Airbus crash/training flight
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I maintain that this discussion is irrelevant and not related to this awful situation.
Aeroperu 603 says it all. Now please get back to topic which is what actually happened with the Excel aircraft.
Aeroperu 603 says it all. Now please get back to topic which is what actually happened with the Excel aircraft.
I maintain that this discussion is irrelevant and not related to this awful situation.
Aeroperu 603 says it all. Now please get back to topic which is what actually happened with the Excel aircraft.
Aeroperu 603 says it all. Now please get back to topic which is what actually happened with the Excel aircraft.
Here is was daylight. There is absolutely no doubt that the crew realized immediately that the plane was not behaving as expected. My completely uninformed theory is that they actually fought against the automation and lost the "battle". I would go further and pretend that they might have had a better chance if they could quickly and simply kill all automation, had adequate training to do so and hand fly the beast...
Obviously this might or might not be confirmed in the final report... as such this discussion is perfectly on topic (as much as my understanding of PPRunE goes, of course...)
Last edited by atakacs; 27th Jan 2009 at 19:20. Reason: typos
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GMDS - I disagree with the core of your statements.
To gain control of the Airbus in an unreliable airspeed/data scenario (ie pitot or static ports/sensor fault) you...
Disconnect autopilot (if engaged) by pressing red button on sidestick
Switch off flight directors
Disconnect autothrust press button on side of thrust levers
Pitch and Power to memory drill datums
It won't pitch up erroneously in manual flight.
How do other aircraft differ?
I am in no way making inferences about the actions of the crew in this scenario, just highlighting that the Airbus is as safe as any other jet with unreliable air data.
To gain control of the Airbus in an unreliable airspeed/data scenario (ie pitot or static ports/sensor fault) you...
Disconnect autopilot (if engaged) by pressing red button on sidestick
Switch off flight directors
Disconnect autothrust press button on side of thrust levers
Pitch and Power to memory drill datums
It won't pitch up erroneously in manual flight.
How do other aircraft differ?
I am in no way making inferences about the actions of the crew in this scenario, just highlighting that the Airbus is as safe as any other jet with unreliable air data.
KN. See my prev. Post yes it can in normal law if the sensors give erroneous info to the flt control computers. You need direct law for direct "manual" flt. That is why this tragic accident possibly happened if one is Reading behind the lines of the airbus release.
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Knackered Nigel
I disagree I'm afraid... and I fly the thing as well 
A lot of posters are getting hung up on the AP... which in the Airbus is a fairly dumb thing, and subject to the same Flt Control Laws as we are in Manual Flying...
If we limit ourselves to Normal Law, then the Airbus, with/without AP, has defined Pitch, Roll and AoA limits. If it determines it is exceeding those, then it will apply controls to try and get within those limits, whether AP is in or out e.g. if it (thinks) is at 70AoB to the left, it will roll right. Trouble is if it was in, say, a 45AoB turn to the right, but thought it was 90AoB to the left, it will roll to 75AoB right, and try to roll more
Of course, the design of multiple IRs / sensors, and degraded Flt Control modes as things fail, is designed to prevent the scenario above occurring. However, it did in the QF72 incident, where, as I understand it, in Manual Flight it "pitched down hard" to reduce a perceived excessive AoA.
Quite where, even if, this fits in to this accident we have yet to find out... and whether the test schedule requirements, with/without known sensor errors / failures, created the final loss of control....
AFAIK the 777 has had similar control "issues" due faulty sensors... although full control inputs are supposed to "override" any protections... ?
NoD
It won't pitch up erroneously in manual flight.
A lot of posters are getting hung up on the AP... which in the Airbus is a fairly dumb thing, and subject to the same Flt Control Laws as we are in Manual Flying...
