Study: Pilots rusty because of automation

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20 years 7 months

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The rest - well I'm not going to bother parading my qualifications on here - but for this discussion, they are comfortably more than sufficient.

But I am not commenting on this based on my personal experience as a pilot. I'm doing it in my professional capacity as an engineer.

So how does this even remotely qualify you to comment on what was happening in the air & what it was like for the crew up there? It doesn't.

You actually saying the gyros used for modern AHs are screwed by a bit of turbulence? :confused:

Of course not, I am saying that in even persistent moderate turbulence, your ability to read the instruments clearly is downgraded, the instrumentation could be displaying whatever the hell it likes, but it doesn't mean you're in a position to read it.

The what happened is very well understood - the telemetry traces show exactly what happened. The why and how is less well understood.

Nuff said, and this is why you shouldn't be so ignorant, arrogant & unqualified to pass judgement.

They had a "visual reference" - its called the artificial horizon. They chose to ignore it and chase after airspeed readings instead (incidentally completely ignoring altitude). If they'd paid heed to it, they wouldn't have stalled - unfortunately it is more or less that simple.

I'm afraid it isn't that simple. Again, you weren't up there. If you read the recorder transcript that you say is so damning then you should know not everything is as black and white as it seems.
If the pitots blocked with ice, which they clearly did, you'll get an IAS Mismatch, this will disconnect the AP & AThr (as the report said). But what you now have is conflicting airspeed readings, they were clearly nearing the edge of "Coffin Corner" (you do know what this is? Don't you?) and were unable to climb to their optimum altitude due to the turbulence which could have sent them into this small window. You now have blocked pitots, and the very likely scenario here is that they are over reading, and the speed is pushing them close to coffin corner (but not in reality). So what they did was pitch the aircraft up in order to slow it down (no idea why they didn't try reducing power, but I wasn't there), all this did was cause the airspeed to increase further because you now have a pitot system that is acting like an altimeter (static element available - maybe), so they pitched even further. Then you have the stall warning go off. How confusing do you think that is for anyone flying in those conditions? If you think that is black and white then you are very much mistaken. What the report also said was that they climbed to a maximum altitude of 37,900ft from 35,000ft. Their rate of climb was 6,900fpm. I am sure you are good at maths, so you do the calculations, that's 25 seconds to reach the stated altitude. A long time in the grand scheme of things? You bet it isn't. 25 seconds, that's all. The report, and your good self makes no reference to this at all, and make out like they had all the time in the world, but they didn't. Also lets not forget the severe icing conditions. Do you know what an accretion of severe ice does to your stall speed? Do you know how this will affect the aerodynamic capability of the aircraft at that altitude?

I don't think anyone has ever said the crew weren't at fault. I am not saying that either. I am saying who are we, well, who are you to judge them when you weren't even in the aircraft to know what was going on that night, who are you to judge them when you have no idea what was presented to them that night? A decaying airspeed then a subsequent pitch up? I don't think so somehow.

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24 years 2 months

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Well spoken, Deano. I also had the coffin corner in mind, but I need to dust off some of my knowledge.

If pilots fail to react as they should in a given situation what else can be at fault except training?

An interesting and perhaps difficult question. SOP for the aircraft and/or the company is also an item which can form a slice in Reason's swiss cheese model, for instance. Human factors can be a complex issue.

Amiga500,

I thought that you might be an engineer of some sort. You also claim that you have some pilot experience. The apparent fact that you at first didn't seem to know a basic principle of VFR flying (using visual references outside the aircraft) makes me a bit puzzled, though.

Yep - with the implicit assumption what is ahead of you is the same ground height as what is to the side.

In my experience, it is of course easier to use the outside horizon as a reference when the surrounding terrain is flat, but it's also fully possible (and often more fun) to fly VFR in e.g. mountainous areas. As I've been taught - if the outside horizon is "cluttered" by mountains and such, try to make it out yourself.

You seem to have a way of being very sure about things. Don't you think a little humility would do you some good?

As I gather more and more experience and knowledge (or try to, anyway), one important thing I realise maybe more and more is that there is so much I don't know.

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19 years 2 months

Posts: 554

Are there any standby instruments on the A330? If so, do these readings come from an alternate pitot static source?

