Ethiopian Airlines Crash/ B737MAX grounding

Hotblack Desiato

.. and the cost of replacement parts/engines and compensation for AOG will end up at RR's door one way or the other

Brennus335

dogmatix wrote: »

There was a poster over on the A380 cancelled thread who referred to airbus as “scarebus”, something to do with airbus not being as safe as boeing. Then the whole 737max story broke. Oh the irony… Strange thing is that the post has now vanished.

Yeah, it was the same eejit.

Brennus335

cnocbui wrote: »

I would have thought that the optional warning light to announce a conflict between the two AOA sensors should just about be mandatory now. Not something that can be provided via software.

The media always calls these things "warning lights". It's not an actual physical light like something out of 1960's Star Trek.
It's just a text message on a screen. All done by software.

billy few mates

Depending on the position of the horizontal stabiliser when they operated the stab trim cutout switches it may be that the elevators did not have the authority to overcome the stab trim?
For example if there was already full nose down stab trim when you switch off the motors the elevators by themselves would not be able to overcome the nose down pitch hence the attempt to manually trim the stab to try and get the nose back up.
Absolutely tragic.

Raging_Ninja

cnocbui wrote: »

Another 787 with engine woes:

https://www.stuff.co.nz/travel/news/111743027/jetstar-787-suffers-problems-with-both-engines-on-approach-to-osaka

This is something that happens probably a thousand times a day.

Edit: my assertion is incorrect.

odyssey06

Brennus335 wrote: »

The media always calls these things "warning lights". It's not an actual physical light like something out of 1960's Star Trek.
It's just a text message on a screen. All done by software.

If that is the case Boeing trying to charge hundreds of thousands of dollars for it as an optional extra is even more outrageous.

Tenzor07

odyssey06 wrote: »

If that is the case Boeing trying to charge hundreds of thousands of dollars for it as an optional extra is even more outrageous.

Hundreds of thousand$$ for a light? Are you sure?

odyssey06

Tenzor07 wrote: »

Hundreds of thousand$$ for a light? Are you sure?

On second thoughts no... unclear how much but if it is similar to the extras noted here more like 10k
https://www.google.com/amp/s/www.nytimes.com/2019/03/21/business/boeing-safety-features-charge.amp.html

mickdw

80,000 dollars was quoted here earlier.

Tenger

mickdw wrote: »

80,000 dollars was quoted here earlier.

Quotes varied as the cost was a fraction of the overall price per airframe. Obviously Boeing has a “list price” and each customer negotiates that price down depending on their clout with Boeing, their order size, their after sales support and their delivery slots.
Thus it could be 200K on a last minute, in a rush small order versus the 100s of airframes ordered by Southwest/Ryanair for delivery over 5-10 years.

mickdw

Tenger wrote: »

mickdw wrote: »

80,000 dollars was quoted here earlier.

Quotes varied as the cost was a fraction of the overall price per airframe. Obviously Boeing has a “list price” and each customer negotiates that price down depending on their clout with Boeing, their order size, their after sales support and their delivery slots.
Thus it could be 200K on a last minute, in a rush small order versus the 100s of airframes ordered by Southwest/Ryanair for delivery over 5-10 years.

So realistically it's just down to customer specification as to whether it was included or not and not necessarily a cost issue.
The important point is though that if it's a safety critical item, it should be standard fit.

cnocbui

Raging_Ninja wrote: »

This is something that happens probably a thousand times a day.

I don't believe you, frankly.

The Jetstar 787 remains grounded at Kansai International Airport while it is inspected by engineers from the airline, General Electric and Boeing.

The ministry classified the situation as a “serious incident” that could have led to a major accident, adding that although there were no reports of injuries it has decided to send inspectors to the airport to look into the plane, which was from the northern Australian city of Cairns.

https://www.japantimes.co.jp/news/2019/04/03/business/jetstar-787-serious-engine-trouble-landing-kansai-international-airport/

cnocbui

billy few mates wrote: »

Depending on the position of the horizontal stabiliser when they operated the stab trim cutout switches it may be that the elevators did not have the authority to overcome the stab trim?
For example if there was already full nose down stab trim when you switch off the motors the elevators by themselves would not be able to overcome the nose down pitch hence the attempt to manually trim the stab to try and get the nose back up.
Absolutely tragic.

