ikramerica
Posts: 14902
Joined: Mon May 23, 2005 9:33 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 12:23 am

rheinwaldner wrote:
hivue wrote:
scythemk wrote:

My understanding is that MCAS was implemented to make the handling resemble that of the 737NG in high thrust situations where the engine mounting caused upward pitch. It was a patch of sorts to make this handling difference transparent to the pilots and I believe was a condition required for it to be certified as essentially the same type rating as 737NG instead of its own type rating.

It's not because the plane became "uncontrollable". There's nothing that MCAS does while in operation that the pilot couldn't do themselves.


My understanding (gleaned months ago from the Lion Air thread so no documentation; anyone with documentation feel free to correct me) is that during the flight test campaign it was discovered that at certain points in the envelope the more forwardly located engines generated unanticipated (during the design and development phases) lift of a sufficiently robust nature to generate a nose-up moment, from where a stall could ensue. A stall is uncontrolled flight. The airplane was deemed not certifiable with this undesirable characteristic so MCAS was put together to mitigate it -- even though the situation likely would never be encountered in normal airline operations.

My thesis was, that due to initial problems with unreliable speed, they did cut off the trim, loosing as a result MCAS, and then while dealing with the unreliable speed they encountered those parts of the flight envelope, where they would have needed MCAS to fly a normal behaving, stable plane. Do you understand? The combination of having lost MCAS and being dependent on it at the same time.

To be clear, this thesis is only one of many possible. And probably not even the most probable one. But the impact would be severe: it would mean, that the trim cut off switches are not eligible to fix a malfunctioning MCAS.

Yes, I had a similar thought many pages ago. You stated it better. Although if flaps never reset, then they may have gotten themselves in a mess trying to climb and gone into a stall and MCAS had nothing to do with it.

The “similarities” are there between the two crashes, but there are also similarities with other crashes in the history of aviation that dont involve MCAS . So other than public hysteria and non-scientist government officials claiming a clear connection (or not), its no more logical to assume these crashes had the same cause than it is to blame all 737NG and ground them all, or all aircraft that use that brand if AoA sensor or pitot tubes or what have you.

This crash may very well be similar to the AF crash of the A330 but at a much lower altitude. They had no idea how fast they were going, tried to prevent stalling by putting the aircraft into a stall, and finally ran out of opportunities to get it wrong before all was lost. The difficulty in controlling the aircraft could come from losing and gaining and losing and gaining flow over the control surfaces.
Of all the things to worry about... the Wookie has no pants.
 
AirCalSNA
Posts: 397
Joined: Mon Mar 08, 2010 9:35 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 12:27 am

Summaries of and some quotes from the Ethiopian CVR have been leaked to the New York Times.
 
ikramerica
Posts: 14902
Joined: Mon May 23, 2005 9:33 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 12:31 am

maui19 wrote:
The info coming out of the Lion Air investigation is very interesting. Apparently the suspect info about AoA didn't come from the sensors. Instead, it came somewhere downstream--exactly where it occurred either isn't known or hasn't been disclosed yet.

FWIW, I would not be surprised if the ET investigation showed that the pilots had switched the Stab trim off, but continued to have problems. Perhpas that's what they found at the crash site that led to the final grounding order in the US.

No, there was no conclusive information found between wednesday noon and wednesday afternoon, as it was already night in Ethiopia.
its clear that the final grounding came after Trump got worried he’d be blamed for not doing it, so he called in chao and others and told them to do it for political reasons, after talking to boeing to warn them. China is beating him soundly at 4D chess.
Of all the things to worry about... the Wookie has no pants.
 
edu2703
Posts: 148
Joined: Sun Oct 25, 2015 12:50 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 12:31 am

AirCalSNA wrote:
Summaries of and some quotes from the Ethiopian CVR have been leaked to the New York Times.


Nope. Just a anonymous report from an air traffic controller
 
GalaxyFlyer
Posts: 3730
Joined: Fri Jan 01, 2016 4:44 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 12:49 am

washingtonflyer wrote:
The Asiana 214 crew had over 25,000 hours of flight time among the three of them but that didn't prevent them from pancaking a 777 onto the threshold at SFO.....


If 24,000 hours was spent on autopilot or in the bunk, they were a 1,000 hour total crew. If the training and SOP never allows for deviance from the canned script, they might as well be in first class seats. It’s not hours, it’s experience, knowledge and training plus some real CRM.

GF
 
flybucky
Posts: 175
Joined: Tue Apr 17, 2018 7:44 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 12:54 am

osiris30 wrote:
is that 9000 feet based on the mercury reading (aka 9400 irl).. if they are using the raw ADS-B data they may be 400 feet off. But around 2K feet AGL would seem about right based on the data we have for the first half of the flight.


I believe it's the other way around. 9000 ft was the corrected altitude. 8600 ft was the raw altitude [1]. I haven't analyzed every single data point, but I checked the terrain elevation at a few points, and have not seen an AGL over 1000 ft.

I didn't notice this before, but AV Herald is giving the last transponder time (05:43:57) much later than the last FR24 time (05:41:02).

Last FR24 data: 05:41:02Z. GPS: 9.01602, 38.98415. Pressure Altitude: 8600 ft. GSpeed: 383 kts. (Corrected Altitude: 9000 ft, Terrain Elevation: 8146 ft, AGL: ~850 ft).

Last AVHerald data: 05:43:57Z. GPS N9.027 E39.153. FL086. Corrected Alt: 9027 ft. Terrain Elevation: 8130 ft. (AGL: ~900 ft).

[1] From AV Herald:

The last transponder data were received from position N9.027 E39.153 about 21nm east of Addis Ababa at FL086 at 05:43:57Z. Terrain elevation at that point is 8130 feet MSL, FL086 reported by the Mode-S Altimeter (which always measures to standard pressure 1013 QNH) corrected for QNH indicates the aircraft was flying at 9027 feet MSL at that position. According to aerial overview and satellite images the aircraft impacted ground at approximate position N8.8772 E39.2512 about 10.7nm southsoutheast of the last transponder position.
 
