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Ethiopian airliner down in Africa

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Ethiopian airliner down in Africa

Old 5th Apr 2019, 21:24
  #3361 (permalink)  
 
Join Date: Feb 2013
Location: 60 north
Age: 56
Posts: 19
DO NOT CHANGE ANYTHING! ( For now)

I do appreciate the sensory overload that ensued after AP dropped out on Flap retraction.
This is why I am a strong believer in 3 things in an Emergency with control problems!
1 Fly the Aircraft ( Analyse)
2 Fly the Aircraft ( Doing nothing makes it worse? No, good!)
3 Fly the Aircraft ( Memory items IF it does not make it worse)

A terrible situation for this crew.
No blame
I just want to learn, and most important : Boeing has to learn or else,,,,,,,,
Respectfully
Cpt B
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Old 5th Apr 2019, 21:42
  #3362 (permalink)  
 
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I don’t fly the 737 Max, but after doing a bit of ‘what-if-ing’, I’ve come to the conclusion that if I were a Max pilot and had stick shaker on take-off, I would not fully retract the flaps. I would retract to Flaps 1. My experience on other Boeing’s (767 & 744) is that Flaps 1 provides the best manoeuvre margin to the stall and in the 737 Max would prevent MCAS doing it’s (evil) thing.
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Old 5th Apr 2019, 21:55
  #3363 (permalink)  
 
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Slightly off-topic.
Boeing is slowing production of 737 by one fifth, from 52 to 42 a month, effective in about ten days.

Boeing will slow 737 production by one-fifth; no layoffs planned
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Old 5th Apr 2019, 22:01
  #3364 (permalink)  
 
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Originally Posted by Bleve View Post
I donít fly the 737 Max, but after doing a bit of Ďwhat-if-ingí, Iíve come to the conclusion that if I were a Max pilot and had stick shaker on take-off, I would not fully retract the flaps. I would retract to Flaps 1. My experience on other Boeingís (767 & 744) is that Flaps 1 provides the best manoeuvre margin to the stall and in the 737 Max would prevent MCAS doing itís (evil) thing.
Thats pretty poignant in this situation because MCAS does not fire with the flaps out, or so I have been told. It's highly doubtful they would have known or thought of that. A really bad situation..
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Old 5th Apr 2019, 22:02
  #3365 (permalink)  
 
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Any electronic system on any aircraft should have a means of isolating the power to that system. Even if it is critical. Is the MCAS system so infailable that such a system does not have a CB tied into it to isolate it? I am not rated on 73s but know the basic stall identification and warning systems on other types. One they do not operate until the weight offs + time delay occur and there is simple methods to deactivate.. I smell a massive regulatory and manufacturer fail that should have been apparent with the Lion Air crash. Then again I am a techie, not a system designer.
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Old 5th Apr 2019, 22:06
  #3366 (permalink)  
 
Join Date: Feb 2013
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Manada

No no no
Me and my short sentences . It was a response to the Trim demand on pwr change in a previous post!
So spot on then , 94% TOGA at 5,6 trim
Then 73%
Trim I might have got wrong as it is not in my scan, but initially we trim AND after lift off and if You are right with 4 units we do not need a big ANU trim , once pwr is established, speed 210 to 240.
Having again read Hans B question , it is twofold
210 kts F5 hardly any change after INITIAL trim at say V2+ 20!
240 F-UP is a good 1 unit plus
Yeah , so lets say 4 to 5 units.
In short , SMALL changes for a safe speed with regards to stall and manual wheel trim, me thinks!
Idle on the other hand out of trim after 101% proved to be more of a problem for FlyDubay
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Old 5th Apr 2019, 22:23
  #3367 (permalink)  
 
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Originally Posted by MemberBerry View Post
Maybe they only applied as much electric trim as needed to bring it close to the green band, that starts at 2.5 on the MAX. The stick shaker suggesting they are close to a stall might have made them reluctant to use more.
[Not a pilot] Yet they had the control column way back (after the ground proximity warning) and, at times, called out, Pull together, and, Pitch together. They decided pitch was not enough.

I think it's still unclear whether they were both on the same page about elevator pitch, manual/electric pitch trim, and hand wheel pitch trim, but do stall concerns fit in with the above?

They spent a total of fifteen seconds working on pitch trim; first the FO, later, "together." It's not clear to me whether at any point they each freed up a hand to use on the hand wheels.

