sgrow787
Posts: 165
Joined: Fri May 16, 2014 8:12 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 2:56 am

So I was able to find the AD linked to the ADIRU Wikipedia entry (w.r.t. mounting issues for ADIRUs):

http://rgl.faa.gov/Regulatory_and_Guida ... 2003-26-03

The FAA is superseding an existing airworthiness directive (AD), which applies to
certain Airbus Model A319, A320, and A321 series airplanes equipped with certain Litton air data
inertial reference units (ADIRUs). That AD currently requires modifying the shelf (floor panel)
above ADIRU 3, modifying the polycarbonate guard that covers the ADIRUs for certain airplanes,
and modifying the ladder located in the avionics compartment for certain airplanes. This new AD
requires those modifications on additional airplanes. This new AD also requires replacing all three
ADIRUs with improved ADIRUs. This new AD also adds Model A318 series airplanes to the
applicability. This AD results from reports that ''NAV IR FAULT'' messages have occurred during
takeoff due to failure of an ADIRU and subsequent analysis showing that the shelf modification has
not sufficiently addressed failure of an ADIRU. We are issuing this AD to prevent failure of an
ADIRU during flight, which could result in loss of one source of critical attitude and airspeed data
and reduce the ability of the flightcrew to control the airplane.


And from another AD from EASA, which seems in the realm of the current 737 Max crashes:

http://rgl.faa.gov/Regulatory_and_Guida ... -19-14.pdf

EASA has also issued MCAI 2013-0107, dated May 17, 2013, which states:
An A330 aeroplane experienced a sudden nose down movement while in cruise. This
event was preceded by an automatic autopilot disconnection, which triggered the
''NAV IR1 FAULT'' Electronic Centralised Aircraft Monitor (ECAM) Caution.
Investigation results highlighted that at the time of the event, the Air Data Reference 1
(ADR) part of ADIRU1 was providing erroneous and temporary wrong parameters in
a random manner. This abnormal behavior of the ADR1 led to several consequences
such as unjustified stall and over speed warnings, loss of attitude information on
Captain Primary Flight Display (PFD) and several ECAM warnings. Among the
abnormal parameters, the provided Angle of Attack (AoA) value was such that the
flight control computers commanded the sudden nose down movement.


I found that one by using the Search tool for "ADIRU" on the FAA's RGL site:

http://rgl.faa.gov/Regulatory_and_Guida ... enFrameset
Last edited by sgrow787 on Sat Apr 06, 2019 3:10 am, edited 1 time in total.
 
hivue
Posts: 1903
Joined: Tue Feb 26, 2013 2:26 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 2:57 am

remcor wrote:


I found this interesting: "But the aggressive MCAS, trimming with a speed 50% higher than the pilot and for a full nine seconds, kicks in at 8 with a force they didn’t expect. Speed is now at 375kts and MCAS was never designed to trim at these Speed/Altitude combinations."

So MCAS was not designed to scale its trim effectiveness at high dynamic pressure? I suppose that's understandable given that the Boeing engineers never thought it would ever activate in that type of situation, but it could have meant the difference between the crew being able to recover and crashing.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
morrisond
Posts: 1179
Joined: Thu Jan 07, 2010 12:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobiq

Sat Apr 06, 2019 3:10 am

Waterbomber2 wrote:
speedbored wrote:
morrisond wrote:

I got this off the other Forum for the NG - apparently it applies to almost all Boeing Models

"A few days back I received a new procedure in my 737 QRH, for airspeed unreliable. We now have a set of thrust settings in combination with a specific pitch attitude, as memory items.
Config flaps up: 4 degrees pitch up, and 75% N1
Config flaps extended: 10 degrees pitch up and 80% N1

Boeing has introduced this for most if not all of their types. I'll simply let Boeing answer this for you:

These pitch and power settings provide a simple reference setting for the crew to use for a short period of time while the initial steps of the checklist are accomplished. These settings do not ensure a level flight or constant airspeed at any particular altitude/airspeed/weight combination. However, they do ensure that at any and all weight/altitude combinations, the aircraft will accelerate from low speeds, and slow from a high speeds, as we cannot assume the aircraft is in stable flight when the NNC is run. It is more likely that the crew or the autopilot has destabilized the airplane as a result of erroneous airspeed indications prior to identification of the need to run the NNC. These memory item pitch and power settings often result in a significant climb (from lower altitudes) and can also result in a gradual descent (from higher altitudes)."

This is a memory item for 737 Pilots and given the low altitude (relative to flying above 30,000') they were at should have produced a climb.

Apparently it was in response to AF447.

It looks like ET302 were trying to hold 4 Degrees but they didn't reduce to 75% N1

At takeoff, they should have had >90% N1 set. Going by your specified "memory items", they should then have reduced this to 75% N1 after the flaps came up. But, before they got as far as reducing thrust to 75% N1, MCAS kicked in and started messing with their pitch, so they worked on that first by following the AD / runaway trim procedure. They never got the chance to get back onto the unreliable airspeed checklist to reduce their thrust.


Wait a minute Jose.
You are on a routine take off roll, you rotate, start climbing and BAM! out of nowhere the stick shaker goes off. Tell everybody that despite having no altitude and the stick shaker is going off, your first instinct is to reduce N1??
That the airspeeds disagree is a mere detail at that point because near the stall range airspeed is going to disagree anyway.
No way Jose, you keep N1 right where it is and reduce the attitude while picking up speed.
Then Bam! out of nowhere MCAS hits, confirming that you are indeed stalling. Everything at that point seems to be pointing to a stall even if you can't explain it. Blocked static ports causing the speed to be exagerated and taking off prematurely?
At that point, you would aim for VMO just to be sure, because that's your safest bet.

The MCAS hits again and again while your speed is picking up rather quickly now.
You start realizing that you may not be stalling and this is the Lion Air situation. That's when you start pulling and flip the switch.
It's too late to reduce N1 now, you are already cornered, so you hope to pull your way out of it.

Remember to see the facts as a sequence the same way the pilots experienced them and not start from the conclusions of the report. If the pilots had the luxury of reading the preliminary report before they got on that flight, there would have been no crash or preliminary report.



I was just replying to speedbored that He didn't believe setting N1 to 75% was the published procedure - of course pulling back power a few seconds after leaving the ground would not be very wise.

However as someone else pointed out up thread - if retracting flaps caused the plane to go screwy your first reaction should have been to return the plane to its previous state - where flaps were down and consequently MCAS would be inactive as well.
 
User avatar
SheikhDjibouti
Posts: 1718
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobiq

Sat Apr 06, 2019 4:13 am

morrisond wrote:
However as someone else pointed out up thread - if retracting flaps caused the plane to go screwy your first reaction should have been to return the plane to its previous state - where flaps were down and consequently MCAS would be inactive as well.

All fine & dandy - except it wasn't retracting the flaps that caused MCAS to operate.

There was a 15 second delay between flaps up and MCAS.
That in itself is enough to break the cause-and-effect chain.

More significantly something else changed in those 15 seconds, something quite significant and not necessarily expected.

Try again!
Nothing to see here; move along please.
 
User avatar
767333ER
Posts: 961
Joined: Wed Jun 15, 2016 5:14 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 4:29 am

Amexair wrote:
MD80Ttail wrote:
767333ER wrote:
In the case of Lion Air, I’m not sure what you think you know about their piloting decisions when the issue first off was literally nothing they’ve ever seen before and something they weren’t trained to deal with thanks to Boeing’s obviously deliberate “negligence” to include it in the differences training and manuals. And now the idea I’ve heard circulating now that the trim might have ended up failing before the crash. Someone who comes on here and says both planes could have and should have landed safely clearly just does not get how flying a plane in a situation like this works or just doesn’t get the situation in the first place. The real point is they should never have allowed the risk from this design to get to the point where it’s almost not humanly possible to mitigate the risk! I don’t know what your background is but when you have most pilots and all the ones I know saying this thing designed the way it is is a death trap, I think it’s pretty close to that.


What trim management mistakes when there is no trim anyway? Turn the power on, you’re fighting MCAS with your thumb switch that has limited authority, turn it off and you have “manual trim” which according to an engineer that was in charge of such things on the NG said at that point it was almost impossible for most pilots to use since they used a smaller trim wheel and different mechanics than the older 737.

Ultimately blaming the crew and considering them the variable that needs to be changed is flawed logic. Why change the inconsistent variable that will always be imperfect? You put another crew in there with different training, they might recover, they might not, we can’t sit here and refute that theywill be able to do it because we just don’t and can’t know. That’s why the constant variable shouldn’t be targeted which is Boeing’s design. Of course this can only be done if there is a design flaw (yes it is a flaw as per Merriam-Webster dictionary: an imperfection or weakness and especially one that detracts from the whole or hinders effectiveness) in the mix which there is. Take this away and you can be guaranteed none of these crashes would’ve happened because there would be no erroneous operation of the trim to have to deal with. A pilot should never have to fly a plane that literally is trying to crash itself, of course this does happen from time to time for various reasons, but when it’s because of lousy engineering, that’s the worst because that junk is flying off the assembly line at a rate of 50-60 a month all with the same flaw, not just one plane that got damaged and now is compromised.


Here’s what I know in Lion. The captain was PF. He was successfully controlling a plane with multiple issues for several minutes. He was able to override MCAS by making trim up inputs. They had issues BUT they were flying. The plane was somewhat stable and I use that term loosely but the point is he WAS in control for several minutes. How do I know this? If he wasn’t they would have crashed sooner. He hands off flying duties to the FO. The FO does not employ the same previously successful techniques as the captain had moments and minutes before. The plane becomes out of control and crashes. I also know there are procedures in place on the Max, the 737 and every single plane equipped with electric trim...since electric trim was invented.....which should be a memory item and should have been sufficient to disable MCAS. I know at least one previous Lion flight crew had a mirror situation on the previous flight and they properly handled the situation and made a safe landing. To say this was an impossible situation the Lion pilots faced is just completely wrong. Would we say AF447 faced an impossible situation? It was also a known situation as the plane had experienced multiple prior failures of the same or similar nature. Information the fatal crew had the benefit of knowing the previous crews did not have. Further we know the previous crew was successful but what we don’t know or haven’t learned....or I don’t know at least....is how many of the other 4-5 previous flight crews also had the same or similar situation and handled it properly. We know there were issues but not how severe. Possibly we had multiple flight crew properly manage the same issue. We do know for sure the previous flight crew had things come completely off the rails and they managed the situation properly.