If we limit ourselves to Normal Law, then the Airbus, with/without AP, has defined Pitch, Roll and AoA limits. If it determines it is exceeding those, then it will apply controls to try and get within those limits, whether AP is in or out e.g. if it (thinks) is at 70AoB to the left, it will roll right. Trouble is if it was in, say, a 45AoB turn to the right, but thought it was 90AoB to the left, it will roll to 75AoB right, and try to roll more
Of course, the design of multiple IRs / sensors, and degraded Flt Control modes as things fail, is designed to prevent the scenario above occurring. However, it did in the QF72 incident, where, as I understand it, in Manual Flight it "pitched down hard" to reduce a perceived excessive AoA.
Quite where, even if, this fits in to this accident we have yet to find out... and whether the test schedule requirements, with/without known sensor errors / failures, created the final loss of control....
AFAIK the 777 has had similar control "issues" due faulty sensors... although full control inputs are supposed to "override" any protections... ?
NoD
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Originally Posted by DC-ATE
Any time you take away ANY portion of control of a human-operated flying device, you increase the odds of an unsuccessful outcome in the event of an emergency.
You also increase the odds of an imbecile "taking control" and crashing the "human-operated flying device"....
The Habsheim crash is the textbook example.
As an ancient aeronautical engineer, not a PF, I'm in favour of the "boing", then stick shaker, then stick pusher, all known and anticipated, rather than having the aircraft decide for you what it thinks is best ... But I may be wrong.
CJ
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Knakered Nigel
I also disagree I'm afraid....even a manual aircraft can pitch up erroneously in manual flight, whether imbecile induced or a broken bell crank/lever/sproket/cable/turnbuckle/split pin or floo floo valve thingy.!!! (take your pick)
I'm intrigued by the 'computer/sensor' debate but presumably they only send the push/pull intention, it requires something more substantial to actually alter the bernoullies.
Sometimes when we make complicated things, we expect complicated problems.....buts its the simple things we forget.
It won't pitch up erroneously in manual flight.
I also disagree I'm afraid....even a manual aircraft can pitch up erroneously in manual flight, whether imbecile induced or a broken bell crank/lever/sproket/cable/turnbuckle/split pin or floo floo valve thingy.!!! (take your pick)
I'm intrigued by the 'computer/sensor' debate but presumably they only send the push/pull intention, it requires something more substantial to actually alter the bernoullies.
Sometimes when we make complicated things, we expect complicated problems.....buts its the simple things we forget.
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The pilots should always be armed with a direct, instant and easy intervention capability.
That is my criticism.
That is my criticism.
I think the Airbus telex was intended to remind all concerned that procedures should be followed, no matter the outcome of this investigation.
Will see in 18 months...
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Completely agree, on the 737 for instance, when the aircraft is about to throw in uncommanded rudder and roll on its back as it does time and again there should be an additional set of pedals to counter it.........
I agree, but there you go yourself with the A vs B slagging.
The rudder design of the 737 proved to be a serious flaw and, i believe, has been corrected. Therefore I would have hoped that Airbus might consider its design not adequate enough (i.e. Qantas incident and eventually this one as well) and provide us with a solution. I don't know how easy it would be.
Let's face it, the same faults on a, say, 777 could have been overcome with switching off AP/AT and some force. This is instinctive and instantanoeus. I disagree with the presumption that this is possible with a Airbus. For that I say again you would need some overhead PRIM/SEC switching. There is no procedure for that and overhead switchings is not instinctive and instantaneous.
Pointing at other aircraft designs, failures and subsequent accidents does in no way let anyone off the hook with their own design. If weaknesses are detected, reported and therefore known, operators, crew and passengers have a right to expect the manufacturor to come up with a viable and flyable solution. Bulletins and accident reports may be a lead to that, but they are NOT the required solutions.
For such events and for the average pilots (that would be me), the situation in an Airbus and having to expect the unexpected, today this design lacks the as I said instinctive and instantaneous possiblity of intervention.
Guest
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No Manual Backup
That fine science fiction writer, Robert A. Heinlein, wrote in "The Moon's A Harsh Mistress" of the utter stupidity of controlling everything from transport to environment to writing paychecks using one large computer system, with no manual reversion or as he called it, the possibility of "jury-rigging" while a problem was solved: because "if it can go wrong, it will".