Please tell me the trim tab isn't actuated by a long threaded shaft attached to a motor with a 'nut' on the shaft attached to the tab?

Cutting power would just lock something like that it in the wrong position. You would need something like an explosive bolt to decouple such a mechanism in an emergency.

Irish Steve

Raging_Ninja wrote: »

This is something that happens probably a thousand times a day.

No, this is very much NOT a regular or even irregular occurrence, and is being regarded as a serious incident. The aircraft is currently grounded and being inspected, they will be looking very closely at a number of data recorder captures to see what went on, and why, as this is very much not an expected or routine event.

Coil Kilcrea

cnocbui wrote: »

I don't believe you, frankly.



https://www.japantimes.co.jp/news/2019/04/03/business/jetstar-787-serious-engine-trouble-landing-kansai-international-airport/

I flew on the 787 last week and will do the same next week to Japan. Much and all as I love the airplane, these issues nag at me. Anyone here know why this problem with the Trent engines seems to be never ending? And I appreciate it’s rare enough but it’s still troubling. Thanks.

Jeff2

cnocbui wrote: »

Please tell me the trim tab isn't actuated by a long threaded shaft attached to a motor with a 'nut' on the shaft attached to the tab?

Cutting power would just lock something like that it in the wrong position. You would need something like an explosive bolt to decouple such a mechanism in an emergency.

I believe it is but there is a way the pilot can manually control it after switching it off.

I'll look for where I got that from.

Found it.
4.30 minutes in.

https://www.youtube.com/watch?v=xixM_cwSLcQ

plodder

Coil Kilcrea wrote: »

I flew on the 787 last week and will do the same next week to Japan. Much and all as I love the airplane, these issues nag at me. Anyone here know why this problem with the Trent engines seems to be never ending? And I appreciate it’s rare enough but it’s still troubling. Thanks.

787 uses GE engines not the Trent which is Rolls Royce.

Coil Kilcrea

plodder wrote: »

787 uses GE engines not the Trent which is Rolls Royce.

I think it’s the Rolls Royce Trent but sorry for posting on the 737 Max thread which might be causing confusion.

plodder

Coil Kilcrea wrote: »

I think it’s the Rolls Royce Trent but sorry for posting on the 737 Max thread which might be causing confusion.

Actually, the 787 supports both, but the Jetstars mentioned in the article used the GE engine afaik.

Coil Kilcrea

JP Morgan reporting today that the cost to Boeing of the disruption caused by the Max grounding will likely cost between 1.7 to 2 Billion dollars a month. Build of the Max is continuing at an increased rate of 56 per month. That’s an an awful lot of working capital wrapped up in an aircraft that may have to be parked for a while.

Airlines typically pay a deposit with the order and then stage payments through build and final delivery. And while Boeing is a cash generating machine when all is well, it burns enormous cash when deliveries are disrupted. So while they’ve deep pockets, the pressure commercially to get back in the air conflicts with the necessity to ensure the plane is safe for flight.

I don’t see this happening as fast as the company would like.

Irish Steve

cnocbui wrote: »

Please tell me the trim tab isn't actuated by a long threaded shaft attached to a motor with a 'nut' on the shaft attached to the tab?

Cutting power would just lock something like that it in the wrong position. You would need something like an explosive bolt to decouple such a mechanism in an emergency.

