Ethiopian plane crash
Discussion
Lemming Train said:
El stovey said:
Completely right.
WTF are some of these people banging on about. They clearly don’t know what they’re talking about and actually making the thread rubbish.
I'M NEVER GETTING ON A 737 MAX IN MY LIFETIME! THEY'RE A DEATHTRAP AND SHOULD BE SCRAPPED!!!!!!!!111111"WTF are some of these people banging on about. They clearly don’t know what they’re talking about and actually making the thread rubbish.
The end of Boeing, nobody getting in a 787, everyone becoming experts about the 787 and the electrical system.
At least then it was being stoked up by that poster who worked for airbus.
Lemming Train said:
You're wasting your breath Dave. Half of this thread is made up of armchair experts banging on about this alleged hardware nonsense and it's become rather tiresome.
A few software changes, wire up the 'other' AoA sensor full-time, flight test the changes, write some extra blurb in FCOM. FAA will be happy with that and rubber stamp it; the rest of the authorities will follow suit shortly after. Max will be back in the air and all the drama forgotten about within a couple of years.
It will be a little bit more complicated than that. If you put both sensors on the MEL then I doubt if the airlines will be happy with the negative impact on serviceability delaysA few software changes, wire up the 'other' AoA sensor full-time, flight test the changes, write some extra blurb in FCOM. FAA will be happy with that and rubber stamp it; the rest of the authorities will follow suit shortly after. Max will be back in the air and all the drama forgotten about within a couple of years.
hutchst said:
Lemming Train said:
You're wasting your breath Dave. Half of this thread is made up of armchair experts banging on about this alleged hardware nonsense and it's become rather tiresome.
A few software changes, wire up the 'other' AoA sensor full-time, flight test the changes, write some extra blurb in FCOM. FAA will be happy with that and rubber stamp it; the rest of the authorities will follow suit shortly after. Max will be back in the air and all the drama forgotten about within a couple of years.
It will be a little bit more complicated than that. If you put both sensors on the MEL then I doubt if the airlines will be happy with the negative impact on serviceability delaysA few software changes, wire up the 'other' AoA sensor full-time, flight test the changes, write some extra blurb in FCOM. FAA will be happy with that and rubber stamp it; the rest of the authorities will follow suit shortly after. Max will be back in the air and all the drama forgotten about within a couple of years.
hutchst said:
It will be a little bit more complicated than that. If you put both sensors on the MEL then I doubt if the airlines will be happy with the negative impact on serviceability delays
And demonstrates he doesn't know how AoA vanes work.The problem is that AoA vanes can give wildly varying readings, so a computer (or pilot) needs to pick which one is right. Whilst computers can use the same variety of other information (I.E. throttle settings, airspeed, et al) as the pilots, the pilots can ultimately look out the window where as the computer cant.
You can hook up multiple AoA vanes to the MCAS, but ultimately the root cause remains, the positioning of the engines, which is the main reason for the MCAS system which isn't present in earlier 737's. Unless that cause is addressed and that is a hardware fault, specifically a hardware design fault, then you're going to have more errors because any software stack relies on the hardware functioning correctly.
Also, calling people "armchair experts" in order to deny that fact only makes you look silly. If you cant rebut their point with reason and fact, don't resort to name calling.
There may not be another AoA vane fault, but there will be another fault. The sooner it happens, the cheaper it will be for Boeing to fix.
Lemming Train said:
You're wasting your breath Dave. Half of this thread is made up of armchair experts banging on about this alleged hardware nonsense and it's become rather tiresome.
A few software changes, wire up the 'other' AoA sensor full-time, flight test the changes, write some extra blurb in FCOM. FAA will be happy with that and rubber stamp it; the rest of the authorities will follow suit shortly after. Max will be back in the air and all the drama forgotten about within a couple of years.
MCAS is there to prevent runaway pitch up effect that can be caused by the larger engines due to the location as the landing gear cannot be modified to accommodate themA few software changes, wire up the 'other' AoA sensor full-time, flight test the changes, write some extra blurb in FCOM. FAA will be happy with that and rubber stamp it; the rest of the authorities will follow suit shortly after. Max will be back in the air and all the drama forgotten about within a couple of years.
