Re:The Case Against Boeing
by WalterBright on Saturday November 16, 2019 @08:46PM
(#21556055)
> Isn't that exactly what an effective shill would say?
Of course. There's no telling how deep this conspiracy to point out publicly available facts goes :-)
> No requirements can ever prevent an accident.
That's not what I meant by requirements. Boeing came up with a set of rules for what the software must do in each situation. This is called the requirements specification for the software.
Anybody who contracts with someone to write some software comes up with such a specification.
> What other underlying reason could there possibly be for MCAS to exist at all?
There's nothing at all wrong with the concept of MCAS. There's a long history of flight control augmentation in jet airliners to make them behave better. In fact, you cannot control a jetliner at all without augmentation, it's too fast and heavy. It's the implementation that was faulty.
The B-17 was perhaps the largest successful airplane with no augmentation, and a strong man could barely handle it (source - my dad was a B-17 pilot).
The 757, which I worked on, has fully powered controls. The control column just opens and closes valves. In order to prevent the pilot from inadvertently making violent maneuvers a hydraulic "feel computer" was added to push back on the stick to fake the behavior of a manually controlled system. The forces it imparted had to be dialed back to accommodate the advent of female pilots, which caused some worry that the men would overcontrol the airplane. Fortunately, that turned out to not be a problem.
> OK, but do you see how someone could come away with that impression?
I not only never defended MCAS' design, I wrote that it was faulty several times. You should ask the someone why they conclude the opposite.
Of course. There's no telling how deep this conspiracy to point out publicly available facts goes :-)
> No requirements can ever prevent an accident.
That's not what I meant by requirements. Boeing came up with a set of rules for what the software must do in each situation. This is called the requirements specification for the software.
Anybody who contracts with someone to write some software comes up with such a specification.
> What other underlying reason could there possibly be for MCAS to exist at all?
There's nothing at all wrong with the concept of MCAS. There's a long history of flight control augmentation in jet airliners to make them behave better. In fact, you cannot control a jetliner at all without augmentation, it's too fast and heavy. It's the implementation that was faulty.
The B-17 was perhaps the largest successful airplane with no augmentation, and a strong man could barely handle it (source - my dad was a B-17 pilot).
The 757, which I worked on, has fully powered controls. The control column just opens and closes valves. In order to prevent the pilot from inadvertently making violent maneuvers a hydraulic "feel computer" was added to push back on the stick to fake the behavior of a manually controlled system. The forces it imparted had to be dialed back to accommodate the advent of female pilots, which caused some worry that the men would overcontrol the airplane. Fortunately, that turned out to not be a problem.
> OK, but do you see how someone could come away with that impression?
I not only never defended MCAS' design, I wrote that it was faulty several times. You should ask the someone why they conclude the opposite.