User avatar
BaconButty
Posts: 807
Joined: Tue Aug 06, 2013 3:42 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 12:56 am

hivue wrote:
Flightsimboy wrote:
would not have the ET pilots known about the switch?


Any 737 pilot who doesn't know about employing the runaway stab trim procedure to cure an MCAS issue has been living on Mars for the last 4 months.


Totally agree - however I get nervous about the idea that "they just needed to flick a switch" - not that you're saying it here, but plenty have. Firstly, MCAS is only realistically going to "go bad" when one of it's inputs does. Which practically means the crew have already lost airspeed or AOA indications. Either of which have overwhelmed crews in the past on their own. So the crew are facing stick shakers and goodness knows what, attempting to follow checklists and negotiate a return to base, avoiding a CFIT, and the flaps are then retracted so MCAS erroneously kicks in. This gives the second problem - it may not be easy to diagnose. ,When someone on pprune suggested "bad MCAS" was just like runaway trim, one pilot pointed out that it was more like normal automatic trim corrections that 737 pilots are used to hearing, due to its intermittent nature. And hence could be missed or ignored by an already task saturated crew. And when it is recognised, if the airspeed is high enough and the trim gone far enough, the PF may well need both hands on the stick just to fight it, and have to communicate with the PNF to ditch whatever he is doing and run the Runaway Trim checklist - so dealing with the (guarded?) switches (whose on/off orientation is apparently non-standard and potentially confusing). And then you've got to recover.

The point I'm am trying to make is that the suggestion that the AD from back in November means an accident should never happen (barring a useless crew) is bollocks, whether this accident is MCAS related or not. I hope there's an interim fix to disable MCAS on any disagreements in the AOA or pitot static system, and a longer commitment to recertify the system in line with the FAA's own regs. Confidence needs to be restored.
Down with that sort of thing!
 
CYCD
Posts: 3
Joined: Fri Apr 16, 2010 11:05 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 12:59 am

ikramerica wrote:
...

This crash may very well be similar to the AF crash of the A330 but at a much lower altitude. They had no idea how fast they were going, tried to prevent stalling by putting the aircraft into a stall, and finally ran out of opportunities to get it wrong before all was lost. The difficulty in controlling the aircraft could come from losing and gaining and losing and gaining flow over the control surfaces.


This sounds reasonable, but--honest question as a non-pilot--is it realistic for a crew travelling at 300+ knots ~1000' AGL on a clear day to have no idea how fast they're going? (I don't mean exact speed; I just mean a subjective sense of going very fast relative to normal.) AF447 took place at night and in poor weather so there's an element of sensory deprivation in play there--had it taken place during clear daylight hours, the crew would presumably have noticed what was wrong sometime over the fall from 38,000'. Given how fast ET302 was going vs. what would be normal for that altitude, would it not have been clear to the pilots that a stall (if that's what their sensors were telling them) was not their main concern?
 
flybucky
Posts: 175
Joined: Tue Apr 17, 2018 7:44 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 1:15 am

Lots of new information about the ATC communications from the NYT article. Excerpts:

Within one minute of Flight 302’s departure, Captain Getachew reported a “flight control” problem in a calm voice. At that point, radar showed the aircraft’s altitude as being well below what is known as the minimum safe height from the ground during a climb.

Within two minutes, the plane had climbed to a safer altitude, and the pilot said he wanted to stay on a straight course to 14,000 feet.

Then the controllers observed the plane going up and down by hundreds of feet, and it appeared to be moving unusually fast, the person said. The controllers, the person said, “started wondering out loud what the flight was doing.”

Captain Getachew, with panic in his voice, interrupted with his request to turn back. Flight 302 was just three minutes into its flight, and appeared to have accelerated to even higher speeds, well beyond its safety limits.


Assuming these accounts from the person who reviewed the ATC communications, the pilots could not stop the aircraft from accelerating. What are some possible causes of this? Unreliable airspeed causing the autopilot to increase throttle, thinking the airspeed was too slow? Could they not cut the autopilot/autothrottle?
 
osiris30
Posts: 2655
Joined: Sat Sep 30, 2006 10:16 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 1:20 am

flybucky wrote:
osiris30 wrote:
is that 9000 feet based on the mercury reading (aka 9400 irl).. if they are using the raw ADS-B data they may be 400 feet off. But around 2K feet AGL would seem about right based on the data we have for the first half of the flight.


I believe it's the other way around. 9000 ft was the corrected altitude. 8600 ft was the raw altitude [1]. I haven't analyzed every single data point, but I checked the terrain elevation at a few points, and have not seen an AGL over 1000 ft.

I didn't notice this before, but AV Herald is giving the last transponder time (05:43:57) much later than the last FR24 time (05:41:02).

Last FR24 data: 05:41:02Z. GPS: 9.01602, 38.98415. Pressure Altitude: 8600 ft. GSpeed: 383 kts. (Corrected Altitude: 9000 ft, Terrain Elevation: 8146 ft, AGL: ~850 ft).

Last AVHerald data: 05:43:57Z. GPS N9.027 E39.153. FL086. Corrected Alt: 9027 ft. Terrain Elevation: 8130 ft. (AGL: ~900 ft).

[1] From AV Herald:

The last transponder data were received from position N9.027 E39.153 about 21nm east of Addis Ababa at FL086 at 05:43:57Z. Terrain elevation at that point is 8130 feet MSL, FL086 reported by the Mode-S Altimeter (which always measures to standard pressure 1013 QNH) corrected for QNH indicates the aircraft was flying at 9027 feet MSL at that position. According to aerial overview and satellite images the aircraft impacted ground at approximate position N8.8772 E39.2512 about 10.7nm southsoutheast of the last transponder position.