You don’t need to be an expert to realise the issue.
George Smiley said:
Lemming Train said:
You're wasting your breath Dave. Half of this thread is made up of armchair experts banging on about this alleged hardware nonsense and it's become rather tiresome.
A few software changes, wire up the 'other' AoA sensor full-time, flight test the changes, write some extra blurb in FCOM. FAA will be happy with that and rubber stamp it; the rest of the authorities will follow suit shortly after. Max will be back in the air and all the drama forgotten about within a couple of years.
MCAS is there to prevent runaway pitch up effect that can be caused by the larger engines due to the location as the landing gear cannot be modified to accommodate themA few software changes, wire up the 'other' AoA sensor full-time, flight test the changes, write some extra blurb in FCOM. FAA will be happy with that and rubber stamp it; the rest of the authorities will follow suit shortly after. Max will be back in the air and all the drama forgotten about within a couple of years.
You don’t need to be an expert to realise the issue.
El stovey said:
What do you mean? Any sensor will be “on the MEL” already anyway?
I appreciate that the evidence available so far is scant, but it appears that the sensors were not working correctly immediately after the wheels left the ground, so if they were required to be operational before departure, then either they weren't checked, or the checks used to verify their condition are ineffective.hutchst said:
El stovey said:
What do you mean? Any sensor will be “on the MEL” already anyway?
I appreciate that the evidence available so far is scant, but it appears that the sensors were not working correctly immediately after the wheels left the ground, so if they were required to be operational before departure, then either they weren't checked, or the checks used to verify their condition are ineffective.Are you saying that the 737 max MEL currently allows you to depart with a faulty AOA vane but if two were fed to MCAS then it wouldn’t and airlines would be unhappy about this?
My point is very simple. If it becomes a requirement for 2 sensors to be verified and working before departing, then given the apparent frequency of these to fail or become unreliable, then it's likely that airlines may ask for more to be fitted so that the plane remains airworthy with one broken.
hutchst said:
My point is very simple. If it becomes a requirement for 2 sensors to be verified and working before departing, then given the apparent frequency of these to fail or become unreliable, then it's likely that airlines may ask for more to be fitted so that the plane remains airworthy with one broken.
3?Or some form of out of range detection software
hutchst said:
My point is very simple. If it becomes a requirement for 2 sensors to be verified and working before departing, then given the apparent frequency of these to fail or become unreliable, then it's likely that airlines may ask for more to be fitted so that the plane remains airworthy with one broken.
That’s not really how the MEL or the two Alpha sensors work. The MEL only covers the two vane heaters. It can’t actually cover whether the vanes are working or not. For anyone that doesn’t know the MEL (Minimum equipment list) is a document produced by Boeing covering what failures you can take off with. If you get on an aircraft and there is a message or information about a failure, you look it up and the MEL tells you if you can go or not.
Once you have started taxing or moving under your own power, the MEL is no longer the legal document you refer to. You look at the QRH (quick reference handbook) and it tells you about how to sort out the problem as the rules consider you to have already left.
These angle of attack vanes everyone is banging on about (along with gyros and accelerometers and other systems) feed data into the two air data inertial reference units, they then process this data and send it to the flight management computer and pilots displays.
The MCAS is controlled by the flight control computer getting inputs from various sensors (including the alpha vanes) and other systems.
So (pre grounding) the MCAS functioning when it shouldn’t means that it’s applying pitch trim due to erroneous data from a single AOA sensor which also leads to other confusing conflicting information and fault messages and other possible effects like disengagement of the autopilot and speed and altitude disagree messages and AOA disagree (if fitted) messages.
At the moment you don’t get AOA (angle of attack) disagree information unless the operator paid for an optional angle of attack disagree display. Any AOA MEL requirements only cover the electric angle of attack heater. Even if the heater is broken, you can still take off as long as you avoid icing conditions) good luck with that in many countries.
