Originally Posted by
RetiredF4
Is this an honest question in relation to technical feasability or in relation to beancounters available assets?
Just remeber, the moon landing was 40 years ago.
I don't doubt for a second that it's technically feasible to do, but the level of reliability required to meet certification necessitated the use of simplistic logic.
I know it's a good-natured joke, but this is where the "HAL" references stop being funny and start being a serious barrier to understanding. The reason for this is that the fictitious HAL was a central computer that had very complex programming and sole control over the entire vessel. What you have in aircraft like the Airbus and Boeing FBW types is a network of computers that are constantly cross-checking each other. The subsystems within are essentially a collection of finite state machines - each one not much more complex than those you'd find in your washing machine, but interlinked together to build a complex interoperating system out of simple parts.
These parts had to be rigorously tested individually and gradually pieced together in a programme that took the best part of a year. My old prof's class started with tales of making safety-critical software reliable and the exciting stuff software could be used for, but most of it was spent poring over graphs from the various regression tests that were run during that programme in order to prove the technology and determining with algebraic functions whether they would meet the stringent reliability requirements imposed by the aviation system.
It's funny that you should mention Apollo, because I've been diving into that a lot recently - Apollo 14 in fact holds the distinction of being the first software patch applied to a mission-critical system on an aircraft, and they did it *in space*. But the Apollo crews were almost all engineering test pilots with the ability to call on 400,000 people to help them solve any issue that came up, and they all accepted a significant degree of risk in order to attempt the journey. That's a far cry from being a line pilot out over the ocean, responsible for a couple of hundred lives and some distance from technical assistance. And as such, the systems need to look after themselves to a greater degree in that situation.
To be honest, I'd be surprised if the A380 systems haven't had a significant upgrade in that area compared to the older types, and the A320NEO will probably have systems derived from that work. But the original FBW series will still be using hardware of a mid-80s vintage, and I doubt it would have excess process bandwidth to cope with such a function - which is why Airbus produced the BUSS option (which can be retrofitted) as a stopgap.