Last edited by fotoguzzi; 5th Apr 2019 at 22:32. Reason: typo; add timeframe info
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Old 5th Apr 2019, 22:24
  #3368 (permalink)  
 
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Simplicity, user friendliness and graceful degradation

Gums,

Like you I have absolutely zero experience in modern liners like the MAX or NEO. But when reading accident and incident reports, I get the feeling that beside the lack of proper and sufficient training, the modern liners are needlessly over complex, not user friendly, have poor and unintuitive man-machine interphase and when their systems degrade, they degrade very ungracefully. I know both Airbus and Boeing pilots who all tell me their machines are a joy to fly when all bells and whistles are working properly, but I donít understand why the manufactures have chosen to go down the path of complexity, when I know from personal experience that an aircraft can be built in another way.

I know that most normal pilots are in love with their specific aircraft type, but going through the types I have flown in my career so far, the F-16 stands out above all other types in the way it is designed. For some reason it appears that when the F-16 was designed, Boyd, Hillaker and the rest of the so-called Fighter Mafia members actually understood what the pilots needed both when every system was working, but also when things went bad. They managed to build a very simple, user-friendly and from a technical point of view genius aircraft.

To begin with, the flight control system, the worlds first full FBW system in a combat aircraft, was very effective, robust, simple, reliable (when the first hiccups were dealt with) and best of all, so fantastically pilot friendly, that most pilots will feel that the aircraft becomes an extension of their body after half the take-off run on their first flight in the aircraft.

I donít understand why it is not possible to build an airliner with such a clever flight control system? As you described, who needs dedicated flap levers? You only need flaps during take-off and landings, so why not integrate the flap function with the gear handle, as you need your gear to be down when taking off or landing. Flaps that can be manually selected down without the landing gear if a situation ever arises where it is needed (intercepting a cessna at 90 knots), and flaps that will retract by themself if an overspeed is about to happen. And by the way, the system changes the control gains from take-off/landing gains to cruise gains with the gear handle position. Automatic leading edge flaps that drop down on rotation to increase lift, and instantly go up to dump lift when touching down on landing. No need to arm them like spoilers and no need to stow them in case of rejected landing. A wing that changes shape (again by the use of leading edge flaps), so as to always have the optimal shape for the actual flight regime (with an envelope much wider than the typical airliner).

And in the very rare case where the system malfunctions, it degrades so gracefully that the pilot probably wont even notice any change in flying characteristics (like when the bus changes to direct law). Loose a control surface (loose like in it has fallen off), have a runaway elevator trim go full nose down, or even worse, have a LEF pointing straight up like in gums LEF incident, and still be able to counteract the roll, pitch or yaw with less then superhuman power, by just applying a bit more force then normal on the side stick.

And all this was designed in the mid 70ís. One would think that it would be possible to make an even better flight control system today. A system that would help the pilots instead of defeating them. Of course, complex systems are fine and work well if the operators are well trained, experienced pilots that understand the systems and all of their sub modes, but the average pilot today as I see him/her, is only trained to the minimum requirements, doesnít get a lot of stick time, and doesnít really understand the system 100%.

Aircraft engineers, is it not possible to keep it simple stupid anymore?
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Old 5th Apr 2019, 22:29
  #3369 (permalink)  
 
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Originally Posted by Bleve View Post
I donít fly the 737 Max, but after doing a bit of Ďwhat-if-ingí, Iíve come to the conclusion that if I were a Max pilot and had stick shaker on take-off, I would not fully retract the flaps. I would retract to Flaps 1. My experience on other Boeingís (767 & 744) is that Flaps 1 provides the best manoeuvre margin to the stall and in the 737 Max would prevent MCAS doing itís (evil) thing.
That's what I learned from LionAir, except that I would have left the flaps at 5 and adopted a pitch attitude of 10 degrees, confirmed that the stick shaker was false, checked for IAS disagree, and set 80% N1 (terrain permitting), flight directors and autothrottle off. Climb above a safe altitude and then carefully run the Airspeed Unreliable checklist, which would identify correct speed on the RHS. Engage autopilot B as per the checklist and return to land. Don't retract flaps. MCAS won't activate and stab trim cutout switches can remain in normal.

Now, I concluded that from the comfort of my armchair AFTER the Lion Air accident, so that if it happened to me, I would know what to do.

The Ethiopian crew obviously didn't, but neither did Boeing.

