Ethiopian plane crash

[Teddy Lop]

scottydoesntknow said:

Lemming Train said:

Not a chance that will happen.

There’s nearly 700 of them. They’ve got to fix ‘em.

Trolomite]Introducing the Boeing 737 iMax

Boeing is too big and important to the American military industrial to fail I suspect, it'll get to the "other people would like your nice FAA job" point.

[tobinen]

Ref MCAS: If the system was only there to avoid pilots having to gain the type rating (AIUI), why not fit the second AoA sensor and relevant redundancy, remove MCAS and have pilots gain type rating on the 'plane? I.e. accept it for what it was meant to be, not what it was trying to be.

Boeing could subsidise or pay for the type rating. Wouldn't that offer a chance to keep the 'plane in production, control losses and fulfil the order book, albeit more slowly?

[Ean218]

tobinen said:

Ref MCAS: If the system was only there to avoid pilots having to gain the type rating (AIUI), why not fit the second AoA sensor and relevant redundancy, remove MCAS and have pilots gain type rating on the 'plane? I.e. accept it for what it was meant to be, not what it was trying to be.

Boeing could subsidise or pay for the type rating. Wouldn't that offer a chance to keep the 'plane in production, control losses and fulfil the order book, albeit more slowly?

Given what's happened and the already accrued losses that is probably the only way out now.

[snotrag]

Munter said:

I think we're 50/50 looking at a lot of scrap metal in the shape of passenger airliners.

Respectfully - not in a million years. It is taking time, but sooner or later it will be type certified, there will be a bit of an initial fuss and a few passengers kicking off, then within months/years the whole thing will be forgotten to all but the aviation enthusiast.


Ref Airbus - In reality it hasnt made THAT much difference to their sales, as just like Boeing, the narrowbodies are on a massive waiting list already anyway. Even if you want a new A320 instead, you can't get one.

What it has done is made the market for older aircraft a lot harder.

[Munter]

tobinen said:

Ref MCAS: If the system was only there to avoid pilots having to gain the type rating (AIUI), why not fit the second AoA sensor and relevant redundancy, remove MCAS and have pilots gain type rating on the 'plane? I.e. accept it for what it was meant to be, not what it was trying to be.

Boeing could subsidise or pay for the type rating. Wouldn't that offer a chance to keep the 'plane in production, control losses and fulfil the order book, albeit more slowly?

A) The 2nd AoA sensor is already there. The system just ignored alternate sensors on alternate flights.
B) MCAS is part of the system required to get the plane certified regardless of pilot training.
C) I don't know who's picking up the tab, but increased pilot training does appear to be part of the solution mentioned in news stories.
D) Other control problems have been identified, and including the 2nd AoA along with other solutions needed, has in simple terms, overloaded the planes CPU. Quite why they were running so close to the limit in the first place is an interesting question.

You have to get MCAS safe, or it doesn't fly.
You have to get the additional training approved, or it doesn't fly.
You have to upgrade the central control system to have enough grunt to implement all the fixes, and get the new system approved (no small task as it involves everything, not just the fixes that need testing*), or it doesn't fly.
You have to convince the authorities, that your corporate processes are robust enough to both create a safe system in the first place (even in areas the authorities don't know to look yet), and maintain it safely in the future, or it doesn't fly.

I'm not convinced they can meet the final item there as so much of this was designed in an era where it's become clear corporate policy was not producing safe systems.

All of this because they didn't have both AoA sensors always hooked up and a central computer powerful enough to cope with doing that. A simple thing to design at the start of the process has become a massive issue to resolve further down the line as nothing Boeing has done can be trusted.

* https://en.wikipedia.org/wiki/Qantas_Flight_72 The A330s control system would occasionally corrupt it's own memory swapping AoA and altitude readings.

"After detailed forensic analysis of the FDR, the FCPC software, and the ADIRU, it was determined that the CPU of the ADIRU corrupted the angle of attack (AOA) data. The exact nature of the corruption was that the ADIRU CPU erroneously re-labelled the altitude data word so that the binary data that represented 37,012 (the altitude at the time of the incident) would represent an angle of attack of 50.625 degrees. The FCPC then processed the erroneously high AOA data, triggering the high-AOA protection mode, which sent a command to the electrical flight control system (EFCS) to pitch the nose down."

[tobinen]

Munter said:

A) The 2nd AoA sensor is already there. The system just ignored alternate sensors on alternate flights.
B) MCAS is part of the system required to get the plane certified regardless of pilot training.