He'd have been interested in this present discussion.
R
He'd have been interested in this present discussion.
R
The Reverend
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atakacs,
I do enjoy your comments on various subjects before the publication of the official findings.
The most accurate one so far is;
I do enjoy your comments on various subjects before the publication of the official findings.
The most accurate one so far is;
Will see in 18 months...
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Soooooo .. after 565 posts it comes down to this:-
.
How do the Airbii keepers of the logic
ensure in future that the pilot/s can override the automation when, the automation is known to be taking the day off i.e.
.
... visual reference and other clues like …. errrm …. geez
.. ****e … we are slow (heaps less airframe slipstream noise), or 
****e, we are stuck to the cabin roof … 
.
... for whatever reason i.e. taped over sensors, or an air data reference unit hissy ..... GIVEN that …
.
OBVIOUSLY, following on from that …. and ... CONVERSLY …
.
.... be smart enough to know when the automation should not allow an "Imbecile" (previous poster description) to override automation went it does know best?!?!?!? … if in fact it REALLY does know better???
.
.
How do the Airbii keepers of the logic
ensure in future that the pilot/s can override the automation when, the automation is known to be taking the day off i.e..
... visual reference and other clues like …. errrm …. geez
.. ****e … we are slow (heaps less airframe slipstream noise), or ****e, we are stuck to the cabin roof … .
... for whatever reason i.e. taped over sensors, or an air data reference unit hissy ..... GIVEN that …
.
OBVIOUSLY, following on from that …. and ... CONVERSLY …
.
.... be smart enough to know when the automation should not allow an "Imbecile"
(previous poster description) to override automation went it does know best?!?!?!? … if in fact it REALLY does know better??? .
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I think some posters here have hinted at a question that would need to be answered to assess the automation and philosophy of Airbus, and that is:
'How may accidents has the automation and design philosophy prevented?'
Unfortunately that is obviously a question that can never be answered, therefore it is hard to make a good argument for or against that automation. Really, would a big red override button have saved this plane, but have resulted in two other accidents? We will never know.
'How may accidents has the automation and design philosophy prevented?'
Unfortunately that is obviously a question that can never be answered, therefore it is hard to make a good argument for or against that automation. Really, would a big red override button have saved this plane, but have resulted in two other accidents? We will never know.
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Opposite argument: what benefits would bring in terms of safety the existence of that big red "Cessna 172 law" button that would silence all the automation? How many accidents would such device had prevented so far.
Suddenly at the mere hiccup of an ECAM screen every Aibus/B777/whatever Captain would be extremely tempted to press it, for whatever reason, probably with a wider range of results, good or bad. Would any Captain want that much responsibility (by pressing said button) on his/her shoulders?
Suddenly at the mere hiccup of an ECAM screen every Aibus/B777/whatever Captain would be extremely tempted to press it, for whatever reason, probably with a wider range of results, good or bad. Would any Captain want that much responsibility (by pressing said button) on his/her shoulders?
Gear Down
Why should we be scared of pressing a big red button that merely gives us control of an a/c. Back when we flew GA we were in big red button mode all the time.
I feel some today are being over awed by all the automation, at the end of the day they are aircraft and simple to fly. If you can't fly them then you need to question your position.
Some great advice I was given as a F/O was to learn how to operate the aircraft in every mode, automated or not, and to push myself while I was an F/O so that when I moved to command the a/c posed no loading upon me, allowing me to manage and observe.
Why should we be scared of pressing a big red button that merely gives us control of an a/c. Back when we flew GA we were in big red button mode all the time.
I feel some today are being over awed by all the automation, at the end of the day they are aircraft and simple to fly. If you can't fly them then you need to question your position.
Some great advice I was given as a F/O was to learn how to operate the aircraft in every mode, automated or not, and to push myself while I was an F/O so that when I moved to command the a/c posed no loading upon me, allowing me to manage and observe.