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 17th Apr 2019, 13:26
  #4101 (permalink)  
 
Join Date: May 2000
Location: London, UK
Posts: 285
Foreign regulators approved MCAS based on 0.5 degree authority. They are off the hook for 2.5 degree authority.

Whether they will accept updated software given the fundamental design issue of engine location relative to the wing is an open question: but the political pressure to do so will be enormous.

Flew on a neo today. Nice plane, significantly quieter than the previous version. And full size emergency exits....
SLF3 is offline  
Old 17th Apr 2019, 19:28
  #4102 (permalink)  
 
Join Date: Feb 2019
Location: shiny side up
Posts: 212
Just a curious observation. The focus has been on DEP and AoA. this is understandable, as the ac in the climb.
In the first instance, the MCAS issues were first noted on ARR, (and corrected) not DEP.
From what has been reported, all pilot reports were issues on DEP....
Smythe is offline  
Old 17th Apr 2019, 21:13
  #4103 (permalink)  
 
Join Date: Dec 2003
Location: Tring, UK
Posts: 1,343
Originally Posted by Lord Farringdon View Post
All good George and seems sensible and expressed by numerous other 737 drivers in this long thread. Especially the 80 percent and 10 degrees. I mean that's just physics isn't it. On a dark night (terrain allowing) you can keep the blessed thing flying while the rest is sorted out. But one thing I wonder about. Is that power and pitch based on any given percent MAC being inside the authorised Cof G envelope? I mean, if you are unknowingly heavier than MAXTOW and with a C of G outside the envelope, in a hot and high airfield with V2 calculated to occur a little closer to the end than you would normally like, is that checklist going to help you stay airborne while you establish why your airspeed has gone to crap and the stick is shaking? Not saying that was the case in this event (especially with in daylight and CAVOK) but seriously just wondering how quick you need to decide that UAS checklist may not be your first and best port of call when the stick is shaking and your decaying airspeed is actually reliable! I suppose a wing drop like Cubana de Aviación Flight 972 might be the teller but I imagine it's all a bit late by then. An agressive pitch up immediatley after take off might also be a clue. Serious question, not trying to be smart a*** . (Ex Mil Loadmaster C130/B727).
Good questions.

I’m seeing quite a few posts of “should have done this”, “should have done that” and "I would have immediately xyz”.

When you get a stick shake during/after rotation or early in the climb out, which may or may not be associated with UAS symptoms, what are you going to do? Well, before you do anything, you need to have some idea if it is genuine or not.

How do you ascertain that? The traditional answer is performance attitudes (which we see a lot of in postings) but an aeroplane can be approaching a stall in a normal takeoff/climb attitude for many reasons, such as: strong adverse wind gradient, temperature inversion (often combined with the item before), incorrect loading, wrong flap setting, incorrect performance data and/or incorrect FMC weight/speed entries. If you leap straight into the UAS checklist at that moment, what will happen if you really *are* on the stick shake? I never tried this in the 737 sim but my gut feeling is that isn't a good place to be: on the back of the drag curve, keeping the nose high and likely take a bit of power off... Hmmm.

Remember, this is at 7,600’ASL, density altitude of nearly 9,500’ at the airport with MSAs of 14-16,000’, so close to the edge of the envelope in many respects. Some thought required before rushing into actions that may make the situation worse and that’s before MCAS rears its ugly head. Will flying the UAS pitch and power give enough of a climb gradient for terrain separation here? I can quite understand any reluctance to reduce power in this scenario, although it’s quite possible the workload was such that it didn’t get actively examined.

TL;DR If you have multiple scenarios with different required actions but similar symptoms, if you don’t do a bit of analysis first you are relying on luck...
FullWings is offline  
Old 17th Apr 2019, 22:31
  #4104 (permalink)  
 