We know with the ET flight the crew turned the trim on and off. What I don’t understand and makes no sense is why they would not return the plane to a properly trimmed state before again shutting off the trim. They almost had a successful outcome but botched the procedure. Kind of an “the operation was a success but the patient died” scenario. In this case and I have been very vocal about the 150-200 hrs FO not having enough experience for this set of circumstances......the crew didn’t make good decisions. They knew about MCAS...don’t tell me a single Max pilot in the world didn’t know about Mcas after the Lion accident. I will not believe you unless the max pilot was in a coma. Every Max, and every non Max pilot knew. I know the ET plane was capable of flying, it had wings, control surfaces, power ect. All of the ingredients. Again the crew managed the Mcas issue partially. They successfully handled it, used the proper procedures and the. Turned back on the system. Ok fine. Probably needed the electric trim. Makes sense. What doesn’t is why after trimming the plane they didn’t disable the system? Knowing what I learned after the Lion crash I probably would have elected to extend the flaps knowing MCAS is disabled AND I had the benefit of full electric trim.

Having a 200 hr guy in the right seat certainly wasn’t an asset to the flight no matter how you want to justify it. All they had to do was trim the plane neutral or slightly nose up and fly pitch and power on a bright, clear sunny day and land. It was that simple and it was that hard.



As crew, your job is not to sit and follow-up on Air investigations as they are happening. Your role is simply to follow operational procedures normal/non-normal and try your best to troubleshoot an issues as they arise. Putting the trim to a "properly trim state" was not indicated in Boeing's Bulletin/ FAA's AD. Unfortunately, the reason is - it would have required additional SIM time since the RUNAWAY TRIM NNC would require revision.

The crew did the best they possibly could. In every situation its always easy to look back and say of "they could have done this/that". At the end of the day, they followed procedure and it did not work, period. So, if that doesn't prove that to you then I don't know what will. I recall saying the same thing to someone on this thread when he was so sure that all they had to do was "Cut-off the Trim switches". Guess what, now we realized that they did then its time we shift our eyes to your lovely Boeing company that you're so passionately defending.

Maybe, we can reenact the whole situation and put you on the controls in the SIM idk.

Thank you, I guess some people just can’t stomach the fact that this is mostly Boeing’s problem and have to look for any excuse they can to blame the crew... Nationalism?
Been on: 732 733 734 73G 738 752 763 A319 A320 A321 CRJ CR7 CRA/CR9 E145 E175 E190 F28 MD-82 MD-83 C172R C172S P2006T
 
MSPNWA
Posts: 3309
Joined: Thu Apr 23, 2009 2:48 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 4:44 am

PW100 wrote:
As you can see in ALL of my posts, I continue asking questions as to why the crew did this, did that, stopped uptrimming way before the control column was balanced in pitch. Why they reinstated electric trimming. Trying to find answers.
The only thing I see from you, is that crew made a lot of mistakes. I have not seen one single effort from your side trying to answer these important questions.

So it seems to me that it is you desperate for finding "facts" to fit a conclusion. I'm sorry, I can't debate against that.


You're not asking questions in this thread (in general). You're continuously making authoritative-sounding, speculative statements that do not follow the facts of the situation.

The facts tell us the crew apparently made multiple mistakes. I'm not saying it. The authorities are saying it. It's up to you whether you want to trust those authorities or make your own "facts".
 
mandala499
Posts: 6587
Joined: Wed Aug 29, 2001 8:47 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 5:48 am

xmp125a wrote:
NOWHERE in the directive is "reenable flaps" mentioned as remedy. So, again, this is Monday morning quarterback syndrome. You know that because you had days to ponder over what to do. They had minutes and ton of work to do, even after being perfectly aware what is the problem.

It is NOT monday morning quarterbacking.
Deployment of flaps to disable MCAS was discussed by some in the industry, one reason is that the crew of JT610 did redeploy flaps at one stage and that disabled the MCAS... but when they retracted it, MCAS came alive again.

The mystery is, what made the Lion Air crew able to maintain trim for several minutes where Ethiopian crew failed to do (but then disabled stab trim power while out of trim)?

morrisond wrote:
While the rate of accidents is low it could be better - many of accidents in the past years were a result of Electronics failures followed by incorrect procedures applied by pilots - and to be fair to them I would have to guess because of a lowering of training standards and Airlines not wanting to spend the money on training it's more a failure of training than anything. With the very few crashes we have had the Airlines probably would not have thought that a very good return on investment.

There is a difference between increasing training within the airline, with the idea that one must have 1000hrs before one can step into a jetliner. The former is OK, the latter, well, other countries are fine with it.

morrisond wrote:
I'm willing to spend $5 more ticket so Pilots get more training.

If all the airlines offering a route has an acceptable standard of minimum training, and one airline spends extra on training and passes it on to the customer, and the other doesn't have the extra, with service and schedules being identical, how many people being offered would choose the one with $5 extra? The sad story is, not 100%... but that's the reality.

Wake up and smell the fresh spring air... :)

mzlin wrote:
It is the final paragraph in this directive which is a restatement of the runaway stabilizer memory checklist:

Thanks... I think we have a problem in how this MCAS thing is trained...
I think the crew of ET followed this AD...
Going from the top to bottom.. Cutout... was told to cut out for the remainder of the flight... and then down at the bottom, "by the way, you can use the electric stabilizer before the cutout if it feels heavy or hard to move the stab trim"... Oh, OK, let's try that... then MCAS starts acting up...


PW100 wrote:
As you can see in ALL of my posts, I continue asking questions as to why the crew did this, did that, stopped uptrimming way before the control column was balanced in pitch. Why they reinstated electric trimming. Trying to find answers.
The only thing I see from you, is that crew made a lot of mistakes. I have not seen one single effort from your side trying to answer these important questions.

See the above (and the reply by MZLIN at $4492)

Planetalk wrote:
tibs wrote:
"Whenever we talk about a pilot who has been killed in a flying accident, we should all keep one thing in mind. He called upon the sum of all his knowledge and made a judgment. He believed it so strongly that he knowingly bet his life on it. That his judgment was faulty was a tragedy, not stupidity. Every inspector, supervisor, and contemporary who ever spoke to him had an opportunity to influence his judgment, so a little of all of us goes with every pilot we lose." --- Anonymous

Thank you for that. The person who responded to a request for respect with 'Americans bow to nobody' is perhaps the most shameful, least humane thing I've ever read on this Forum. From a fellow pilot too. The sad thing is, many before held such attitudes, probably many pilots far more skilled than this individual, until the moment they too faced death and realised it can happen to them and they are not so special. Arrogance is the enemy of safety and I cannot believe there are still pilots out there who haven't learned that.

I don't even get it. A pissing match could go on forever pointing out American pilots who crashed planes that really did have nothing wrong with them. What does anyone learn from this crap? AsI noted, Ethiopians are the only pilots ever to have successfully ditched a widebody and while fighting off highjackers who insisted they keep a plane without fuel in the the air. And some here have been frankly disgusting in their allusions to the competence of pilots from their nation. Would all the armchair pilots here have done so well? Unlikely.

Agree to both of you.
In the discussions, asking why the crew did this and not that, should be done with the mindset of trying to understand what he was faced with, and what made his thought process go the direction of what he did... rightly or wrongly, because he didn't want to do wrong. The sad part of these discussions is that many, including pilots sadly, go through with the mindset of "he should have known he should have done this and not that, therefore he was being stupid or was trained wrong, because that's not how I would do it"... which is simply arrogance and is disgusting.

I've had the pleasure of dealing with this kind of people (real pilots and armchair pilots} by shoving them into a simulator and get the sim instructor operator to throw them malfunction combos (and often in varying sequences that's different from what they expected) and see them fail... miserably...

MD80Ttail wrote:
Notice after the ET crash and before the grounding I believe it was India (possibly wrong country) increased the min hours for cockpit crews to fly Max.

Lion Air raised the minimum total hours and the minimum total 737NG hours for Max left and right seaters, once the FDR content was known... Unfortunately, the manufacturer was adamant that such actions was unnecessary. :(

MD80Ttail wrote:
Boeing doesn’t tell airlines the min requirements to fly said type

They do for certain clients... (Lion was one, back in the early 737-900ER days, until the airline had enough 737NG pilots with a certain level of 737NG experience, then they stopped the requirement).
Airbus set the minimum requirements for Batik Air pilots for the 320, but this is done through the training partnership. This is probably because both Boeing and Airbus, didn't want their jets creating smoking holes in the ground on a regular basis... Yeah this ain't 1st world problems though... but it's part of reality with us down here...

hivue wrote:
I found this interesting: "But the aggressive MCAS, trimming with a speed 50% higher than the pilot and for a full nine seconds, kicks in at 8 with a force they didn’t expect. Speed is now at 375kts and MCAS was never designed to trim at these Speed/Altitude combinations."

So MCAS was not designed to scale its trim effectiveness at high dynamic pressure? I suppose that's understandable given that the Boeing engineers never thought it would ever activate in that type of situation, but it could have meant the difference between the crew being able to recover and crashing.

Hence the need for the fix to prevent pilots losing control...

SheikhDjibouti wrote:
There was a 15 second delay between flaps up and MCAS.

Which accident? ET or JT? From the ET302, the MCAS played immediately once flaps were up... It takes time from the flap handle being moved to UP and the flap reaching the UP position... and yes, in the ET302 case... that was the "macig 15seconds"... The cause-and-effect chain wasn't broken... in fact, it is reinforced by it.
In the FDR plot, the green line is the flap handle position, not the flap's actual position (blue line)... you'll see the 15 second gap.
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
Waterbomber2
Posts: 383
Joined: Mon Feb 04, 2019 3:44 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobiq

Sat Apr 06, 2019 6:03 am

morrisond wrote:
Waterbomber2 wrote:
speedbored wrote:
At takeoff, they should have had >90% N1 set. Going by your specified "memory items", they should then have reduced this to 75% N1 after the flaps came up. But, before they got as far as reducing thrust to 75% N1, MCAS kicked in and started messing with their pitch, so they worked on that first by following the AD / runaway trim procedure. They never got the chance to get back onto the unreliable airspeed checklist to reduce their thrust.


