Some talk about a 'synthetic' AoA sensor : Foreign regulators demand substantial new changes to Boeing 737 MAX flight controls | The Seattle Times
Something internally in addition to two external one definitely makes sense to me.
Meanwhile not only aircraft manufacturers cheat. Scary!
Pakistan′s top airline PIA to ground some 150 pilots over ′dubious′ licenses | News | DW | 25.06.2020
The thing that is needed, specifically to the MAX, is not more sensors, although a 3rd AOA would not be unwarranted, but instead not relying on a single sensor as the original MCAS system was programmed.
Read this The inside story of MCAS: How Boeing’s 737 MAX system gained power and lost safeguards | The Seattle Times
Read this The inside story of MCAS: How Boeing’s 737 MAX system gained power and lost safeguards | The Seattle Times
Yes, all this is (as I recall) correct AND it's also (IMO) outrageous. It's one of those "how could this have happened" things, even if there had been no accident related to it. It's enough (again, IMO) to ground aircraft until it's fixed.
Non-USA aviation certification organizations are not just within their rights, but should be obligated to make their own determinations that such an aircraft is ready to fly, and not rely on any FAA determinations (as I seem to recall they might have done before).
If I seem a little hot under the collar, it's because the way things were done last century vs. the last decade or two. When airplane accidents happened before, it was often because situations occurred that hadn't been thought of before. Things were changed so the situations wouldn't occur again, or at least wouldn't cause another accident. THIS event happened because (among other things) a safety idea obvious to any engineer, a redundancy that would cost almost nothing, wasn't done.
No point in getting into the politics of this. It’s a done deal.
I am interested more in the engineering decisions that were taken or permitted to circumvent a basic tenet of safety engineering which requires backup and redundancy in critical systems.
Years ago when I worked in industrial electronics, the company I worked for designed and marketed a special two out of three safety shutdown system for use in the petroleum industry. People were serious about this stuff and spent a lot of money on it.
I am interested more in the engineering decisions that were taken or permitted to circumvent a basic tenet of safety engineering which requires backup and redundancy in critical systems.
Years ago when I worked in industrial electronics, the company I worked for designed and marketed a special two out of three safety shutdown system for use in the petroleum industry. People were serious about this stuff and spent a lot of money on it.
This applies to a lot of modern business and manufacturing practices. In general sound business practice has been replaced by financial engineering and "logistics." And it's modern logistics that got us into shortages during this pandemic.
I did not read all ofvthis thread but found 5 eurocent to leave here
My opinion on the MCAS System design is that is an improvised solution to mimic features only a throughly fly by wire design by using or modifying features of the autopilot system. An autopilot of a semi-mechanical plane like the 737 is not designed to "fly" an aircraft but it is the only way to "steer" it using present electrical systems. The trimmable horizontal stabilizer was easy to use as it just needed software in the autopilot system to move it up or down. Cheap, quick and potentially dangerous.
I don't know much about Boeing's avionics and flight control design of specific military aircraft but I think this MCAS kind of solution would not have make it into any military prototype. Redundancy in military aircraft is not as high as in commercial aircraft by design but care is taken to prevent unnecessary failures.
If not yet mentioned, Airbus planes had similar problems (uncomnanded flight control movements) but the planes could be saved due to higher redundancy or just luck.
You may google for "ADIRU Spikes" or Quantas Flight 72.
Frozen AOA sensors on a A319 caused the plane to go into a dive that could fortunately be stopped without an incident mainly because the crew had more time as it happened during cruise flight in high altitude.
https://ad.easa.europa.eu/blob/EASA_AD_2015_0135_R3.pdf/AD_2015-0135R3_1&ved=2ahUKEwiAzpOOk6TqAhVbhlwKHY8-Cw0QFjAAegQIAxAC&usg=AOvVaw36vylBfYxNCIvsxHl0kRyf&cshid=1593334996148
My opinion on the MCAS System design is that is an improvised solution to mimic features only a throughly fly by wire design by using or modifying features of the autopilot system. An autopilot of a semi-mechanical plane like the 737 is not designed to "fly" an aircraft but it is the only way to "steer" it using present electrical systems. The trimmable horizontal stabilizer was easy to use as it just needed software in the autopilot system to move it up or down. Cheap, quick and potentially dangerous.
I don't know much about Boeing's avionics and flight control design of specific military aircraft but I think this MCAS kind of solution would not have make it into any military prototype. Redundancy in military aircraft is not as high as in commercial aircraft by design but care is taken to prevent unnecessary failures.
If not yet mentioned, Airbus planes had similar problems (uncomnanded flight control movements) but the planes could be saved due to higher redundancy or just luck.
You may google for "ADIRU Spikes" or Quantas Flight 72.
Frozen AOA sensors on a A319 caused the plane to go into a dive that could fortunately be stopped without an incident mainly because the crew had more time as it happened during cruise flight in high altitude.
https://ad.easa.europa.eu/blob/EASA_AD_2015_0135_R3.pdf/AD_2015-0135R3_1&ved=2ahUKEwiAzpOOk6TqAhVbhlwKHY8-Cw0QFjAAegQIAxAC&usg=AOvVaw36vylBfYxNCIvsxHl0kRyf&cshid=1593334996148
Not sure where you got this, but you got it backwards. Military jets are designed to keep on flying with all kinds of failures and broken stuff.
Jan
... the F-35 being a textbook example : Lockheed Martin F-35 has 873 deficiencies | News | Flight Global
The Comet disaster ushered in air crash investigation methodology. I don’t know how people will view the 737 max. Could be they say since it’s had every nut and bolt examined, it’s actually a safer plane.
Whatever, I hope this disaster has put an end the ‘self certification’ nonsense.
You can’t ask any company led by stock market jockeys to stick by the spirit and letter of the law if they can see an opportunity to save money by circumventing it. It’s human nature.
If I were running Boeing, I’d have teams going over every other plane right now.
Whatever, I hope this disaster has put an end the ‘self certification’ nonsense.
You can’t ask any company led by stock market jockeys to stick by the spirit and letter of the law if they can see an opportunity to save money by circumventing it. It’s human nature.
If I were running Boeing, I’d have teams going over every other plane right now.
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