A) Yes, you're correct. I forgot that bit, thanks

B) This bit I don't understand. If MCAS wasn't there, why would that stop the 'plane being certified? My understanding was that with the new engines it really wants to climb and pitch up, and that was the fundamental difference from a 'normal' 737. If dealing with that characteristic was part of the required type rating for the pilot (i.e. it's a different airplane), then it's not an issue, is it?

Happy to be enlightened as I am not a pilot.

[JuniorD]

Munter said:

tobinen said:

Ref MCAS: If the system was only there to avoid pilots having to gain the type rating (AIUI), why not fit the second AoA sensor and relevant redundancy, remove MCAS and have pilots gain type rating on the 'plane? I.e. accept it for what it was meant to be, not what it was trying to be.

Boeing could subsidise or pay for the type rating. Wouldn't that offer a chance to keep the 'plane in production, control losses and fulfil the order book, albeit more slowly?

A) The 2nd AoA sensor is already there. The system just ignored alternate sensors on alternate flights.
B) MCAS is part of the system required to get the plane certified regardless of pilot training.
C) I don't know who's picking up the tab, but increased pilot training does appear to be part of the solution mentioned in news stories.
D) Other control problems have been identified, and including the 2nd AoA along with other solutions needed, has in simple terms, overloaded the planes CPU. Quite why they were running so close to the limit in the first place is an interesting question.

You have to get MCAS safe, or it doesn't fly.
You have to get the additional training approved, or it doesn't fly.
You have to upgrade the central control system to have enough grunt to implement all the fixes, and get the new system approved (no small task as it involves everything, not just the fixes that need testing*), or it doesn't fly.
You have to convince the authorities, that your corporate processes are robust enough to both create a safe system in the first place (even in areas the authorities don't know to look yet), and maintain it safely in the future, or it doesn't fly.

I'm not convinced they can meet the final item there as so much of this was designed in an era where it's become clear corporate policy was not producing safe systems.

All of this because they didn't have both AoA sensors always hooked up and a central computer powerful enough to cope with doing that. A simple thing to design at the start of the process has become a massive issue to resolve further down the line as nothing Boeing has done can be trusted.

* https://en.wikipedia.org/wiki/Qantas_Flight_72 The A330s control system would occasionally corrupt it's own memory swapping AoA and altitude readings.

"After detailed forensic analysis of the FDR, the FCPC software, and the ADIRU, it was determined that the CPU of the ADIRU corrupted the angle of attack (AOA) data. The exact nature of the corruption was that the ADIRU CPU erroneously re-labelled the altitude data word so that the binary data that represented 37,012 (the altitude at the time of the incident) would represent an angle of attack of 50.625 degrees. The FCPC then processed the erroneously high AOA data, triggering the high-AOA protection mode, which sent a command to the electrical flight control system (EFCS) to pitch the nose down."

Haven't your read this thread - all these issues can be corrected by software/coding like a piece of piss

[Drihump Trolomite]

Ean218 said:

tobinen said:

Ref MCAS: If the system was only there to avoid pilots having to gain the type rating (AIUI), why not fit the second AoA sensor and relevant redundancy, remove MCAS and have pilots gain type rating on the 'plane? I.e. accept it for what it was meant to be, not what it was trying to be.

Boeing could subsidise or pay for the type rating. Wouldn't that offer a chance to keep the 'plane in production, control losses and fulfil the order book, albeit more slowly?

Given what's happened and the already accrued losses that is probably the only way out now.

Except you could easily get into a situation where you get runaway lift

[Munter]

tobinen said:

Munter said:

A) The 2nd AoA sensor is already there. The system just ignored alternate sensors on alternate flights.
B) MCAS is part of the system required to get the plane certified regardless of pilot training.

A) Yes, you're correct. I forgot that bit, thanks

B) This bit I don't understand. If MCAS wasn't there, why would that stop the 'plane being certified? My understanding was that with the new engines it really wants to climb and pitch up, and that was the fundamental difference from a 'normal' 737. If dealing with that characteristic was part of the required type rating for the pilot (i.e. it's a different airplane), then it's not an issue, is it?

Happy to be enlightened as I am not a pilot.

I think it's because it's listed as part of the design that makes the plane safe. To take it out now means starting the "safety concept" from scratch, and trying to get a nervous regulator to agree it. That's never going to happen.

"Yes we know it crashed a bit, but we took this safety device out and told the crew to fly better. Hope that's OK. Rgds Boeing"

FAA Reply: F**k off. No.

