AF447 wreckage found
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Even a moving needle on a digital display doesn't get the mental recognition and attention that the real thing gets.
Then the guys actually running cars on the track figured out that good old analog gages were actually better. They found the driver didn't have to actually look at the gages to know all was ok and what the car was doing. The information was received and processed by the subconscious within the normal scan of the instruments because the regular positions of the needles were within the driver’s memory. Not sure that tapes can give the same situational awareness as good old fashioned gages.
I'm sure modern glass cockpits are much better than steam gages, but maybe there are some things like altitude, airspeed and vertical speed that might be better presented by a gage.
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Originally posted by bearfoil ...
Complex is for rules. Simple is for survival. We have known that for thousands of generations, yet we convince ourselves it is 'different' now, we have 'evolved'.
Complex is for rules. Simple is for survival. We have known that for thousands of generations, yet we convince ourselves it is 'different' now, we have 'evolved'.
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Ears, Brains and Seats
Speaking of brains and our human response to various stimuli -- computer aided or not -- what would the "seat of the pants" part of the pilots' brains be experiencing?
In this type of stall, would they feel increased positive G's which would then seem to decrease (or even go negative) as they rapidly descend in the continued stall? I gather the BEA will provide a graph with G forces plotted with a full report of FDR data, but no doubt it could influence the pilot's actions or lack thereof.
In this type of stall, would they feel increased positive G's which would then seem to decrease (or even go negative) as they rapidly descend in the continued stall? I gather the BEA will provide a graph with G forces plotted with a full report of FDR data, but no doubt it could influence the pilot's actions or lack thereof.
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BreezyDC
The following applies to the developed steady state stall:
If they were not accelerating or decelerating and the wings were level, and the nose was 16 degrees in the air, then they would feel like they were in a slight climb attitude, but without that push in the back that says you are accelerating.
When a wing drops in the stall, the wing is still generating some lift which can turn the aircraft, but since the aircraft fuselage is also now being supported somewhat by the uprushing air, there will be much more lateral acceleration (downward) than you customarily experience in a wing down attitude.
When in doubt remember, all forces have to be in balance or the aircraft would be accelerating.
Speaking of brains and our human response to various stimuli -- computer aided or not -- what would the "seat of the pants" part of the pilots' brains be experiencing?
In this type of stall, would they feel increased positive G's which would then seem to decrease (or even go negative) as they rapidly descend in the continued stall? I gather the BEA will provide a graph with G forces plotted with a full report of FDR data, but no doubt it could influence the pilot's actions or lack thereof.
In this type of stall, would they feel increased positive G's which would then seem to decrease (or even go negative) as they rapidly descend in the continued stall? I gather the BEA will provide a graph with G forces plotted with a full report of FDR data, but no doubt it could influence the pilot's actions or lack thereof.
If they were not accelerating or decelerating and the wings were level, and the nose was 16 degrees in the air, then they would feel like they were in a slight climb attitude, but without that push in the back that says you are accelerating.
When a wing drops in the stall, the wing is still generating some lift which can turn the aircraft, but since the aircraft fuselage is also now being supported somewhat by the uprushing air, there will be much more lateral acceleration (downward) than you customarily experience in a wing down attitude.
When in doubt remember, all forces have to be in balance or the aircraft would be accelerating.
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As all you would know, their seat of the pants would be
a) screaming at them when they shouldn't or
b) not screaming at them when they should
c) or ( most probably ) both at once
and most of the resulting spatial inferences in this situation would be incorrect and dangerous
a) screaming at them when they shouldn't or
b) not screaming at them when they should
c) or ( most probably ) both at once
and most of the resulting spatial inferences in this situation would be incorrect and dangerous
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engine-eer
I would like to point out, that "better" has different modes of comparison.
Price? Cost of ownership? Reliability? Ease of maintenance? Intelligibility?
More easily integrated into the instrument panel? More rapidly assimilated?
ETC.
It is all a tradeoff. The issue is how to cover the maximum number of bases, and still give the crew what they need in the worst case they may face.
A mix of old style (steam gage) and new instruments (digital) can best do this.
I'm sure modern glass cockpits are much better than steam gages, but maybe there are some things like altitude, airspeed and vertical speed that might be better presented by a gage.
Price? Cost of ownership? Reliability? Ease of maintenance? Intelligibility?
More easily integrated into the instrument panel? More rapidly assimilated?
ETC.
It is all a tradeoff. The issue is how to cover the maximum number of bases, and still give the crew what they need in the worst case they may face.
A mix of old style (steam gage) and new instruments (digital) can best do this.
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G's
Originally Posted by BreezyDC
In this type of stall, would they feel increased positive G's which would then seem to decrease (or even go negative) as they rapidly descend in the continued stall?
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to Harryman
'Best read the few thousand previous posts on all AF447 threads to catch up a bit first, then maybe post.'
Thankyou for your slightly patronising tone! I have already read all posts. If you think I have said something dumb, please could you explain - I would prefer to be educated than mocked ! thanks, paul
'Best read the few thousand previous posts on all AF447 threads to catch up a bit first, then maybe post.'
Thankyou for your slightly patronising tone! I have already read all posts. If you think I have said something dumb, please could you explain - I would prefer to be educated than mocked ! thanks, paul
HN39, am I reading your graph correctly ? Shortly after 2:10:30 the a/c started to descend (g less than 1.0) at which time the pitch was greater than 10 degrees (and increasing) and the FPA was about 8 degrees and just about to max ?