Is that for the FR data or the Arieon data? The CAA used Aireon ... this whoel thing is getting super confusing trying to piece together this fragments without definitive sources and using media reports...
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
osiris30
Posts: 2655
Joined: Sat Sep 30, 2006 10:16 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 1:22 am

flybucky wrote:
Lots of new information about the ATC communications from the NYT article. Excerpts:

Within one minute of Flight 302’s departure, Captain Getachew reported a “flight control” problem in a calm voice. At that point, radar showed the aircraft’s altitude as being well below what is known as the minimum safe height from the ground during a climb.

Within two minutes, the plane had climbed to a safer altitude, and the pilot said he wanted to stay on a straight course to 14,000 feet.

Then the controllers observed the plane going up and down by hundreds of feet, and it appeared to be moving unusually fast, the person said. The controllers, the person said, “started wondering out loud what the flight was doing.”

Captain Getachew, with panic in his voice, interrupted with his request to turn back. Flight 302 was just three minutes into its flight, and appeared to have accelerated to even higher speeds, well beyond its safety limits.


Assuming these accounts from the person who reviewed the ATC communications, the pilots could not stop the aircraft from accelerating. What are some possible causes of this? Unreliable airspeed causing the autopilot to increase throttle, thinking the airspeed was too slow? Could they not cut the autopilot/autothrottle?


Unless there was a mechanical failure, yes, the pilots have the ability to control the engines. The odds of a failure to affect BOTH engines in such a way to keep them in sync thrust wise (aka there was no turn from the aircraft due to differential thrust) but continuing to accelerate is INSANELY unlikely.
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
mzlin
Posts: 115
Joined: Sat Mar 31, 2012 6:32 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 1:59 am

flybucky wrote:
Lots of new information about the ATC communications from the NYT article. Excerpts:

Within one minute of Flight 302’s departure, Captain Getachew reported a “flight control” problem in a calm voice. At that point, radar showed the aircraft’s altitude as being well below what is known as the minimum safe height from the ground during a climb.

Within two minutes, the plane had climbed to a safer altitude, and the pilot said he wanted to stay on a straight course to 14,000 feet.

Then the controllers observed the plane going up and down by hundreds of feet, and it appeared to be moving unusually fast, the person said. The controllers, the person said, “started wondering out loud what the flight was doing.”

Captain Getachew, with panic in his voice, interrupted with his request to turn back. Flight 302 was just three minutes into its flight, and appeared to have accelerated to even higher speeds, well beyond its safety limits.


Assuming these accounts from the person who reviewed the ATC communications, the pilots could not stop the aircraft from accelerating. What are some possible causes of this? Unreliable airspeed causing the autopilot to increase throttle, thinking the airspeed was too slow? Could they not cut the autopilot/autothrottle?


Yes I wonder if it was a faulty pitot tube causing overspeed. The article mentions speed beyond safe limits so makes you wonder if the stabilizer suffered a structural failure somewhere. This doesn't sound related to mcas although the article made it sound like it is.

Of course two different problems doesn't exonerate Boeing or make the max seem safer. Rather it makes it seem even less safe. This was always the weird thing about Boeing's response. Two loss of control accidents is very concerning and merit grounding until the causes are known and if necessary fixed, regardless of what they are.
Last edited by mzlin on Fri Mar 15, 2019 2:00 am, edited 1 time in total.
 
ikramerica
Posts: 14902
Joined: Mon May 23, 2005 9:33 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:00 am

edu2703 wrote:
AirCalSNA wrote:
Summaries of and some quotes from the Ethiopian CVR have been leaked to the New York Times.


Nope. Just a anonymous report from an air traffic controller

Right its not CVR but its interesting.

Notes:

-did not climb correctly. Much too low. Cant be MCAS in that phase
-pilot was panicking 3-4 minutes before crash (maybe knew he didnt know how to recover)
-ATC could see erratic flight levels and severe overspeed before pilot signalled anything wrong
- attempted a turn back without control of the aircraft, plummetting to the ground (Lion also attempted a turn back without control)
- entered restricted millitary airspace and crashed

Question: considering there are hours worth of fuel, why would both pilots turn back so soon without more attempts to stablize the aircraft? Im not a pilot but it doesnt seem like a wise choice unless they are having engine trouble or low fuel.
Of all the things to worry about... the Wookie has no pants.
 
User avatar
SheikhDjibouti
Posts: 1781
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:11 am

flybucky wrote:
Assuming these accounts from the person who reviewed the ATC communications, the pilots could not stop the aircraft from accelerating. What are some possible causes of this? Unreliable airspeed causing the autopilot to increase throttle, thinking the airspeed was too slow? Could they not cut the autopilot/autothrottle?

I suggest you take a step back from " the pilots could not stop the aircraft from accelerating."

An aircraft needs high power settings for a standard climb-out. Basic physics dictates that all that thrust either gets converted into altitude, or in this case speed. I see the excess speed as an unintended consequence of something preventing a normal climb. I haven't seen anything to suggest the pilots could not stop the aircraft from accelerating.

Hence it is not so much a case of the pilots increasing the throttle, more a case of them failing to reduce the throttle because the energy wasn't being converted into altitude as it should.

Perhaps somebody with a better understanding of the 737MAX autothrottle can tell me whether under such circumstances an AT set for climb/thrust would react to the changing circumstances and automatically reduce the power delivered at anything less than VNE. I suspect manual over-ride is the more likely option.
Nothing to see here; move along please.
 
Buffalomatt1027
Posts: 392
Joined: Sun Aug 20, 2017 4:02 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:12 am

The AA pilot said that he noticed the nose of the plane dipping once during a takeoff..... he switched off Autopilot immediately and raised the nose of the plane. The flight went on as planned. - read that from a yahoo.com article as work this morning.

MAYBE ... just maybe ...... the Lion airlines and Ethiopian pilots panics and kept the autopilot on and nose dived straight into the ground?

