Ethiopian airliner down in Africa

[groundbum]

Originally Posted by mfeldt

So there was a captain unable to quickly grasp what was happening because it was only his/her second flight on the type, and an FO with less than month of experience who couldn't grasp what was wrong??? I'm never going to fly again!

And here I was thinking a 737 was a 737 was a 737 was a 737 ;-)

G

[Rated De]

Originally Posted by N600JJ

Has anyone criticized the work that was done by French BEA re. the analysis of data from AF447 involving both the French national carrier and an aircraft manufactured by European Airbus whose ties with France are well known to all? From a pure France's perspective AF447 was presumably much more critical to France than ET302 may ever be. And I doubt that anyone (sensible) in France feels happy that this is happening to Boeing today....

Certainement pas, nous sommes tous connectés!

Perhaps the CVR/FDR being sent to France may be a tacit recognition underneath pragmatism, that there needs to be other eyes looking at this?

[FCeng84]

Originally Posted by ManaAdaSystem

How large? I have tried to let it trim without counter trimming just to see how far out of trim the aircraft gets. I get more and more back pressure on the yoke but STS keeps trimming.
On top of that, STS trims on all departures, not only in the light aircraft, high thrust aft CG situation.
It’s a weird system that I could do without.

The switch involved is the same one that interrupts pilot electric pitch trim if opposite the column displacement direction. I believe this interrupt is also active on the ground. When positioning the stabilizer for takeoff using wheel mounted thumb switch try moving the column in the opposite direction at the same time to see how far it has to be out of detent before stabilizer motion stops even though thumb switch remains activated. A note of caution that thumb switch input in opposition to column such that the column cutout activates if held for very long may trip a monitor designed to detect persistent contradictory column and trim commands. That might take some explaining. I apologize that I don't know the details on such monitoring (in particular how long the condition must persist before said monitor trips). I'm sure there must be some 737 savvy PPRUNErs out there who know and by the amount of traffic on this thread they are probably monitoring.

[rcsa]

Originally Posted by DaveReidUK

OK, thanks. I wonder why the ECAA didn't ascertain the BFU's capability before announcing that they were sending the recorders to Germany.

Absolute guess here, but Lufthansa have managed and supervised ET's tech and mech support for many years, so it's possible the default response to a problem in Addis is 'send it to Germany', or 'ask the Germans'.

[futurama]

Originally Posted by DaveReidUK

OK, thanks. I wonder why the ECAA didn't ascertain the BFU's capability before announcing that they were sending the recorders to Germany.

I don't think the ECAA is driving this decision to have the black boxes analyzed in Europe, and I didn't see them announcing anything in this regard.

Rather, I think this maneuvering is coming from Ethiopian Airlines -- more specifically, the airline's CEO, who has a lot of influence in the country's aviation sector.

[ChicoG]

Paris/Addis Ababa - Two black boxes from the Boeing 737 MAX aeroplane that crashed in Ethiopia arrived on Thursday in Paris for expert analysis, officials said, as regulators around the world awaited word on whether it was safe to resume flying the jets.

A spokesman for France's BEA air accident investigation agency said the flight data and cockpit voice recorders would be handed over to the agency later in the day.

https://www.iol.co.za/news/africa/et...lysis-19877943

[Cows getting bigger]

To quote a 737 Max pilot:

"..what else don’t I know?"


From https://leehamnews.com/2019/03/13/co...-transparency/

"Herein lies an essential lesson for Boeing: When your reputation depends on safety, it does not matter what has been proven or who is at fault. What matters is that you are seen taking the lead to protect the safety of the public – at all costs."

[ManaAdaSystem]

Originally Posted by FCeng84

The switch involved is the same one that interrupts pilot electric pitch trim if opposite the column displacement direction. I believe this interrupt is also active on the ground. When positioning the stabilizer for takeoff using wheel mounted thumb switch try moving the column in the opposite direction at the same time to see how far it has to be out of detent before stabilizer motion stops even though thumb switch remains activated. A note of caution that thumb switch input in opposition to column such that the column cutout activates if held for very long may trip a monitor designed to detect persistent contradictory column and trim commands. That might take some explaining. I apologize that I don't know the details on such monitoring (in particular how long the condition must persist before said monitor trips). I'm sure there must be some 737 savvy PPRUNErs out there who know and by the amount of traffic on this thread they are probably monitoring.

It works on ground. I have seen this when the wind push the yoke forward and I want to set takeoff trim. I need to pull the yoke back before I can engage the trim.
With STS it will continue to trim up even if I need to apply quite a lot of forward pressure to keep the nose from rising. I thing the parameters for the trim cut out to function are very high. Or possibly it doesn’t stop STS from operating.

[Less Hair]

France is one of the MAX engine Co-manufacturers. This is why they likely have all the software needed from the very beginning.

[Rated De]

Originally Posted by Cows getting bigger

To quote a 737 Max pilot:

"..what else don’t I know?"


