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Ethiopian airliner down in Africa

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Ethiopian airliner down in Africa

Old 12th Mar 2019, 18:06
  #781 (permalink)  
 
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It is an undeniable fact that if Airbus had deleted the pilot from the flightdeck entirely, back in the 80s, none of these incidents would have occurred.
And in how many other incidents have pilots made a positive contribution? Not just in the technical aspects of operating the aircraft safely, but in the whole decision making process of things like medical diversions, security incidents etc. Letís not forget that the job of a Captain is a legal responsibility of the safety of the aeroplane and all the people on it, not just safely flying from A-B. The human factor may sometimes be a weak link, but other times be a vital intervention in enhancing safety.
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Old 12th Mar 2019, 18:14
  #782 (permalink)  
 
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I openly admit that I am no fan of the way in which EASA works - being overly reliant on rules and law with sometimes peculiar interpretations of that law - but it's strange to see, following rather than leading, its member States' CAAs, that it chooses to issue an AD which appears to fail to meet the legal requirements set out in Commission Regulation No 748/2012 for such documents.

Of course, if evidence shows that the safety level of this aircraft may be compromised I would hope that this would be declared, even if the details of that evidence are not provided. Overall, as others have suggested, this is a situation which is being driven by public opinion (which may include a good many pilots). Those who claim that it's driven by safety I fear may be deluding themselves. I'm not suggesting that it is wrong that these aircraft are being grounded, but actions are hardly being led by the agencies that are established to protect the travelling and innocent ground-dwelling public.
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Old 12th Mar 2019, 18:36
  #783 (permalink)  
 
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The 737 Max is now the most well known aircraft type ever to Joe public for all the wrong reasons. There was sadly no other option but to ground them at least apart from the U.S where they are still flying for now.
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Old 12th Mar 2019, 18:38
  #784 (permalink)  
 
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Originally Posted by BleedingOn View Post


And in how many other incidents have pilots made a positive contribution? Not just in the technical aspects of operating the aircraft safely, but in the whole decision making process of things like medical diversions, security incidents etc. Letís not forget that the job of a Captain is a legal responsibility of the safety of the aeroplane and all the people on it, not just safely flying from A-B. The human factor may sometimes be a weak link, but other times be a vital intervention in enhancing safety.
DC10 Sioux City, DHL A300 Bagdad come to mind
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Old 12th Mar 2019, 18:38
  #785 (permalink)  
 
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Originally Posted by 22/04 View Post
Social media drives the world!
Oh, for social media back when the American DC-10 cargo door blew out.

And regarding the Lipstick On A Pig Max, I've never seen so many professionals on social media right here (and you can always pick them out) say that now they would not ride on it. Just look at this thread. It was strong enough after Lion Air ...
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Old 12th Mar 2019, 18:43
  #786 (permalink)  
 
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Currently the Max -9 has (7) in flight. The Max-8 has (94) in flight.
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Old 12th Mar 2019, 18:44
  #787 (permalink)  
 
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Originally Posted by HowardB View Post
DC10 Sioux City, DHL A300 Bagdad come to mind
And very much the Hudson river. That would almost guaranteed been a loss of all passengers, and very possibly a significant number on the ground too.
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Old 12th Mar 2019, 18:45
  #788 (permalink)  
 
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EASA says "no":
https://www.easa.europa.eu/newsroom-...rations-europe
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Old 12th Mar 2019, 18:52
  #789 (permalink)  
 
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While there is not yet sufficient information to draw a clear link between the ET accident that is the subject of this thread and MCAS I am deeply troubled by the amount of misinformation regarding MCAS that is being spread here. Reluctantly I offer the explanation below without any suggestion that this system contributed to the tragedy in Ethiopia this last weekend. The truth will be revealed by the recorder data and the full investigation. I strongly implore those who do not know MCAS details to stop providing incorrect information here or anywhere else. Posing questions is fine, but please do not state as fact that about which you are not sufficiently knowledgeable.

MCAS Operation Clarification

MCAS is triggered when all of the following are true:
A. Sensed AOA exceeds a flight condition based activation threshold
B. Flaps are fully retracted (i.e., up)
C. Autopilot is not engaged

When triggered, MCAS commands nose down stabilizer as a function of how much AOA has exceeded the activation threshold and the current Mach number. For large exceedence of the MCAS activation AOA threshold, MCAS will command 2.5 degrees of stabilizer at low Mach number but less than 1/3rd of that at cruise Mach number (gradual Mach number based schedule between). For a lesser exceedence of the MCAS activation AOA threshold the size of the stabilizer increment will be proportionally less. MCAS stabilizer command will be stopped immediately upon pilot activation of pitch trim. (Pilot trim input also serves as MCAS reset - see next paragraph.)