No, it's not at all like that, there are 2 wheels, about 12" diameter, either side of the centre console, and there is a fold out handle in each wheel to enable manual winding.
They are then linked via cables to a winding system, the problem being that it requires a massive number of turns of the wheel to make a significant change to the trim of the aircraft, the motors move the wheels at a very high revolution rate compared to what can be done winding them by hand, and if the aircraft is significantly out of trim, the control column loads are significant, which can require both hands of the flying pilot to be on the yoke to apply sufficient force to overcome the out of trim load, leaving the non flying pilot to operate the handle and wind as quickly as possible.

example

https://www.youtube.com/watch?v=cQirIH_DuAs

It's a very short video, but this gives an idea of how fast the wheel moves if the motor is in control. Now imagine that the motor has been running for several seconds, and you now have to manually undo what it's done, while at the same time, performing check list work to try and analyse and resolve the problem that's threatening to crash the aircraft.

Not easy, or quick, or the sort of thing that the non flying pilot is prepared for, and to make it worse, the flying pilot is probably more than fully committed to just trying to keep the control yoke in about the right place to maintain stable flight, and constantly trying to overcome the out of trim forces.

MJohnston

https://arstechnica.com/information-technology/2019/04/ethiopian-air-pilots-turned-off-737-max-anti-stall-system-then-it-turned-on-again/

Data from the ill-fated aircraft’s flight recorder revealed that the anti-stall feature of the aircraft’s MCAS was triggered at least three times—and at least one time after the pilots followed the correct steps to shut it down.

Both Reuters and The Wall Street Journal report that the air crew followed procedures laid out by Boeing following the crash of a Lion Air 737 MAX in October, according to officials briefed on the initial findings of the investigation. But the pilots failed to regain control of the system, and the MCAS was reactivated again—triggering yet another automated correction of the aircraft’s stabilizers that would have pushed the nose of the plane down.

It is not clear at this point whether the pilots purposely reactivated the MCAS’ stabilizer control or if the software reactivated on its own after shutdown. While a Wall Street Journal source said that it appeared the pilots turned the system back on in hopes of regaining control over the stabilizers, Reuters reports that the software may have reactivated without human intervention, and further investigations of that possibility are ongoing.

Coil Kilcrea

Irish Steve wrote: »

No, it's not at all like that, there are 2 wheels, about 12" diameter, either side of the centre console, and there is a fold out handle in each wheel to enable manual winding.
They are then linked via cables to a winding system, the problem being that it requires a massive number of turns of the wheel to make a significant change to the trim of the aircraft, the motors move the wheels at a very high revolution rate compared to what can be done winding them by hand, and if the aircraft is significantly out of trim, the control column loads are significant, which can require both hands of the flying pilot to be on the yoke to apply sufficient force to overcome the out of trim load, leaving the non flying pilot to operate the handle and wind as quickly as possible.

example

https://www.youtube.com/watch?v=cQirIH_DuAs

It's a very short video, but this gives an idea of how fast the wheel moves if the motor is in control. Now imagine that the motor has been running for several seconds, and you now have to manually undo what it's done, while at the same time, performing check list work to try and analyse and resolve the problem that's threatening to crash the aircraft.

Not easy, or quick, or the sort of thing that the non flying pilot is prepared for, and to make it worse, the flying pilot is probably more than fully committed to just trying to keep the control yoke in about the right place to maintain stable flight, and constantly trying to overcome the out of trim forces.

Thanks Irish Steve for a great post. I can only imagine how difficult it must be for the pilots to manage this process whilst in the critical take off and climb phase of the Ethiopian flight. My long held admiration of pilots continues.

cnocbui

Irish Steve wrote: »

No, it's not at all like that, there are 2 wheels, about 12" diameter, either side of the centre console, and there is a fold out handle in each wheel to enable manual winding.
They are then linked via cables to a winding system, the problem being that it requires a massive number of turns of the wheel to make a significant change to the trim of the aircraft, the motors move the wheels at a very high revolution rate compared to what can be done winding them by hand, and if the aircraft is significantly out of trim, the control column loads are significant, which can require both hands of the flying pilot to be on the yoke to apply sufficient force to overcome the out of trim load, leaving the non flying pilot to operate the handle and wind as quickly as possible.

example

It's a very short video, but this gives an idea of how fast the wheel moves if the motor is in control. Now imagine that the motor has been running for several seconds, and you now have to manually undo what it's done, while at the same time, performing check list work to try and analyse and resolve the problem that's threatening to crash the aircraft.

