It does always seem to go to the Boeing vs Airbus thing but there have been several losses or near losses of 737's with rudder hard over problems and they were not fly by wire issues but hydro-mechanical (I'm sure someone will be able to correct this assumption for me :}) and no amount of manual reversion would have saved them as the solution was in fact not to pull but push in order to get better response from the ailerons ( I think that makes sense but see above proviso..... )
Any system can and will be subject to murphy's law and having done more than 5000 hours on the bus I am pretty satisfied that it will look after me.

And what about the B-2 crash
 

In the fever of A vs. B argument you seem to forget, that the most expensive and sophisticated AC in the world was downed by a sensor error as well...

A rather expensive experience at 2 billion dollar price tag.

No system is 100% immune against human error and simple, stupid negligence...

About 13 years ago an A320 became very difficult to control on a go-around at Hong Kong. Something to do with the Flaps locked in the full position but the flap lever in posn 3. If I am right this situation can not occur these days as the control laws in effect take their que from actual flap position NOT lever position. Now what could paint/tape do to the flap position sensor ?
As I've said before the results of the investigation will be very interesting to read. As for Boeing/Airbus they are both a/c so if you set an sensible attitude and set a sensible thrust setting you will get a sensible flight profile. But in normal law will the Airbus allow you to set a sensible attitude & thrust, if the flight control computers are getting erroneous data. I know you can in the Boeing (75/76) but as am just back on the Airbus am not convinced you could. But then again I may be totaly wrong.;)

Enough of the pathetic Boeing vs Airbus nonsense
 

Firstly, I am not one to speculate, hence rarely post on this forum. However I do find the continous "Manual vs Auto" "Boeing vs Airbus" argument somewhat tedious. No aircraft is perfect, they all require the crew to be trained thoroughly and to know the procedures to be carried out should failures occur.

Of course, as I fly the 'bus I do feel somewhat defensive, but not to the extent of thinking one fundamentally safer than the other (give me Normal Law anyday :) )

An airbus can be flown manually either in Normal Law, or if things go wrong, Alternate and then Direct. They all offer some protections, Normal Law giving you the ability to pull back full stick and bank fully without fear of losing control. A fabulous attribute, surely.

Now on the subject of Unreliable Air Data, if that should happen to be a factor here, no aircraft can cope with it. It is up to the pilots to notice the problem and then carry out Memory Drills for datum pitch and power settings.

I did this just the other day in the sim as it happens as part of my recurrent check. Very odd and disturbing to see conflicting readouts on PFDs, but once you have noticed a discrepancy, you are halfway there to staying safe.

Whatever the cause of the crash, it is a great loss for the families and friends involved. Let's all wait for the official results.

Maybe we can concentrate the discussion to the following question:

Which airplane(s) will be out of control if pitot/static ports, AoA-vanes are blocked/jammed.

Concerning 727, A300 I know the answer. A320/340 and the qantas incident I don't recall.

Yes, I've had this on the ancient coal-fired 4-jets I used to fly for HMFC.

No-one except us god-like Qualified Flying Instructors was normally allowed to practise flapless or slatless approaches. One day, I was flying a practice flapless approach in an aged old VC10K when all of a sudden, at around 800 ft agl, the stall warning system suddenly operated the stick pusher....

Fortunately I was able to overcome the large nose down pitching moment, executed a go-around, landed off the next approach and threw the old wreck at the maintenance people. Or 'engineeers' as they liked to call themselves.

They found a couple of 'interesting' facts:

• It had been stuck in some god-forsaken desert $hithole supporting Bliar's wars for some weeks and the AoA probe bearing was gummed up with sand and crap, so that when it moved jerkily on the approach, it triggered a false 'phase advance' signal (spurious detection of a rapid increase of AoA).
  
• The 'lift rate modifier' box (which corrects the stall protection system trigger AoA values for configuration) had NEVER been connected since BWoS allegedly re-built the old heap a decade or so earlier - the wires were neatly tucked behind the associated black box, but had never actually been connected.

http://i14.photobucket.com/albums/a3...rnet/zxzxz.jpg
Post-maintenance test flights could often prove most interesting, which is why very few of us were cleared to conduct them. But as long as you remembered the basics and didn't rush into blind checklist reading, things were normally OK.

That could have been very nasty. Did you ever look into which particular (non engineer) sky god carried out the acceptance test flight? Or who wrote the acceptance check list? That would have been a useful activity.

It was rather obvious that this accident has something to do with the air data sensors. I mentioned it in the very beginning

Click here

But noone believed me...

It is very well possible that the air data error only occured in a special set of configuration and was not yet dangerous in the beginning of the flight. Only when they pulled the levers or pushed the buttons, something went wrong. Let's see what the specialists will find out!

Dani

The unconnected Lift Rate Modifier had gone undetected for many years - it was only when the stick pusher went off that the error was found.....

The real problem was the sticky AOA probe and the fact that aircraft were rarely flown to the limits they once were when airframes were rotated between training and operational use.

Various other horrors were found on other aircraft - mainly down to poor conversion by BWoS, not as a result of routine maintenance. For example, when refuelling from other aircraft, we used to dump the stall protection system to prevent spurious warnings or idents at AAR speeds caused by airflow disturbance. But one VC10K was found to have NEVER had a serviceable stall dump system; the pin in the linkage had never been fitted as corrosion in the locating hole proved only too clearly.

An old BOAC teaspoon was also found floating about in the electrical bay - it had been there throughout the aircraft's entire service with Gulf Air after they bought it from BOAC - and it had then been rebuilt by BWoS for the RAF....:hmm:

But the A320 accident has yet to be explained. Back now to the thread, I hope!

Not just taped over ports and sensors but a/c washing as well...
 

