Voyager Plummets (Merged)
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For my part I'm baffled by your determinedly hostile stance to everything about this operation and dislike of being challenged on it. Nothing personal!
From the limited facts I couldn't say what law it was in -you're the one hearing the rumours -but any change would likely be the result rather than the cause of this excursion. Trainers aren't supposed to make statements like "it can't stall" since none of the very impressive protections make an airbus invulnerable.
I don't see parallels with AF 447 here, but a principal reason its pitch remained so high was an erroneous full back stick input by the RHS pilot until shortly before impact.
From the limited facts I couldn't say what law it was in -you're the one hearing the rumours -but any change would likely be the result rather than the cause of this excursion. Trainers aren't supposed to make statements like "it can't stall" since none of the very impressive protections make an airbus invulnerable.
I don't see parallels with AF 447 here, but a principal reason its pitch remained so high was an erroneous full back stick input by the RHS pilot until shortly before impact.
The civvy A330 has all of the cb located under the cockpit floor. There are however some reset buttons for various systems. You can downgrade the FBW by turning off some of the fbw computers or messing with the hydraulics. The hydraulic panel is next to the fuel panel on the overhead panel and i believe many years ago an A340 crew (system architecture is virtually identical)managed to turn off most of the hydraulics when they thought they were turning off fuel pumps to balance the fuel.
ShotOne,
Will you admit that, having never having heard of "abnormal attitude flight law", your technical expertise on this matter is obviously considerably less than some of those that are posting?
Nothing personal you understand!
Will you admit that, having never having heard of "abnormal attitude flight law", your technical expertise on this matter is obviously considerably less than some of those that are posting?
Nothing personal you understand!
Even if the event was triggered by a fault in the left hand sidestick, what I find perplexing is that the extreme manoeuvre was seemingly not contained within the Normal Law flight envelope protection limits.
In theory, if a pilot were to make a deliberate full nose-down demand, the aircraft should not exceed Normal Law limits.
The wall of silence over this and the prompt resumption of flight operations reminds me of the behaviour of the managers in the movie The China Syndrome....
An 'unscheduled change of flight level' indeed......
In theory, if a pilot were to make a deliberate full nose-down demand, the aircraft should not exceed Normal Law limits.
The wall of silence over this and the prompt resumption of flight operations reminds me of the behaviour of the managers in the movie The China Syndrome....
An 'unscheduled change of flight level' indeed......
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Are there any scenarios where the system won't let the autopilot disconnect or allow pilot input? The crew might have perceived the ap wouldn't kick out, but there was a lot going on at the time. As they will have the QAR data, I'm sure all of this will be apparent!
Last edited by VinRouge; 23rd Feb 2014 at 08:34.
I would suggest that there is likely to be a massive difference between knowing what happened, which should be relatively simple, and why it happened - which is the real crux of the matter.
Especially if the "why" involves determining why a computer controlled system didn't behave in the way it is designed/intended to...
But I'll fully admit now that I have limited technical knowledge in this area - before anyone points it out on my behalf! I do have some experience in software design and testing however.....
Especially if the "why" involves determining why a computer controlled system didn't behave in the way it is designed/intended to...
But I'll fully admit now that I have limited technical knowledge in this area - before anyone points it out on my behalf! I do have some experience in software design and testing however.....
In theory, if a pilot were to make a deliberate full nose-down demand, the aircraft should not exceed Normal Law limits.
I first saw abnormal attitude law on the A330 on my convex in the sim and that was a long time ago. I have seen it subsequently, again in the sim, when looking at recovery from high altitude stalls. It is a non-event as far as control of the aircraft goes, you don't notice it kicking in nor reverting out.
There is a wealth of difference between quoting from the FCOMs and understanding how the system works. I have seen some very experienced pilots flounder in the sim because they have been seduced by the seemingly complexity of the systems and have in some circumstances overanalysed events in others they have forgotten the basic rule of "fly the aircraft." The latter comment does not support the viewpoint of skill erosion due to fly by wire, in my opinion, knowing the individuals, their skill level peaked early in their career and waned because time pressures meant that they couldn't indulge their love of flying by widening their experiences beyond 'the job.'
The possibility of CM1 control input problems appears to have sneaked in to the discussion. Where did that come from? If that did happen was CM1 PF or PNF at the time?
Interesting discussion but aside from the arcane aspects of Airbus FBW does anybody have a handle on what attitude was really achieved -I've seen nothing other than 20/40/60 degrees nose down (the later of which I must admit sounds close to terminal to me) mentioned in an early post?
