Breaking news: Ethiopian Airlines flight has crashed on way to Nairobi

[Evan]

I'd assume that since 1988 (or since 1985 when this rather unimportant airline ordered their first A320) the alpha protection on board an A320 is described
where it has to be described.

In the A320 manual.

There was no excuse for a pilot not being very aware of the alpha max behavior when that crash occurred. It was in the manual. It was in the training. There is no comparison between that and these 737-Max crashes.

[elaw]

Breaking news: Boeing has conducted a number of test flights with the MCAS software fix: https://www.cnbc.com/2019/04/11/boei...tware-fix.html

Of course they conducted thousands of "test flights" with the previous, defective software. It's just that the pax on those flights didn't know they were test flights.

[TeeVee]

Even respected journals are beginning to pick at the bones of this thing for a another story. Because enquiring minds want to know...

or, there are more skeletons in boeing's closet that are now being revealed because where there's smoke there's usually fire

[Gabriel]

Hm. You should explain your point of view to German Television. I am not able to invent such things!

On serious German News Television, there was a short video which showed... what. Imho the cockpit of a Boeing 737 Max . Do you think one Aviation Enthusiast who works for serious German News Television has constructed a video

which shows two switches in a Boeing 737 Max Cockpit, which are precisely located, and you should keep in mind, I'm not able to show you the exact position in Randazzo's 737 simulator, because I only own his B744 QotS I fsx ..
so, which is precisely located, and you probably don't really know how a B744 cockpit looks like... ,

let's say you take the leftseat, then your right hand is responsible for the throttle quadrant. Then you move your right hand further backwards. In a B744 cockpit then comes a rather big round knob which is the aileron trim knob. Further backwards.

The last two switches which you are able to reach down there at the cockpit floor. Or let's compare it to a car. The ash tray which sits above the cardan shaft, for seat row #2.

There, Heinrich Großbongardt, former company spokesman for Cessna Aviation, showed two switches in a B737 Max.

I don't know if Mr Großbongardt is a jetphotos member, but this topic would be a brilliant occasion to become one.

I like to repeat that, I have not dreamed this video. It was shown either on ARD or ZDF (serious German News Television), one or two weeks ago.

You mean these switches:



These are the TRIM CUTOUT SWITCHES.
Not the MCAS CUTOUT SWITHCES.

Now: re-read my post:

And there are no MCAS switch. The report shows how the MCAS kept making trim inputs even after the trim was disconnected with the cutout switches. Only that the trim, turned off in this way, did not respond to the MCAS commands.

Ok? MCAS kept telling the trim what to do, and the trim did not respond because the crew had used these cutout switches.

[Gabriel]

Now I understand why the Flight Captain of flight #ET 302 on board his 737 Max 8 tried to engage the a/p. He tried to switch off MCAS!

And his 737 didn't allow him to engage a/p.


What the hell. Again, I know nothing about the 737 Max. But what would I do in a B744 simulator by Randazzo
if the B744 a/p does not react,
regardless if with or without warning.

I'd think, what the hell, let me throw this stupid computer out of the cockpit window. Half a second later, I'd try to return to the airport where I took off only minutes ago.

And I'm sure. This is exactly what the Ethiopian Flight Captain tried to do. But MCAS did not allow him to do so.

The rest are known facts.

The MCAS didn't allow the pilot to do what?

The 2 failed attempts to engage the AP that resulted in the 2 AP disengage warnings were BEFORE the MCAS actuated for the first time, and the reason why the MCAS did not actuate at that time is because the flaps were still extended.

Why would the AP not engage? I don't know, it may be because the stickshaker was shaking, because a the AoA reading of one vane was way too high, because there was airspeed disagree, altitude disagree, flight director disagree... I am not familiar with the logic of the AP. But I know that the reason why the AP did not engage was NOT the MCAS.

By the way, the pilot was able to engage the AP some seconds later, when they tried for the 3rd time. They engaged the AP, all was fine, they moved the flaps level to the retracted position, the flaps started to retract, and in the middle of the retraction the AP disengaged (I don't know if it was manually disengaged by the pilot or if it disengaged by itself). The flaps were still retracting by then and continued retracting. Guess what happened as soon as they fully retracted? First MCAS input. AP was off, flaps were retracted.

[LH-B744]

There was no excuse for a pilot not being very aware of the alpha max behavior when that crash occurred. It was in the manual. It was in the training. There is no comparison between that and these 737-Max crashes.

I totally second what you say. Thus, in 1988 the A320 Flight Captain was 'invited' to live in jail for... I don't quite remember.. 10 months?
There are some words which I still can't translate. Fahrlässige Tötung. 2 dead adults and, 1 dead child!