The changes Boeing are implementing ensure that AOA disagreement alert is no longer an optional upgrade and MCAS uses both sensors data to deploy rather than one at the moment. There are also changes to how much trim it can apply to the stabiliser and it will be easier to override it. Plus there will be more initial training about MCAS for pilots transitioning into the MAX from other types.
My view is that changes will make the aircraft safe and I’d be happy flying on one.
I agree with your conclusion, but my point (and post) was in reply to one that siggested that all that is required is a software upgrade and a couple of wires reconnected.
It will require hardware upgrades, software, testing, certification, training and documentation upgrades (all as you suggest).
FWIW it's rapidly coming up to the 50th anniversary of the first time I travelled in a 737 on 26th September 1969 and I won't be worried about flying in a MAX after they take to the air again.
It will require hardware upgrades, software, testing, certification, training and documentation upgrades (all as you suggest).
FWIW it's rapidly coming up to the 50th anniversary of the first time I travelled in a 737 on 26th September 1969 and I won't be worried about flying in a MAX after they take to the air again.
El stovey said:
That’s not really how the MEL or the two Alpha sensors work. The MEL only covers the two vane heaters. It can’t actually cover whether the vanes are working or not.
For anyone that doesn’t know the MEL (Minimum equipment list) is a document produced by Boeing covering what failures you can take off with. If you get on an aircraft and there is a message or information about a failure, you look it up and the MEL tells you if you can go or not.
Once you have started taxing or moving under your own power, the MEL is no longer the legal document you refer to. You look at the QRH (quick reference handbook) and it tells you about how to sort out the problem as the rules consider you to have already left.
These angle of attack vanes everyone is banging on about (along with gyros and accelerometers and other systems) feed data into the two air data inertial reference units, they then process this data and send it to the flight management computer and pilots displays.
The MCAS is controlled by the flight control computer getting inputs from various sensors (including the alpha vanes) and other systems.
So (pre grounding) the MCAS functioning when it shouldn’t means that it’s applying pitch trim due to erroneous data from a single AOA sensor which also leads to other confusing conflicting information and fault messages and other possible effects like disengagement of the autopilot and speed and altitude disagree messages and AOA disagree (if fitted) messages.
At the moment you don’t get AOA (angle of attack) disagree information unless the operator paid for an optional angle of attack disagree display. Any AOA MEL requirements only cover the electric angle of attack heater. Even if the heater is broken, you can still take off as long as you avoid icing conditions) good luck with that in many countries.
The changes Boeing are implementing ensure that AOA disagreement alert is no longer an optional upgrade and MCAS uses both sensors data to deploy rather than one at the moment. There are also changes to how much trim it can apply to the stabiliser and it will be easier to override it. Plus there will be more initial training about MCAS for pilots transitioning into the MAX from other types.
My view is that changes will make the aircraft safe and I’d be happy flying on one.
What I'm questioning is that if the dual AoA input to MCAS was available from the catalogue (I do have one here, so I should check through it and see what it says) and some relatively small changes such as how much trim is applied "fixes" the problem, then why is such comprehensive software rewrite going on now?For anyone that doesn’t know the MEL (Minimum equipment list) is a document produced by Boeing covering what failures you can take off with. If you get on an aircraft and there is a message or information about a failure, you look it up and the MEL tells you if you can go or not.
Once you have started taxing or moving under your own power, the MEL is no longer the legal document you refer to. You look at the QRH (quick reference handbook) and it tells you about how to sort out the problem as the rules consider you to have already left.
These angle of attack vanes everyone is banging on about (along with gyros and accelerometers and other systems) feed data into the two air data inertial reference units, they then process this data and send it to the flight management computer and pilots displays.
The MCAS is controlled by the flight control computer getting inputs from various sensors (including the alpha vanes) and other systems.
So (pre grounding) the MCAS functioning when it shouldn’t means that it’s applying pitch trim due to erroneous data from a single AOA sensor which also leads to other confusing conflicting information and fault messages and other possible effects like disengagement of the autopilot and speed and altitude disagree messages and AOA disagree (if fitted) messages.