Join Date: Mar 2018
Location: Central UK
Posts: 247
How do you ascertain that? The traditional answer is performance attitudes (which we see a lot of in postings) but an aeroplane can be approaching a stall in a normal takeoff/climb attitude for many reasons, such as: strong adverse wind gradient, temperature inversion (often combined with the item before), incorrect loading, wrong flap setting, incorrect performance data and/or incorrect FMC weight/speed entries. If you leap straight into the UAS checklist at that moment, what will happen if you really *are* on the stick shake? I never tried this in the 737 sim but my gut feeling is that isn't a good place to be: on the back of the drag curve, keeping the nose high and likely take a bit of power off... Hmmm.
Good question. How indeed?
For a moment or two after rotation when the stickshaker and stall warning burst out you are doubtless momentarily and firmly in the land of half-crown, threepenny bit, dustbin lid. But within a very short period of time you see TOGA thrust confirmed, airspeed/groundspeed confirmed, attitude correct and your sphincter begins to relax the dustbin lid to manageable proportions; then you see the usual huge Boeing ROC and realise the thing is flying as normal and thus the warnings must be false and the laundry-threatening event is all but over. The mere fact you're not mushing along the runway at thirty feet and 20' pitch in ground effect should tell you this. IMMEDIATELY.
Then you know the next thing to do is AIRSPEED UNRELIABLE chex. - What else fer chrissakes? WHAT tf ELSE???
If you don't - in the sim - you've just failed that check. Bombed it.
That's why we train these events in the sim, so we learn to recognise them and know better than to repeat them on the line.
I know I won't be thanked for it but it appears to me that these crews hadn't left this lesson behind in the sim.

Why?
Well, that's quite another matter...and one I suspect will become the crux of investigation in the months to come.

There can be little doubt that merely carrying out AIRSPEED UNRELIABLE chex would have pevented these accidents altogether.
(as would a number of other fundamental vital/airmanship actions too)

The more I think about this the more I see this as a training/culture/airmanship/professionalism/HF failure than anything else.
That's not to exonerate Boeing by any means, but when all else is said and done all 4 pilots had it entirely within their power and ostensibly within their training (tbc) to avoid both these accidents regardless of what the airplane seems to have done. In neither case did the airplane begin the event in anything approaching an unflyable condition, but just as in AF 447 the pilots very quickly and unnecessarily managed to put it in one through gross mishandling.

Last edited by meleagertoo; 17th Apr 2019 at 23:00.
meleagertoo is offline  
Old 17th Apr 2019, 22:41
  #4105 (permalink)  
 
Join Date: Jun 2006
Location: Terra Firma
Posts: 160
Originally Posted by FullWings View Post
When you get a stick shake during/after rotation or early in the climb out, which may or may not be associated with UAS symptoms, what are you going to do? Well, before you do anything, you need to have some idea if it is genuine or not.
I would suggest that if a stick shaker is genuine at rotation, you wouldn't be getting airborne, you would be tail scraping your a*** down the runway. If the take-off has been normal (ie normal acceleration, rotation and lift-off at the expected distance to run, airspeed and pitch attitude) and you get a stick-shaker, it's the stick-shaker that is not normal. In which case the Airspeed Unreliable checklist is the correct procedure to follow.

Interestingly in Airbus world, they have a memory checklist procedure for Stall Warning at Lift-Off. It says to set TOGA thrust, 15° nose up and wings level, which unsurprisingly are essentially the same initial actions as their Unreliable Speed checklist. No wasting time in a time critical situation - go straight to the Power + Attitude settings that will give you the fly away from the ground Performance that you want.

Last edited by Bleve; 17th Apr 2019 at 22:54.
Bleve is offline  
Old 17th Apr 2019, 22:56
  #4106 (permalink)  
 
Join Date: Mar 2018
Location: Central UK
Posts: 247
If Bleve appears to have mimiced my post above it is only fair to say they were posted simultaneously.
meleagertoo is offline  
Old 17th Apr 2019, 23:07
  #4107 (permalink)  
 
Join Date: Jun 2006
Location: Terra Firma
Posts: 160
Thanks meleagertoo. Yes simultaneous postings. Thankfully with the same message. As they say out in my part of the world: 'Happy Landings'.
Bleve is offline  
Old 17th Apr 2019, 23:23
  #4108 (permalink)  
Psychophysiological entity
 
Join Date: Jun 2001
Location: Tweet Rob_Benham Famous author. Well, slightly famous.
Age: 79
Posts: 4,596
Do the engines in the MAX have a time limit at TOGA?
Loose rivets is offline  
Old 17th Apr 2019, 23:54
  #4109 (permalink)  
 
Join Date: Nov 2006
Location: Dallas
Posts: 419
Originally Posted by Loose rivets View Post
Do the engines in the MAX have a time limit at TOGA?
In my AOM, the only time limit on TOGA is associated with max EGT. 1038 C for 5 mins, with a 30 sec exceedence allowed to 1048.

