Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

Ethiopian airliner down in Africa

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

Ethiopian airliner down in Africa

Old 15th Mar 2019, 09:58
  #1441 (permalink)  
 
Join Date: Oct 2017
Location: Vienna
Posts: 129
Originally Posted by WHBM View Post
If that is the case then there is likely only one version of the code (eases management of it), but a flag set Yes or No if the fee has been paid or not.

If so, and the right code to avoid the issue was actually installed in the aircraft but deliberately switched off, lawyers for the pax, especially those from the second accident, will have a field day.
Ineed, after Lion Air I though Boeing should have made this feature available for free in all MAX airplanes. Could the ET be prevented if they had this display? Interestingly, Boeing only lost 15% at NYSE. For comparison, Volkswagen lost over 60% due to their emission scandal. But this could be, and should be big if it's due to MCAS.
derjodel is offline  
Old 15th Mar 2019, 09:59
  #1442 (permalink)  
 
Join Date: May 2016
Location: Nantes
Posts: 63
Originally Posted by Cloudee View Post
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.
If "safer" means avoiding a crash every six months, I would say that "safe" for Boeing means "dangerous". If not, why would a safe aircraft be grounded ?
deltafox44 is offline  
Old 15th Mar 2019, 10:03
  #1443 (permalink)  
 
Join Date: Jul 2010
Location: Asia
Posts: 928
And this time EASA may well not rely on the FAA for lifting ban or even worse re-certification if required...
D.P. Davies required modifications to the B707 before it was allowed on the British register so the above scenario is very possible, especially if the French want to give Airbus a leg up.

I'm surprised we haven't seen the ambulance chasing lawyers descending on the victims families en mass yet. Those of us who remember the Bhopal disaster involving Union Carbide in 1984 will remember the spectacle.
krismiler is offline  
Old 15th Mar 2019, 10:06
  #1444 (permalink)  

I Have Control
 
Join Date: May 2004
Location: North-West England
Posts: 9
Red face Options

Options on a new aircraft have long been offered, just as in a motor car. Some enhance safety, some convenience, some comfort. They all cost. To incorporate all options as standard would render the product unsaleable.

If the airline decides not to take-up certain safety-related options, on their own head be it. Not the manufacturer's.
RoyHudd is offline  
Old 15th Mar 2019, 10:09
  #1445 (permalink)  
 
Join Date: May 2000
Location: SV Marie Celeste
Posts: 593
In summary then:

The newer engines required to optimise the MAX have a larger diameter than that allowed by the wing/ fuselage geometry. In order to fit those engines Boeing had to move them forward which changed the aerodynamic characteristics of the aircraft. That change consisted on insufficient pitch down moment when close to the stall in clean configuration. In order to meet certification criteria Boeing introduced a system that automatically moved the stabiliser to artificially induce the pitch down moment . In order to introduce this system with minimal costs existing equipment was used including a data input from a single source - the AOA probe. In order to reduce qualification costs this system was not mentioned in the MAX operation manuals.

In the Lion Air case the AOA probe was not calibrated properly, meaning the direction and magnitude where correct but the value was 20 degrees out. When the flaps where retracted the MCAS started to work as intended -based on the erroneous aoa data- by introducing bursts of down trim, those bursts got interrupted every time the pilot trimmed manually via the electric trim. At a certain point the crew started to pull hard at the yoke and the automatic stab trim cutout switch operated, with the effect that electric manual trim no longer worked, MCA trim in the other hand did continue to operate but it no longer got interrupted by manual pilot trim eventually trimming all the way nose down, a position that exceeds the authority of the elevator. At that point they only had two options left
1. Offload control column pressure to release the automatic stab trim cut-out then trim back to neutral.
2. Manually disconnect the electric stab trim via the override switches at the base of the throttle quadrant then use manual trim for the remainder of the flight.