Wait a minute Jose.
You are on a routine take off roll, you rotate, start climbing and BAM! out of nowhere the stick shaker goes off. Tell everybody that despite having no altitude and the stick shaker is going off, your first instinct is to reduce N1??
That the airspeeds disagree is a mere detail at that point because near the stall range airspeed is going to disagree anyway.
No way Jose, you keep N1 right where it is and reduce the attitude while picking up speed.
Then Bam! out of nowhere MCAS hits, confirming that you are indeed stalling. Everything at that point seems to be pointing to a stall even if you can't explain it. Blocked static ports causing the speed to be exagerated and taking off prematurely?
At that point, you would aim for VMO just to be sure, because that's your safest bet.

The MCAS hits again and again while your speed is picking up rather quickly now.
You start realizing that you may not be stalling and this is the Lion Air situation. That's when you start pulling and flip the switch.
It's too late to reduce N1 now, you are already cornered, so you hope to pull your way out of it.

Remember to see the facts as a sequence the same way the pilots experienced them and not start from the conclusions of the report. If the pilots had the luxury of reading the preliminary report before they got on that flight, there would have been no crash or preliminary report.



I was just replying to speedbored that He didn't believe setting N1 to 75% was the published procedure - of course pulling back power a few seconds after leaving the ground would not be very wise.

However as someone else pointed out up thread - if retracting flaps caused the plane to go screwy your first reaction should have been to return the plane to its previous state - where flaps were down and consequently MCAS would be inactive as well.


Yeah but you also have the flaps speed limit.
If your initial assumption is that you are stalling and the speed is overindicating, then retracting the flaps is superfluous.
But remember that you are getting conflicting information: the stick shaker at the same time as indicated speed rising above the flap limit and towards VMO.
You are not sure what's going on and until you can isolate the issue with high certainty, you should fly within the normal parameters for flight to avoid making things worse.
When you are already fighting 200 demons, it's not the right moment to destroy your slats and flaps.
This is the reason they retracted the flaps in the first place.

The El AL cargo Bijlmer accident is an example where flaps were deployed after initial retraction. The aircraft's flight envelope was already severely compromised but the pilots were fighting like hell to align the aircraft with the runway. Deploying the flaps for landing made the aircraft uncontrollable and spin into the apartment block.
 
YYZatcboy
Posts: 1167
Joined: Fri Apr 22, 2005 2:15 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 6:05 am

BEG2IAH wrote:
xmp125a wrote:
SimonL wrote:
Did any checklist or procedure suggest that they should have?


It does. Issued after Lion Air crash and does not even mention flaps. Anywhere.

https://www.aviationtoday.com/wp-conten ... rgency.pdf

So either this is big omission and negligence by FAA and Boeing or there is a reason that flaps are not to be attempted as remedy.


Shouldn't this be common sense and part of a basic pilot training? Do you really need a checklist to tell you that something you just did made your aircraft hard to fly and you should go back to the previous configuration? e.g., if you stall your aircraft do you need a checklist to push the nose down or you just do it? Come on, guys, let's not be too pedantic to prove our point here. It's getting old.


Know what, that's what the Colgan FO did, and it killed them.

Shocking to see so many people here saying if the plane does something you don't like after you change configs, change it back in light of the result of that accident.

https://en.wikipedia.org/wiki/Colgan_Air_Flight_3407

Following the clearance for final approach, landing gear and flaps (5 degrees) were extended. The flight data recorder (FDR) indicated the airspeed had slowed to 145 knots (269 km/h).[3] The captain then called for the flaps to be increased to 15 degrees. The airspeed continued to slow to 135 knots (250 km/h). Six seconds later, the aircraft's stick shaker activated, warning of an impending stall as the speed continued to slow to 131 knots (243 km/h). The captain responded by abruptly pulling back on the control column, followed by increasing thrust to 75% power, instead of lowering the nose and applying full power, which was the proper stall recovery technique. That improper action pitched the nose up even further, increasing both the g-load and the stall speed. The stick pusher activated ("The Q400 stick pusher applies an airplane-nose-down control column input to decrease the wing angle-of-attack [AOA] after an aerodynamic stall"),[3] but the captain overrode the stick pusher and continued pulling back on the control column. The first officer retracted the flaps without consulting the captain, making recovery even more difficult.[23]
DH1/3/4 MD11/88 L1011 A319/20/21/30/50/80 717 727 735/6/7/8/9 744 762/3 77E/W E40/75/90 CRJ/700/705 CC150
J/S DH8D 736/7/8 763
 
User avatar
speedbored
Posts: 2207
Joined: Fri Jul 19, 2013 5:14 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobiq

Sat Apr 06, 2019 7:33 am

Waterbomber2 wrote:
speedbored wrote:
morrisond wrote:

I got this off the other Forum for the NG - apparently it applies to almost all Boeing Models

"A few days back I received a new procedure in my 737 QRH, for airspeed unreliable. We now have a set of thrust settings in combination with a specific pitch attitude, as memory items.
Config flaps up: 4 degrees pitch up, and 75% N1
Config flaps extended: 10 degrees pitch up and 80% N1

Boeing has introduced this for most if not all of their types. I'll simply let Boeing answer this for you:

These pitch and power settings provide a simple reference setting for the crew to use for a short period of time while the initial steps of the checklist are accomplished. These settings do not ensure a level flight or constant airspeed at any particular altitude/airspeed/weight combination. However, they do ensure that at any and all weight/altitude combinations, the aircraft will accelerate from low speeds, and slow from a high speeds, as we cannot assume the aircraft is in stable flight when the NNC is run. It is more likely that the crew or the autopilot has destabilized the airplane as a result of erroneous airspeed indications prior to identification of the need to run the NNC. These memory item pitch and power settings often result in a significant climb (from lower altitudes) and can also result in a gradual descent (from higher altitudes)."

This is a memory item for 737 Pilots and given the low altitude (relative to flying above 30,000') they were at should have produced a climb.

Apparently it was in response to AF447.

It looks like ET302 were trying to hold 4 Degrees but they didn't reduce to 75% N1

At takeoff, they should have had >90% N1 set. Going by your specified "memory items", they should then have reduced this to 75% N1 after the flaps came up. But, before they got as far as reducing thrust to 75% N1, MCAS kicked in and started messing with their pitch, so they worked on that first by following the AD / runaway trim procedure. They never got the chance to get back onto the unreliable airspeed checklist to reduce their thrust.


Wait a minute Jose.
You are on a routine take off roll, you rotate, start climbing and BAM! out of nowhere the stick shaker goes off. Tell everybody that despite having no altitude and the stick shaker is going off, your first instinct is to reduce N1??
That the airspeeds disagree is a mere detail at that point because near the stall range airspeed is going to disagree anyway.
No way Jose, you keep N1 right where it is and reduce the attitude while picking up speed.
Then Bam! out of nowhere MCAS hits, confirming that you are indeed stalling. Everything at that point seems to be pointing to a stall even if you can't explain it. Blocked static ports causing the speed to be exagerated and taking off prematurely?
At that point, you would aim for VMO just to be sure, because that's your safest bet.

The MCAS hits again and again while your speed is picking up rather quickly now.
You start realizing that you may not be stalling and this is the Lion Air situation. That's when you start pulling and flip the switch.
It's too late to reduce N1 now, you are already cornered, so you hope to pull your way out of it.

Remember to see the facts as a sequence the same way the pilots experienced them and not start from the conclusions of the report. If the pilots had the luxury of reading the preliminary report before they got on that flight, there would have been no crash or preliminary report.

Maybe my post wasn't that clear but I was trying to refute morrisond's assertion that the pilots should have had the thrust at 75% N1. I totally agree with you that, at the phase of flight they were in, with everything that was going on with the aircraft, this is not the case.

Only the final report will tell us what, if anything, the pilots did wrong. But right now I can see little, if anything at all, in the data or interim report, that the pilots should be faulted for. Seems to me that they followed all the correct procedures, and it was the procedures that failed.
 
WIederling
Posts: 8490
Joined: Sun Sep 13, 2015 2:15 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 8:06 am

Pluto707 wrote:
Thx Etheereal for explanation, but there are a few constraints where MCAS cannot operate, i stay convinced that low agl must be one of them also, MCAS can still do its job but only at higher altitudes



That as an example would have made the Habsheim crash near 100% lethal.
IMU it is preferable to fly into terrain over falling stalled into terrain.
( In a very convoluted and marginally functional way MCAS is an envelope protection.)

But to allow this use case ( as envelope protection ) sensor input must be sanitized and vetted carefully.
I just can't be vastly less reliable than the rest of the airplanes mandatory functions.
Murphy is an optimist
 
User avatar
speedbored
Posts: 2207
Joined: Fri Jul 19, 2013 5:14 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobiq

Sat Apr 06, 2019 8:24 am

morrisond wrote:
I was just replying to speedbored that He didn't believe setting N1 to 75% was the published procedure

I still do not believe it, because it is not true. At no point was the aircraft ever below FL050, not even while still on the runway.

Take note of the phase of flight that the pilots were in (climb - they were trying to get to 14,000ft), and the altitude they were actually at, and look at the pitch and power settings again.

Regardless of the tables, it is clear from the CVR recordings of overspeed warnings, that the pilots maintained an airspeed within the limits of the airframe for at least the first half of the flight, until they really started to struggle with, and get distracted by, controlling the aircraft. Even then, the overspeed was minor and intermittent according to one side of the aircraft, When presented with multiple different issues, and expending considerable effort on trying to keep the nose up (the overspeed warnings don't kick in until ~80 seconds after both pilots start pulling hard back on the yokes), the pilots have to prioritise what they work on.
 
User avatar
SomebodyInTLS
Posts: 1683
Joined: Wed Jun 15, 2016 12:31 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 8:54 am

VV wrote:
If you switch them OFF it is then to fly the aircraft manually. And manual means the manual trim wheel (and the handle) without the help of any electrical power. That's my interpretation anyway.

So I am totally confused by the report.


I can't understand why when it's been pointed out dozens of times already.

1) they followed all of the memory items according to the AD issued after the Lion Air crash, however they had not fully corrected the MCAS trim with electric trim during this process (referred to as manual electric trim in the preliminary report)

2) at the end of this (trim switches cut off) they were physically trying to apply more manual trim using the wheels but were unable to presumably due to aerodynamic forces from the high speed (blowback)

3) they switched electric trim back on to try and correct the trim with "manual electric" again, but their trim corrections were less than those in the opposite direction by the re-connected MCAS

So the issue is why their manual electric trim was repeatedly less than sufficient - it now seems possible that the electric trim was also having issues with blowback.