From https://leehamnews.com/2019/03/13/co...-transparency/

"Herein lies an essential lesson for Boeing: When your reputation depends on safety, it does not matter what has been proven or who is at fault. What matters is that you are seen taking the lead to protect the safety of the public – at all costs."

Precisely, the old Boeing would not need reminding.
Nor would they have lobbied the President to intervene if they were certain the data supported their public rehearsed statements of safety.

[N600JJ]

Originally Posted by Non-Driver

And exactly how many F-reg MAX's are there I wonder .......

Not so much a question of D-reg or F-reg aircrafts here but more on Honeywell software (and potentially associated hardware), expertise, timescales and bandwidth I guess

[Redbeard]

Originally Posted by poldek77

It is quite unavoidable with a new model joining a fleet

i partially agree with you on that, yes the captain possible first/ second flight as one day you just have to start. But the decision to add a totally fresh out of school,FO, no experience in aviation is just bad planning and judgement of the airline.
wondering how much extra sim emergency training (if at all possible) crew’s got after the Lion crash and info given by Boeing

[boxmover]

Originally Posted by mickjoebill

Have we passed the point in modern aviation where it is not possible to (quickly) switch off all these pilot and performance aids and fly “manually”?

At very least, the last resort if flying in VFR conditions?


Mjb

With a aircraft with powered flying controls let alone fly by wire signaled power controls define what manual control is.

Without any force feedback and at higher speeds it would be easy to badly over stress an aircraft.

plus

If you want pilots trained and current to fly without the “aids to flight” under stressful conditions you will need significant training both initial and recurrent. That won’t come cheap.

[procede]

Originally Posted by Less Hair

France is one of the MAX engine Co-manufacturers. This is why they likely have all the software needed from the very beginning.

More that they are the home of Airbus and Dassault and electronics manufacturers such as Thales.

[Rated De]

“Boeing has determined — out of an abundance of caution and in order to reassure the flying public of the aircraft’s safety — to recommend to the FAA the temporary suspension of operations of the entire global fleet of 371 737 MAX aircraft,”

Does anybody find it odd, that Boeing's public statement is attempting to suggest they the company 'ordered' the grounding?
Isn't that Cart before the Horse?
Or is it evidence of regulatory capture??

[infrequentflyer789]

Originally Posted by DaveReidUK

OK, thanks. I wonder why the ECAA didn't ascertain the BFU's capability before announcing that they were sending the recorders to Germany.

<cynic mode> First announcement for political reasons (i.e. not France) then unavoidably changed to France for technical reasons?

[HarryMann]

MCAS Raison d'etre

So MCAS was born from meeting certification requirements re: stick force per alpha (or maybe stick force per G) in the 》1G range.

Can anyone tell.ne authoritatively whether this requirement stems from stall or maneouvre overload prevention ?

Oh! Or both!

thanks

[boxmover]

Originally Posted by bill fly

As has been very well explained, the reason for MCAS was to cause ANU stick force to increase or at least not to decrease when AoA approaches stall angle. That was a certification requirement.
However, by repeating the trim input at remaining high AoA, something more than just desired stick force increase is achieved.
What is needed is a one time increment in stick force to bring the Max into line with the other 737 models - if that was the aim.
This can be achieved by adding feel spring force to the control run, cut in point determined by AoA.
If there were then a fault in the AoA signal, the increment would be applied - once - which would be trimmable and controllable.
The whole sorry idea of playing with the stab trim to achieve what is really a desired primary control feel correction is unnecessary and as we see, unsatisfactory and potentially dangerous.
A feel spring solution should satisfy the certification authorities and the desire by the manufacturer to keep the Max in the 737 family, rating wise.

But your proposed solution wouldn’t be free to produce. The Boeing solution used existing hardware and a bit of new software.
Its not difficult to see why Boeing went the way it did. To me the question is what level of scrutiny did the plan receive.

[averow]

Your summation of the situation 'bill fly' is much appreciated. There seems to me to be something "off" about the concept of MCAS as it currently exists, and seems to be causing problems for flight crews. The repetitive, insidious nature of the correction is what baffles me. I do not understand why this mismatch of "real life application" of MCAS in its intended role was not thoroughly wrung out during the test pilot phase.

[boxmover]

Originally Posted by Redbeard

i partially agree with you on that, yes the captain possible first/ second flight as one day you just have to start. But the decision to add a totally fresh out of school,FO, no experience in aviation is just bad planning and judgement of the airline.
wondering how much extra sim emergency training (if at all possible) crew’s got after the Lion crash and info given by Boeing

At lots of airlines crews get 4 days per year in the sim, either 4 individual days or 2 blocks of 2 days. Few if any airlines will have added extra sim trips. Adding sim trips is not straight forward, you need both sim capacity and the ability to take crews off flying. These days most airlines have very little slack in their system.