PPRuNe Forums - View Single Post - Air Asia Indonesia Lost Contact from Surabaya to Singapore
Old 28th Jan 2015, 10:47
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NigelOnDraft
 
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So in the end in an Airbus you can still fly it like a non FBW conventional aircraft if you required to do so regardless of which "Law" it's in or faults/malfunctions in "Normal Law" or am I and others missing something?
Not strictly true

If you turn off AP/ATHR and FDs (in fact FDs academic) then you should be flying "attitude and power". However, if you are in Normal Law, then auto-trim and protections are still present, and you are not commanding control surface movements, but performance changes that the computers action.

In Direct Law the computers are still between the stick and controls, but in a fairly dumb way (stick relates to control surface movement).

Alternate Law somewhere between.

The "problem" some seem very concerned with is when a "protection" incorrectly kicks in, or limits you inappropriately, such it prevents you from flying normal attitudes. The recent OEB I believe, after many years of Airbus FBW Ops, is the first acknowledgement this can happen. Others here claim it has happened on numerous occasions.

I do not see that issue relevant to AF447. Without re-reading the whole thing again, I do not believe a "protection" incorrectly kicked in? Sensor failures led to FBW downgrades and allowed the pilots to fly the aircraft conventionally into an unrecoverable situation.

Perpignan ditto - again faults then downgrades allowed the pilots to crash the aircraft.

China 747 - yes he pulled 5g or whatever, bent the wings, and people say "couldn't do that in an Airbus - they'd all have died". With FBW working, the Airbus would have stopped the situation arising. Even if it got into that, I see no evidence the 747 recovery required 5g? A correctly flown 2g recovery would likely have been fine.

A Qantas A330, then the run up to the OEB, did see the aircraft behave inappropriately due FBW protections (as did a SQ777?). I suspect these are now designed out, or being so.

There are 000s of FBW Airbuses out there, and I doubt more accidents than say 737s? It is not perfect, but then nor is the 737. I very much doubt we will see a significant change (linked sidesticks, moving throttles, Law basics) requiring extensive hardware modification and re-training. I suspect we will see tweaks to the software and training to try and close off the loopholes as they arise.

Won't stop the Airbus bashers on here, who are now so desperate they blame the Airbus for the 777 SFO crash

I fly it, fine piece of kit, would prefer something "fun/real" to fly like the 757, (but get that outside the airline world). It's pretty reliable, albeit has it's French quirks. As is being repeatedly shown however, like all aircraft in the past, it is not crash (or idiot) proof.
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