The difference in training .... could be an issue.

Flying a MAX 737 is also not the same as the previous models. The pilots could have reverted back to the old ways of doing things.
 
maui19
Posts: 9
Joined: Sun May 21, 2017 6:19 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:24 am

So was the pilot flying the plane and handling radio comm?
 
User avatar
SheikhDjibouti
Posts: 1781
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:27 am

ikramerica wrote:
Notes:

-did not climb correctly. Much too low. Cant be MCAS in that phase
-pilot was panicking 3-4 minutes before crash (maybe knew he didnt know how to recover)
-ATC could see erratic flight levels and severe overspeed before pilot signalled anything wrong
- attempted a turn back without control of the aircraft, plummetting to the ground (Lion also attempted a turn back without control)
- entered restricted millitary airspace and crashed


I haven't read the NYT article, so can I ask for clarification on two of your comments that caught my eye.

Item #3 "severe overspeed" - elsewhere I only see words to the effect of "faster than normally expected"
As per my earlier answer, this is a perfectly natural physical result of maintaining a climb throttle setting whilst failing to actually climb.
"Overspeed" is a specific term usually linked to engines, and implies a speed at which damage might occur.
Do you (or the NYT) have some data to quantify use of that term or is "faster than normal" equally acceptable?

Item #5 "entered restricted millitary airspace"
I am assuming somebody has accessed relevant charts in order to make that statement, in which case I am obliged.
However, if this emergency manoeuvre was acceptable to ATC, is it especially relevant? Would the Ethiopian military be likely to shoot down one of their own?
Nothing to see here; move along please.
 
Trin
Posts: 167
Joined: Mon May 02, 2011 4:45 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:27 am

ikramerica wrote:
Question: considering there are hours worth of fuel, why would both pilots turn back so soon without more attempts to stablize the aircraft? Im not a pilot but it doesnt seem like a wise choice unless they are having engine trouble or low fuel.


I'm not sure. Not a pilot. But in my mind knowing what I know of human nature - I could certainly understand it if the crew experienced serious flight control issues from the get-go. I would imagine that your first instinct in such a case would be to immediately return to the airport you came from - especially seeing as how you aren't even away from their tower's visual range yet.
 
blrsea
Posts: 1913
Joined: Fri May 20, 2005 2:22 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:33 am

Looks like it might have been case of MCAS kicking-in as per this report below:

New evidence links jackscrews and automated system to deadly Boeing crashes

NBC News has learned that physical evidence is a jackscrew, a mechanism that controls the angle of the horizontal stabilizer, that smaller wing structure in the rear of the plane. A new automated system called MCAS is connected to the horizontal stabilizer, and is only found on the 737 MAX.

MCAS is a safety device designed to run in the background and keep the plane from stalling. But it’s been implicated in the Indonesian accident through Airworthiness Directives from last November issued by the FAA.

The jackscrew was found in a position that would have raised the leading edge of the stabilizer up, which would have forced the nose down. Fixing a condition known as “runaway trim” would have been easy, a matter of turning off a couple of switches.

In the Indonesian crash, data released in a preliminary report by the Indonesian government indicated that didn’t happen and the pilots were fighting the automation.
 
osiris30
Posts: 2655
Joined: Sat Sep 30, 2006 10:16 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:37 am

SheikhDjibouti wrote:
ikramerica wrote:
Notes:

-did not climb correctly. Much too low. Cant be MCAS in that phase
-pilot was panicking 3-4 minutes before crash (maybe knew he didnt know how to recover)
-ATC could see erratic flight levels and severe overspeed before pilot signalled anything wrong
- attempted a turn back without control of the aircraft, plummetting to the ground (Lion also attempted a turn back without control)
- entered restricted millitary airspace and crashed


I haven't read the NYT article, so can I ask for clarification on two of your comments that caught my eye.

Item #3 "severe overspeed" - elsewhere I only see words to the effect of "faster than normally expected"
As per my earlier answer, this is a perfectly natural physical result of maintaining a climb throttle setting whilst failing to actually climb.
"Overspeed" is a specific term usually linked to engines, and implies a speed at which damage might occur.
Do you (or the NYT) have some data to quantify use of that term or is "faster than normal" equally acceptable?

Item #5 "entered restricted millitary airspace"
I am assuming somebody has accessed relevant charts in order to make that statement, in which case I am obliged.
However, if this emergency manoeuvre was acceptable to ATC, is it especially relevant? Would the Ethiopian military be likely to shoot down one of their own?



Overspeed is not just related to engines, not even close. The entire frame has a designed speed limit. At 380kts at 8600' alt, the aircraft was definitely in a 'severe overspeed' condition. That is a speed that can incur structural failure unless managed very well.
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
User avatar
QuarkFly
Posts: 369
Joined: Mon Aug 15, 2016 4:20 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:37 am

ikramerica wrote:
edu2703 wrote:
AirCalSNA wrote:
Summaries of and some quotes from the Ethiopian CVR have been leaked to the New York Times.


Nope. Just a anonymous report from an air traffic controller

Right its not CVR but its interesting.

Notes:

-did not climb correctly. Much too low. Cant be MCAS in that phase
-pilot was panicking 3-4 minutes before crash (maybe knew he didnt know how to recover)
-ATC could see erratic flight levels and severe overspeed before pilot signalled anything wrong
- attempted a turn back without control of the aircraft, plummetting to the ground (Lion also attempted a turn back without control)
- entered restricted millitary airspace and crashed

Question: considering there are hours worth of fuel, why would both pilots turn back so soon without more attempts to stablize the aircraft? Im not a pilot but it doesnt seem like a wise choice unless they are having engine trouble or low fuel.


Sounds a lot like speculation. Nobody yet knows what was going on in the cockpit or with the aircraft systems and we don't know if the crew was panicking. We should avoid speculating or impugning the crew until more information about what really happened is available.