Hoke
ILUVHOKE is offline  
Old 18th Apr 2019, 09:02
  #4110 (permalink)  
 
Join Date: Dec 2003
Location: Tring, UK
Posts: 1,343
Originally Posted by meleagertoo View Post
Good question. How indeed?
For a moment or two after rotation when the stickshaker and stall warning burst out you are doubtless momentarily and firmly in the land of half-crown, threepenny bit, dustbin lid. But within a very short period of time you see TOGA thrust confirmed, airspeed/groundspeed confirmed, attitude correct and your sphincter begins to relax the dustbin lid to manageable proportions; then you see the usual huge Boeing ROC and realise the thing is flying as normal and thus the warnings must be false and the laundry-threatening event is all but over. The mere fact you're not mushing along the runway at thirty feet and 20' pitch in ground effect should tell you this. IMMEDIATELY.
So. Imagine for some reason you’ve cocked up the performance calculation and/or entered the wrong weights in the FMC, like EK407, maybe even not as grossly. What are you going to see? Thrust - what you intended, airspeed - as bugged, attitude - somewhere in the takeoff range. Nothing *obviously* wrong? Given differing density altitudes, runway parameters, terrain constraints, variable flap settings, ATM & fixed derates, etc. there is no “one size fits all” measure of performance these days. In a FBW aircraft, any “feel” in the controls will be based on false data.
Then you know the next thing to do is AIRSPEED UNRELIABLE chex. - What else fer chrissakes? WHAT tf ELSE???
If the crew on the BA56 had dismissed the stall warning as false, things would most likely not have gone well from then on. They had no indication that anything was amiss but they respected the stick shaker.

JK5022 is what can happen when you ignore a stall warning at low-level.

If you don't - in the sim - you've just failed that check. Bombed it.
That's why we train these events in the sim, so we learn to recognise them and know better than to repeat them on the line.
I know I won't be thanked for it but it appears to me that these crews hadn't left this lesson behind in the sim.
You could also say that you are training a single response to something that is much more nuanced in reality. Yes, you can pass the sim but fail dramatically in real life...

Last edited by FullWings; 18th Apr 2019 at 09:28.
FullWings is offline  
Old 18th Apr 2019, 10:19
  #4111 (permalink)  
 
Join Date: Dec 2001
Location: Brisvegas
Posts: 2,615
You could also say that you are training a single response to something that is much more nuanced in reality.
Yes possibly but that single response is a bloody starting point.

Fullwings are you a pilot?
Icarus2001 is offline  
Old 18th Apr 2019, 11:42
  #4112 (permalink)  
 
Join Date: Sep 1999
Posts: 542
Lots of people getting upset at experienced B737 drivers being “ judgmental” and assuming they would have done better.
Well, back to basics.
- Stick shaker on rotation. Do NOT engage the autopilot.
- Commence Airspeed Unreliable Checklist.
Yes you DO reduce thrust to 80% and maintain 10 degrees nose up.
The procedure is specifically designed to keep you flying at a safe speed and rate of climb. Just do it.
Disconnect the auto throttle as per the checklist.
-Fly the aircraft
-DO NOT maintain straight and level with autopilot and autothrottle engaged and allow aircraft to continue to accelerate to VNE while failing to ensure terrain clearance.
-Uncommanded Trim? Complete Runaway Stabilizer checklist as per training and specific Boeing recommendation in AD briefing we have all read ,and presumably understood ,as a result of previous accident.
-DO NOT allow airspeed and trim status to runaway to the extent that recovery becomes difficult or impossible.
Anything so far beyond the wit of a well trained Pilot?
Am I a Boeing troll? No, just an experienced B737 Pilot who still cant understand how you can get an aircraft so out of shape.
What do you think we get paid for?
George Glass

All good but...what you're saying is that in the case of the Birgenair crash,The Captain should have set 80% N1 and 10 degrees instead of......simply handing control to the FO whose ASI was totally functional?
IAS DISAGREE is not UAS.
We dont wish to criticize dead men.We all now know MCAS design was erroneous but that doesnt excuse a pilot from flying the plane does it now?
Some have said that establishing that the stick shaker activation was spurious was not possible and that the crew should have flown the UAS procedure.
This is not correct.
Flaps were set,takeoff power was confirmed,pitch attitude consistent with takeoff(a stable flight regime),no windshear warning,stick shaker active on Captains side only,disagree warnings are seen,FO's ASI agrees with ISFD....all point to a faulty sensor and not a real stall warning.
Its not wrong or dangerous for the Captain to retain control,set 80% N1 and fly 10 degrees but why?Why would you do that ?
In reflection,these 2 accidents are more about airmanship and crew composition than MCAS.
MCAS is stealing the headlines but actually an experienced FO would immediately say "I have control",just as the Birgenair FO should have done 23 years ago.
Rananim sends....for the last time
Rananim is offline  
Old 18th Apr 2019, 11:54
  #4113 (permalink)  
 
Join Date: Dec 2003
Location: Tring, UK
Posts: 1,343
Originally Posted by Icarus2001 View Post
Yes possibly but that single response is a bloody starting point.
Yes. But it might be an ending point as well, if you are doing it for the wrong reasons. Try the UAS drill from *actually* being close to stalled and see how that goes. In the 747 incident I linked above, had they done the UAS drill instead of reducing pitch because of the stick shake, I doubt they’d be around now to talk about it.

