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> At least three Ryanair Boeing 737s have been grounded due to cracks between the wing and fuselage but this was not disclosed to the public, the Guardian can reveal.
> The budget Irish airline is the latest to be affected by faults in the “pickle fork” structure, which has sparked an urgent grounding of 50 planes globally since 3 October.
[1] https://www.theguardian.com/business/2019/nov/06/boeing-737-...
If TFA is to believed, Boeing has embarked on a project to take what is currently a master-slave failover design and jury-rig it into a master-master real-time system. This is based on bad performance in the simulator—not because of MCAS—but while testing errant memory errors from a simulated gamma ray strike!
The obvious question of how can dual-master ever work when they disagree if there isn’t a 3rd source of truth to vote out the failure? This means the software running in both computers has to somehow agree which one is wrong, while one of them is in a potential failure state. This... isn’t how flight control systems are designed from first principals.
I’m not a flight system designer, but there must be hundreds of physical, electrical, and architectural considerations taken at every point in the design process which enable multi-master controllers with the ability to vote out a failure. Everything from the particular sensor suite, the number of sensors, the way they are wired, the way data is acquired and bused through the system, the timing and synchronization of the system clocks, the way that control outputs are calculated, queued, and ultimately issued to downstream controllers... none of the necessary pieces will be in place in a system which up until now makes you select a single master controller before embarking on your flight.
The only conclusion I can reach is that Boeing has lost its mind, and this project is absolutely doomed to fail. The architecture that Boeing has apparently committed itself to now is extremely difficult to design from first principals and a blank slate. I just don’t see how it’s something that can realistically be papered onto a legacy dual-computer system after the fact.
The part in TFA about “adding a wire” practically made me spit out my coffee. The sheer level of arrogance that Boeing management must have to think this would be possible - is just a classic example of an elitist MBA management group totally disconnected from any technical domain expertise. Boeing said they would have this ready for certification by the end of this year?!
FWIW, the near-crash in the simulator was apparently not directly related to MCAS, but occurred when Boeing "simulated what would happen if gamma rays from space scrambled data in the plane’s flight-control computers." > In one scenario, the plane aggressively dove in a way that mimicked what happened in the crashes on the grounded jetliner, the people said. While such a failure had never occurred in the 737’s histor…
Soft-errors are a prime concern when designing safety-critical systems, both in hardware and in software. It's not some outlandish edge case.
Incidentally, while soft-errors in an airplane are probably primarily particles from space, on the ground we're still sometimes talking about it, but in reality it's mostly chip packages that are low radioactive and emitting a alpha particle or so.
FWIW, the near-crash in the simulator was apparently not directly related to MCAS, but occurred when Boeing "simulated what would happen if gamma rays from space scrambled data in the plane’s flight-control computers." > In one scenario, the plane aggressively dove in a way that mimicked what happened in the crashes on the grounded jetliner, the people said. While such a failure had never occurred in the 737’s histor…
And I'm guessing their not using pilots of average skill here...
These should not fly for a decade. They're rewriting the avionics from scratch. This should require a years-long process of testing, external auditing, and approvals. I'd even go so far as to say in flight, we should require competitor review. That's right, no trade secrets. If you want your Hello World up in the air, you better let your competitor vet the source code. This is an engineering boondoggle and an embarra…
A decade is too long but I agree with your sentiment. The underlying problem with the 737 Max was commercial pressure leading to cutting corners and creating an unsafe plane (or plane with an unsafe core component) ... and now commercial pressure is again being applied on their R&D teams, which are probably scrambling because they know every day means millions in losses. That's not a great environment for quality and…
Considering that MCAS is an added ‘feature’ to avoid stall, you would think they could just remove it and be done. After all, it wasn’t part of the original 737. Sadly, from my limited understanding, due to the engine location change on the airframe, the plane naturally pitches up... making it necessary. One thing seems clear to the external observer, this is a 737 in name only.
Considering that MCAS is an added ‘feature’ to avoid stall, you would think they could just remove it and be done. After all, it wasn’t part of the original 737. Sadly, from my limited understanding, due to the engine location change on the airframe, the plane naturally pitches up... making it necessary. One thing seems clear to the external observer, this is a 737 in name only.
The 737 has a feature almost no other new plane have: you can order it with a internal staircase so people can leave the plane without a specialized airport terminal.
This feature requires the plane to keep its current overall shape, otherwise the staircase thingy would not work.
So to keep this feature, while putting a bigger engine on the plane, they had to move the engine forward, and change its shape too, otherwise the engine wouldn't fit between the wing and the ground.
Then THAT caused the necessity of MCAS.
So long story short: wanting to keep backward compatiblity with the 737 staircase, led to the engine hack, that then to maintain backward compatiblity with the handling led to the MCAS hack...
So, it IS a 737, in the sense they kept the staircase and to do that ended needing the MCAS...
The other option would have been abandon the staircase entirely and make a taller plane, this would allow a bigger engine with no handling changes, but although this would remain a 737 from handling perspective, it would not be a 737 from the airports perspective: it would need to remodel the airports to install bridges or purchase of ladder trucks.
There are also issues with 737 NG[1]: > At least three Ryanair Boeing 737s have been grounded due to cracks between the wing and fuselage but this was not disclosed to the public, the Guardian can reveal. > The budget Irish airline is the latest to be affected by faults in the “pickle fork” structure, which has sparked an urgent grounding of 50 planes globally since 3 October. [1] https://www.theguardian.com/business…
I'm saying this to highlight that what you're pointing out, while not desired, is kinda expected. That's the point of the routine inspection and maintenance - to catch these.
It's not the same as the conversation we're having under the OP: catastrophic failure due to bad assumptions in software (in this case, memory safety)
What changes have been made to the regulatory framework to prevent Boeing from signing off on their own safety tests? What changes has the FAA made to bring more public transparency to the flight certification process?
When is the sentencing date for Boeing executives? They are not getting a plea deal I hope?
I'm not worried about the overly complicated flight control software or MCAS, I'm worried about the next system that will fail because nobody at this company seems to care about engineering any more.
FWIW, the near-crash in the simulator was apparently not directly related to MCAS, but occurred when Boeing "simulated what would happen if gamma rays from space scrambled data in the plane’s flight-control computers." > In one scenario, the plane aggressively dove in a way that mimicked what happened in the crashes on the grounded jetliner, the people said. While such a failure had never occurred in the 737’s histor…
> a simulated edge case involving "gamma rays from space"? Soft-errors are a prime concern when designing safety-critical systems, both in hardware and in software. It's not some outlandish edge case. Incidentally, while soft-errors in an airplane are probably primarily particles from space, on the ground we're still sometimes talking about it, but in reality it's mostly chip packages that are low radioactive and emi…
But it's not the gamma rays that are the reason for the systems redesign, it's the fact that "at least one of the pilots who flew the scenario in a simulator found it difficult to respond in time to maintain control of the plane".
Boeing's assumption that pilots could respond quickly enough to a loss of control in the cockpit was an underlying motivation for designing MCAS with inadequate safety measures.