Not easy, or quick, or the sort of thing that the non flying pilot is prepared for, and to make it worse, the flying pilot is probably more than fully committed to just trying to keep the control yoke in about the right place to maintain stable flight, and constantly trying to overcome the out of trim forces.

Thanks, I was watching the other video and it confirmed my fears. I'm gobsmacked, actually. That is a fail dangerous system, not fail safe. So the MCAS system keeps incrementing the trim by 4 times the stated design amount, with multiple cumulative iterations, doing so with the benefit of high speed electric motors, so when a pilot offs the stab trim switches, the pilot/s are left to manually unwind that large trim deflection by operating the screw - via the trim wheel handle - through many, many rotations?

Surely that process is far too slow if you are nose down with not much altitude?

Raging_Ninja

Irish Steve wrote: »

No, this is very much NOT a regular or even irregular occurrence, and is being regarded as a serious incident. The aircraft is currently grounded and being inspected, they will be looking very closely at a number of data recorder captures to see what went on, and why, as this is very much not an expected or routine event.

Thanks for the correction, will update my post.

Wheeliebin30

In the headlines from a leaked report it was hit by an object that sent it into a dive?

https://www.buzz.ie/news/ethiopian-airlines-boeing-737-hit-object-causing-crash-322582?fbclid=IwAR10L3wNWnFTLZ8XV_44r4C7fH8oRyNGrzX6U9CaAX2B4mRgl67vkdBc-Qs

Raging_Ninja

Wheeliebin30 wrote: »

In the headlines from a leaked report it was hit by an object that sent it into a dive?

https://www.buzz.ie/news/ethiopian-airlines-boeing-737-hit-object-causing-crash-322582?fbclid=IwAR10L3wNWnFTLZ8XV_44r4C7fH8oRyNGrzX6U9CaAX2B4mRgl67vkdBc-Qs

Well, something had to break the AoA sensor in order for MCAS to activate and crash the plane.

Wheeliebin30

Raging_Ninja wrote: »

Well, something had to break the AoA sensor in order for MCAS to activate and crash the plane.

Yeah true I was under the impression it was just a faulty sensor.

Stimpyone

Raging_Ninja wrote: »

Well, something had to break the AoA sensor in order for MCAS to activate and crash the plane.

buzz.ie quotes ABC news as the source. ABC news quotes two unnamed aviation sources familiar with the investigation.

Tin foil hat time, but I'm guessing an incident beyond Boeings control causing the crash would be advantageous in any future investigations, law suits or sales.

I'd hold my powder just yet.

ZiabR

News just breaking.

Pilots "repeatedly" followed procedures recommended by Boeing before last month's crash of an Ethiopian Airlines flight, according to the first official report into the disaster.

https://www.bbc.com/news/business-47812225

The problem as I see it though is that the pilots didn't have the correct training to deal with MCAS.

Expect more information to follow later today.

More news: https://www.bbc.com/news/business-47812225

Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

This is a carbon copy of the Lion Air flight. Plane nosedived numerous times before eventually crashing.

zilog_jones

ZiabR wrote: »

The problem as I see it though is that the pilots didn't have the correct training to deal with MCAS.

I wouldn't say that at all. Going by what I've read here, they did follow the correct procedure of overriding the stab trim, but this means having to manually wind back the stabilisers with these big wheels - the physical effort required to do this, while also controlling the yoke (which requires significant force in this situation), when you only have 40 seconds, sounds pretty much impossible to do with two people.

As we've heard there was an MCAS incident that was resolved on a Lion Air flight before the crash - but there were three people in the cockpit at the time.

Hotblack Desiato

Stimpyone wrote: »

Tin foil hat time, but I'm guessing an incident beyond Boeings control causing the crash would be advantageous in any future investigations, law suits or sales.