Then the question is why they didn't reduce airspeed - well they didn't have pitch control and couldn't simply reduce thrust since they were very close to the ground
"As with most things related to aircraft design, it's all about the trade-offs and much more nuanced than A.net likes to make out."
 
WIederling
Posts: 8490
Joined: Sun Sep 13, 2015 2:15 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 9:01 am

sgrow787 wrote:
So I was able to find the AD linked to the ADIRU Wikipedia entry ....t


Interesting. what they don't tell is what changing of the polycarbonate cover and the ladder
effects ( beyond avoiding ADIRU errors :-) ( final solution replacing ADIRU with a newer "fixed" model)

Was it a cooling issue, vibration causing connector contacts to "flutter", something else ?
Murphy is an optimist
 
User avatar
SomebodyInTLS
Posts: 1683
Joined: Wed Jun 15, 2016 12:31 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 9:01 am

MD80Ttail wrote:
I have stated this before but no one has discussed.....if I was in the ET cockpit...and I had considered this before the ET crash after learning from the lion accident.....I would have lowered flaps to disable the MCAS while still allowing use of the electric trim. Thoughts?


In overspeed...
"As with most things related to aircraft design, it's all about the trade-offs and much more nuanced than A.net likes to make out."
 
asdf
Posts: 329
Joined: Tue Mar 18, 2014 12:03 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 9:01 am

SomebodyInTLS wrote:
So the issue is why their manual electric trim was repeatedly less than sufficient - it now seems possible that the electric trim was also having issues with blowback.
Then the question is why they didn't reduce airspeed - well they didn't have pitch control and couldn't simply reduce thrust side they were very close to the ground


The note in the AD to FIRST get a level flight and THEN cutout the electric trim is completely ridiculous
because if they could manage to have a level flight they do not need to cutout ... problem is already solved

its like:

DIRECTIVE:
in emergency use the hand break to reduce speed of the car
NOTE:
we recommend you to stop the car bevor you apply hand break
 
MD80Ttail
Posts: 159
Joined: Wed Dec 07, 2016 1:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 10:58 am

SomebodyInTLS wrote:
MD80Ttail wrote:
I have stated this before but no one has discussed.....if I was in the ET cockpit...and I had considered this before the ET crash after learning from the lion accident.....I would have lowered flaps to disable the MCAS while still allowing use of the electric trim. Thoughts?


In overspeed...


That’s not what I said.....when flaps were retracted the problems started. I would have redeployed the flaps immediately while still at a safe speed. I have been reading here 10 plus years and finally made an account...but the whole forum has become like the news. Pick one word and focus on it to try and make a point. I never suggested deploying the flaps at an unsafe speed. My point was I would have wanted electric trim and no MCAS. Understanding the system after the Lion crash I would have immediately redeployed flaps which should give me what I want.

Also, those saying I’m wrong if you do somthing in a plane and it immediately doesn’t like what you did go to back to prior config. That’s piloting 101. Taught from the very beginning. It’s also common sense. In the Colgan crash cited as an example the poster cherry picked the FO retracted the Flaps trying to say my point is dangerous. NOT so. The FO did retract the flaps ONLY AFTER the El Capitan’ hauled back on the yoke, nosed up the plane and didn’t increase to max thrust. Since he was flying a T-tail and since he just had training on tail stalls...which are special phenomena to t-tails my guess he he wrongly concluded he had a tail stall rather than a wing stall. Point being it’s not like they extended the flaps and immediately retratced them and the plane crashed. There was a series of major mistakes in stall recovery that caused the crashed. The flap retraction came AFTER the botched recovery and further worsened their condition.

If flying or do anything really and you make an action and get an unexpected REaction immediately return to previous stable state. Just because that’s not “written” in a specific check list doesn’t mean it’s “illegal” or unwise to do. To the person stating I would be personally liable for gross negligence and find myself in front of the Chief pilot that’s totally BS. If you put your hand on a hot surface you didn’t expect to be hot and it’s burning you take your hand off immediately. Probably won’t find that in the instructions to a stove either but it’s good practice.

For me w flaps I like to get into a good nose down dive wait until severe buffeting hoping I’m close to the speed of sound and then put in full flaps on the MD80. It’s my preferred technique and the pax really love it...the FO and FAs too. I also pop out the gear. The combo of the flaps separating the plane while the gear doors separate at the same time.....a sound to behold. Gets the blood running bonus points if I can feel a thud knowing I hit the departing parts w the tail too!! Oh ya also I throw in a loop and an Immelmann If we aren’t running behind. I like to go that extra step for my pax.

Some folks here are really really incredible.
 
WIederling
Posts: 8490
Joined: Sun Sep 13, 2015 2:15 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 11:04 am

asdf wrote:
The note in the AD to FIRST get a level flight and THEN cutout the electric trim is completely ridiculous
because if they could manage to have a level flight they do not need to cutout ... problem is already solved

its like:

DIRECTIVE:
in emergency use the hand break to reduce speed of the car
NOTE:
we recommend you to stop the car bevor you apply hand break


Think of a leaky brake. You can use it to stop the car, you may have to pump it to achieve that
but you can't keep the car in place on an incline -> use hand brake.

Here you have MCAS kicking the pilot in the shins in idle moments but you need it to get into reasonable trim.
If you stop trimming MCAS, stealth is my name, will again start to act up.
Thus it is probably correct to use electric trim for a sane trim position ( which also disallows MCAS to intervene)
and then cut trim hard and do the now reasonable trim requirements per handjob. :-)
Murphy is an optimist
 
User avatar
SheikhDjibouti
Posts: 1718
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 11:12 am

Firstly, another most excellent post from Mandala499.
So many good points, even including the one where you point out my clumsiness. :lol:
mandala499 wrote:
SheikhDjibouti wrote:
There was a 15 second delay between flaps up and MCAS.

From the ET302, the MCAS played immediately once flaps were up... It takes time from the flap handle being moved to UP and the flap reaching the UP position... and yes, in the ET302 case... that was the "macig 15seconds"... The cause-and-effect chain wasn't broken... in fact, it is reinforced by it.
In the FDR plot, the green line is the flap handle position, not the flap's actual position (blue line)... you'll see the 15 second gap.

Yes, I was indeed referencing ET302. And I have expressed myself very poorly. My bad.
Can I draw your attention to the sentence that followed;
More significantly something else changed in those 15 seconds, something quite significant and not necessarily expected.
This is probably my fault for not spelling out my main point clearly enough.
The "something else" was autopilot randomly disengaging.
If flaps retraction had been the only action in this 15 second window, MCAS would not have activated at 05:40:00 :shakehead:

On another day we could have been looking at a scenario where 60 seconds elapsed followed the successful stowage of flaps. I would argue that would represent a break in the chain. And in such circumstances it would appear to an onlooker that it was the autopilot disengagement that actually triggered MCAS.
This would undermine the argument for retracing one's steps and re-engaging flaps.
However I am forced to accept that wasn't the case on ET302.

I use the phrase "autopilot randomly disengaging", but I suppose this action was inevitable due to IAS disagree; it was only the timing that was random.

Once again, apologies for not making myself clear, and thanks for your excellent observations. :bigthumbsup:
Nothing to see here; move along please.
 
Exeiowa
Posts: 147
Joined: Fri Jul 06, 2018 4:49 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 11:27 am

I think its possible that the pilots follwed the check list thinking they had an MCAS issue. But once completed the plane was not behaving the way they expected based on what the list said. At that point they conclude it a different problem and they really need electronic trim function back. This is plausible but I dont think what actually happened
 
User avatar
SheikhDjibouti
Posts: 1718
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 11:32 am

SomebodyInTLS wrote:
2) at the end of this (trim switches cut off) they were physically trying to apply more manual trim using the wheels but were unable to presumably due to aerodynamic forces from the high speed (blowback)

3) they switched electric trim back on to try and correct the trim with "manual electric" again, but their trim corrections were less than those in the opposite direction by the re-connected MCAS

So the issue is why their manual electric trim was repeatedly less than sufficient - it now seems possible that the electric trim was also having issues with blowback.

Captain Hindsight with a possible answer here;

1. Re-engage stab trim cut-out
2. Immediately (or even sooner than that!) use thumb switches, and continue to depress the thumb switch to prevent MCAS function.(*)
3. Now, in conjunction with the electric motor attempting to move the stabiliser, both pilots crank the manual trim wheel
4. You now have one electric motor plus two pilots attempting to move the jackscrew
5. If that fails; pray.

(*) on both control columns, the thumb switch is located on the outside, leaving the inside arm free to operate the trim wheel.
I assume this is exactly what was intended.... or did it just happen that way by chance?

Maybe this procedure is exactly what both JT610 and ET302 attempted in their final moments? Unfortunately neither CVR nor FDR appear to show us their exact actions at this time.

If I knew that the thumb switch was the only thing holding MCAS back, my thumb would be locked in position holding that switch. Like this. :thumbsup:
A roll of gaffer tape would be even more useful....

If for some reason the pilots maintained pressure on the thumb switch and yet MCAS still activated, then maybe this is the hidden problem Boeing are now trying to solve. :scratchchin:
Nothing to see here; move along please.
 
dragon6172
Posts: 1068
Joined: Sat Jul 14, 2007 9:56 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 11:42 am

asdf wrote:
The note in the AD to FIRST get a level flight and THEN cutout the electric trim is completely ridiculous
because if they could manage to have a level flight they do not need to cutout ... problem is already solved

its like:

DIRECTIVE:
in emergency use the hand break to reduce speed of the car
NOTE:
we recommend you to stop the car bevor you apply hand break

You don't understand how MCAS works if you think the problem is solved. The note says trim to reduce control forces before turning system off. If you don't turn it off, MCAS will trim nose down and increase control forces again.
Phrogs Phorever
 
dragon6172
Posts: 1068
Joined: Sat Jul 14, 2007 9:56 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 11:45 am

SheikhDjibouti wrote:
Captain Hindsight with a possible answer here;

1. Re-engage stab trim cut-out
2. Immediately (or even sooner than that!) use thumb switches, and continue to depress the thumb switch to prevent MCAS function.(*)
3. Now, in conjunction with the electric motor attempting to move the stabiliser, both pilots crank the manual trim wheel
4. You now have one electric motor plus two pilots attempting to move the jackscrew
5. If that fails; pray.