Mind you, I AM adopting a Boeing procedure here (the Airspeed Unreliable checklist) - It's just that I'm being choosey about which Boeing procedure to adopt and how, and using some additional system knowledge which we didn't have prior to the Lion Air report (i.e. flaps stops MCAS!).
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Old 5th Apr 2019, 22:35
  #3370 (permalink)  
 
Join Date: Jan 2008
Location: Netherlands
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I think engineers have more freedom when designing fighters, then when designing airliners.
Itís all about liability.
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Old 5th Apr 2019, 22:43
  #3371 (permalink)  
 
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Originally Posted by astonmartin View Post
I think engineers have more freedom when designing fighters, then when designing airliners.
Itís all about liability.
I think piggybacking onto a 50 year old airframe may be more of an obstacle, than any legal liability is, when designing flight controls.
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Old 5th Apr 2019, 22:51
  #3372 (permalink)  
 
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ViperBoys et al

I trained 50 or 60 active Dutch F16 chaps in AMS on MCC Courses.
5 sessions in FFS A320 and later in B737-800
An absolute delight, BUT as they all remarked on the last night at the mandatory WetBrief.
" Dude, we respect You civilians a bit more now"
The thing is that the A320 was easy for them, when they realized , NO 4 handed , lightning quick selections!!
The Boeing 737 they wondered about?
"Which Museum did You steal this rig from"

In short:
Civil aviation has gone backwards since say mid 1990s.
I suspect the latest events will do to Aircraft Design and Certification what 9/11 did to Airport Security.
Without any direct comparison intended from me, of-course.
Regards
Cpt B

PS There is 9 flap settings on the 737.
I rest my case.
DS

Last edited by BluSdUp; 5th Apr 2019 at 22:56. Reason: Added PS
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Old 5th Apr 2019, 22:53
  #3373 (permalink)  
 
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F-16Guy I think you really know the an$wer.
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Old 5th Apr 2019, 22:59
  #3374 (permalink)  
 
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Yepp
Ibiza for 15£
Sorry 9£
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Old 5th Apr 2019, 23:00
  #3375 (permalink)  
 
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Originally Posted by BuzzBox View Post
So what happens next time somebody has a different type of problem for which they have had no specific training?
Depends on what the problem is.

If the problem is ill thought-out automation, incomplete documentation and missing training, then the answer will be fix the automation, revise the documentation and add training.

Which is what Boeing are doing here.
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Old 5th Apr 2019, 23:05
  #3376 (permalink)  
 
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The isolation for MCAS is the STAB OFF switches beside pilots knee. Anything that moves the stab goes through these switches. But, you would have to recognize the problem. Clearly the pilots knew nothing about MCAS like the rest of us. All they may have seen is the STAB running AND - nose down.
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Old 5th Apr 2019, 23:10
  #3377 (permalink)  
 
Join Date: Aug 2005
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It might be worth looking into an older crash A6-FDN. FDB 981. Strange that a 5000h PF sets 12 seconds of continuos stab down trim from which he could not recover. Was not a MAX.
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Old 5th Apr 2019, 23:39
  #3378 (permalink)  
 
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Originally Posted by Airbubba View Post
I still can't figure out why nobody pulled back the power with continuous overspeed warnings on both sides and obviously too much thrust for attempted level flight.
Attempted level was FL320 !

With stall warning and attempting to clear the terrain, more speed means more potential energy, so I think overspeed was not on top of their priorities.

If Boeing NNC for trim runaway had included "reduce speed if manual trimming is too hard", perhaps they would have done it...
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Old 5th Apr 2019, 23:50
  #3379 (permalink)  
 
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Originally Posted by yanrair View Post
The isolation for MCAS is the STAB OFF switches beside pilots knee.
That's not isolation, it disables all electric trim. Isolation would mean disabling MCAS only.

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Old 5th Apr 2019, 23:53
  #3380 (permalink)  
 
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Woof woof, it's dark here....

So the dog that hasn't barked, as far as I know, is this:

Aside from the three-crew Lion Air flight that preceded the mishap flight, where are all the crews who might have experienced an AoA failure that triggered MCAS at flaps-up, and handled the situation safely?

For this to happen means that one of the AoA sensors has to be bad from the start, that it has to be bad enough to call a spurious stall warning, and it has to be the sensor that is driving MCAS on this flight (the last being a 50:50 chance). How often has this happened in the MAX's history? I have not seen a single such account in this long thread (I stand corrected if I missed one).

Clearly, that number would provide some valuable context to the two occurrences when the result has been fatal.
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