Fullwings are you a pilot?
Are you?

All I’m doing is pointing out that in a scenario which may have multiple causes and multiple recovery (or not) options, a hasty reflex action may not always work as expected. A situation with warnings, some possibly true, some possibly false is difficult to evaluate when the data you are using to make that evaluation may itself be compromised. This is just to balance the assertions that it was an “easy” recovery for the two lost 737s.
FullWings is offline  
Old 18th Apr 2019, 12:27
  #4114 (permalink)  
 
Join Date: Apr 2019
Location: USA
Posts: 217
Fly the Aircraft....

Originally Posted by FullWings View Post
Yes. But it might be an ending point as well, if you are doing it for the wrong reasons.
I think what some of us are trying to say is that if you are in tune with your aircraft, it becomes apparent very quickly what kind of situation you are dealing with. Initial rotation is approximately 10 degrees. No matter what alarms are going off, if the aircraft rises into the air as it normally does then it is almost certain that you are not approaching a stall. Maintain takeoff power setting, continue rotation to 15 degrees and get some space between you and the ground. At some point later, according to preference, execute the Airspeed Unreliable procedures.

On the other hand, if the aircraft acts mushy and hovers in ground effect, then respect the stick shaker. Gingerly apply full power, carefully manage the pitch, accelerate and climb.

If a pilot puts the aircraft into the proper rotation attitude and the PIC can't tell the difference between these two situations within seconds, then, quite frankly, they are not qualified to be in that seat. People's lives are literally hanging in the balance as to whether the Captain can make this distinction.

Let me stress, however, the crew's actions in either of the MAX accidents are not necessarily because they were "bad" pilots. I do not have any personal experience with the training and operational cultures at either Ethiopian or Lion Air. If these crews were simply responding according to their training, then the scrutiny should be placed there.

I strongly suspect that there is a mismatch between the proficiency standard implicit in the aircraft design and the actual training and experience level in the field. Sadly, I think Boeing, the airlines and the certificate authorities are all aware of this mismatch, but fail to either 1) insist the aircraft design be sufficiently fault tolerant, or 2) emphasize the need for better training and deeper experience.

Last edited by 737 Driver; 18th Apr 2019 at 16:14. Reason: added additional comments
737 Driver is offline  
Old 18th Apr 2019, 13:14
  #4115 (permalink)  
 
Join Date: Aug 2010
Location: sussex
Posts: 38
Icarus
"Fullwings are you a pilot?"
I have to observe, having trawled these forums for over 20 years (and knowing 'FullWings' for most of those ), that your response is typical of those who flee into a batcave when people do not seem to agree with them/worship their utterances/genuflect before them. They find, scrawled on the wall of the cave, in ancient hieroglyphics, the words 'Is u a pilut' which they then copy and paste (with spellchecker, of course) into their next post.

I can assure you that
a) 'Fullwings' is indeed a pilot
b) 'Fullwings' is very experienced in jet transport operation
c) 'Fullwings' is indeed capable of measured and logical thought processes.


Which, if any of the above, do you fit?
42go is offline  
Old 18th Apr 2019, 13:56
  #4116 (permalink)  
 
Join Date: Dec 2001
Location: Brisvegas
Posts: 2,615
Great, well not why not just answer the question? I also fly jet transport category aircraft. Now, the reason I asked is that there seems to be a rough split, in that actual pilots seem to be more likely to be critical of the crews actions whereas the non pilots, indeed non aviation posters, seem to be blaming Boeing more. I find this interesting.
Settle down 42g all good, I just asked a question.

ps. I meant to write"...a bloody good starting point" but finger on phone trouble.

Last edited by Icarus2001; 18th Apr 2019 at 14:03. Reason: Ps added
Icarus2001 is offline  
Old 18th Apr 2019, 14:43
  #4117 (permalink)  
 
Join Date: Mar 2006
Location: expat
Posts: 112
Now hang on a minute. Nowhere in any Boeing document does it say that stick shaker alone is necessarily Airspeed Unreliable.