Presume in a stall vertical acceleartion (g) is less than 1 and FPA will decrease, so are there two stalls, each starting where FPA starts to decrease (and g about 1 and falling ?).
Presume in a stall vertical acceleartion (g) is less than 1 and FPA will decrease, so are there two stalls, each starting where FPA starts to decrease (and g about 1 and falling ?).
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Originally Posted by Mr Optimistic
HN39, am I reading your graph correctly ?
Per BEA the airplane stalls around 2:11:00, after AoA exceeds alphamax and then approx. 9 degrees and continues increasing as shown in the first graph. At 2:10:30 the vertical acceleration reduces to less than 1g. Vertical acceleration above/below 1g is the rate of change of vertical speed, which is 7000 fpm at that point and starts reducing to 700 fpm.
Last edited by Jetdriver; 5th Jun 2011 at 12:59.
...........pilots prefer analogue to digital readouts,...........
I long ago threw away one of those new-fangled Seiko World Time digital watches, one looks at The Picture on a normal watch, don't have to 'read' and assimilate the information.
Mind you, I then went for one of those Glycine jobs where the hour hand goes around only once in 24 hours, so that 12 Noon is at the bottom - that threw me for awhile !
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There is one way to settle this once and for all.
Get Airbus test crews to take up an A330, with the same w & b and put the thing into a deep stall. Ballast could be gleaned from the sales team. The data from the result could be feed into all the A330 Sims and it could benefit all.
They wouldn't need parachutes as the AB is uncrashable I am told as the built in protections and proper pilot's would guard against this..
Get Airbus test crews to take up an A330, with the same w & b and put the thing into a deep stall. Ballast could be gleaned from the sales team. The data from the result could be feed into all the A330 Sims and it could benefit all.
They wouldn't need parachutes as the AB is uncrashable I am told as the built in protections and proper pilot's would guard against this..
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doubleu-anker
Doubleu-anker, I know your are being a bit facetious, but the core of the idea has merit.
Suppose we took a life-limit A330 or a ferryable but badly damaged aircraft, mounted high time engines, installed an ejection seat for the test pilot (singular), installed a ballast control system so you could move the c.g. around quickly, installed high speed telemetry, and went flying.
You could fill all the high risk niches of the A330 performance curves with relatively low human and financial risk. Might even collect enough data in one flight to do the job.
And when you get done you will have one sweaty test pilot who is an expert in flying the A330 at any angle of attack.
There is one way to settle this once and for all.
Get Airbus test crews to take up an A330, with the same w & b and put the thing into a deep stall. Ballast could be gleaned from the sales team. The data from the result could be feed into all the A330 Sims and it could benefit all.
They wouldn't need parachutes as the AB is uncrashable I am told as the built in protections and proper pilot's would guard against this..
Get Airbus test crews to take up an A330, with the same w & b and put the thing into a deep stall. Ballast could be gleaned from the sales team. The data from the result could be feed into all the A330 Sims and it could benefit all.
They wouldn't need parachutes as the AB is uncrashable I am told as the built in protections and proper pilot's would guard against this..
Suppose we took a life-limit A330 or a ferryable but badly damaged aircraft, mounted high time engines, installed an ejection seat for the test pilot (singular), installed a ballast control system so you could move the c.g. around quickly, installed high speed telemetry, and went flying.
You could fill all the high risk niches of the A330 performance curves with relatively low human and financial risk. Might even collect enough data in one flight to do the job.
And when you get done you will have one sweaty test pilot who is an expert in flying the A330 at any angle of attack.
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...as the AB is uncrashable I am told...
This arrogance was payed with blood pretty soon and some airlines made up their mind to improve training and not to reduce it, like the smart AB managers suggested.
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HN39, I looked at the second graph, and see that toward the right side, there are vertical velocities up to 13,000 fpm. I gather that you have integrated the whole postulated flight path so that the end time works out the same as the real deal.
I also interpret all the acceleration figures to be relative to the surface of the earth. Have you worked out the perceived accelerations relative to the aircraft axis? That would give us the seat of the pants feel, or have you already made this transformation?
I also interpret all the acceleration figures to be relative to the surface of the earth. Have you worked out the perceived accelerations relative to the aircraft axis? That would give us the seat of the pants feel, or have you already made this transformation?
Last edited by Machinbird; 5th Jun 2011 at 15:26. Reason: spelling
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Another autotrim kill
MOTOROLA
Thanks for that report. I hadn't seen it before and it is relevant. The crew in the linked report tried to get more performance from the aircraft than they should, but autotrim is what led them down the primrose path.
I wonder if we still had the trim buttons on the stick/wheel whether we would be having this type of accident?
Yes, trim runaways seem to be prevented with properly designed autotrim, but the surreptitious changing of trim without annunciation is clearly hazardous.
At the minimum, the Airbus needs some sort of loud clicker when it changes trim so that the crew is aware of what it is doing.
A whole string of loud clicks would be a warning to see what is going on.
But with the AF447 commotion in the cockpit, would it have been audible?
Over to you, Airbus, for some redesign work.
I wonder if we still had the trim buttons on the stick/wheel whether we would be having this type of accident?
Yes, trim runaways seem to be prevented with properly designed autotrim, but the surreptitious changing of trim without annunciation is clearly hazardous.
At the minimum, the Airbus needs some sort of loud clicker when it changes trim so that the crew is aware of what it is doing.
A whole string of loud clicks would be a warning to see what is going on.
But with the AF447 commotion in the cockpit, would it have been audible?
Over to you, Airbus, for some redesign work.
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Easily distinguished from just about everything else.