the autothrottle would have set climb N1. I suspect that this is where the thrust stayed throughout the flight. That would partially explain the high speed.

I have sim in a few weeks. One of the scenarios involves a runaway stabilizer. It's been a long while since I did one of these. I'll let you know the effect of airspeed vs manual trim force. I suspect it will be negligible, as the aeroplane is designed to be trimmable throughout the full flight speed range.

John.

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Originally Posted by Hugh Jars

The opening minute or so of the above video seems to imply that the stabiliser screwjack is to blame, whereas it definitely is NOT.

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No. He merely states that it has been "widely reported". Also, he relates what the ATSB stated, that the jack screw was in the "full nose down position".

The author of the video is a pilot of possibly more hours than you ( sorry, I have no idea how many hours you have, but he states his in subsequent vids. Maybe you should watch. However, I'll bow to your superior knowledge ), and he goes on to quote the preliminary report at length in his vids. He never blames the jack screw. He blames the poor implementation and initial design of MCAS, in particular the non redundancy of that system. He blames pilot error ( like you say, the switches should have stayed OFF, as Boeing said). He blames poor training for the event of MCAS 'runaway' ( my words ), He describes the problem with the autothrottle in take off mode, and clearly describes the issues all of the above would have created for pilots with only 2,000 ft AGL to work with.

He also describes the difficulty actuating manual trim at the airspeed the aircraft had. As a layman, I can only go with what the people who actually fly the things say. He is one of them, although I believe his currency is on the 777.

And people want self driving cars... If Boeing can't work out automation, you can be damned sure that neither can Google.

Meanwhile, Boeing is losing a reported 70 MILLION a day. Can you still travel to Europe by sea?

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Originally Posted by Hugh Jars

Hi John,
What I'm suggesting is twofold: To slow down from such a high speed (without any control input at all) would move the CP forward (reducing the pitch-down tendency from mach tuck). Remember the elevator only provides part of the total pitch force with a fully trimmable stabiliser. Nevertheless, if they did have difficulty with manual trim, slowing down may have made trimming easier (see my last para).

If they could not trim, and control force required prevented lifting the nose with elevator, wouldn't the only way of slowing be to reduce thrust - which I presume would cause some pitch down? In any case, by this stage the nose was well below the horizon, so this may not have made much difference.

Part of the checklist requires the autothrottle to be disengaged. This probably happened after acceleration altitude when the autothrottle would have set climb N1. I suspect that this is where the thrust stayed throughout the flight. That would partially explain the high speed.

Yes, I assume something like that - the control issue clearly had nothing to do with the thrust setting, so there would be no reason to touch it.

I have sim in a few weeks. One of the scenarios involves a runaway stabilizer. It's been a long while since I did one of these. I'll let you know the effect of airspeed vs manual trim force. I suspect it will be negligible, as the aeroplane is designed to be trimmable throughout the full flight speed range.

John.

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Thanks. While I have limited experience, never having flown anything with more than one engine, I got my PPL in 1967, and still maintain an interest in aviation, although I have been inactive for nearly twenty years.

What's scary here is that the aircraft systems clearly fought the pilots. We can argue until we are blue in the face, but the system fought the pilots, and it did so due to apparently faulty inputs. MCAS used data from ONE AOA sensor, and ignored the other, if the preliminary report is to be believed. The 737/8/9 Max is grounded on the basis of the prelim report, and events prior. The MCAS system would seem, on first basis, to be at fault here. Remember, the Ethiopian flight was not the first to crash. MCAS has been blamed for the LionAir Flight 610 crash as well.

Boeing is in very deep ****. So they should be. Airbus have been criticised about their cockpit layout. "Sully" has picked them up over Air France Flt 447, and so he should. He is absolutely correct that stick inputs on one side should be replicated on the other side. 447 proves this.

Boeing has failed us. They have put a system in place that overrides pilots. 189 people died on LionAir 610, and 157 on Ethiopian 302. Boeing is in spin control. It is not good enough.

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Remember, the Ethiopian flight was not the first to crash.

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There can be no argument that Boeing has a lot to answer for, but as I have posted previously, (not sure if it was on here) there are 350 B737Max in service, of which only 2 have crashed, and it has to be said, both of them in 3rd World countries.

Where did Boeing's 737 MAX go wrong?
Boeing's billion-dollar bungle has tainted American aviation prestige — how will it recover? - ABC News (Australian Broadcasting Corporation)

It has become clear that the issue stems from the design criteria - no new pilot training, extend the current 737 certification (a new design would face a lot more costly and time consuming certification process). It seems to have been allowed to get through as a result of the close relation between Boeing and FAA, but as pointed out, no aviation authority in the world has enough money to technically supervise a company like Boeing.

However, it seems Boeing has failed to maintain the expected level of expertise expected, specifically in designing a flight critical system that depends on a single sensor. While it is unreasonable to expect the FAA to have spotted this, they are tarred with the same brush.

Something is inherently wrong with Boeing's work practices. Warning bells must ring when a new factory is opened, and the stipulation is, no union employees. Tales of defective parts taken out of bins and fitted to aircraft to make deadlines , if there is anything 3rd world, that's it.

Boeing 787 Dreamliner: complaints of shoddy work on another jet

What sort of monkeys have Boeing got writing their control software or whatever you call it in a jet. How can the guy writing not see that a single sensor failure will cause a crash & then not report it/do something about it? Maybe the software is written by committee. I work as a control systems software engineer & something like this would be 'what if'd' to death & tested off line to destruction before it went live. It is completely unfathomable to me that this has been allowed to happened. Somebody or a whole bunch of somebodys need to be locked up for this. Boeing have obviously become blase over their position in the industry & no regulatory body has the means or the will to challenge them.

So much for software to prevent the pilot killing the passengers! Must have been terrifying for the pilots, not to mention the pax.

What puzzles me is how Boeing could think it was acceptable to fit bigger engines upsetting the balance of the plane, install a system to automatically push the nose down and then not train pilots or even mention it in the manual. The charitable explanation is sheer incompetence.