I think they are all FBW now or going that way. Personally I don't see that as a problem. I'd be more concerned with cables, pulleys and hydraulics to be honest. And, there's the requirement to reduce weight to improve efficiency as well.
In the early 2000's I was working in the auto industry (supplying power semiconductors - serious reliability demands - ABS, EMU etc) and one of the projects we worked on with a major European tier 1 supplier was electric steering using a motor. The concept was to completely do away with the mechanical linkage between the steering wheel and the front wheels.
(I don't know if it ever went into production, but most modern cars have electric steering assist of some sort)
Hilarious - agree.
The shameless self-promotion of some types is staggering. (go onto LinkedIn to see some of it for a laugh. Unbelievable)
Out of interest, is it the case that the trim wheels next to the pilots can be manually stopped and turned even if the autopilot is trying to turn them? IOW is it the case that to fix an erroneous trim either pilot can manually adjust (by applying moderate force) the trim wheel even if the MCAS or autopilot are engaged?
I went through a similar certification process as a welder.
We were making some commercial structures and insurance companies would only insure it if it had been welded by a certified person.
It was the insurance companies which did the certification.
The certification itself became invalid once I stopped welding aluminium pipe of a certain diameter for a year but I was never certified for pipe of over 100mm or below 10mm.
Air France 447 where they managed to get it in the state where one pilot was pushing the stick and the other pulling and the system averaged it out made me realise that there are still a bucket of edge cases in FBW. A linked control column suddenly seems a really good idea! And yes I am aware that a very specific and unfortunate sequence of events led up to that point which would have been hard to predict.
Not sure if anybody posted this, but I was just checking production rates, its something like 52 a month. So close to 2 a day, which is crazy when you think about it. They start at around $100 million, depending on the exact model and options chosen. A ton on money they can't collect.
Boeing has to be going crazy right now to fix this problem, they can't afford an extended period without 737 max deliveries.
Boeing has to be going crazy right now to fix this problem, they can't afford an extended period without 737 max deliveries.
A visual inspection covers rivets and any flaws are easily drilled out and replaced if not passed by inspection
In fuel tanks an inspector looks at your work before final sealant coverage of B2
Regards
David
Thanks David. I just remember something on TV back in the early 80s that looked like an ultrasound for scanning rivets. You ran it across and an experienced operator could tell from the waveforms if something was amiss. They also had one that would actually measure any cracks for angle and depth but it took about 30 seconds per rivet which kind of made it an non-starter!
I'd like to chime in some information that is specific to commercial avionics.
Pretty much any electronic box on a Boeing or Airbus plane is certified for flight. If it has Software, the SW certification requirements depend on the Design Assurance Level (DAL)
Background info on DALs DO-178B - Wikipedia
The SW involved here has to be DAL A. If it can cause a crash it would be DAL A, pretty much be definition of the DAL levels. (DAL A is Catastrophic)
My point here is that all avionics are not treated equally, its a LOT harder to certify a DAL A system than a DAL D system, and it should be.
There is a table in the Wikipedia link that shows for DAL A, there are 66 objectives to satisfy, 25 with independence.
The 25 with independence is significant because those 25 objectives have to be verified by an independent team. So you have your normal SW development team, and then you have a completely separate set of people to look at these objective.
I don't work on DAL A systems, so I don't know what the actual objectives are, but I would imagine they are the more significant ones, and the lessor objectives would not need independent evaluation.
I'm also sure that for a DAL A software change, there would be a mountain of documentation to update, even for a simple change. So any change to SW for this incident would take a lot of testing and documentation, now probably even more so, before it rolls out.
Pretty much any electronic box on a Boeing or Airbus plane is certified for flight. If it has Software, the SW certification requirements depend on the Design Assurance Level (DAL)
Background info on DALs DO-178B - Wikipedia
The SW involved here has to be DAL A. If it can cause a crash it would be DAL A, pretty much be definition of the DAL levels. (DAL A is Catastrophic)
My point here is that all avionics are not treated equally, its a LOT harder to certify a DAL A system than a DAL D system, and it should be.
There is a table in the Wikipedia link that shows for DAL A, there are 66 objectives to satisfy, 25 with independence.
The 25 with independence is significant because those 25 objectives have to be verified by an independent team. So you have your normal SW development team, and then you have a completely separate set of people to look at these objective.
I don't work on DAL A systems, so I don't know what the actual objectives are, but I would imagine they are the more significant ones, and the lessor objectives would not need independent evaluation.
I'm also sure that for a DAL A software change, there would be a mountain of documentation to update, even for a simple change. So any change to SW for this incident would take a lot of testing and documentation, now probably even more so, before it rolls out.
Sometimes you can, sometimes you can't see where it matters, sometimes it just too many to make it realistic.
But there are many other similar situations. I remember a fuel line swage that went into an F16 fighter wing. There was no way to test it afterwards, not even by pressurizing, don't remember the details why not.
I can tell you that the person doing the swage was certified ten times around. He also was very well paid; you don't want to train the best swager in the industry just to see him go to the competition for a few 1000 extra dollars! The managers called him sir.
Jan
Part of the issue, though, was that the software was self-certified as DAL B - Hazardous. This was based on the system ability to move the control surface by 0.6 degrees. However during testing, it was found that that increment was ineffective in preventing a high speed stall, so the value was raised to 2.5 degree increments.
The documentation was not changed to reflect the increase in authority and the aircraft was certified upon the lower figure.
(Allegedly).
I saw a device recently that the operator runs across lines of rivets and it uses machine learning to process the visual information and flag any that are suspect. Good for large fuselage runs of rivets but again, not so good for confined areas.
It's just starting. "FBI joining criminal investigation into certification of Boeing 737 MAX"
FBI joining criminal investigation into certification of Boeing 737 MAX | The Seattle Times
That sounds like a modern version of what I saw. It's good to remember whenever any of us thinks we have a logistical nightmare on something its nothing compared to trying to keep an aircraft production line running!
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