Back to flight #ET 302. The German wiki just is on my table.
'The merits of the 29 year old Flight Captain of ET 302 as a jetpilot are respectable.' That's what people say who are able to say it.
An Ethiopian Flight Captain with more than 8,000 flight hours of experience.

Imho that's clearly more than the minimum to stay alive. Rest in Peace, you young Flight Captain.

[LH-B744]

You mean these switches:

[ATTACH=CONFIG]23433[/ATTACH]

These are the TRIM CUTOUT SWITCHES.
Not the MCAS CUTOUT SWITHCES.
[...]
Ok? MCAS kept telling the trim what to do, and the trim did not respond because the crew had used these cutout switches.

You are a genius. From the description of somebody who never in his life sat in the cockpit of a 737 Max 8,
i.e. by my description,

you knew at once which switches I meant? Or did you find the video which they broadcasted on German News TV. Doesn't matter.

So. Stabilizer Trim cut out. Two switches, 1 for each wing, as I assume. I just try to imagine situations in Randazzo's B744 simulator where I'd use
Stabilizer Trim cut out switches.

Again I only see 1 situation. In case the 744 had an (erroneous) MCAS and I immediately have to turn it off.

One thing is true, you said, there is no switch on this planet which is able to completely AND DIRECTLY switch off MCAS. Right? Don't confuse me, that's what you say. But what if MCAS is not as perfect as everbody thought.
---

Dude, you are definitely not able to imagine how glad I am that with or without my help not a single Boeing 747 will be equipped with MCAS!
You sometimes read the first sentence in my profile? This is my opinion concerning MCAS.

You are person #... I don't know, #25 who I asked questions about MCAS. And really really good answers came back. But one question until today nobody has answered.

The 737-800 is perfect (!) without MCAS.

So, why on earth is a 29 year old Flight Captain with more than 8,000 flight hours (he died on board ET 302), not able
to rescue his 737 Max 8,

regardless if with or without MCAS!

[Gabriel]

You are a genius. From the description of somebody who never in his life sat in the cockpit of a 737 Max 8,
i.e. by my description,

you knew at once which switches I meant? Or did you find the video which they broadcasted on German News TV. Doesn't matter.

I knew these switches from well before you ever mentioned them or saw that video. The were discussed ad-nauseum since the Lion Air crash in:
- The Lion Air preliminary report
- The Boeing letter to operator with the initial, limited explanation of the MCAS.
- The Boeing Service Bulletin telling operators to follow the trim runaway procedure in case of MCAS malfunction.
- The FAA AD mandating the Boeing Service Bulletin.
- The Boeing procedure for trim runaway
- Several YouTube videos.
- Many news report in different news outlets in TV, newspaper and on-line.
- Several blogs, podcasts, etc...
- Several threads in several discussion forums, including the Lion Air and the Ethiopian threads in this forum.

So. Stabilizer Trim cut out. Two switches, 1 for each wing, as I assume.

No. They are labeled. Check this picture.

[brianw999]

. So. Stabilizer Trim cut out. Two switches, 1 for each wing, as I assume

No, wrong. The stabiliser is the small pair of wing like structures immediately below the tail fin and control pitch. The wings are big wing like structures each side of the middle of the fuselage that have a different type of trim system that controls roll.

[KGEG]

The wings are big wing like structures each side of the middle of the fuselage that have a different type of trim system that controls roll.

Give this man a Pulitzer prize.

Sometimes even the basics need to be gone over again.

[Schwartz]

It seems Simon is not giving the pilots/pilot updates by Ethiopian all the benefit of the doubt here.

https://avherald.com/h?article=4c534c4a/0045&opt=0

...

In short my view: It might have been possible to avoid the crash despite the false AoA value and despite MCAS activation, especially with plenty of time available and hindsight. However, without proper preparation and information available, under serious time pressure and a stressful cockpit environment it is well possible, that the humans were well overwhelmed with the scenario, fell victim to startle effect, tunnel view and task saturation and thus were unable to come up with the correct responses to this scenario. This needs a serious review by human factors experts as well as by procedures experts. In addition, I believe the corporate culture within the airline with respect to distribution of crucial flight safety information as well as verifying that such crucial flight safety information has been correctly understood needs a review.

The lack of a complete CVR transcript makes it extremely difficult to understand the sequence of events and just creates a lot of uncertainty and speculation, the release of a reliable transcript, including all sounds that occurred in the cockpit (e.g. the clack sounds of switches, the sounds of rotaries etc. besides the crew and ATC communication) would be necessary to develop a better understanding of what happened.

As a final remark: there may or may not be a link to actions taken by Russia's MAK to suspend the airworthiness certificate of all Boeing 737 family aircraft in 2015 due to suspected constructive deficiencies in the pitch control system, see News: Russia suspends airworthiness certification for Boeing 737s, but does not prohibit operation of 737s It remains unfortunate, that the MAK never provided further details about what constructive deficiency they found and what unsatisfactory reply they received from the FAA in response to their inquiry.