(*) on both control columns, the thumb switch is located on the outside, leaving the inside arm free to operate the trim wheel.
I assume this is exactly what was intended.... or did it just happen that way by chance?

More likely the thumb switches are on the outside hand because the inside hand is on the throttles
Phrogs Phorever
 
morrisond
Posts: 1179
Joined: Thu Jan 07, 2010 12:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 11:46 am

YYZatcboy wrote:
BEG2IAH wrote:
xmp125a wrote:

It does. Issued after Lion Air crash and does not even mention flaps. Anywhere.

https://www.aviationtoday.com/wp-conten ... rgency.pdf

So either this is big omission and negligence by FAA and Boeing or there is a reason that flaps are not to be attempted as remedy.


Shouldn't this be common sense and part of a basic pilot training? Do you really need a checklist to tell you that something you just did made your aircraft hard to fly and you should go back to the previous configuration? e.g., if you stall your aircraft do you need a checklist to push the nose down or you just do it? Come on, guys, let's not be too pedantic to prove our point here. It's getting old.


Know what, that's what the Colgan FO did, and it killed them.

Shocking to see so many people here saying if the plane does something you don't like after you change configs, change it back in light of the result of that accident.

https://en.wikipedia.org/wiki/Colgan_Air_Flight_3407

Following the clearance for final approach, landing gear and flaps (5 degrees) were extended. The flight data recorder (FDR) indicated the airspeed had slowed to 145 knots (269 km/h).[3] The captain then called for the flaps to be increased to 15 degrees. The airspeed continued to slow to 135 knots (250 km/h). Six seconds later, the aircraft's stick shaker activated, warning of an impending stall as the speed continued to slow to 131 knots (243 km/h). The captain responded by abruptly pulling back on the control column, followed by increasing thrust to 75% power, instead of lowering the nose and applying full power, which was the proper stall recovery technique. That improper action pitched the nose up even further, increasing both the g-load and the stall speed. The stick pusher activated ("The Q400 stick pusher applies an airplane-nose-down control column input to decrease the wing angle-of-attack [AOA] after an aerodynamic stall"),[3] but the captain overrode the stick pusher and continued pulling back on the control column. The first officer retracted the flaps without consulting the captain, making recovery even more difficult.[23]


Sorry - but Colgan crashed because the Pilot followed the incorrect stall recovery procedure - he didn't know how to fly a T-tail - they were most likely going down even without the flaps being raised.

However It does bring up a good point - The Pilot didn't know what the first officer was doing or vice-versa.

In the case of ET302 that could have been what transpired in the last few seconds in the reverse.

I'm not saying this happened but it is Plausible and fits the timeline as they were faced with an impossible situation - please take this as a discussion topic and not me blaming the pilots. I'm really just trying to understand what happened and what could be done better - through better training.

From earlier in the flight we do know that it was the FO who brought up "both Trim Cutoff Switches to Off"

Thereafter there is no discussion of MCAS - the Memo or anything which is very weird. Wouldn't a normal reaction after you figure something out to remark to basically say Eureka! I figured it out - it was MCAS just like Lionair. There is no discussion at all.

It is possible the Captain was not familiar with the Memo and due to the FO's lack of experience was reticent to bring it up as he probably assumed the Captain knew all about it.

There is no back and forth in the cockpit - the FO just waited for commands from the Pilot.

The First Officer had just been through the Sim (end of Jan) so presumably got some training on MCAS procedures. The Pilot was scheduled too after the fateful flight.

So you have one person in the cockpit who possibly knew the procedures (FO) and one who possibly didn't and really didn't understand what was going on which is understandable if they didn't have the proper training.

Then in the final seconds the Pilot not knowing that turning on Electric Trim again was a big no-no and the FO who can't see what the Captain is doing or bowing to Authority and not speaking up says nothing when the Captain reaches over and reenergizes the Electric trim and tries it again - the Captian not knowing that he should turn it off right away (the Co-Pilot might have assumed he would) but by that time it is too late.

As they are travelling so fast there is no time to react from MCAS again.

One final comment - it is mentioned in the crash report that the throttle levers were never moved from 94% N1 the whole flight.

Over on the other forum a 737 Pilot did point out that small changes in throttle (a few percent) would have literally no effect on the nose pitching down.

I know faced with an impossible situation - but with all the overspeed warnings - don't you think they would have tried to pull it back a least a few percent to see the effect when they could both pull to offset it and if didn't work they could have pushed the throttle up again? They did have about 8,000' of altitude at that point.

Again - I am not blaming the pilots - I consider this Boeing's big screwup along with a fault in the Worldwide training system.

Please take this as a discussion topic to help us all understand better what happened.
 
User avatar
speedbored
Posts: 2207
Joined: Fri Jul 19, 2013 5:14 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 11:49 am

MD80Ttail wrote:
That’s not what I said.....when flaps were retracted the problems started. I would have redeployed the flaps immediately while still at a safe speed.

But, according to the data in the preliminary report, the right indicated airspeed was already over the "safe speed" for flaps before MCAS kicked in, and the left IAS was also over the limit less than 5 seconds later. I doubt very much that you would have even identified that "problems had started" before the aircraft was already over the flaps limit speed.
 
maint123
Posts: 175
Joined: Sun Nov 04, 2018 4:18 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 11:50 am

People arguing like -
Pilots were not properly trained. A good pilot would just let his training kick in a emergency.
AND
Screw the training, if the pilot feels something is wrong he should just use his intuition and common sense.
AND
So what the pilots have to do is counterintuitive but what has to be done has to be done.

All points have some merit but as a passenger I would expect my pilot to be fully conversant with his plane and trust his training, and not be doing, let's try this or this or this at a couple of 1000 ft above the ground. Not a video game that you fail and start again.
Pl do the experiments on a empty plane not on the paying public.
 
MD80Ttail
Posts: 159
Joined: Wed Dec 07, 2016 1:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 12:05 pm

I think we need to regroup a min here. As far was we know.....MCAS was “working properly”—by that it was doing what it was designed to do. No matter how poorly designed the facts as we have them tell us it was working within its design parameters. We apparently have an IAS / one or more multiple sensor problem which in turn affected MCAS but again MCAS was performing as designed albeit with bad input data.

Can we all agree on these points? We are so in the weeds here.

So if we agree MCAS was working properly (the system itself was doing what it is designed to do albeit w bad inputs)...we know two very important things about MCAS..again if it was properly functioning.

One it can not activate with flaps extended. Two when the pilot commmands a trim input the system times out and resets. There is a period of time. I cannot remember the number of seconds it times out for but it’s enough time for multiple pilot trim inputs.

These two facts to me are very important.

One. Why didn’t the crew immediately redeploy flaps return the aircraft to last stable config immediately after retracting the flaps and MCAS engaging. (For my “fanboys” don’t argue there was a delay between flap retractions and MCAS. Yes there was. No I don’t know how long. I’m going to guess 15-17 seconds but I don’t fly the 737. Every pilots knows flaps are not instantaneous so trying to say the delay while the retract breaks the chain I do not believe this is the case to a pilot. To a pilot understanding flaps take some time rolling in or out it’s still “immediate after” in our world)

Two. Why didn’t the pilots up trim inputs time out MCAS allowing for the electric trim to be shut off after the pilots had commanded an acceptable trim condition? When conditions changed and the pilots needed more trim ok from what I’ve read and learned the manual trim wheel maybe was useless. That’s a Huge concern. No plane should ever be designed that can’t be manually trimmed. Again I don’t fly the 737 so can’t speak how effective manual trim is. Back to changing conditions and needing to retrain. Manual not working. Switch on the system (yes for fanboys the ck list doesn’t say this but if you need it you need it if the manual isn’t working). So back on it goes...pilot uptrims as needed. Again expecting MCAS to time out w each pilot input. Then the system gets shut back off. Except they didn’t shut if off apparently.

I’m not understanding the hole in the ground.
 
MD80Ttail
Posts: 159
Joined: Wed Dec 07, 2016 1:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 12:13 pm

morrisond wrote:
YYZatcboy wrote:
BEG2IAH wrote:



Sorry - but Colgan crashed because the Pilot followed the incorrect stall recovery procedure - he didn't know how to fly a T-tail - they were most likely going down even without the flaps being raised.

However It does bring up a good point - The Pilot didn't know what the first officer was doing or vice-versa.



The FO didn’t know what he was doing either. Maybe he thought he knew what he was doing.....not his fault. But having a FO with 150-200hrs TOTAL time is literally criminal. At 200hrs TT the plane is flying you....you are not flying the plane.....you are behind the aircraft w 200hrs TT.
 
User avatar
hilram
Posts: 733
Joined: Wed Aug 20, 2014 11:12 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 12:16 pm

MD80Ttail wrote:
I think we need to regroup a min here. As far was we know.....MCAS was “working properly”—by that it was doing what it was designed to do. No matter how poorly designed the facts as we have them tell us it was working within its design parameters. We apparently have an IAS / one or more multiple sensor problem which in turn affected MCAS but again MCAS was performing as designed albeit with bad input data.

Can we all agree on these points? We are so in the weeds here.

So if we agree MCAS was working properly (the system itself was doing what it is designed to do albeit w bad inputs)...we know two very important things about MCAS..again if it was properly functioning.

One it can not activate with flaps extended. Two when the pilot commmands a trim input the system times out and resets. There is a period of time. I cannot remember the number of seconds it times out for but it’s enough time for multiple pilot trim inputs.

These two facts to me are very important.

One. Why didn’t the crew immediately redeploy flaps return the aircraft to last stable config immediately after retracting the flaps and MCAS engaging. (For my “fanboys” don’t argue there was a delay between flap retractions and MCAS. Yes there was. No I don’t know how long. I’m going to guess 15-17 seconds but I don’t fly the 737. Every pilots knows flaps are not instantaneous so trying to say the delay while the retract breaks the chain I do not believe this is the case to a pilot. To a pilot understanding flaps take some time rolling in or out it’s still “immediate after” in our world)

Two. Why didn’t the pilots up trim inputs time out MCAS allowing for the electric trim to be shut off after the pilots had commanded an acceptable trim condition? When conditions changed and the pilots needed more trim ok from what I’ve read and learned the manual trim wheel maybe was useless. That’s a Huge concern. No plane should ever be designed that can’t be manually trimmed. Again I don’t fly the 737 so can’t speak how effective manual trim is. Back to changing conditions and needing to retrain. Manual not working. Switch on the system (yes for fanboys the ck list doesn’t say this but if you need it you need it if the manual isn’t working). So back on it goes...pilot uptrims as needed. Again expecting MCAS to time out w each pilot input. Then the system gets shut back off. Except they didn’t shut if off apparently.