If so, do they have an alternate anti-ice supply?

Strange if all airspeed info was 'corrupt' due to icing.

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20 years 7 months

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Is there not standby instruments on the A330?

Most definitely. Yes it would come from the Alternate Pitot/Static Probe, which unfortunately would be susceptible to the same icing conditions as the other 2 probes. The Stby Pitot heater is most likely DC powered, whereas the primary pitot heaters will be AC powered. I'm not Airbus rated so it could be the other way around, but very unlikely.

The pitot heaters usually run very, very hot, if you touched them you'll burn your hands, but it has been proven that in severe icing conditions this heat will eventually not be sufficient to stop the pitots from icing over.
So in all, not that strange that all sources would ice up, afterall they are all presented to the relative airflow.

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19 years 2 months

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So how does this even remotely qualify you to comment on what was happening in the air & what it was like for the crew up there? It doesn't.

.

That's all of us then unless we fly A330's and have been in the same conditions.

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19 years 2 months

Posts: 554

[QUOTE

The pitot heaters usually run very, very hot, if you touched them you'll burn your hands, but it has been proven that in severe icing conditions this heat will eventually not be sufficient to stop the pitots from icing over.
So in all, not that strange that all sources would ice up, afterall they are all presented to the relative airflow.[/QUOTE]

Absolutely, i've seen pilots and engineers scarred to that effect. It would be interesting to know the full extent of the icing conditions and the effects on pitots and their heating.

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20 years 7 months

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Well no. Alot of us have been in the same conditions, the type of aircraft is largely irrelevant because my argument to Amiga is all about what it is like to operate in those kind of conditions, i.e. in a thunderstorm, in severe turbulence, in severe icing, whereas he is sat in his little armchair sipping soup in front the fire pretending he knows what it is like. If he has then fair play, but he has chosen to ignore this part of the argument because he most likely hasn't.

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19 years 2 months

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Icing certification requirements are discussed in the interim report (2) : here - 1.18.5 System certification page 60. Seems like ice should never build up on a pitot according to JAR requirements and Airbus design exceeds those requirements.

The report does mention the failure of the probes though.

Anyway, this is all drifting off the original purpose of this thread. It's turning into a body function over distance competition and there's a headwind developing.

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14 years 1 month

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If the pitots blocked with ice, which they clearly did, you'll get an IAS Mismatch, this will disconnect the AP & AThr (as the report said). But what you now have is conflicting airspeed readings, they were clearly nearing the edge of "Coffin Corner" (you do know what this is? Don't you?) and were unable to climb to their optimum altitude due to the turbulence which could have sent them into this small window. You now have blocked pitots, and the very likely scenario here is that they are over reading, and the speed is pushing them close to coffin corner (but not in reality).

So what they did was pitch the aircraft up in order to slow it down (no idea why they didn't try reducing power, but I wasn't there), all this did was cause the airspeed to increase further because you now have a pitot system that is acting like an altimeter (static element available - maybe), so they pitched even further.

No, not the way it works. That is physically impossible given the way a pitot-static tube works and the supposed overspeed you postulate earlier.

If you had an underspeed earlier, then yes, you could possibly have a speed increase with altitude increase (Pitot probe is blocked while static probe reduces pressure due to ambient). But you can't have both.

Conversely, if the static port was blocked earlier, and you had an overspeed, then when you increase altitude and bleed off real airspeed, your indicated speed will reduce.

Pt/P = [1 + {(gamma-1)/2}*Mach^2] ^ (gamma/[gamma-1])

gamma is ratio of specific heats, Pt is total pressure (pitot probe), P is static pressure (static probe).


Then you have the stall warning go off. How confusing do you think that is for anyone flying in those conditions?

It is confusing only if you mis-diagnose the problem in the first place.

In that instance, it would be more than confusing, it would be alarming.


If you think that is black and white then you are very much mistaken.

First thought should always be; retain control of the aircraft. Everything else is a distant second to that.

They had faulty airspeeds, they knew that. Yet they made the decision to try and react to those airspeed readings. Why on earth would you make the decision to try and respond to what you know to be potentially bad airspeed readings?

That is why it is black and white to me.