Once MCAS has commanded one increment of stabilizer motion, it will not command more until it has been reset. MCAS is reset if any of the following occur:
1. Pilot makes a manual trim command. (MCAS will not re-activate until there have been 5 continuous seconds without pilot trim command.)
2. AOA drops below MCAS activation threshold and MCAS has run stabilizer in the airplane nose up direction taking out the increment of airplane nose down command it inserted earlier.
3. Autopilot is engaged and then disengaged.

Without pilot trim input, MCAS will not run the stab more than one increment (up to 2.5 degrees) unless MCAS is reset via either 2 or 3 above.

Talk of MCAS running the stabilizer for 10 seconds, pausing for 5 seconds, and then running it again repeatedly without pilot trim input are patently incorrect.
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Old 12th Mar 2019, 18:54
  #790 (permalink)  
 
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Originally Posted by LandASAP View Post
According to FR24 almost all remaining airborne 737 max flights are currently diverting to the nearest Airport. What else should you tell your passengers in this Situation?
And some seem to have difficulty finding someone to make a decision where to park the static display:





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Old 12th Mar 2019, 19:01
  #791 (permalink)  
 
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FCENG

so you are 1000 feet and MCAS dials 2.5degrees nose down WHAT DO YOU DO?
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Old 12th Mar 2019, 19:01
  #792 (permalink)  
 
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Originally Posted by Marty-Party View Post
Seriously ? While we all know that pilot error has been involved in a number of accidents, this potential fault in the 737Max shows that the pilots can be the last line of defence if properly trained. The Lion Air accident shows that the previous day the pilots successfully managed a serious computer error and saved all those on board. Unfortunately that is not always the case. The pilots were not successful in saving the AF447 but the aircraft would certainly have crashed anyway if just the computer systems were involved.
Wrong on all counts.
a. The 737 is not a computer controlled aircraft by any stretch of the imagination. It is the original fly-by-wire aircraft (yup - 5mm steel cables).
b. The Indonesian, Ethiopian(?), A320, A340, and many other incidents demonstrate that the pilots were NOT able to be the last line of defence. Quite the reverse.
c. AF447 could easily have been saved by computer software. If Normal-law drops out because of input errors, the aircraft defaults to Alternate-law, which is a basic control system running on attitude and power. It would take Airbus a couple of years to knock up this new Alternate-law, which assumed no pilot assistance.
d. The Sioux DC10 crash was easily flown with a computer (just on engines, with no flight controls). They knocked up that new software inside a year.

.
Originally Posted by SLFinAZ View Post
So I'm curious, exactly how would you handle both of the recent tragedies in question here. Both are the direct result of sensor malfunctions which disconnected the AP (or made AP enablement impossible) so what happens when HAL gets booted off the flight deck?
Fairly simple in computer terms. Do remember that the 737 is not a computer-driven aircraft at all. It has some auto-systems that have been hastily (and inadvisably) bolted onto an aircraft that is no more complex than a Cessna 152 (same type of flight-control system). As mentioned above, on a computer controlled aircraft, if Normal-law drops out because of input errors, the aircraft defaults to Alternate-law -- which is a basic control system running on attitude and power. It would take Airbus a couple of years to knock up this new Alternate-law, which assumed no pilot assistance.

Silver

Last edited by silverstrata; 12th Mar 2019 at 19:38.
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Old 12th Mar 2019, 19:03
  #793 (permalink)  
 
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Originally Posted by silverstrata View Post
Wrong on all counts.
a. The 737 is not a computer controlled aircraft by any stretch of the imagination. It is the original fly-by-wire aircraft (yup - 5mm steel cables).
b. The Indonesian, Ethiopian(?), A320, A340, and many other incidents demonstrate that the pilots were NOT able to be the last line of defence. Quite the reverse.
c. AF447 could easily have been saved by computer software. If Normal-law drops out because of input errors, the aircraft defaults to Alternate-law, which is a basic control system running on attitude and power. It would take Airbus a couple of years to knock up this new Alternate-law, which assumed no pilot assistance.
d. The Sioux DC10 crash was easily flown with a computer (just on engines, with no controls). They knocked up that new software inside a year.

Silver

And how many times did the pilots save the airplane from the automation?
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Old 12th Mar 2019, 19:05
  #794 (permalink)  
 
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Originally Posted by ReturningVector View Post
And don't forget that most accidents that have happened would also have happened if there were no pilots.
Really? Last year alone pilot errors in airliners contributed to almost 500 fatalities.

Also the case with Lion Air, that plane would have crashed without pilots as well, only sooner. And the day before, the pilots had even saved that plane from the failing automation.
A fully automated aircraft would probably detect the AOA-mismatch while still on ground, and would have no need for MCAS to begin with. 😉
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Old 12th Mar 2019, 19:10
  #795 (permalink)  
 
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Originally Posted by KRUSTY 34 View Post
The FAA shouldnít be anywhere near the investigation.
I fully agree!
While the NTSB is a great Organisation (the worldwide benchmark when it comes to flight safety) and beyond the slightest doubt, the FAA has presented themselves time and again mainly as a lobbyist for the industry. Safety does not appear to be anywhere near the top ten on their agenda. And that is nothing new. Sadly.
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Old 12th Mar 2019, 19:11
  #796 (permalink)  

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Originally Posted by The Bartender View Post
Really? Last year alone pilot errors in airliners contributed to almost 500 fatalities.