I’m not understanding the hole in the ground.

They didn’t do any of those things because firstly, due to Boeing alert bulletin regarding MCAS in the wake of the first crash they were able to correctly identify the problem.
Secondly, because of relevant training they then followed the by Boeing / FAA prescribed procedure to counter-act it.

In other words, precisely what they were supposed to do.
Flown on: A319, 320, 321, 332, 333, 343 | B732, 734, 735, 736, 73G, 738, 743, 744, 772, 77W | BAe-146 | DHC-6, 7, 8 | F50 | E195 | MD DC-9 41, MD-82, MD-87
 
Exeiowa
Posts: 147
Joined: Fri Jul 06, 2018 4:49 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 12:18 pm

At no point did the pilots have any information that the problem actually was MCAS. No think about problem solving withoit any definitive information just guess work. These people got 1 try to get it right. And no one else picking now would choose the same set, because we know how it ends.
 
SimonL
Posts: 39
Joined: Tue Mar 12, 2019 3:38 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 12:19 pm

1) it was not in any established procedure to do so. And as all pilots they stick to the procedures before starting to improvise.
2) Probably because they felt that they had the situation under control and as others have stated, its hard to judge how far off in trim you are without releasing the yoke. They also expected to be able to deal with the misstrim with the wheels
When they turned back on they most likely expected that they could handle the MCAS, problem was as the FDR shows, that at that speed the MCAS literary kick them out of their seats and when they managed to get control again it was too late.
 
mjoelnir
Posts: 8364
Joined: Sun Feb 03, 2013 11:06 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 12:29 pm

MD80Ttail wrote:
I think we need to regroup a min here. As far was we know.....MCAS was “working properly”—by that it was doing what it was designed to do. No matter how poorly designed the facts as we have them tell us it was working within its design parameters. We apparently have an IAS / one or more multiple sensor problem which in turn affected MCAS but again MCAS was performing as designed albeit with bad input data.

Can we all agree on these points? We are so in the weeds here.

So if we agree MCAS was working properly (the system itself was doing what it is designed to do albeit w bad inputs)...we know two very important things about MCAS..again if it was properly functioning.

One it can not activate with flaps extended. Two when the pilot commmands a trim input the system times out and resets. There is a period of time. I cannot remember the number of seconds it times out for but it’s enough time for multiple pilot trim inputs.

These two facts to me are very important.

One. Why didn’t the crew immediately redeploy flaps return the aircraft to last stable config immediately after retracting the flaps and MCAS engaging. (For my “fanboys” don’t argue there was a delay between flap retractions and MCAS. Yes there was. No I don’t know how long. I’m going to guess 15-17 seconds but I don’t fly the 737. Every pilots knows flaps are not instantaneous so trying to say the delay while the retract breaks the chain I do not believe this is the case to a pilot. To a pilot understanding flaps take some time rolling in or out it’s still “immediate after” in our world)

Two. Why didn’t the pilots up trim inputs time out MCAS allowing for the electric trim to be shut off after the pilots had commanded an acceptable trim condition? When conditions changed and the pilots needed more trim ok from what I’ve read and learned the manual trim wheel maybe was useless. That’s a Huge concern. No plane should ever be designed that can’t be manually trimmed. Again I don’t fly the 737 so can’t speak how effective manual trim is. Back to changing conditions and needing to retrain. Manual not working. Switch on the system (yes for fanboys the ck list doesn’t say this but if you need it you need it if the manual isn’t working). So back on it goes...pilot uptrims as needed. Again expecting MCAS to time out w each pilot input. Then the system gets shut back off. Except they didn’t shut if off apparently.

I’m not understanding the hole in the ground.


If MCAS was working as designed, than it was designed to crash the frame.

We know that MCAS was activated by a defect sensor or electronic.

We do not know if manual electrical trim overrides MCAS in every situation, perhaps that is the next design flaw?

We know that the abnormal run away trim checklist does not include leveling trim before throwing the switches.

Following the abnormal run away trim checklist does not safe the plane.

You have to lean quite far out of the window to blame the pilot.

Are you on the payroll at Boeing or the FAA.?
 
rheinwaldner
Posts: 1709
Joined: Wed Jan 02, 2008 4:58 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 12:30 pm

MD80Ttail wrote:
The FO didn’t know what he was doing either. Maybe he thought he knew what he was doing.....not his fault. But having a FO with 150-200hrs TOTAL time is literally criminal. At 200hrs TT the plane is flying you....you are not flying the plane.....you are behind the aircraft w 200hrs TT.

Your opinion is wrong because your figures are wrong. The FO had more total hours than you mention. More than double (you find the number e.g. on the avherald page). More than required in the US some years ago.

and, you know, every pilot who has 500 hrs once had 200...
Many things are difficult, all things are possible!
 
sadiqutp
Posts: 277
Joined: Thu Sep 08, 2016 5:05 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 12:35 pm

MD80Ttail wrote:
I think we need to regroup a min here. As far was we know.....MCAS was “working properly”—by that it was doing what it was designed to do. No matter how poorly designed the facts as we have them tell us it was working within its design parameters. We apparently have an IAS / one or more multiple sensor problem which in turn affected MCAS but again MCAS was performing as designed albeit with bad input data.

Can we all agree on these points? We are so in the weeds here.

Here we go....

Are you writing this analogy with a straight face? I am asking seriously!

If I designed a robot that would cause you harm, due to faulty sensors or whatever, are you gonna just be like.... Well, the robot cut my arm off but it performed the way it was designed to!!!!
 
User avatar
SheikhDjibouti
Posts: 1718
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 12:36 pm

morrisond wrote:
From earlier in the flight we do know that it was the FO who brought up "both Trim Cutoff Switches to Off"

Thereafter there is no discussion of MCAS - the Memo or anything which is very weird. Wouldn't a normal reaction after you figure something out to remark to basically say Eureka! I figured it out - it was MCAS just like Lionair. There is no discussion at all.

Whoa there, pardner!
We are reading a preliminary report, rushed out to satisfy the hungry hordes.
It does not contain a full CVR transcript. We can only imagine what words are missing, or indeed what silent nods of agreement took place in that cockpit.

It is possible the Captain was not familiar with the Memo and due to the FO's lack of experience was reticent to bring it up as he probably assumed the Captain knew all about it.

There is no back and forth in the cockpit - the FO just waited for commands from the Pilot.
See above.
Also note that the Captain did not hesitate when the FO requested "stab trim cut-out", and knew enough to very quickly instigate "pull up" at 05:40:44
Neither suggests a Captain who is playing catch-up.

I know faced with an impossible situation - but with all the overspeed warnings - don't you think they would have tried to pull it back a least a few percent to see the effect when they could both pull to offset it and if didn't work they could have pushed the throttle up again? They did have about 8,000' of altitude at that point.

No, not 8,000'. Although people often confuse 5's and 8's, especially if their computer screen is covered in.....

Please take this as a discussion topic to help us all understand better what happened.

In that case I will only quietly remind you that it was yourself who argued that the FO didn't have nearly enough hours, and that in Canada it would be impossible to fly a big jet with so few hours. Until a fellow Canuck set that record straight! :lol:
But don't worry; there is always another poster on this forum ready to bang that drum for all he is worth. In fact there is one here right now, totally unable to remember anything before 2009 :banghead:

In the absence of a full CVR transcript, the edited text leaves me with the impression that both pilots were as competent as any other mixed pair you might find around the world.

(To be fair, I am noticing a slightly modified tone from you in recent posts, and indeed I am smiling here so hopefully all is good) :D
Nothing to see here; move along please.
 
MD80Ttail
Posts: 159
Joined: Wed Dec 07, 2016 1:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 12:47 pm

sadiqutp wrote:
MD80Ttail wrote:
I think we need to regroup a min here. As far was we know.....MCAS was “working properly”—by that it was doing what it was designed to do. No matter how poorly designed the facts as we have them tell us it was working within its design parameters. We apparently have an IAS / one or more multiple sensor problem which in turn affected MCAS but again MCAS was performing as designed albeit with bad input data.

Can we all agree on these points? We are so in the weeds here.

Here we go....

Are you writing this analogy with a straight face? I am asking seriously!

If I designed a robot that would cause you harm, due to faulty sensors or whatever, are you gonna just be like.... Well, the robot cut my arm off but it performed the way it was designed to!!!!


Yes. I would. See the forest through the trees. MCAS did what is was designed to do. Was the design good? Probably not. But MCAS as far as we know didn’t malfunction here per se. MCAS got bad data as far as we know. Based on the data it was given it did what it was designed.....unless there is another issue we don’t know about which is what I am pondering. The Max has made a large number of flights and carried substantial pax safely two crashes in a short time after introduction are two too many, yes. However, MCAS doesn’t crash the plane itself and isn’t designed to crash the plane. The design might be flawed and I agree needs tweaking but from what we know the root cause was bad input data. Understand what I’m saying. The system itself didn’t apparently malfunction but was given bad dad, except MCAS didn’t know that data was bad so it responded as programmed. Now, probably shouldn’t be programmed that way but again it did was it was designed to do. I have a very straight face.
 
marcelh
Posts: 649
Joined: Wed Jun 19, 2013 12:43 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 12:52 pm

MD80Ttail wrote:
The FO didn’t know what he was doing either. Maybe he thought he knew what he was doing.....not his fault. But having a FO with 150-200hrs TOTAL time is literally criminal. At 200hrs TT the plane is flying you....you are not flying the plane.....you are behind the aircraft w 200hrs TT.

I repeat my statement: if lack of training/hours is so criminal, why don’t we read that a NG or A320 has made a crater once a week?
Last edited by marcelh on Sat Apr 06, 2019 1:09 pm, edited 1 time in total.
 
Pentaprism
Posts: 12
Joined: Mon Mar 11, 2019 1:12 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:00 pm

What this Crash Highlights to me is that Sensors/Pitot Tubes are pretty much the weakest links in Modern Aircraft - which are otherwise incredibly safe.