Also, overspeed can easily be stopped by retarding the throttle and/or raising the nose...again, let's not assume the crew did not know this.
Always take the Red Eye if possible
 
flybucky
Posts: 175
Joined: Tue Apr 17, 2018 7:44 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:44 am

SheikhDjibouti wrote:
I see the excess speed as an unintended consequence of something preventing a normal climb. I haven't seen anything to suggest the pilots could not stop the aircraft from accelerating.


Yes, that makes much more sense. It's not that the pilots couldn't reduce the throttle, it's that they didn't want to reduce the throttle because they needed the thrust to gain altitude, which they were having problems doing. Excessive speed was just the byproduct.
 
ikramerica
Posts: 14902
Joined: Mon May 23, 2005 9:33 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:46 am

SheikhDjibouti wrote:
ikramerica wrote:
Notes:

-did not climb correctly. Much too low. Cant be MCAS in that phase
-pilot was panicking 3-4 minutes before crash (maybe knew he didnt know how to recover)
-ATC could see erratic flight levels and severe overspeed before pilot signalled anything wrong
- attempted a turn back without control of the aircraft, plummetting to the ground (Lion also attempted a turn back without control)
- entered restricted millitary airspace and crashed


I haven't read the NYT article, so can I ask for clarification on two of your comments that caught my eye.

Item #3 "severe overspeed" - elsewhere I only see words to the effect of "faster than normally expected"
As per my earlier answer, this is a perfectly natural physical result of maintaining a climb throttle setting whilst failing to actually climb.
"Overspeed" is a specific term usually linked to engines, and implies a speed at which damage might occur.
Do you (or the NYT) have some data to quantify use of that term or is "faster than normal" equally acceptable?

Item #5 "entered restricted millitary airspace"
I am assuming somebody has accessed relevant charts in order to make that statement, in which case I am obliged.
However, if this emergency manoeuvre was acceptable to ATC, is it especially relevant? Would the Ethiopian military be likely to shoot down one of their own?

I’m only summarizing the article.

#3. Yes. The article indicates that the arcraft was traveling beyond safe limits for the frame. I am not an expert and don’t have any way of knowing if that’s true.

#5. The article says that the unnamed ATC said they entered restricted military airspace and crashed less than a minute after starting to bank to return to the airport.

Edit: if #5 is true it adds a new wrinkle. Is it only the airspace? Is the crash site near a military installation? What kind of video is there from that area that may be hard to procure?
Of all the things to worry about... the Wookie has no pants.
 
ikramerica
Posts: 14902
Joined: Mon May 23, 2005 9:33 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 2:57 am

Trin wrote:
ikramerica wrote:
Question: considering there are hours worth of fuel, why would both pilots turn back so soon without more attempts to stablize the aircraft? Im not a pilot but it doesnt seem like a wise choice unless they are having engine trouble or low fuel.


I'm not sure. Not a pilot. But in my mind knowing what I know of human nature - I could certainly understand it if the crew experienced serious flight control issues from the get-go. I would imagine that your first instinct in such a case would be to immediately return to the airport you came from - especially seeing as how you aren't even away from their tower's visual range yet.

Instincts can be deadly if the solution goes against instinct. I remember reading there was a hill in the path that might be in the way if they coukdnt gain altitude, and that would make it urgent to turn but at this point there’s so much conflicting information it’s hard to know what’s true.
Of all the things to worry about... the Wookie has no pants.
 
User avatar
7BOEING7
Posts: 3039
Joined: Fri Oct 12, 2012 5:28 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 3:00 am

blrsea wrote:
Looks like it might have been case of MCAS kicking-in as per this report below:

New evidence links jackscrews and automated system to deadly Boeing crashes

NBC News has learned that physical evidence is a jackscrew, a mechanism that controls the angle of the horizontal stabilizer, that smaller wing structure in the rear of the plane. A new automated system called MCAS is connected to the horizontal stabilizer, and is only found on the 737 MAX.

MCAS is a safety device designed to run in the background and keep the plane from stalling. But it’s been implicated in the Indonesian accident through Airworthiness Directives from last November issued by the FAA.

The jackscrew was found in a position that would have raised the leading edge of the stabilizer up, which would have forced the nose down. Fixing a condition known as “runaway trim” would have been easy, a matter of turning off a couple of switches.

In the Indonesian crash, data released in a preliminary report by the Indonesian government indicated that didn’t happen and the pilots were fighting the automation.


Did the Ethiopian pilots not receive the information on how to disable the MCAS?
 
ikramerica
Posts: 14902
Joined: Mon May 23, 2005 9:33 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 3:07 am

7BOEING7 wrote:
blrsea wrote:
Looks like it might have been case of MCAS kicking-in as per this report below:

New evidence links jackscrews and automated system to deadly Boeing crashes

NBC News has learned that physical evidence is a jackscrew, a mechanism that controls the angle of the horizontal stabilizer, that smaller wing structure in the rear of the plane. A new automated system called MCAS is connected to the horizontal stabilizer, and is only found on the 737 MAX.

MCAS is a safety device designed to run in the background and keep the plane from stalling. But it’s been implicated in the Indonesian accident through Airworthiness Directives from last November issued by the FAA.

The jackscrew was found in a position that would have raised the leading edge of the stabilizer up, which would have forced the nose down. Fixing a condition known as “runaway trim” would have been easy, a matter of turning off a couple of switches.

In the Indonesian crash, data released in a preliminary report by the Indonesian government indicated that didn’t happen and the pilots were fighting the automation.


Did the Ethiopian pilots not receive the information on how to disable the MCAS?

ET management claims they had training on it after Lion crash.
Of all the things to worry about... the Wookie has no pants.
 
WNbob
Posts: 38
Joined: Mon Nov 26, 2007 6:36 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 3:10 am

All I know is, 2 crashes within short period, same aircraft type, during climb out, clear weather, similar satellite data, Lion's already points at the MCAS. Lion's pilot didn't know how to deal with disparate AOA readings. Haven't we learned from malfunctioning sensors by now? In the end it may point that foreign pilots don't get the same training as Westerners do and that would be a shame and fault of the operators.
 