Three crews managed the above but the fourth got overwhelmed in the Lion Air case. The Ethiopian on the face of it looks quite similar but there isn't enough data yet to even have a guess. A bit of a mess but where I tend to agree with Boeing is in which way is this any different from a classic runaway stabiliser? Ok there is more distractions going on but bottom line is if the stabiliser starts to run and you dont get on those disconnect switches soon enough you will end up in the same place.
calypso is offline  
Old 15th Mar 2019, 10:16
  #1446 (permalink)  
 
Join Date: Oct 2003
Location: UK
Posts: 1,494
Originally Posted by RoyHudd View Post
If the airline decides not to take-up certain safety-related options, on their own head be it. Not the manufacturer's.
Except the aircraft is required to achieve certain standards of safety and, it appears, does not achieve that standard without the option activated. Ergo the default design should have additional features and it is back with the manufacturer and their regulator to take action.
Daysleeper is offline  
Old 15th Mar 2019, 10:21
  #1447 (permalink)  
 
Join Date: Mar 2010
Location: on a blue balloon
Posts: 339
Rated De said "As year after year business schools pump out MBA graduates the only thing they conceive is cost and lowering it"

Stop and think whether this is not utter nonsense.
You imagine Airbus gave the A320 a seven inches wider fuselage than the 737 to save operating cost?
oldchina is offline  
Old 15th Mar 2019, 10:26
  #1448 (permalink)  
 
Join Date: May 2016
Location: Nantes
Posts: 63
Originally Posted by Capt Kremin View Post
The data shows a 63 second ground roll followed by a rotation at 207 knots. At this point the MCAS may have simply been doing its job.
The FR24 data do NOT show that.

After about 45" roll (05:38:45.798) and for 5 seconds the ground speed is stable at 182/183 kts while the vertical speed is positive, reaching 2368 ft/mn. Though the pressure altitude is not consistent with the speed and vspeed evolution, speed and vspeed indicates the aircraft is already airborne and climbing at 182 kts (about 170 kts IAS). And one minute later it has gained 1000 ft and speed (250 kts). Then only the problems begin, may be after retracting the flaps.
deltafox44 is offline  
Old 15th Mar 2019, 10:32
  #1449 (permalink)  
 
Join Date: Sep 2017
Location: Europe
Posts: 1,679
Originally Posted by oldchina View Post
Rated De said "As year after year business schools pump out MBA graduates the only thing they conceive is cost and lowering it"

Stop and think whether this is not utter nonsense.
You imagine Airbus gave the A320 a seven inches wider fuselage than the 737 to save operating cost?
Did they build the MCAS?
MCAS saved re-certification cost. It appears increasingly likely that a system considered necessary for safety wasn't explained and trained to the pilot. Why do you think that would be?

Post graduate courses are indeed pumping out the said graduates.
When did Airbus actually design the A320?

Go and listen to the opinions of the Boeing engineers who actually used to build the product.
Listen to what they say changed. Then have a look at any Ivy league business school, read the curriculum, look at the individual modules and see what the graduate is focused upon.

Rated De is offline  
Old 15th Mar 2019, 10:39
  #1450 (permalink)  
 
Join Date: May 2016
Location: Nantes
Posts: 63
Originally Posted by calypso View Post
Three crews managed the above but the fourth got overwhelmed in the Lion Air case. The Ethiopian on the face of it looks quite similar but there isn't enough data yet to even have a guess. A bit of a mess but where I tend to agree with Boeing is in which way is this any different from a classic runaway stabiliser? Ok there is more distractions going on but bottom line is if the stabiliser starts to run and you dont get on those disconnect switches soon enough you will end up in the same place.
Two crashes and 3 near crashes, that means that only above average (or more lucky) pilots can avoid a crash after a single AOA sensor failure...

It would be interesting to know whether the MCAS ever was activated and avoided a stall in nominal conditions

Last edited by deltafox44; 15th Mar 2019 at 10:39. Reason: typo
deltafox44 is offline  
Old 15th Mar 2019, 10:40
  #1451 (permalink)  
 
Join Date: Feb 2007
Location: Glasgow
Age: 55
Posts: 24
Originally Posted by Kolossi View Post
So, accepting it contradicts Occam's Razor and needs another cheesy hole, perhaps something else non-MCAS-related was seriously wrong, but then on turning back, MCAS nose down trim becomes the final nail in the coffin as evidenced by trim jack screw position on ground.
For me it's difficult to see how this doesn't potentially finish off the "Max" IMO.

