I was facinated to read the problems with that early 380 flight.
Whilst an early flight in both the type’s life, and my time on it (about the 3rd or 4th trip after I qualified) it actually behaved exactly as it was designed to.
Could you please explain the effects of alternate law I, law ll etc.
The laws are basically the rules by which the aircraft will fly. Consider them only in manual flight.
In the smartest of modes (normal law), the aircraft has all sorts of protections that defend against quite normal aviation. It can’t be stalled, because it has angle of attack protection. It can’t be oversped to any extent, because it will attempt to pitch up to reduce speed. If you place it in an attitude (say 20º angle of bank), it will stay there. Conversely, if it’s in a constant state, and is disturbed by wake or turbulence, it will correct it by itself. All automatics work (i.e. autopilot and auto thrust).
In alternate law II, the automatics may still work, depending upon the failure. The aircraft behaviour is still quite normal, but most of the protections have gone. You can stall it. Automatic pitch trim, but no roll trim.
Alternate law I generally requires a double failure of some sort. All protections are gone. Autothrust may still work, but no autopilots.
Direct law will require multiple failures, for instance, loss of all three primary flight control computers, or all four generators. No protections. No automatic pitch trim, no roll trim. All control inputs are directly related to stick position, with no computer moderation. In many ways this is simply an electronic version of the way all non FBW aircraft are, all of the time.
There are some other minor laws, which are subsets of these, used for specific purposes. In particular, during take off and landing, pitch law is basically direct, as that most closely emulates the feel of ‘normal’ aircraft, and this washes out over about 100’.
Are these laws related only to AB aircraft or also to Boeing?
There has been more discussion about the Airbus laws over the years, most probably because they have existed for longer than Boeing’s. All FBW aircraft, from an airliner to an F22 have flight control laws, and various reversionary modes. Whilst I’m not familiar with any of the Boeing FBW aircraft, they will have similar laws to the Airbus.
What I find really scary is that the aircraft auto systems dropped their bundle resulting in manual control being necessary.
Bit sad isn’t it, a pilot having to be a pilot. These reversions exist because it is normally much safer to drop the aircraft back into the pilot’s lap than it is to allow the automatics to continue to fly the aircraft using what may be false inputs. You only have to look at QF72 to see what can happen when the automatics make unmoderated, and frankly, stupid, inputs. The problem, of course, is that if you are going to dump anything into the pilot’s lap, it’s probably a good idea to ensure that he actually is a pilot, and not just a systems operator, or keyboard warrior. This sort of thing is why I see the idea of single pilot or zero pilot airliners as a bit of a joke. It will happen eventually, but I expect I’ll long be pushing up daisies when it does.
Can you reboot the systems back to 100% or a "limp home" mode?
In most cases, once a law reversion happens, then that is how it will stay for the rest of the flight. You may be able to restore the systems that caused the failure, but flight control computers are not something to be played with in flight. But, all of these laws are ‘limp home’ in their own right. All that differs is how much work it will be for the pilots in the interim. After my double failure, we flew for 5 or so hours before landing. We were in exactly the same modes as AF447...and they lost control within a minute or two! QF32 was in alternate law I. I’m not sure, but I think QF72 was forced into direct law by the Captain.
Has AB fixed the occurrence of this type of problem?
No. The reversions are themselves protections. This is how it was designed, and it will not change.
Miss you again. QF93 on 4/7.