GalaxyFlyer
Posts: 3730
Joined: Fri Jan 01, 2016 4:44 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 3:44 am

If the attitude is about 12-15 degrees nose up on either the PFD backed up by the Standby AI or visual reference to Earth and the power is set at climb or around 90% N1– it’s flying. It’s flying regardless of erroneous stall warnings, bells belling, EICAS or Master Warning blinking. Keep the attitude and power set, then start shutting off the problems.
 
User avatar
SheikhDjibouti
Posts: 1781
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 3:48 am

osiris30 wrote:
SheikhDjibouti wrote:
Item #3 "severe overspeed" - elsewhere I only see words to the effect of "faster than normally expected"
Do you (or the NYT) have some data to quantify use of that term or is "faster than normal" equally acceptable?

At 380kts at 8600' alt, the aircraft was definitely in a 'severe overspeed' condition. That is a speed that can incur structural failure unless managed very well.

Perhaps I didn't make myself clear; do you have some reference source to back that up?

I do not dispute that it is faster than normal, considerably faster than normal if you wish. But what is VNE or VMO for a 737 at 8600ft?

I have seen Hawaiian 717s exceed that figure at altitudes that are not much higher. (On their short inter-island hops they rarely reach "normal" cruising altitudes; instead they crack on at low level)

If it helps, VMO for a 767 is 360kts. I believe that applies from sea level up to 10,000ft.(can somebody confirm that?)
If 360kts is acceptable at sea level, then it doesn't require Einstein to see that at FL86 you could exceed that figure quite considerably before the same potentially damaging aerodynamic forces were exerted on the airframe. Technically it is still overspeed, but in reality it would be less of an issue.

If 380kts for a 737MAX is "severe overspeed", why is it so inferior? Is it down to those pesky over-sized engines interfering with air flow over the wings? :scratchchin:

I would still like to know the actual numbers, instead of people's opinions.

EDIT; Just found Vd for an A320 is 381kts.
Nothing to see here; move along please.
 
mcdu
Posts: 1535
Joined: Thu Apr 28, 2005 5:23 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 3:58 am

SheikhDjibouti wrote:
osiris30 wrote:
SheikhDjibouti wrote:
Item #3 "severe overspeed" - elsewhere I only see words to the effect of "faster than normally expected"
Do you (or the NYT) have some data to quantify use of that term or is "faster than normal" equally acceptable?

At 380kts at 8600' alt, the aircraft was definitely in a 'severe overspeed' condition. That is a speed that can incur structural failure unless managed very well.

Perhaps I didn't make myself clear; do you have some reference source to back that up?

I do not dispute that it is faster than normal, considerably faster than normal if you wish. But what is VNE or VMO for a 737 at 8600ft?

I have seen Hawaiian 717s exceed that figure at altitudes that are not much higher. (On their short inter-island hops they rarely reach "normal" cruising altitudes; instead they crack on at low level)

If it helps, VMO for a 767 is 360kts. I believe that applies from sea level up to 10,000ft.(can somebody confirm that?)
If 360kts is acceptable at sea level, then it doesn't require Einstein to see that at FL86 you could exceed that figure quite considerably before the same potentially damaging aerodynamic forces were exerted on the airframe. Technically it is still overspeed, but in reality it would be less of an issue.

If 380kts for a 737MAX is "severe overspeed", why is it so inferior? Is it down to those pesky over-sized engines interfering with air flow over the wings? :scratchchin:

I would still like to know the actual numbers, instead of people's opinions.

EDIT; Just found Vd for an A320 is 381kts.


You won’t see pilots operating at those speeds normally. First of all in the USA and many other places the limit is 250kts below 10k. Did you see the Hawaiian airspeed indicator or just the data showing TAS?
 
User avatar
SheikhDjibouti
Posts: 1781
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:08 am

ikramerica wrote:
#5. The article says that the unnamed ATC said they entered restricted military airspace and crashed less than a minute after starting to bank to return to the airport.

Edit: if #5 is true it adds a new wrinkle. Is it only the airspace? Is the crash site near a military installation? What kind of video is there from that area that may be hard to procure?

The military installation is almost certainly the Ethiopian AF base at Harar Meda (QHR), which in a bizarre coincidence is exactly where the original crash site was incorrectly marked in newspaper reports.
If the more senior Ethiopian Captain had spent any time at all with the Air Force, he would be completely aware of that base, and may even have taken advantage of it's 9,540 ft runway if he couldn't make ADD.

Earlier today, several ET flights passed reasonably close to the actual crash site on their way in to ADD, and two southbound departures went even closer to QHR itself. The Ethiopian AF must be quite used to living with civilian neighbors all around them.
Nothing to see here; move along please.
 
User avatar
SheikhDjibouti
Posts: 1781
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:23 am

mcdu wrote:
osiris30 wrote:
At 380kts at 8600' alt, the aircraft was definitely in a 'severe overspeed' condition. That is a speed that can incur structural failure unless managed very well.

You won’t see pilots operating at those speeds normally. First of all in the USA and many other places the limit is 250kts below 10k.

That is an ATC restriction, and nothing to do with aircraft structural issues.
The 250kt limit would apply to a Piper Malibu just as it would apply to Concorde (if it was still flying)

Did you see the Hawaiian airspeed indicator or just the data showing TAS?

I was half expecting that comment, and it is a fair question.
It was ground speed, but I believe I have seen it on flights operating in both directions at the same time, which means only one of them is benefitting from any tailwind. Tell me if I'm wrong.