At the moment you don’t get AOA (angle of attack) disagree information unless the operator paid for an optional angle of attack disagree display. Any AOA MEL requirements only cover the electric angle of attack heater. Even if the heater is broken, you can still take off as long as you avoid icing conditions) good luck with that in many countries.
The changes Boeing are implementing ensure that AOA disagreement alert is no longer an optional upgrade and MCAS uses both sensors data to deploy rather than one at the moment. There are also changes to how much trim it can apply to the stabiliser and it will be easier to override it. Plus there will be more initial training about MCAS for pilots transitioning into the MAX from other types.
My view is that changes will make the aircraft safe and I’d be happy flying on one.
This is where I am smelling a rat, I suspect there is a bigger issue that has been dug out and work is going on desperately trying to get sorted. It is total supposition on my part, but this length of time is a very long one in software development terms even including the probably abnormal level of controls being put over this one.
hutchst said:
I agree with your conclusion, but my point (and post) was in reply to one that siggested that all that is required is a software upgrade and a couple of wires reconnected.
It will require hardware upgrades, software, testing, certification, training and documentation upgrades (all as you suggest).
FWIW it's rapidly coming up to the 50th anniversary of the first time I travelled in a 737 on 26th September 1969 and I won't be worried about flying in a MAX after they take to the air again.
Sorry, I was confused by what you meant by this.It will require hardware upgrades, software, testing, certification, training and documentation upgrades (all as you suggest).
FWIW it's rapidly coming up to the 50th anniversary of the first time I travelled in a 737 on 26th September 1969 and I won't be worried about flying in a MAX after they take to the air again.
hutchst said:
It will be a little bit more complicated than that. If you put both sensors on the MEL then I doubt if the airlines will be happy with the negative impact on serviceability delays
And thought you were suggesting there might be some kind of change to the MEL or something? IforB said:
What I'm questioning is that if the dual AoA input to MCAS was available from the catalogue (I do have one here, so I should check through it and see what it says) and some relatively small changes such as how much trim is applied "fixes" the problem, then why is such comprehensive software rewrite going on now?
This is where I am smelling a rat, I suspect there is a bigger issue that has been dug out and work is going on desperately trying to get sorted. It is total supposition on my part, but this length of time is a very long one in software development terms even including the probably abnormal level of controls being put over this one.
Good luck in getting much MCAS info from a Boeing manual. This is where I am smelling a rat, I suspect there is a bigger issue that has been dug out and work is going on desperately trying to get sorted. It is total supposition on my part, but this length of time is a very long one in software development terms even including the probably abnormal level of controls being put over this one.
The software changes alone are quite considerable in my view. Especially as there has been two crashes, the pressure is on now to get it 100% right.
The 787 was grounded for a very long time with the battery issue.
The software changes probably wouldn't take that long on their own, assuming they're well understood. But I'd imagine it would be internal and second/third party code and design reviews, flying various people around who need to work together, documentation ad nauseum, through several rounds, extensive testing in isolation and even more so integrated, briefings to management and authorities. Certification.
And then being told to go back and check it all again probably.
And then being told to go back and check it all again probably.
Normally aircraft manufacturers for updated planes try to make training for pilots minimal moving from the older model, as was the case here.
Now with all this scrutiny I wonder what the extra training requirements will be? Ok they will have made it more fool proof, but the pilots now will need to get up to speed with the changes and how to fly it all under the eye of everyone.
A quick summary is that the Airbus A3xx got NEO engines better into service than Boeing did as more inherently suitable to the change it seems.
Ironically 12 months back all the talk was about issues with the engines, especially P&W. Taken the pressure off them.
Now with all this scrutiny I wonder what the extra training requirements will be? Ok they will have made it more fool proof, but the pilots now will need to get up to speed with the changes and how to fly it all under the eye of everyone.
A quick summary is that the Airbus A3xx got NEO engines better into service than Boeing did as more inherently suitable to the change it seems.
Ironically 12 months back all the talk was about issues with the engines, especially P&W. Taken the pressure off them.
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