They should have went with set attitude and thrust. They should have known to go with set attitude and thrust. That is why it is extremely bad airmanship and that is why I am not happy at the authorities dancing around the issue (my rants in here are reflective of that - call a spade a spade - being politically correct when lives matter helps no-one).


The report, and your good self makes no reference to this at all,

http://www.bea.aero/docspa/2009/f-cp090601e3/pdf/f-cp090601e3.pdf

pg 44

The traces are all there.

Climb initiation at ~2:10:12, then starts to tail off around 2:10:34 - not even 25 secs.


and make out like they had all the time in the world, but they didn't.

They had all the time in the world if they had given themselves it.

It is also interesting to note the crew previously decelerated to Mach 0.8. Quite a ways short of the A330 0.86 limit.

As for 'coffin corner' - explain their rational for climbing then...


Also lets not forget the severe icing conditions. Do you know what an accretion of severe ice does to your stall speed? Do you know how this will affect the aerodynamic capability of the aircraft at that altitude?

No idea. Please enlighten me. :rolleyes:

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Well no. Alot of us have been in the same conditions, the type of aircraft is largely irrelevant because my argument to Amiga is all about what it is like to operate in those kind of conditions, i.e. in a thunderstorm, in severe turbulence, in severe icing, whereas he is sat in his little armchair sipping soup in front the fire pretending he knows what it is like. If he has then fair play, but he has chosen to ignore this part of the argument because he most likely hasn't.

Not in icing thankfully.

But, that is pretty much irrelevant. Again, as I said earlier, I'm not commenting on this on my personal experiences of flying - I'm commenting as an engineer.

The thought process is completely wrong, and it is completely wrong because too many pilots don't think but blindly follow numbers. "Oh, thats too high, I need to reduce it" and visa versa. No thought of "why is that too high?".

Maybe I am being unfair as I would think more along the lines of a test pilot than a regular line pilot - but I don't see it as unreasonable to expect a line pilot to think along those lines either.

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Maybe I am being unfair as I would think more along the lines of a test pilot than a regular line pilot - but I don't see it as unreasonable to expect a line pilot to think along those lines either.

A test pilot thinks like that so that a line pilot doesn't have to. It is the test pilot's (and engineer's) job to query, find reasons etc. The last thing the travelling public need is line pilots acting like test pilots.

AP (former flight test engineer)

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The last thing the travelling public need is line pilots acting like test pilots.

:D

Thinking... not acting!

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The thought process is completely wrong, and it is completely wrong because too many pilots don't think but blindly follow numbers. "Oh, thats too high, I need to reduce it" and visa versa. No thought of "why is that too high?"

I think you seem a bit judgemental based on how you think it works.

Depending on a number of situational factors such as the nature of the problem itself, the phase of the flight, the weather etc., one doesn't always have the time and margins to think long and hard about problems when flying an aircraft.

A general example: Detection, identification, confirmation, conduct of by heart items and completion/follow-up using the QRH can form the initial steps taken to resolve an issue occurring during flight.
This might seem mechanical to you, but given e.g. sufficient training and mental resources, this way of doing things can have the desired quality of being more resilient to stress. The long-term memory plays an important part here. The process of trying to analyse and understand a problem can easily be more vulnerable.

Maybe there's time and opportunity for a deeper problem analysis, discussion with the other crewmember and/or people on the ground etc. after the flight crew has attempted (and hopefully succeeded) to contain an immediate threat (if possible/relevant) and things have calmed down.

Also, perhaps the industry has a potential for improvement when it comes to preparing flight crews for dealing with problems outside the scope of existing SOP. As far as I know, this is a known issue.

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Also, perhaps the industry has a potential for improvement when it comes to preparing flight crews for dealing with problems outside the scope of existing SOP. As far as I know, this is a known issue.

Hmm... there is a thought.

Instead of focusing on immediately fixing/compensating for an/the issue, perhaps crews should be taught the first objective is simply to buy yourself time. i.e. put the thing into a position where you know you'll have a relatively slow descent (for example, a nose down angle of 3 degrees and 50-60% N1*).

So what if you lose altitude, squawk it to anyone around and veer out of the lane. You can turn & climb back in later on when the problem is fixed, or ad-hoc'd.

Obviously not applicable for loss of engines, but the problem then is immediately obvious.