Here is the text from the Boeing QRH for items that may be evidence of Airspeed Unreliable:

Speed/altitude information not consistent with pitch attitude and thrust setting
•Airspeed or Mach failure flags
•PFD current airspeed box amber
•An amber line through one or more PFD flight mode annunciations
•Blank or fluctuating airspeed display
•Variation between captain and first officer airspeed displays
•Radome damage or loss
•Overspeed warning
Simultaneous overspeed and stall warnings

If the stick shaker activates after lift off and power, pitch, flap position, aircraft performance and primary and secondary Airspeed indications are normal the decision whether or not to perform QRH Airspeed Unreliable actions is purely discretionary.The whole point of the checklist is to determine which, if any, ASI is reliable. Even engaging the autopilot is not prohibited and I would say that by the time it was engaged there would have been time to assess that the stick shaker was spurious and no hazard would result from engaging it, given that it could be immediately disconnected.

So let’s not start making opinion fact and tarnishing those who aren’t around to defend themselves.
HPSOV L is offline  
Old 18th Apr 2019, 14:50
  #4118 (permalink)  
 
Join Date: Apr 2019
Location: USA
Posts: 217
Originally Posted by Icarus2001 View Post
Now, the reason I asked is that there seems to be a rough split, in that actual pilots seem to be more likely to be critical of the crews actions whereas the non pilots, indeed non aviation posters, seem to be blaming Boeing more. I find this interesting.
I will also make the observation that much of the critical commentary toward the crew's action is focusing on their initial response to the event (stick shaker at rotation) before they ever got to the point where MCAS activated (flaps retracted). Up to that point, there was no significant difference between how a MAX responds vs an NG, so you can't really pin their initial response on Boeing's hash job with MCAS. The fact that these crews were struggling with basics of airmanship and compliance with a well known procedure is suggestive of an overall human factors issue.

Last edited by 737 Driver; 18th Apr 2019 at 16:08. Reason: typo
737 Driver is offline  
Old 18th Apr 2019, 15:10
  #4119 (permalink)  
 
Join Date: Dec 2015
Location: Cape Town, ZA
Age: 57
Posts: 295
Originally Posted by Icarus2001 View Post
Great, well not why not just answer the question? I also fly jet transport category aircraft. Now, the reason I asked is that there seems to be a rough split, in that actual pilots seem to be more likely to be critical of the crews actions whereas the non pilots, indeed non aviation posters, seem to be blaming Boeing more. I find this interesting.

I am not a pilot, but having followed this thread (and others) very carefully, there seems to be not just a simple split, but a culture-gulf spanning a broad spectrum. Excuse the bluntness, but it may help emphasize the polarisation:
1. Anything that happened was entirely the fault of the 3rd world pilots, and our glorious Boeing is perfect (the "Trump" option).
2. Boeing made a boo-boo, but any half-competent pilot could easily have recovered the situation, and this would never have happened to my airline.
3. Boeing made a very serious error, but the pilots should have done better, and could have recovered the situation.
4. There is a chain of errors, from Boeing, the FAA , the documentation and pilots training, all of which need remediation.
5. Boeing is a criminal enterprise, and entirely responsible (the "Ralph Nader" option).

Fortunately in most posts on this informed but open forum, the extreme options do not come up. However, it is sometimes hard to distinguish the nuances between the remaining human-factors arguments, without lengthy examination of the whole decision making tree.
GordonR_Cape is online now  
Old 18th Apr 2019, 15:21
  #4120 (permalink)  
 
Join Date: Apr 2019
Location: USA
Posts: 217
Originally Posted by HPSOV L View Post
If the stick shaker activates after lift off and power, pitch, flap position, aircraft performance and primary and secondary Airspeed indications are normal the decision whether or not to perform QRH Airspeed Unreliable actions is purely discretionary.
If you look at the DFDR data, the indicated airspeeds were already diverging from liftoff, so no, they were not "normal".

The preliminary accident report contains a synopsis of the discussion between the Captain and the First Officer. At 400', the FO selected VNAV and the Captain called for "Command", but the A/P did not engage. The Captain called out for "Command" again. The A/P did not engage. He asked the FO to change to a new ATC frequency. The FO checked in with radar, received an ATC instruction, and responded. The Captain called for flap retraction, and the FO responded. The Captain asked the FO to request runway heading from ATC. The FO did so.

What is conspicuously absent from the dialogue is any attempt to confirm that their airspeeds were indeed "normal". They were not. Despite having multiple warnings that are explicitly stated in AD 2018-23-51 (the 737 AD published post Lion Air), this crew made no apparent attempt to determine this crucial fact. If they had done so, then performance of the Airspeed Unreliable non-normal would have been anything but discretionary.

Last edited by 737 Driver; 18th Apr 2019 at 15:25. Reason: typo
737 Driver is offline  

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

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