Increasingly the perception is that It isn't really a software problem, it's a aerodynamics design problem. Apparently those engines don't work with that body, at least not comfortably. Sure it can be sellotaped over with some software fixes/more sensor redundancy, whatever. But it doesn't solve the design issue and nowadays it isn't only regulator certification that has to be overcome, it's "public opinion certification" as well. We're not in the DC-10 era where controversy takes years to eek out into the open but in the age of instant global knowledge - even if that knowledge is incomplete or based on un-authoratitive sources. 1 hull loss can maybe be got away with by saying "we fixed it". But with 2 it's difficult to see how any ongoing controversy doesn't just mean that people won't refuse to get on the thing.
indigopete is offline  
Old 15th Mar 2019, 10:49
  #1452 (permalink)  
 
Join Date: May 2003
Location: USA
Posts: 67
"The normailization of deviance." This. Exactly this. Shown to be a factor in many disasters, including Challenger. Sober thinking, smart people advised against certain actions and designs, and were shut down by others worried more about short term costs or schedule pressure.
averow is offline  
Old 15th Mar 2019, 10:52
  #1453 (permalink)  
 
Join Date: Mar 2019
Location: Prag
Posts: 1
Originally Posted by CONSO View Post
Bird strike or ramp rash or software error are three most obvious- the point is to alllow a SINGLE sensor to directly override pilot input and not be documented that it even exists is as close to criminal as one can imagine.
There is no such thing as 100% reliable sensor. You can vote in software, but in case of two sensors you dont know, which value is OK and which is bad, you need at least three to have confident voting system. There are much better options sw engineer can use, if he knows something about the subject and phisical reality it deals with. I'm just plain earth based industry programmer, but can imagine some verification methods that works even with one sensor. The basic method is to observe sensor behavior in time, just as you watching if it works by your own eyes, in many phases of flight.
- during the takeoff run just before plane goes airborne, you can assume that values AoA should be close to zero. If not, sensor is stuck or misaligned.
- after that should the values change to positive normal range, if not, the sensor is stuck. This is also the case of normal in/flight behavior, values in acceptable range, that change slowly and possibly with small difference between two sensors according to actual flight conditions. So you can tell its still living and not stuck somewhere.
And the most significant, dont check for value constantly over the set threshold. You should check if value rises from accepted range dynamically and in one moment oversets it, then act.
Programmers working for Boeing or component manufactors should have known this. I'm somewhat surprised they obviously dont. Or maybe the flight computer is totally out of resources after mods.

Last edited by Prag; 15th Mar 2019 at 12:19.
Prag is offline  
Old 15th Mar 2019, 10:58
  #1454 (permalink)  
 
Join Date: Jan 2008
Location: Reading, UK
Posts: 12,075
Originally Posted by deltafox44 View Post
The FR24 data do NOT show that.

After about 45" roll (05:38:45.798) and for 5 seconds the ground speed is stable at 182/183 kts while the vertical speed is positive, reaching 2368 ft/mn. Though the pressure altitude is not consistent with the speed and vspeed evolution, speed and vspeed indicates the aircraft is already airborne and climbing at 182 kts (about 170 kts IAS). And one minute later it has gained 1000 ft and speed (250 kts). Then only the problems begin, may be after retracting the flaps.
The first thing I would normally do with FR24 data, after correcting for QNH, is to throw away transmitted VS values.

The aircraft climbed fairly steadily before levelling off at approximately 1050' AAL just over 60 seconds after rotation, so 2000+ fpm at any point seems a tad unlikely.
DaveReidUK is offline  
Old 15th Mar 2019, 11:11
  #1455 (permalink)  
 
Join Date: Mar 2007
Location: Roguesville, cloud cuckooland
Posts: 1,178
Originally Posted by deltafox44 View Post
The FR24 data do NOT show that.

After about 45" roll (05:38:45.798) and for 5 seconds the ground speed is stable at 182/183 kts while the vertical speed is positive, reaching 2368 ft/mn. Though the pressure altitude is not consistent with the speed and vspeed evolution, speed and vspeed indicates the aircraft is already airborne and climbing at 182 kts (about 170 kts IAS). And one minute later it has gained 1000 ft and speed (250 kts). Then only the problems begin, may be after retracting the flaps.
You must be looking at different data then.
The vertical speed is positive but nothing happens to the altitude till 207 knots is reached. The other possible scenario, which is probably more likely, may be that the aircraft was carrying out a Flaps 1 takeoff, which would be consistent with the speeds reached on the runway at rotate and the gear up call, (the 182 knots). The brand new FO, who at 200 hours may have been doing his first line sector, then inadvertently selected flap up instead of gear up. The aircraft settled back on to the runway and the captain rotated again at 207 knots, which would be a normal recovery, but now the MCAS is activated in a hot and high, extremely low altitude situation.