[Munter]

JuniorD said:

Haven't your read this thread - all these issues can be corrected by software/coding like a piece of piss

When it was just a single point of failure and all the hardware appeared to be there to resolve the issue. I was in that camp.

Whoever decided that no headroom in the processing of central control system to allow for changes...well that kinda stupid idea doesn't just happen by accident, that requires bad corporate culture.

This should have been a simple software change (as simple as any change can be to an aircraft's control system software). As soon as they had to start changing the hardware...that's very close to drop it and run territory.

[stevemcs]

Getting it past the FAA might be the easy bit, getting European approval might be the difficult bit. They also have to get it 100% right as one more fatal crash would almost certainly be the end of the 737 (max varient)

[Lemming Train]

There was an article a while back saying that EASA wanted to do rigorous testing of the handling characteristics with MCAS fully disabled before even considering recertifying it. Boeing refused. Could get interesting..

[hidetheelephants]

Teddy Lop said:

scottydoesntknow said:

Lemming Train said:

Not a chance that will happen.

There’s nearly 700 of them. They’ve got to fix ‘em.

Trolomite said:

Introducing the Boeing 737 iMax

Boeing is too big and important to the American military industrial to fail I suspect, it'll get to the "other people would like your nice FAA job" point.

That's fine for the domestic market and countries who follow the FAA's lead, but is unlikely to impress EASA very much.

Edited by hidetheelephants on Wednesday 18th December 23:42

[S1KRR]

El stovey said:

They’re going to have to find new places to store them.

Whats going on here then?

[Lemming Train]

S1KRR said:

Whats going on here then?

Train derailed from Wichita to Renton some years ago and the fuselages rolled down the hill into the river.

https://www.youtube.com/watch?v=fb3OnI4bGC0

Edited by Lemming Train on Wednesday 18th December 16:17

[Starfighter]

MCAS could be removed and the aircraft is still safe to fly. The MCAS system is needs to allow exiting 737 crews to fly without needing to be retrained. The retraining would need to cover the flight characteristics of the larger engine nacelles and forward higher position on the wing.

The certification was done so that the aircraft can be flown without MCAS operation but not in passenger service. Many aircraft were allowed a ferry flight for storage post the ban.

Source - A US based 737 training captain I know.

[M4cruiser]

YouTalkinToMe said:

737 Fine toothcomb

Eh?
You don't comb your teeth, no matter how good the comb is!
I think you mean "fine-tooth comb".

[surveyor]

Starfighter said:

MCAS could be removed and the aircraft is still safe to fly. The MCAS system is needs to allow exiting 737 crews to fly without needing to be retrained. The retraining would need to cover the flight characteristics of the larger engine nacelles and forward higher position on the wing.

The certification was done so that the aircraft can be flown without MCAS operation but not in passenger service. Many aircraft were allowed a ferry flight for storage post the ban.

Source - A US based 737 training captain I know.

If it was that easy surely they would have done it long ago. A subsidy to train pilots would cost Boeing far less than the current situation.

[Speed 3]

surveyor said:

Starfighter said:

MCAS could be removed and the aircraft is still safe to fly. The MCAS system is needs to allow exiting 737 crews to fly without needing to be retrained. The retraining would need to cover the flight characteristics of the larger engine nacelles and forward higher position on the wing.

The certification was done so that the aircraft can be flown without MCAS operation but not in passenger service. Many aircraft were allowed a ferry flight for storage post the ban.

Source - A US based 737 training captain I know.

If it was that easy surely they would have done it long ago. A subsidy to train pilots would cost Boeing far less than the current situation.

MCAS was introduced to counter poor airmanship in go-arounds loss of control (at least a couple of crashes) due to the thrust line on TOGA power. The Max is even more vulnerable than the NG's & Classics in this respect. At this point of public opinion trading one reason for crashing for another isn't going to work so Boeing will be holding onto MCAS on the 737, just making it less invasive and less (falsely) trigger-happy.

Edited by Speed 3 on Wednesday 18th December 20:00

[hidetheelephants]

Starfighter said:

MCAS could be removed and the aircraft is still safe to fly. The MCAS system is needs to allow exiting 737 crews to fly without needing to be retrained. The retraining would need to cover the flight characteristics of the larger engine nacelles and forward higher position on the wing.

The certification was done so that the aircraft can be flown without MCAS operation but not in passenger service. Many aircraft were allowed a ferry flight for storage post the ban.

Source - A US based 737 training captain I know.

It wouldn't meet FAA airworthiness requirements, that's why they fitted MCAS in the first instance; having an airliner with uncommanded pitch-up when you open the taps isn't a particularly good idea.