Sensors fail. A single failed sensor should not threaten to bring down an aircraft.

Stimpyone

Hotblack Desiato wrote: »

Sensors fail. A single failed sensor should not threaten to bring down an aircraft.

Agreed.

funkey_monkey

Hotblack Desiato wrote: »

Sensors fail. A single failed sensor should not threaten to bring down an aircraft.

Yes, there should not be a single point of failure. The safety analysis should have uncovered this.

jasper100

Stimpyone wrote: »

Agreed.

= manufacturer at fault. Which contradicts your earlier "guess" that it leaves manufacturer off the hook to some degree.

It won't

Tenzor07

Boeing's CEO takes flight in a Max yesterday:

https://www.airlineratings.com/news/boeing-ceo-muilenburg-aboard-737-max-test-flight/

josip

Tenzor07 wrote: »

Boeing's CEO takes flight in a Max yesterday:

https://www.airlineratings.com/news/boeing-ceo-muilenburg-aboard-737-max-test-flight/

Do they have parachutes on board test flights? (Genuine question)

Man Vs ManUre

josip wrote: »

Do they have parachutes on board test flights? (Genuine question)

Don’t think there would be an exit point on these large commercial planes that would be safe to jump from without being hit by engines, other plane part. You can probably only jump from the rear cargo bottom opening on those type of planes.
Also no eject option like with fighter planes.
These test pilots for Boeing and Airbus are probably ex fighter pilots and the elite. Still must be a very dangerous job to do. They fly the planes in ways that would terrify a passenger if it happened.

elmolesto

josip wrote: »

Do they have parachutes on board test flights? (Genuine question)

Airbus pilots carry them for the flutter test.

https://youtu.be/s3-g9B6Fgjs

TomSweeney

Wheeliebin30 wrote: »

If this finishes Boeing off what does that mean for the future of flying?

Airbus will cash in on it I'd imagine

Panrich

Sky reporting that the pilots followed Boeing process to deal with the MCAS error and that they eventually turned off MCAS but that it turned itself back on. This is from the report by the Ethiopian authorities.

billy few mates

josip wrote: »

Do they have parachutes on board test flights? (Genuine question)

I've heard of a Boeing 737 test flight with Boeing test pilots where they wore parachutes and had some sort of a special device fitted to the door to blow it open in case of emergency...

billy few mates

Irish Steve wrote: »

No, it's not at all like that, there are 2 wheels, about 12" diameter, either side of the centre console, and there is a fold out handle in each wheel to enable manual winding.
They are then linked via cables to a winding system, the problem being that it requires a massive number of turns of the wheel to make a significant change to the trim of the aircraft, the motors move the wheels at a very high revolution rate compared to what can be done winding them by hand, and if the aircraft is significantly out of trim, the control column loads are significant, which can require both hands of the flying pilot to be on the yoke to apply sufficient force to overcome the out of trim load, leaving the non flying pilot to operate the handle and wind as quickly as possible.

example

https://www.youtube.com/watch?v=cQirIH_DuAs

It's a very short video, but this gives an idea of how fast the wheel moves if the motor is in control. Now imagine that the motor has been running for several seconds, and you now have to manually undo what it's done, while at the same time, performing check list work to try and analyse and resolve the problem that's threatening to crash the aircraft.

Not easy, or quick, or the sort of thing that the non flying pilot is prepared for, and to make it worse, the flying pilot is probably more than fully committed to just trying to keep the control yoke in about the right place to maintain stable flight, and constantly trying to overcome the out of trim forces.

That's not an entirely accurate representation of the automatic trim system.
There are two servo motors installed on the base of the screwjack, the main electric trim servo motor is larger than the autopilot trim servo motor.
What you're seeing is the main electric trim motor trimming the stab (via the pickle switches). The auto pilot trim servo motor doesn't trim as fast as that and doesn't trim through the same range. I can't remember the exact figures but the autopilot trim servo can trim it X number of degrees nose down and y number of degrees nose up but the main electric trim motor can trim it a few degrees further in either direction and the manual trim wheels can trim it even further in each direction, it's all controlled by limit switches.
Next time you're on a 737 (on the ground) trim it forward or aft to the stops and then see how much further you can wind it on manually.
Then try engaging the autopilot on the ground, push the control column forward and watch how much slower the autopilot trim servo trims the stab.