We will know soon anyway. The flight recorders are being looked at now in Germany.
Capt Kremin is offline  
Old 15th Mar 2019, 11:15
  #1456 (permalink)  
 
Join Date: Apr 2010
Location: Europe
Posts: 18
Originally Posted by Capt Kremin View Post
You must be looking at different data then.

We will know soon anyway. The flight recorders are being looked at now in Germany.
I thought that they were in France.

jsypilot is offline  
Old 15th Mar 2019, 11:16
  #1457 (permalink)  
 
Join Date: Jun 1999
Location: world
Posts: 3,423
I think that Capt Kremin is out of touch!
Hotel Tango is offline  
Old 15th Mar 2019, 11:22
  #1458 (permalink)  
 
Join Date: Jan 2008
Location: Reading, UK
Posts: 12,075
Originally Posted by jsypilot View Post
I thought that they were in France.
They are. Presumably at Le Bourget, HQ of the BEA.

I don't buy the "double rotation" scenario either.
DaveReidUK is offline  
Old 15th Mar 2019, 11:22
  #1459 (permalink)  
 
Join Date: Nov 2013
Location: Under the Galaxy
Posts: 12
Wondering if / when was AP engaged on ET302 - FDR will tell

Last edited by N600JJ; 15th Mar 2019 at 12:25.
N600JJ is offline  
Old 15th Mar 2019, 11:25
  #1460 (permalink)  
 
Join Date: Sep 2017
Location: Europe
Posts: 1,679
Originally Posted by bud leon View Post
It's utter nonsense for many reasons, not least because of this odd idea that getting an MBA turns humans into sociopaths. All this rhetoric about bean counting, criticism of an aviation culture that has become one in which the industry doesn't care if people die, that pilots can't fly planes any more, and that technology has made planes unsafe, flies in the face of aviation safety statistics which show a continuous reduction in fatality frequency that any industry would be immensely proud of.

We simply do not live in a world in which humans don't make mistakes. To err is human. We must always learn from mistakes, and the history of aviation safety is an exemplar of that. Excluding malicious acts, every single death in the history of travel has occurred because one or more people made a mistake in strategy, decision making, design, or operation. It's quite possible that the Max story is going to become a classic safety case study. But witch hunting doesn't get us anywhere.

So the statistics of which you speak saw the Challenger launch successfully 10 times.
So the statistics of which you speak saw the 737 MAX fly successfully until it didn't last year. Statistically, extrapolating the hull loss of the 737 MAX indicates that the hull loss rate is now intolerable.
So which statistical data set is the valid sample?

The focus of the post graduate program in the modern age is to be relevant to business. Perpetual profit in a finite world is utter nonsense, yet every graduate is taught grow revenue and cut cost. Seemingly inexhaustible right?
How low can cost be cut before it matters? An endless loop question?
Nobody stated the graduates were sociopaths, that is alarmist. What is obvious to those of us who witness it is that these graduates know little of process, know little of design. Their skill set can be readily applied to any corporate endeavour. After all it is marketed as an Masters of Business Administration (Generic) One size fits all.

The normalisation of deviance is not a witch hunt, it is a scientific investigation into acceptance of deviance from safe practice.
The deviation takes place an increment at a time. Boeing engineers foretold their concerns about Boeing. The very people charged with building the product stated the process had been compromised.
Their focus was not to be quality, rather schedule and self evidently cost.

Management documents state that clearly, deviation from accepted quality was permitted to protect schedule. Not the 737 MAX program incidentally, it was the 787.
Similarly, the NASA engineers had their concerns with O-Ring by pass. As did the engineers of Morton Thiokol.
Progam management dismissed their concerns, focused on schedule and budget.

Sound familiar?
Program cost, budgets, schedule and commercial viability overcame opposition from concerns for launch integrity. Everybody knows what happened next.

The case study of which you speak need not have been the 737 MAX. People made mistakes in design, strategy, decision making and operation.
The Boeing 787 program had all the hallmarks, the engineers in Boeing noticed the change, they called out the deviance. Statistically they have gotten away with it so far.

Perhaps the 737 MAX need not be a case study, the Challenger Launch Decision shows the template to anybody bothered enough to read it, having read it, the similarities are stark.

If this horrible loss of life was triggered by the same system that is believed responsible for the Lion Air accident, then statistically Boeing is going to have a hard time pointing to their statistics.












Rated De is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.