I accept it isn't brilliant science, but currently it's better than anything anybody else has added to the subject. :D

Is there nobody here with actual verifiable figures from Boeing?
Nothing to see here; move along please.
 
ikramerica
Posts: 14902
Joined: Mon May 23, 2005 9:33 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:29 am

SheikhDjibouti wrote:
ikramerica wrote:
#5. The article says that the unnamed ATC said they entered restricted military airspace and crashed less than a minute after starting to bank to return to the airport.

Edit: if #5 is true it adds a new wrinkle. Is it only the airspace? Is the crash site near a military installation? What kind of video is there from that area that may be hard to procure?

The military installation is almost certainly the Ethiopian AF base at Harar Meda (QHR), which in a bizarre coincidence is exactly where the original crash site was incorrectly marked in newspaper reports.
If the more senior Ethiopian Captain had spent any time at all with the Air Force, he would be completely aware of that base, and may even have taken advantage of it's 9,540 ft runway if he couldn't make ADD.

Earlier today, several ET flights passed reasonably close to the actual crash site on their way in to ADD, and two southbound departures went even closer to QHR itself. The Ethiopian AF must be quite used to living with civilian neighbors all around them.

Im sure, just like in the USA when military bases are close. I was wondering what kind of video the bases might have of tge incident.

If the crash isnt close to the base then maybe the NYT info is out of date. Wouldnt be first time.
Of all the things to worry about... the Wookie has no pants.
 
ikramerica
Posts: 14902
Joined: Mon May 23, 2005 9:33 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:33 am

SheikhDjibouti wrote:
osiris30 wrote:
SheikhDjibouti wrote:
Item #3 "severe overspeed" - elsewhere I only see words to the effect of "faster than normally expected"
Do you (or the NYT) have some data to quantify use of that term or is "faster than normal" equally acceptable?

At 380kts at 8600' alt, the aircraft was definitely in a 'severe overspeed' condition. That is a speed that can incur structural failure unless managed very well.

Perhaps I didn't make myself clear; do you have some reference source to back that up?

I do not dispute that it is faster than normal, considerably faster than normal if you wish. But what is VNE or VMO for a 737 at 8600ft?

I have seen Hawaiian 717s exceed that figure at altitudes that are not much higher. (On their short inter-island hops they rarely reach "normal" cruising altitudes; instead they crack on at low level)

If it helps, VMO for a 767 is 360kts. I believe that applies from sea level up to 10,000ft.(can somebody confirm that?)
If 360kts is acceptable at sea level, then it doesn't require Einstein to see that at FL86 you could exceed that figure quite considerably before the same potentially damaging aerodynamic forces were exerted on the airframe. Technically it is still overspeed, but in reality it would be less of an issue.

If 380kts for a 737MAX is "severe overspeed", why is it so inferior? Is it down to those pesky over-sized engines interfering with air flow over the wings? :scratchchin:

I would still like to know the actual numbers, instead of people's opinions.

EDIT; Just found Vd for an A320 is 381kts.

What if you are bouncing around and pitching and having control issues. Would that speed lead to possible structural damage, control surface issues, etc?
Of all the things to worry about... the Wookie has no pants.
 
User avatar
SheikhDjibouti
Posts: 1781
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:36 am

ikramerica wrote:
What if you are bouncing around and pitching and having control issues. Would that speed lead to possible structural damage, control surface issues, etc?

Yes, absolutely, which is probably why speed limits in turbulence are somewhat lower.....
Nothing to see here; move along please.
 
User avatar
Jouhou
Posts: 1969
Joined: Tue May 24, 2016 4:16 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:37 am

Between the new info being discussed and the prior mentioned witness accounts, it sort of seems likely the actual crash was due to structural failure. The witnesses note debris coming from the plane before it crashed. They can't be trusted to identify specifically what, but they saw things flying off or out of it. They heard rattling. They saw it turn side to side. It might have actually reached a speed that resulted in structural failure.

That still doesn't resolve what put them in that situation in the first place, but it does imply their final dive might not have been an MCAS nose down.
 
Chemist
Posts: 584
Joined: Tue Oct 20, 2015 4:46 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:42 am

I read the NYT article. Very interesting.
A few unrelated thoughts:

    If they had problems almost immediately after takeoff, then would MCAS be the issue? MCAS doesn't go into effect until flaps are retracted.
    If the captain was on the radio, was he flying too? Or the low-time FO? Or is the authori of the article being sloppy saying that the captain radioed when it could have been the FO?
    If you are having control problems and can't climb, or if airspeed is unreliable, then shouldn't you set power and pitch (or set power appropriately for the current pitch) to avoid excessive speed?
    If you are flying very low AGL at very high speed, it's not going to take much of a pitch anomaly to plunge you into the ground. You don't have much leeway in altitude. The turnback to airport won't make things any easier, either.
 
User avatar
SheikhDjibouti
Posts: 1781
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:48 am

ikramerica wrote:
#5. The article says that the unnamed ATC said they entered restricted military airspace and crashed less than a minute after starting to bank to return to the airport.

Edit: if #5 is true it adds a new wrinkle. Is it only the airspace? Is the crash site near a military installation? What kind of video is there from that area that may be hard to procure?

SheikhDjibouti wrote:
The military installation is almost certainly the Ethiopian AF base at Harar Meda (QHR), which in a bizarre coincidence is exactly where the original crash site was incorrectly marked in newspaper reports.


If the crash isnt close to the base then maybe the NYT info is out of date. Wouldnt be first time.

Not necessarily, and maybe I explained myself badly.
The airbase itself is not in the immediate vicinity, but the Air Force may have earmarked a route for their own traffic (including fast jets), particularly at low level.
ET302, flying at low level, may well have strayed into their reserved traffic zone.

Hence the NYT can still be correct, but the issue is not necessarily a big one under these circumstances.
Nothing to see here; move along please.
 
Jetty
Posts: 975
Joined: Wed Nov 11, 2015 12:27 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:50 am

Chemist wrote:
If they had problems almost immediately after takeoff, then would MCAS be the issue? MCAS doesn't go into effect until flaps are retracted.