AF447 31/5/09
6W703 11/2/18
JT610 29/10/18
ET302 10/3/19
 
kalvado
Posts: 1820
Joined: Wed Mar 01, 2006 4:29 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:04 pm

kalvado wrote:
MD80Ttail wrote:
I have stated this before but no one has discussed.....if I was in the ET cockpit...and I had considered this before the ET crash after learning from the lion accident.....I would have lowered flaps to disable the MCAS while still allowing use of the electric trim. Thoughts?

So you're violating Boeing approved procedure - and basically take any possible consequences as your personal liability at this point.
What other SOPs you ignore as part of your work? What about your airlines chief pilot - is he aware of that? Can you envision how debriefing would go once you say "I got a problem in flight, I followed a non-approved procedure - I didn't like procedure BOeing approved - and after all I returned to the base"? Would you expect suspension or termination?

In general, I think flaps should work - but you may also ask why Boeing didn't put flaps down as a possible action into the AD.

And back to the subject of flaps and MCAS... an old "roller coaster" trim correction procedure - https://theaircurrent.com/aviation-safe ... tigations/
says "if nose down trim is required, slowing down and extending the flaps will account for most of nose-up trim"
So flaps down effectively means trim changes for nose-down, in a situation where you're already nose-down. I assume this is the reason Boeing didn't recommend that as a resolution, and why unapproved action may result in unexpected consequences.
 
MD80Ttail
Posts: 159
Joined: Wed Dec 07, 2016 1:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:08 pm

Yes every 500hr pilot was a 200hr pilot. The 200hr pilot should be flying somthing more in-line with his / her skill set and not a mainline aircraft or even an RJ. Period. Why does everyone just spew well the 6,000hr pilot was once a 200hr pilot. Yes but that 200hr pilot shouldn’t be sitting right seat in a 737. Too big, too complex, too fast...too much plane at 200hrs.

Do you give your newly license 16yo kid a Ferrari, or Porsche or Corvette? He’s got a license. NO. Reasonable people don’t. Reasonable people give their kid a car that has less power and requires less skills to drive to build experience.

Nobody at 200hrs TT is an asset in the cockpit of a 737or any mainline / RJ at 200hrs. They become an order taker and pax themselves. Not a fully integrated part of a team with experience (what experiences can you have in 200hrs) to draw from.

99 percent of time flying is boring. You follow the numbers. Follow the procedures. Planes are so good and so safe that 99 percent of the time it works flawlessly and the 200 hrs TT guy doesn’t kill anyone. But. But when things go off the rails there are often NOT procedures for the really difficult situations and that’s when you want both pilots to be equals with substantial experience and skills. UA232, Japan 123, NW4 (the 747 w massive rudder issues) and Sully. Don’t forget Sully’s FO was very seasoned and had thousands of hours.

Finally what does 200 hrs mean? Let’s translate to somthing more familiar. Cars today keep track of all sorts of data. Someone driving average miles per year and an average mix of city and hwy in a medium sized city will average between 35-40mph over the year.

Now take 35-40mph speed multiplied by 200hrs of driving and you get 7,000 to 8,000 miles of driving experience in 200 hours. How do you feel about the a pilot tasked with flying say a Max with 150-200 people alone with the road equivalent of 7,000 miles TOTAL experience under his / her belt? Why alone? Sometimes pilots become incapacitated. The rate is low but higher than you think on the other hand.

How do you feel sending your kids to school on a bus where the driver has in their ENTIRE life driven 7,000 miles. All of the experience and expertise this person has in high winds, slick roads, hills, mountain descents, horrible rain and snow all combined is 7,000 miles. Heck that person might never even have experienced snow or mountains because of his short career. Put your kids on that bus?

School bus drivers are required to have MORE experience driving than the equivalent required in many countries to fly a Max or even widebodies.

How can anyone defend this?? How??? Because it works? Ya it works UNTIL something happens which is rare but that’s what pilots are for anyways. Otherwise the planes could just be fully automated. Pilots are here for those moments when things have gone wrong. We need prior experience to draw from. Theory only gets you so far. You don’t get that in 200 hours.
Last edited by MD80Ttail on Sat Apr 06, 2019 1:16 pm, edited 3 times in total.
 
MD80Ttail
Posts: 159
Joined: Wed Dec 07, 2016 1:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:09 pm

marcelh wrote:
MD80Ttail wrote:
The FO didn’t know what he was doing either. Maybe he thought he knew what he was doing.....not his fault. But having a FO with 150-200hrs TOTAL time is literally criminal. At 200hrs TT the plane is flying you....you are not flying the plane.....you are behind the aircraft w 200hrs TT.

I repeat my statement: if lack of training/hours is so criminal, why don’t we read that a NG or A320 has made a crater?



Too many to list.
 
User avatar
speedbored
Posts: 2207
Joined: Fri Jul 19, 2013 5:14 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:10 pm

SheikhDjibouti wrote:
If for some reason the pilots maintained pressure on the thumb switch and yet MCAS still activated, then maybe this is the hidden problem Boeing are now trying to solve. :scratchchin:

I suspect that the additional problem Boeing are investigating will be related to the lack of response from the trim system to the pilots electric trim command at 5:40:15, when the aircraft was still considerably below Vmo. Compare the pitch trim response to the response seen to a slightly shorter trim commands at ~5:39:20, or ~5:38:50. Why was the response at 5:40:15 almost non-existant?
 
dtw2hyd
Posts: 7070
Joined: Wed Jan 09, 2013 12:11 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:12 pm

MD80Ttail wrote:
But MCAS as far as we know didn’t malfunction here per se. MCAS got bad data as far as we know. Based on the data it was given it did what it was designed.....unless there is another issue we don’t know about which is what I am pondering.
...
The Max has made a large number of flights and carried substantial pax safely two crashes in a short time after introduction are two too many, yes. However, MCAS doesn’t crash the plane itself and isn’t designed to crash the plane. The design might be flawed and I agree needs tweaking but from what we know the root cause was bad input data. Understand what I’m saying. The system itself didn’t apparently malfunction but was given bad dad, except MCAS didn’t know that data was bad so it responded as programmed. Now, probably shouldn’t be programmed that way but again it did was it was designed to do. I have a very straight face.


The very fact that MCAS
1) Couldn't detect/predict bad data
2) Acted upon bad data
3) Indefinitely

Indicates it is bad design.

Even with single "bad" sensor, software should be able to detect, #1 sensor readings are off the chart(just by comparing to basic specs) and #2 the cumulative trim down pitch is unrecoverable.
Last edited by dtw2hyd on Sat Apr 06, 2019 1:13 pm, edited 1 time in total.
 
sadiqutp
Posts: 277
Joined: Thu Sep 08, 2016 5:05 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:12 pm

MD80Ttail wrote:
sadiqutp wrote:
MD80Ttail wrote:
I think we need to regroup a min here. As far was we know.....MCAS was “working properly”—by that it was doing what it was designed to do. No matter how poorly designed the facts as we have them tell us it was working within its design parameters. We apparently have an IAS / one or more multiple sensor problem which in turn affected MCAS but again MCAS was performing as designed albeit with bad input data.

Can we all agree on these points? We are so in the weeds here.

Here we go....

Are you writing this analogy with a straight face? I am asking seriously!

If I designed a robot that would cause you harm, due to faulty sensors or whatever, are you gonna just be like.... Well, the robot cut my arm off but it performed the way it was designed to!!!!


Yes. I would. See the forest through the trees. MCAS did what is was designed to do. Was the design good? Probably not. But MCAS as far as we know didn’t malfunction here per se. MCAS got bad data as far as we know. Based on the data it was given it did what it was designed.....unless there is another issue we don’t know about which is what I am pondering. The Max has made a large number of flights and carried substantial pax safely two crashes in a short time after introduction are two too many, yes. However, MCAS doesn’t crash the plane itself and isn’t designed to crash the plane. The design might be flawed and I agree needs tweaking but from what we know the root cause was bad input data. Understand what I’m saying. The system itself didn’t apparently malfunction but was given bad dad, except MCAS didn’t know that data was bad so it responded as programmed. Now, probably shouldn’t be programmed that way but again it did was it was designed to do. I have a very straight face.


Here is what's staggering about your argument. You continue to use the words " might", "may", "probably" when you talk about the design of the MCAS, a system that Boeing itself is on the record saying that it's working to fix it. However, these words changed to " why didn't the crew immediately" when you were talking about the crew. Again, I don't think anyone could claim that they know exactly what the crew did or didn't do beside investigators.

If a system was designed to be dependent on a single input, and that system has the ability to repeatedly trim the elevators nose down based on that single input. That system IS what crashed the airplane. AOA doesn't command the nose down!!! Get it?MCAS does. MCAS wasn't deigned intentionally to crash the airplane but it ultimately "allegedly" did, twice!
Last edited by sadiqutp on Sat Apr 06, 2019 1:16 pm, edited 1 time in total.
 
morrisond
Posts: 1179
Joined: Thu Jan 07, 2010 12:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:14 pm

MD80Ttail wrote:
Yes every 500hr pilot was a 200hr pilot. The 200hr pilot should be flying somthing more in-line with his / her skill set and not a mainline aircraft or even an RJ. Period. Why does everyone just spew well the 6,000hr pilot was once a 200hr pilot. Yes but that 200hr pilot shouldn’t be sitting right seat in a 737. Too big, too complex, too fast...too much plane at 200hrs.

Do you give your newly license 16yo kid a Ferrari, or Porsche or Corvette? He’s got a license. NO. Reasonable people don’t. Reasonable people give their kid a car that has less power and requires less skills to drive to build experience.

Nobody at 200hrs TT is an asset in the cockpit of a 737or any mainline / RJ at 200hrs. They become an order taker and pax themselves. Not a fully integrated part of a team with experience (what experiences can you have in 200hrs) to draw from.

99 percent of time flying is boring. You follow the numbers. Follow the procedures. Planes are so good and so safe that 99 percent of the time it works flawlessly and the 200 hrs TT guy doesn’t kill anyone. But. But when things go off the rails there are often NOT procedures for the really difficult situations and that’s when you want both pilots to be equals with substantial experience and skills. UA232, Japan 123, NW4 (the 747 w massive rudder issues) and Sully. Don’t forget Sully’s FO was very seasoned and had thousands of hours.

Finally what does 200 hrs mean? Let’s translate to somthing more familiar. Cars today keep track of all sorts of data. Someone driving average miles per year and an average mix of city and hwy in a medium sized city will average between 35-40mph over the year.