I'm a Normal/Secondary/Direct person myself so I've nothing to add to the technical stuff.
I'm a Normal/Secondary/Direct person myself so I've nothing to add to the technical stuff.
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The US military gave over on Kapton decades ago (the USN banned it in 1987)- to the point they sent aircraft with Kapton-coated wiring to rework to have it removed, and properly-insulated wiring installed!
The USN, in 1983, rewired its F-14s that had a very similar wiring insulation - Poly-X.
The USN, in 1983, rewired its F-14s that had a very similar wiring insulation - Poly-X.
If the temporary suspension of operations, or whatever they called it, only applied to the military registered aircraft, why not return the military registered aircraft to the civil register? QED!
What happens if a UK military passenger refuses to get on one because they consider the aircraft 'unsafe'. The fact that they stopped flying, and the basic reason why, was reported by the BBC, so is widely known in the community. By contrast the reasoning behind the resumption of flying doesn't appear to have been published, or if it has, not widely.
No doubt any such above action by someone subject to military law would be considered as 'refusing an order' and could result in an interesting military court case...
No doubt any such above action by someone subject to military law would be considered as 'refusing an order' and could result in an interesting military court case...
The US military gave over on Kapton decades ago (the USN banned it in 1987)- to the point they sent aircraft with Kapton-coated wiring to rework to have it removed, and properly-insulated wiring installed!
The USN, in 1983, rewired its F-14s that had a very similar wiring insulation - Poly-X.
The USN, in 1983, rewired its F-14s that had a very similar wiring insulation - Poly-X.
beardy wrote:
Well yes. You are of course correct - I was trying to keep things simple.
Ah, not quite. Should the aircraft remain in normal law, it will attempt to modify control inputs to attempt to remain within normal law limits, ie override control inputs. Environmental factors can upset the aircraft to put it outside normal law limits despite the best efforts of the aircraft. Failures can remove normal law protections, some of the symptoms on the PFD can be quite subtle, a simple removal of small green tags which can be easily missed.
Oversimplification can be misleading which, I am sure, was not your intent, but was the result.
As an example ADR problems can lead to false indications of over/under speed. Normal law inputs would try to prevent the perceived over/under speed and could lead to a real stall, or normal law could drop out and be unnoticed whilst dealing with the overspeeed. All of which sounds a bit radical and busy, indeed the QRH makes it sound like a big deal. It's not. Fly the aircraft, which AP is in? If it's the one linked to the PFD that is giving the false inputs, use the other one, job done aircraft under control. Check indications from all inputs, the other PFD, STBY inst and GPS readout, identify which ADR is faulty and turn it off. Crisis over without having to understand the inner working of the ADIRU, nor control law rules.
Where did the possibility of CM1 control input errors come from?
As an example ADR problems can lead to false indications of over/under speed. Normal law inputs would try to prevent the perceived over/under speed and could lead to a real stall, or normal law could drop out and be unnoticed whilst dealing with the overspeeed. All of which sounds a bit radical and busy, indeed the QRH makes it sound like a big deal. It's not. Fly the aircraft, which AP is in? If it's the one linked to the PFD that is giving the false inputs, use the other one, job done aircraft under control. Check indications from all inputs, the other PFD, STBY inst and GPS readout, identify which ADR is faulty and turn it off. Crisis over without having to understand the inner working of the ADIRU, nor control law rules.
Where did the possibility of CM1 control input errors come from?
The latest Reuter's article deepens the mystery further:
Britain lifts flying suspension on Airbus-made Voyager fleet | Reuters
Britain lifts flying suspension on Airbus-made Voyager fleet | Reuters
beardy wrote:
Sorry, but for now ICATQ. In any case, a deliberate CM1 error is not postulated.
Where did the possibility of CM1 control input errors come from?
Notwithstanding the details of this event, which seem to be top-secret, this quote from the link above is worthy of consideration...
"The Ministry of Defence (MoD) said it was inappropriate to speculate on the cause of the incident but, following critical safety advice, the RAF chain of command had been reassured that the likelihood of a repeat was negligible."
Why is speculation inappropriate? Also, if reassurance can be given do we assume the cause is identified? Surely the risk of the event was classed as negligible before it happened?
Smacks of NFF.
OAP
"The Ministry of Defence (MoD) said it was inappropriate to speculate on the cause of the incident but, following critical safety advice, the RAF chain of command had been reassured that the likelihood of a repeat was negligible."
Why is speculation inappropriate? Also, if reassurance can be given do we assume the cause is identified? Surely the risk of the event was classed as negligible before it happened?
Smacks of NFF.
OAP