A fully automated aircraft would probably detect the AOA-mismatch while still on ground, and would have no need for MCAS to begin with. 😉
You ever flown an airliner Bartender.?
Didnít think so..
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Old 12th Mar 2019, 19:11
  #797 (permalink)  
 
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Sort of...

MCD inspired by the brilliant crew handling of the Sioux City incident, using thrust vectors, then worked out a system they called ďfly by fireĒ where the control inputs were sent tho the engine fcus instead of the flight controls. Visiting pilots were invited to try it in flight and apart from a little lag, were very impressed.
I donít know whether the system was marketed, however.
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Old 12th Mar 2019, 19:22
  #798 (permalink)  
 
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Originally Posted by oldoberon View Post
FCENG

so you are 1000 feet and MCAS dials 2.5degrees nose down WHAT DO YOU DO?
1. First thing is pull the column to put in the between 5 to 8 degrees of airplane nose up elevator needed to offset the MCAS stabilizer increment.
2. Use manual pitch trim to re-establish trim to the point of not needing to hold column.
3. If stabilizer runs airplane nose down again, recognize it as inappropriate and arrest by using manual pitch trim to stop MCAS stabilizer motion and move stabilizer back to trimmed position. (No need to sit idly by and watch 10 seconds of stabilizer motion taking you away from trim go in when you have determined that is not appropriate.)
4. Call for PNF to toggle stabilizer cutout switches and discuss managing pitch trim via manual trim wheel for the balance of this flight.
5. Make sure that this event is squawked in a manner that assures:
- The source of the errant stabilizer motion is identified and corrected prior to the next flight
- The next crew to fly this bird knows full well what was encountered on this flight and what was done to work around it.
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Old 12th Mar 2019, 19:29
  #799 (permalink)  
 
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Originally Posted by FCeng84 View Post
While there is not yet sufficient information to draw a clear link between the ET accident that is the subject of this thread and MCAS I am deeply troubled by the amount of misinformation regarding MCAS that is being spread here. Reluctantly I offer the explanation below without any suggestion that this system contributed to the tragedy in Ethiopia this last weekend. The truth will be revealed by the recorder data and the full investigation. I strongly implore those who do not know MCAS details to stop providing incorrect information here or anywhere else. Posing questions is fine, but please do not state as fact that about which you are not sufficiently knowledgeable.

MCAS Operation Clarification

MCAS is triggered when all of the following are true:
A. Sensed AOA exceeds a flight condition based activation threshold
B. Flaps are fully retracted (i.e., up)
C. Autopilot is not engaged

When triggered, MCAS commands nose down stabilizer as a function of how much AOA has exceeded the activation threshold and the current Mach number. For large exceedence of the MCAS activation AOA threshold, MCAS will command 2.5 degrees of stabilizer at low Mach number but less than 1/3rd of that at cruise Mach number (gradual Mach number based schedule between). For a lesser exceedence of the MCAS activation AOA threshold the size of the stabilizer increment will be proportionally less. MCAS stabilizer command will be stopped immediately upon pilot activation of pitch trim. (Pilot trim input also serves as MCAS reset - see next paragraph.)

Once MCAS has commanded one increment of stabilizer motion, it will not command more until it has been reset. MCAS is reset if any of the following occur:
1. Pilot makes a manual trim command. (MCAS will not re-activate until there have been 5 continuous seconds without pilot trim command.)
2. AOA drops below MCAS activation threshold and MCAS has run stabilizer in the airplane nose up direction taking out the increment of airplane nose down command it inserted earlier.
3. Autopilot is engaged and then disengaged.

Without pilot trim input, MCAS will not run the stab more than one increment (up to 2.5 degrees) unless MCAS is reset via either 2 or 3 above.

Talk of MCAS running the stabilizer for 10 seconds, pausing for 5 seconds, and then running it again repeatedly without pilot trim input are patently incorrect.
So, in other words, much the same as has been said here already.
So MCAS activates, due to faulty AoA sensor reading.
Pilot resets the system by applying counter trim.
MCAS rolls again... (repeat, while airplane accelerates and finally MCAS wins...)

Why does MCAS run the stab? Why not offset the elevator?

Will MCAS also reset, if it is switched off and switched on again?

Why does MCAS not also read - for instance - vertical and horizontal speeds and their trends first, instead single-pointedly relying on the AoA reading and deciding the airplane is about to stall and start fu****g with the stab?
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Old 12th Mar 2019, 19:29
  #800 (permalink)  
 
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That post suggests that using the electric trim button (presumably the most convenient practice) generates issues. Whereas, after toggling the stab off, the geriatric trim wheel solves all problems?

Oh, and using primary flying controls instead of autopilot settings, I assume?
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