[Gabriel]

Mentour's deleted video is back!!! Well, sort of... Now it is a "generic" video about miss-trim condition with stuck trim wheel due to aerodynamic forces, "completely unrelated" with the 737 MAX MCAS accidents.

The "couch" part of the video is totally new and doesn't include the words MCAS, Ethiopian, accident, or MAX anymore.
The sim part is the same but edited, still most of it is there, I can't tell what parts were removed, except clearly the beginning where the incident started as an unreliable speed event (that's why they are trying to hold 4 degrees).

Also, added post-sim couch part explaining the roller coaster maneuver.

Very worth watching.

[Chris K]

Mentour's deleted video is back!!! Well, sort of... Now it is a "generic" video about miss-trim condition with stuck trim wheel due to aerodynamic forces, "completely unrelated" with the 737 MAX MCAS accidents.

The "couch" part of the video is totally new and doesn't include the words MCAS, Ethiopian, accident, or MAX anymore.
The sim part is the same but edited, still most of it is there, I can't tell what parts were removed, except clearly the beginning where the incident started as an unreliable speed event (that's why they are trying to hold 4 degrees).

Also, added post-sim couch part explaining the roller coaster maneuver.

Very worth watching.

These videos are great. Have to say (as a non-pilot) it's pretty scary to watch pilots fighting the airplane like this, and it's even more eerie knowing that's likely what the Lion and Ethiopian pilots likely battled in a losing effort.

While I realize dealing with a scenario like this happens infrequently (seems pretty clear the MCAS was the initial culprit that put them in this bind in the first place) I was curious if the 737 is particularly tough to handle with a runaway trim issue. And what about designs that are "Fly by Wire". Does that eliminate the possibility of getting into this situation?

[Evan]

Mentour's deleted video is back!!! Well, sort of... Now it is a "generic" video about miss-trim condition with stuck trim wheel due to aerodynamic forces, "completely unrelated" with the 737 MAX MCAS accidents.

The "couch" part of the video is totally new and doesn't include the words MCAS, Ethiopian, accident, or MAX anymore.
The sim part is the same but edited, still most of it is there, I can't tell what parts were removed, except clearly the beginning where the incident started as an unreliable speed event (that's why they are trying to hold 4 degrees).

Also, added post-sim couch part explaining the roller coaster maneuver.

Very worth watching.

I watched them at the beginning of the video struggle with manual pitch and yoke forces. Nobody thought to retard the thrust levers.

15:30 into the video he finally mentions that, as an alternative to the 'roller coaster maneuver", you could always reduce speed.

I involuntarily shouted out "Duh!"

Why are we talking about a procedure to escape from a mistrim at these speeds that is anything other than reducing the speed?

The MCAS scenario is deleterious to situational awareness and results in tunneling concentration to the pitch control rather than the thrust/speed situation. That is the real danger it represents. If the Ethiopian crew had simply reduced thrust, especially at the Vmo alert, they would not have gotten into a mistrim situation that exceeds manual trim ability. You can't fix that. You have to REMOVE the possibility that an erroneous MCAS activation will ever happen, or at least limit the amount of mistrim it can create.

[Gabriel]

While I realize dealing with a scenario like this happens infrequently (seems pretty clear the MCAS was the initial culprit that put them in this bind in the first place) I was curious if the 737 is particularly tough to handle with a runaway trim issue. And what about designs that are "Fly by Wire". Does that eliminate the possibility of getting into this situation?

The trim runaway in the 737 happens very infrequently but is controllable in many different ways. It is not so tough to handle UNLESS a lot of things go wrong. In this video they had to let the trim go runaway, used the cutout switches in a nose-down situation (when you would ideally first trim with the thumb switches and THEN use the cutout), let the plane gain a lot of speed, trim in the wrong direction until the trim wheel could not be moved anymore, and even then the situation was still possibly correctable in a number of ways, some less kosher than others: re-connect the cutout switches to trim nose-up with the thumb switch BUT FOR GOD SAKE IF YOU DO THAT DO USE THE THUMB SWITCH TO TRIM UP!!!, try to move the trim wheel both pilots together (even if it means briefly pulling back with only one hand and not being able to keep the nose up), or reduce speed either by pulling back on the throttles or by pulling up (together if needed) on the yoke to pitch up and reduce speed.

Airplanes with fly by wire are susceptible of trim runaway too (the electric motor can have a short, the hydraulic motor can have a stuck valve) but as far as I know they don't have trim wheel. The backup is a second trim motor so when you cutout the rogue one you have a backup motor to keep trimming. This is a modern innovation that came with the... uhmmm, first version for the DC-9 that entered service at about the same time that tn the 1st version of the 737.