When trapped water in a static system freezes during flight, above that freeze altitude the ASI will underread (and below that height it will overread - dangerous wrt (to) stall speed). Altimeters may freeze and VSI will......

Of course it all depends upon how many static ports there are - and how they're plumbed in to air data.....

Gentlemen, you are missing the point and the arguments.
This is not a slagging match A vs B!
Adhering to the thread this is about an accident of a Airbus.

Sensors and computers will always be prone to failures or mishandling. My criticism is that with the Airbus philosophy, a failure leading to erroneous electronic inputs or commands is not easy enough to counter. We know this aircraft pitched erroneously before crashing. We all assume that this was not done by deliberate pilot inputs.

Many assume that it has been done by electronic inputs, or at least caused by such. The reason has to be determined. We also know that Airbus technology does only allow a override of these electronic inputs in special circumstances (alt or dir law). To reach such a condition, there needs to be some switching. With ADIRU faults there is a procedure (CB pulling) which is not suited as a emergency procedure, no CB pulling/switching is designed for such operations, therfore it is not suited for events like Qantas experienced.

To reach dir law, with switching of PRIMs or SECs, there is no ECAM or other procedure determined as how to reach such status in an emergency, therfore again it is not suited for an emergency situation.

Any other aircraft will allow a pilot intervention, with some force and by switching off the AP/AT and such a procedure IS suited for a emergency situation, as it is a natural, trained and instant manoever.

Airbus might come up with some drill or memory items to counter erroneous, rapid inputs of electronic flight, and I would warmly welcome such procedures. But as long as there is only CB pulling or overhead switching, I will uphold my criticism of the Airbus system as it remains prone to catastrophies for such situation, as remote they may be and as much they might be induced by non Airbus systems/outside human error.

The pilots should always be armed with a direct, instant and easy intervention capability.
That is my criticism.

@GMDS

Spot on! I totally agree with you. Have flown 340 and 320, now on A300 I feel much better about that particular issue.

regards

GMDS,
As a confirmed Boeing luddite I find that info disquieting but not entirely surprising. :ooh:
I knew there had to be a good reason to sit in uncomfortable seats in a cramped noisy little space, now I know why. :rolleyes:

GMDS

Excellent post - my view exactly

I'm afraid that the ultimate answer by Airbus, although not worded in those exact terms, is "we know better, it is actually a feature of the aircraft not to let you take over"...

That's possibly as key point where they "philosophically" differ from Boeing.

Sorry the last few arguments are technically flawed.

Both Boeing and Airbus build inherently safe aircraft. But the type of technology used dictates the type of approach to be taken by the flight crew as problems will manifest themselves in different ways due to different technologies.

Safety statistics do not support any of your comments about a potentially flawed philosophy or the need for humans to be given more control over an "automated" process.

The direction this thread is taking actually highlights nothing more than a human reluctance to accept change and does not advance the discussion on the Excel tragedy.

Rubbish. Even the Space Shuttle can be flown manually if need be.

@dc-ate someone has already said it but it holds true. This thread is showing the holes in peoples knowledge and nothing else.

An Airbus can be flown manually and the whole argument has no place here in a discussion about a dreadful accident.

Once you are able to distinguish between fact and fiction come back and say something sensible. Otherwise your post reflects your own knowledge levels.

- going slightly 'off thread' here (and NOT directed at Airbus), but there is an understandable reluctance to embrace 'change' at any cost. The B2 accident referred to before shows what can happen when sensors and chips have such authority as to render the a/c unflyable in a failure mode. It is not "the need for humans to be given more control over an automated" process" so much as "the need for humans to be given..." (while pilots remain in cockpits) a way to take over when things don't work as they should, allied to the training to fully understand what the system is doing. I have for a long time believed that failure to provide the latter was a key factor in the early days of the 'modern' Airbus and certainly caused a few crashes. Until we have infallible systems there is going to be the need for pilots to be able to revert to the old-fashioned way of doing it - assuming pilots are still trained to do that............................. Anything which prevents raw input producing raw control, albeit without all the bells and whistles, is dangerous.

Thank you, I have returned.

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.

I must have missed something.

I never suspected they was a question about whether it could be flown manually but the issue was that you do need recognition and reaction time and therfore a safe altitude.

I could be confused but wasn't this the issue?

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 was very different because it was a night fly over sea. The pilot never fully understood that their instruments where not working correctly (they might / should have but it wasn't obvious without any outside reference).

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...)

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.

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.

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

Maybe....
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

Reality
 

I think the Airbus telex was intended to remind all concerned that procedures should be followed, no matter the outcome of this investigation.

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.:8

Sometimes when we make complicated things, we expect complicated problems.....buts its the simple things we forget.:hmm:

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..............

My take is that any informed reader can infer a lot more than that from this "telex". It's by no way the final report but you can bet that the root cause was some sensor failure post paint job and some procedures not followed...

Will see in 18 months... ;)

.....

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.

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

atakacs,
I do enjoy your comments on various subjects before the publication of the official findings.:rolleyes:

The most accurate one so far is;:ok:

Why Wait?
 

If we always waited for the final report to comment, there would be no PPRuNe. :}

Soooooo .. after 565 posts it comes down to this:-
.
How do the Airbii keepers of the logic :E 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 :suspect: .. !!!!e … we are slow (heaps less airframe slipstream noise), or :ooh: !!!!e, we are stuck to the cabin roof … :eek:
.
... 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" :ooh: (previous poster description) to override automation went it does know best?!?!?!? … if in fact it REALLY does know better??? :{
.
http://www.improvresourcecenter.com/...es/popcorn.gif

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.

Can those that are in favor of all this automation explain what the purpose of the pilot is?

to feed the dog

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?

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.