Jeff2

I posted a picture of the trim from the inside that was a screenshot from a video I posted and it's been deleted.

If I did wrong I didn't know but I'v a pm that I can't access for some reason, maybe mods can delete sent pms.

Irish Steve

billy few mates wrote: »

That's not an entirely accurate representation of the automatic trim system.

Understood, the main reason for posting was to try and make it clear for the non pilots that the wheel is a large item, and moves relatively quickly over a long range of travel, with the emphasis being on that if the motors are no longer available to drive the trim, and the crew are forced to revert to manual winding using the handles, that's a relatively slow process, made more difficult if the aircraft is badly out of trim, as significant out of trim loads on the yoke are likely to require a lot of manual effort to manage them. Fully understand that normally, the automatic trim moves more slowly.

I don't have experience of the differences that came about as a result of the MCAS changes with the MAX, but it would seem from as yet unsubstantiated comments that the MCAS is not a user friendly system.

I also don't have any details of how quickly it applies the change of pitch to the system in comparison to the older and more widely known trim systems.

What is clear is that there are some very worrying unanswered questions that have to be answered before the MAX can be put back into commercial operation, and a quick fix will not be acceptable to many regulators, or potential passengers.

Irish Steve

Jeff2 wrote: »

I posted a picture of the trim from the inside that was a screenshot from a video I posted and it's been deleted.

If I did wrong I didn't know but I'v a pm that I can't access for some reason, maybe mods can delete sent pms.

It was deleted because the link was incorrect, and went to an error page on the external site. By all means try it again, but please check after posting that it is working correctly.

Coil Kilcrea

TomSweeney wrote: »

Airbus will cash in on it I'd imagine

For sure, but Boeing will batten down the hatches, take the inevitable battering and get back to business. Too big to fail springs to mind.

I do think that the revenue acceleration that followed the Max order book will take a hammering and that the 797 plans are probably being dusted off.

Hotblack Desiato

Airbus's order book for the 320 family is full for years, so they won't directly benefit. Secondhand/lease prices will go up, but that was happening anyway due to industry growth (and a recession will quickly reverse that)

Boeing have a huge order book for the MAX too, and I doubt they'll see more than a small number of cancellations. Costs of changing your fleet from one to the other are huge, running a mixed fleet is inefficient and operationally inflexible

It'll probably boil down to Airbus being able to play a bit more hardball on negotiations for future orders, Boeing having to sweeten deals a bit more.

Steve

Sorry if already posted, the preliminary report makes for some interesting reading.

http://www.ecaa.gov.et/documents/20435/0/Preliminary+Report+B737-800MAX+%2C%28ET-AVJ%29.pdf/4c65422d-5e4f-4689-9c58-d7af1ee17f3e

Notable imo are the stabilizer trim adjustments and whether they were manual or from the AND after it was disabled.

Turbulent Bill

Hotblack Desiato wrote: »

Airbus's order book for the 320 family is full for years, so they won't directly benefit. Secondhand/lease prices will go up, but that was happening anyway due to industry growth (and a recession will quickly reverse that)

Boeing have a huge order book for the MAX too, and I doubt they'll see more than a small number of cancellations. Costs of changing your fleet from one to the other are huge, running a mixed fleet is inefficient and operationally inflexible

It'll probably boil down to Airbus being able to play a bit more hardball on negotiations for future orders, Boeing having to sweeten deals a bit more.

Agreed, Boeing and Airbus form a duopoly and it's in both of their interests to keep this going. Airbus took a financial hit on the A380, same for Boeing on the MAX, but overall I wouldn't see either being seriously damaged long term.