It shouldn’t go into effect until flaps are retracted. That doesn’t mean it doesn’t go into effect until flaps are retracted. From the Lion Air crash we know it has gone into effect when it shouldn’t before and there’s no way of knowing if this is isolated to one specific set of circumstances or an wider issue.
 
cat3appr50
Posts: 164
Joined: Wed Jan 16, 2013 10:44 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:22 am

In response to post #2340
Regarding the Lion Air JT610 accident flight, at 23:22:05 UTC, the DFDR recorded the aircraft altitude was approximately 2,150 feet and the flaps were retracted. After the flaps reached 0, the DFDR recorded automatic aircraft nose down (AND) trim active for 10 seconds followed by flight crew commanded aircraft nose up (ANU) trim. MCAS was not activated on this flight until the flaps were up.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:22 am

Reuters Top News

@Reuters
BREAKING: Investigators of Ethiopian crash found piece of stabilizer with trim in unusual position similar to doomed Lion Air jet - sources

231
1:15 AM - Mar 15, 2019

Wonder how they found that, given the pics of the site.
 
Planetalk
Posts: 436
Joined: Thu Aug 27, 2015 5:12 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:52 am

LTC8K6 wrote:
Reuters Top News

@Reuters
BREAKING: Investigators of Ethiopian crash found piece of stabilizer with trim in unusual position similar to doomed Lion Air jet - sources

231
1:15 AM - Mar 15, 2019

Wonder how they found that, given the pics of the site.


Wow, someone here pondered many posts back if they might have found the jackscrew. With the new FDR evidence from the LionAir crash as well that suggests the problem was somewhere deeper than the AoA sensors, it's beginning to look alarmingly like there is some scenario in which this plane behaves extremely strangely. And I hope people can ease up on some of the references to the competencies of the pilots. As it stands there is no evidence their skills or training were lacking. Just incredibly sad all round.
 
Pluto707
Posts: 37
Joined: Sun Mar 10, 2019 2:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:02 am

ikramerica wrote:
Notes:
-did not climb correctly. Much too low. Cant be MCAS in that phase

Why a suggestion that MCAS cannot be involved at low agl ?
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:02 am

Planetalk wrote:
LTC8K6 wrote:
Reuters Top News

@Reuters
BREAKING: Investigators of Ethiopian crash found piece of stabilizer with trim in unusual position similar to doomed Lion Air jet - sources

231
1:15 AM - Mar 15, 2019

Wonder how they found that, given the pics of the site.


Wow, someone here pondered many posts back if they might have found the jackscrew. With the new FDR evidence from the LionAir crash as well that suggests the problem was somewhere deeper than the AoA sensors, it's beginning to look alarmingly like there is some scenario in which this plane behaves extremely strangely. And I hope people can ease up on some of the references to the competencies of the pilots. As it stands there is no evidence their skills or training were lacking. Just incredibly sad all round.


It seems like the evidence they claim to have found wouldn't have survived the crash though?

Maybe they can tell positions by witness marks on what's left.
 
Eyad89
Posts: 637
Joined: Fri Sep 02, 2016 10:47 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:28 am

7BOEING7 wrote:


Did the Ethiopian pilots not receive the information on how to disable the MCAS?


In my opinion, the worst case scenario for Boeing would be if the the Ethiopian pilots did receive the information and followed Boeing’s instructions, but that was not enough to bring the plane back into control. We will know that in time.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:29 am

Investigators on the ground near the crash site of the Ethiopian Airlines 737 MAX found the plane’s jackscrew, a part that moves the horizontal tail of the aircraft, and it indicates that the tail was in an unusual position, according to an aviation safety consultant briefed on the findings.


This, along with evidence from a new satellite-based system that tracked the flight data and revealed similar trajectories on the two flights, is what finally led the Federal Aviation Administration (FAA) to ground the MAX on Wednesday, following regulators around the world.


https://www.seattletimes.com/business/b ... eings-fix/

So it seems like they are narrowing in on stabilizer movement / position.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:32 am

The company said it will change the MCAS software to give the system input from more than one AOA sensor. It will limit how much MCAS can move the horizontal tail in response to an erroneous AOA signal. And when activated, the system will kick in only for one cycle, rather than multiple times.

So that is the planned fix.
 
mandala499
Posts: 6589
Joined: Wed Aug 29, 2001 8:47 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:38 am

Jetty wrote:
It shouldn’t go into effect until flaps are retracted. That doesn’t mean it doesn’t go into effect until flaps are retracted. From the Lion Air crash we know it has gone into effect when it shouldn’t before and there’s no way of knowing if this is isolated to one specific set of circumstances or an wider issue.

What I fear is that there is unreliable airspeed from the take off roll, and they were shocked to see stick shaker on from the take off roll, and decided to shallow out the climb to "get out of it"... only to not see it not disappear.... with the increasing speed and confusion with the stick shaker and the unreliable airspeed then comes the next question... did they pull up the flaps at 800' AGL?
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
User avatar
Kindanew
Posts: 164
Joined: Tue May 30, 2017 11:07 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:51 am

Jouhou wrote:
Between the new info being discussed and the prior mentioned witness accounts, it sort of seems likely the actual crash was due to structural failure. The witnesses note debris coming from the plane before it crashed. They can't be trusted to identify specifically what, but they saw things flying off or out of it. They heard rattling. They saw it turn side to side. It might have actually reached a speed that resulted in structural failure.

That still doesn't resolve what put them in that situation in the first place, but it does imply their final dive might not have been an MCAS nose down.


I can’t see how there can be any suggestion of structural damage based on the info released.

As far as we know, no wreckage has been found away from the crash site and it’s now 6 days since the accident.

Eyewitness accounts to plane crashes are often not correct.
 
Pluto707
Posts: 37
Joined: Sun Mar 10, 2019 2:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:54 am

MCAS is not the cause, but it gave the final blow

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