Now take 35-40mph speed multiplied by 200hrs of driving and you get 7,000 to 8,000 miles of driving experience in 200 hours. How do you feel about the a pilot tasked with flying say a Max with 150-200 people alone with the road equivalent of 7,000 miles TOTAL experience under his / her belt? Why alone? Sometimes pilots become incapacitated. The rate is low but higher than you think on the other hand.

How do you feel sending your kids to school on a bus where the driver has in their ENTIRE life driven 7,000 miles. All of the expreice this person has in high winds, slick roads, hills, mountain descents, horrible rain and snow all combined is 7,000 miles. Heck that person might never even have experienced snow or mountains because of his short career. Put your kids on that bus?

School bus drivers are required to have MORE experience driving than the equivent required in many countries to fly a Max or even widebodies.

How can anyone defend this?? How??? Because it works? Ya it works UNTIL something happens which is rare but that’s what pilots are for anyways. Otherwise the planes could just be fully automated. Pilots are here for those moments when things have gone wrong. We need prior experience to draw from. Theory only gets you so far. You don’t get that in 200 hours.


Great post and perfect Analogy.
 
marcelh
Posts: 649
Joined: Wed Jun 19, 2013 12:43 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:18 pm

MD80Ttail wrote:
marcelh wrote:
MD80Ttail wrote:
The FO didn’t know what he was doing either. Maybe he thought he knew what he was doing.....not his fault. But having a FO with 150-200hrs TOTAL time is literally criminal. At 200hrs TT the plane is flying you....you are not flying the plane.....you are behind the aircraft w 200hrs TT.

I repeat my statement: if lack of training/hours is so criminal, why don’t we read that a NG or A320 has made a crater?



Too many to list.

Too easy....

I don’t want to misjudge your opinion about 200 hours and if it’s enough or not to become a FO. Fact is that it happens and the 737NG or A320 are very safe planes to fly. Otherwise we should have a crater once a week with 100-180 victims. Boeing sells the 737 MAX as “just another 737”, but when the shit hits the fan, it isn’t just another 737.
 
mandala499
Posts: 6587
Joined: Wed Aug 29, 2001 8:47 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:21 pm

speedbored wrote:
I still do not believe it, because it is not true. At no point was the aircraft ever below FL050, not even while still on the runway.

Take note of the phase of flight that the pilots were in (climb - they were trying to get to 14,000ft), and the altitude they were actually at, and look at the pitch and power settings again.

Regardless of the tables, it is clear from the CVR recordings of overspeed warnings, that the pilots maintained an airspeed within the limits of the airframe for at least the first half of the flight, until they really started to struggle with, and get distracted by, controlling the aircraft. Even then, the overspeed was minor and intermittent according to one side of the aircraft, When presented with multiple different issues, and expending considerable effort on trying to keep the nose up (the overspeed warnings don't kick in until ~80 seconds after both pilots start pulling hard back on the yokes), the pilots have to prioritise what they work on.

Yeah, well, the idea of reducing N1 to 75% is... well... you know...

For the benefit perhaps Morrisond...
Climb at flaps up at unreliable airspeed, as we know, is at max climb thrust (N1 way over 75%), with pitch at 9.5 or more degrees, for a 737-800... The max would have similar numbers...

75% N1 is for cruise with unreliable airspeed at 15000ft... pitch 3.5, N1 75%... and that is for LEVEL flight...

The overspeed warnings, probably came from not reducing the thrust once they wanted to go level... but then, given what they were faced with, am not surprised they didn't end up doing a pitch and power for level flight, because they were task saturated in getting control of the aircraft.

For the Lion Air, both 043 and 610 they didn't overspeed... the question is, why did ET302 have overspeed? Not saying who/what's wrong, but important to understand what went on in the mind of the pilot and what he was trying to prioritize at the time.

asdf wrote:
DIRECTIVE:

in emergency use the hand break to reduce speed of the car

NOTE:

we recommend you to stop the car before you apply hand break

Spot on!

MD80Ttail wrote:
That’s not what I said.....when flaps were retracted the problems started. I would have redeployed the flaps immediately while still at a safe speed. I have been reading here 10 plus years and finally made an account...but the whole forum has become like the news. Pick one word and focus on it to try and make a point. I never suggested deploying the flaps at an unsafe speed. My point was I would have wanted electric trim and no MCAS. Understanding the system after the Lion crash I would have immediately redeployed flaps which should give me what I want.

I agree with this. The crew of 610 did redeploy flaps when MCAS initially played up... but they retracted it again. The mindset flow goes with your saying of "if you do somthing in a plane and it immediately doesn’t like what you did go to back to prior config"... And before anyone has a go at you for this, let me also say, that, this is not monday morning quarterbacking like some would like to accuse you of.

SheikhDjibouti wrote:
This is probably my fault for not spelling out my main point clearly enough.
The "something else" was autopilot randomly disengaging.
If flaps retraction had been the only action in this 15 second window, MCAS would not have activated at 05:40:00

The autopilot disengaging is likely to be due to the MCAS wanting to engage. After all, if you set your autopilot to a selection where you would cause a stall, you'd want it to disengage... not sure of the detailed logic of the 737 Autopilot in the realms of near stall, plus the addition of MCAS on the Max on top... but just by common sense, you'd want the MCAS to disengage the A/P and then command trim nose down if you're in an actual stall... especially if the A/T isn't disengaged.

SheikhDjibouti wrote:
Captain Hindsight with a possible answer here;

1. Re-engage stab trim cut-out
2. Immediately (or even sooner than that!) use thumb switches, and continue to depress the thumb switch to prevent MCAS function.(*)
3. Now, in conjunction with the electric motor attempting to move the stabiliser, both pilots crank the manual trim wheel
4. You now have one electric motor plus two pilots attempting to move the jackscrew
5. If that fails; pray.

You mean 1 = provide power back to the stab trim? :)
I really wonder what Boeing was thinking, having the yoke in the aft (nose up) position and trying to manually crank the trim wheel (especially with heavier than normal forces), isn't an easy walk in the park for some.
What the crew of 302 tried to do was probably what you said above, except for #3, because I think just use the thumb switch for the electric trim should be enough but they needed to do it immediately after reengaging power to the stab trim.
I think the investigation will go deeper into this...

MD80Ttail wrote:
Two. Why didn’t the pilots up trim inputs time out MCAS allowing for the electric trim to be shut off after the pilots had commanded an acceptable trim condition? When conditions changed and the pilots needed more trim ok from what I’ve read and learned the manual trim wheel maybe was useless. That’s a Huge concern. No plane should ever be designed that can’t be manually trimmed.

I think the AD was badly worded that caused pilots reading it, to think, "OK I'll cut it off immediately"... and then lower down, it says, "you may use electric trim to reduce the load forces" (or something like that)... BUT HECK! YOU TOLD ME TO CUT IT OFF !!!!

The lack of emphasis to retrim the aircraft prior to cutting out the stab trim within the AD's wording and content structure, is my guess as being the culprit.

Oh hang on, is someone going to accuse me of being on Boeing's or FAA's payroll for saying that?
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
morrisond
Posts: 1179
Joined: Thu Jan 07, 2010 12:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobiq

Sat Apr 06, 2019 1:21 pm

speedbored wrote:
morrisond wrote:
I was just replying to speedbored that He didn't believe setting N1 to 75% was the published procedure

I still do not believe it, because it is not true. At no point was the aircraft ever below FL050, not even while still on the runway.

Take note of the phase of flight that the pilots were in (climb - they were trying to get to 14,000ft), and the altitude they were actually at, and look at the pitch and power settings again.

Regardless of the tables, it is clear from the CVR recordings of overspeed warnings, that the pilots maintained an airspeed within the limits of the airframe for at least the first half of the flight, until they really started to struggle with, and get distracted by, controlling the aircraft. Even then, the overspeed was minor and intermittent according to one side of the aircraft, When presented with multiple different issues, and expending considerable effort on trying to keep the nose up (the overspeed warnings don't kick in until ~80 seconds after both pilots start pulling hard back on the yokes), the pilots have to prioritise what they work on.


You do understand the normal speed for the 737 is 230 Knots indicated? Close to Vmo would be way out of the normal operating range but still within the flight envelope - Vmo would be the speed you would not really want to above or get near too while descending.
 
mandala499
Posts: 6587
Joined: Wed Aug 29, 2001 8:47 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:26 pm

[photoid][/photoid]
morrisond wrote:
You do understand the normal speed for the 737 is 230 Knots indicated? Close to Vmo would be way out of the normal operating range but still within the flight envelope - Vmo would be the speed you would not really want to above or get near too while descending.

You do realize/understand the normal climb / descent speed for a 737 above 10,000ft is 280kts or 0.76M (for NG and Max, 0.72 or 0.74 for the Classics) whichever is lower? (indicated airspeed)
Last edited by mandala499 on Sat Apr 06, 2019 1:26 pm, edited 1 time in total.
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
morrisond
Posts: 1179
Joined: Thu Jan 07, 2010 12:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Apr 06, 2019 1:26 pm

SomebodyInTLS wrote:
VV wrote:
If you switch them OFF it is then to fly the aircraft manually. And manual means the manual trim wheel (and the handle) without the help of any electrical power. That's my interpretation anyway.

So I am totally confused by the report.


I can't understand why when it's been pointed out dozens of times already.

1) they followed all of the memory items according to the AD issued after the Lion Air crash, however they had not fully corrected the MCAS trim with electric trim during this process (referred to as manual electric trim in the preliminary report)

2) at the end of this (trim switches cut off) they were physically trying to apply more manual trim using the wheels but were unable to presumably due to aerodynamic forces from the high speed (blowback)

3) they switched electric trim back on to try and correct the trim with "manual electric" again, but their trim corrections were less than those in the opposite direction by the re-connected MCAS

So the issue is why their manual electric trim was repeatedly less than sufficient - it now seems possible that the electric trim was also having issues with blowback.

Then the question is why they didn't reduce airspeed - well they didn't have pitch control and couldn't simply reduce thrust since they were very close to the ground


From the printed conversation it appears they only tried manual trim for 8 seconds and it was probably only one of them.

They were 8,000’ AGL - which while low is still sufficient altitude to try a few things - they were not 1,000’ AGL as speculated and repeated to me before this thread was started.

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos