AF 447 Thread No. 11
I don't consider this as "nose is abruptly pitched up"
It is, however, entirely consistent with use of the FD as airspeed bleeds off.
I'm unable to see this as "Flight director is now firmly below aeroplane symbol"
From this point as the airspeed decays more rapidly, yes, the nose goes up, up, up...as does, if you notice, the FD pitch steering command
PFD picture at 2:11:39
edit: BTW the PFD picture with the FD well below pitch attitude is from 2:10:27, well before that very critical moment at 2:10:47 when pitching direction is reversed.
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My version (with apologies to the authors of BEA's Final Report, paragraph 2.1.3.3.1):
The flight director displays, the doubt regarding the relevancy of the aural stall warning and the identification of the possibility of an overspeed situation did not allow the PF to make a correct diagnosis. He therefore implemented a combination of antagonistic actions to respond to both an overspeed situation (reduction in thrust, nose-up inputs) and to a stall situation (application of maximum thrust).
Thus, it seems likely that the flight director exerted an influence.
The flight director displays could have prompted him to command a positive pitch angle, of about 15°. This value is the first option in the UAS procedure for the take-off phase below thrust reduction altitude. It is possible that, even though he did not call it out, the PF had recalled this memorised value and then had clung to this reference without remembering that it was intended for a different flight phase. The conjunction of this remembered value and the flight director displays may have constituted one of the few (and maybe even the only) points of consistency in his general incomprehension of the situation.
The flight director displays, the doubt regarding the relevancy of the aural stall warning and the identification of the possibility of an overspeed situation did not allow the PF to make a correct diagnosis. He therefore implemented a combination of antagonistic actions to respond to both an overspeed situation (reduction in thrust, nose-up inputs) and to a stall situation (application of maximum thrust).
Thus, it seems likely that the flight director exerted an influence.
The flight director displays could have prompted him to command a positive pitch angle, of about 15°. This value is the first option in the UAS procedure for the take-off phase below thrust reduction altitude. It is possible that, even though he did not call it out, the PF had recalled this memorised value and then had clung to this reference without remembering that it was intended for a different flight phase. The conjunction of this remembered value and the flight director displays may have constituted one of the few (and maybe even the only) points of consistency in his general incomprehension of the situation.
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Seems that all you need for a career is education
Back to the plot. somebody advocated - just leave the aircraft as it is and it would fly stright and level more or less.
If, due to trim condition changes, for example have we got auto trim when auto pilot is out?
Is the aircraft/would the aircraft maintain S&L when in its little mind it thinks it is Overspeeding - even with the A/P out?
Take one aeroplane - set it up for straight and level and trim - aeroplane flies straight and level.
If the nose should rise or ondeed lower then ther would follow and ensuing climb or descent.
If left alone the aircraft in the descent would increase speed and eventually pitch up due to the increase in Lift it would then climb until the speed dropped off again when the nose would lower causing a descent and increase in speed ad-nauseam until (dependant on Trim setting and other things**) everything had equalled out and the aircraft had naturally stabilized in a descent or a climb or straight and level - but** with shifting CofG due to fuel being used at about 2180kgs per hour (in the case of a 320 in the crz, more for a 330) then a climb or descent would ensue. Perhaps then this would explain the climb up to service ceiling? and the descent down to . . see that chart above.
Last edited by Natstrackalpha; 19th Jun 2013 at 12:22.
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I guess if the FD and all that really cool stuff doesn't work you could just lower the nose so you aren't stalled any more like in a J3Cub, P51, F86, F4, Concorde, B747 and all other aircraft certified to fly.
Attitude, flight path, AoA, displays
Guess we folks from another career field have lost the battle about an AoA indication ( a simple one). Same for a HUD.
Being an aviation dinosaur, I was amazed at the first HUD I saw back in 1971. Easy to use, and really helped to see what the plane was actually doing with respect to the Earth, although we still had the "steam gauges" like attitude indicator, turn needle, altimiter, airspeed indicator, etc. Those were the "primary flight instruments", as the really old dinosaurs insisted on flying with them. In practice, 99% of the pilots used the HUD for almost everything, despite its obvious use with weapon delivery. Sure, we used the steam gauges to correlate with the inertial data on the HUD - the flight path marker ( FPV for the 'bus, I guess). But the HUD had the altitude, speed and vertical velocity ( inertial or baro) and heading displayed. The biggie was the pitch line display. No kidding lines that showed actual angle WRT to the Earth, and not a simple attitude. Put the FPM on the horizon line and you were level. Put it at 2 1/2 degrees down and you had a great approach angle. Put it 1000 feet down the runway and that''s where you were gonna hit unless you flared.
Our AoA was not a separate indicator most of the time. The Navy jets had "indexer" lights beside the gunsight or HUD to provide optimum approach AoA for any gross weight.
Yet I see "professional" pilots here that kiss off a HUD and a simple AoA indication. At the same time, they seem to put up with the main displays that seem very cluttered. Then the chirps and bongs and cavalry charge sounds. Sheesh.
I submit a PR link for a "civilian" HUD. I also think you can look at my leading edge flap failure approach video to see the value of the FPM. And be advised I used power to bring the aircraft vector back up after screwing up, and barely made it to the RWY. AoA bracket was low, and I kept it that way because I still had one pound of roll authority unless I let the AoA increase. Hence I used power to achieve rate of descent and flight path ( rate of climb is proportional to power available minus power required, huh?).
I will guarantee that if the AF447 crew had an inertial-based HUD that the PF would not have continued to pull up to an obscene pitch attitude and allow the speed to decay. The thing would have worked as normal without ANY AIR DATA!!!
Look at a cost-effective HUD that I found for this rant:
HGS-3500 Head-up Guidance System
rant ends...
Being an aviation dinosaur, I was amazed at the first HUD I saw back in 1971. Easy to use, and really helped to see what the plane was actually doing with respect to the Earth, although we still had the "steam gauges" like attitude indicator, turn needle, altimiter, airspeed indicator, etc. Those were the "primary flight instruments", as the really old dinosaurs insisted on flying with them. In practice, 99% of the pilots used the HUD for almost everything, despite its obvious use with weapon delivery. Sure, we used the steam gauges to correlate with the inertial data on the HUD - the flight path marker ( FPV for the 'bus, I guess). But the HUD had the altitude, speed and vertical velocity ( inertial or baro) and heading displayed. The biggie was the pitch line display. No kidding lines that showed actual angle WRT to the Earth, and not a simple attitude. Put the FPM on the horizon line and you were level. Put it at 2 1/2 degrees down and you had a great approach angle. Put it 1000 feet down the runway and that''s where you were gonna hit unless you flared.
Our AoA was not a separate indicator most of the time. The Navy jets had "indexer" lights beside the gunsight or HUD to provide optimum approach AoA for any gross weight.
Yet I see "professional" pilots here that kiss off a HUD and a simple AoA indication. At the same time, they seem to put up with the main displays that seem very cluttered. Then the chirps and bongs and cavalry charge sounds. Sheesh.
I submit a PR link for a "civilian" HUD. I also think you can look at my leading edge flap failure approach video to see the value of the FPM. And be advised I used power to bring the aircraft vector back up after screwing up, and barely made it to the RWY. AoA bracket was low, and I kept it that way because I still had one pound of roll authority unless I let the AoA increase. Hence I used power to achieve rate of descent and flight path ( rate of climb is proportional to power available minus power required, huh?).
I will guarantee that if the AF447 crew had an inertial-based HUD that the PF would not have continued to pull up to an obscene pitch attitude and allow the speed to decay. The thing would have worked as normal without ANY AIR DATA!!!
Look at a cost-effective HUD that I found for this rant:
HGS-3500 Head-up Guidance System
rant ends...
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My version (with apologies to the authors of BEA's Final Report, paragraph 2.1.3.3.1):
The flight director displays, the doubt regarding the relevancy of the aural stall warning and the identification of the possibility of an overspeed situation did not allow the PF to make a correct diagnosis. He therefore implemented a combination of antagonistic actions to respond to both an overspeed situation (reduction in thrust, nose-up inputs) and to a stall situation (application of maximum thrust).
Thus, it seems likely that the flight director exerted an influence.
The flight director displays could have prompted him to command a positive pitch angle, of about 15°. This value is the first option in the UAS procedure for the take-off phase below thrust reduction altitude. It is possible that, even though he did not call it out, the PF had recalled this memorised value and then had clung to this reference without remembering that it was intended for a different flight phase. The conjunction of this remembered value and the flight director displays may have constituted one of the few (and maybe even the only) points of consistency in his general incomprehension of the situation.
The flight director displays, the doubt regarding the relevancy of the aural stall warning and the identification of the possibility of an overspeed situation did not allow the PF to make a correct diagnosis. He therefore implemented a combination of antagonistic actions to respond to both an overspeed situation (reduction in thrust, nose-up inputs) and to a stall situation (application of maximum thrust).
Thus, it seems likely that the flight director exerted an influence.
The flight director displays could have prompted him to command a positive pitch angle, of about 15°. This value is the first option in the UAS procedure for the take-off phase below thrust reduction altitude. It is possible that, even though he did not call it out, the PF had recalled this memorised value and then had clung to this reference without remembering that it was intended for a different flight phase. The conjunction of this remembered value and the flight director displays may have constituted one of the few (and maybe even the only) points of consistency in his general incomprehension of the situation.
HazelNuts39
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Guess we folks from another career field have lost the battle about an AoA indication ( a simple one).
so tying this picky (stripper idea) up with an accelerometer would give you your 3d ATT. In the design it only has to measure Longitudianal, Lateral, and Neutral or Normal Axis and Bob`s yer auntie. Or `change in the aformentioned long, lat, Neut plane(s) Its not difficult - all you need is a computor programmer a mathmetician and a games developer, throw in a pilot or two and job done. Anyone study Ada?
Anyone from Airbus out there PM me and I`ll have a team down there in a week and we can put it together. Notwithstanding the entire thing to be logical and do-able in which case no one will reply.
Last edited by Natstrackalpha; 19th Jun 2013 at 12:31.
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Originally Posted by HN39
No panic?
- On perd le contrôle de l'avion là
- Le problème c'est que j'ai plus de vario là
- J'ai plus aucune indication
- J'ai l'impression qu'on a une vitesse de fou non qu'est-ce que vous en pensez ?
Someone who is panicking would either :
- not say a single word
- or would desperately call his mother
Probably a bit of both.
Completely lost in the first place and then likely creeping up panic preventing them to step back and think about what is really going on, i.e. thinking about the basics. (Pull => cows get smaller, pull more => cows get bigger again)
Completely lost in the first place and then likely creeping up panic preventing them to step back and think about what is really going on, i.e. thinking about the basics. (Pull => cows get smaller, pull more => cows get bigger again)
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I guess if the FD and all that really cool stuff doesn't work you could just lower the nose so you aren't stalled any more like in a J3Cub, P51, F86, F4, Concorde, B747 and all other aircraft certified to fly.
Besides which, sooner or later - someone is going to twig that it had no reliable ATT info and you won`t hear the last of it from me . . .tum ti tum . . . .
What information exactly would this show to the crew?
If you want to play fighter pilots then yea, ok, bring in a HUD - this may even be easier to . . produce than my cartoon type 3D aircraft symbol which acts on all planes/axis. In fact (sorry, am rolling) you could simplify the whole shabuble with a green light on all of the three INS`s:
If L/R/UP/DOWN/Yaw = zero then zero = S&L When S&L (during alignment) a little green light shows on the front of the INS there are five lights 1 up 1 down 1 left and 1 right and 1 in the middle the one in the middle is green. The 1s on the outside (up/dn/left/right) are red - if you get a red light you are not S&L. If you get the green centre one you are.
Last edited by Natstrackalpha; 19th Jun 2013 at 18:35.
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NTA
yeah but what information is your gadget giving them in order to do this?
I guess if the FD and all that really cool stuff doesn't work you could just lower the nose so you aren't stalled any more like in a J3Cub, P51, F86, F4, Concorde, B747 and all other aircraft certified to fly.
Last edited by busTRE; 19th Jun 2013 at 18:24.
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The J3 cub didn't have a battery so no fancy stuff to help but pilots didn't have any problem recovering from a stall. You feel this shaky stall and the stick doesn't do much so you lower it and try to keep is straight. We even had a venturi turn and bank indicator so it was very simple. Now for some people it is very hard with FD's and all the new stuff. Why?
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NTA
The aircraft already has something that displays this info, the FPV. Unfortunately, the information from the giros is subject to drift and is also very eratic in its raw state. For that reason it is damped by baro data, otherwise it would be effectively unuseable. If your ADRs are shot then your baro data is unreliable or erroneous and so the data from the giros becomes unuseable which is why the FPV cannot be used with unreliable baro data (as the crew of 447 had at least at first). Thus, your gadget, whilst a good idea on the face of it would suffer from the same issues and thus be of no use in the situation the were in.
The aircraft already has something that displays this info, the FPV. Unfortunately, the information from the giros is subject to drift and is also very eratic in its raw state. For that reason it is damped by baro data, otherwise it would be effectively unuseable. If your ADRs are shot then your baro data is unreliable or erroneous and so the data from the giros becomes unuseable which is why the FPV cannot be used with unreliable baro data (as the crew of 447 had at least at first). Thus, your gadget, whilst a good idea on the face of it would suffer from the same issues and thus be of no use in the situation the were in.
Oh man. No names, per J.T.'s observation ( but you can quote me by name anytime and my profile on the entries has my real state of residence, etc.)
The HUD's in the military aircraft since 1968 use the inertial system to display the flight path marker/vector and the pitch lines WRT to the Earth. Early ones had some small drift - think one mile in one hour. Short interval data was prolly a thousandth of a degree off from the real world. The A-7 used a doppler system to help keep the inertial very stable, and you could actually takeoff and align the inertial using the doppler in 15 minutes or so. Then we had GPS. With GPS we could align the inertial in a few minutes.
So negative comments about gyros and such for the HUD/main display flight path should look at the record of reliability and accuracy of such systems since the late 60's. The things work without any air data at all!!!! Think AF447, et al, and loss of air data, but a fully operational inertial system that only uses GPS for some positional data now and then, but displays your actual flight path. Would you keep pulling back stick as the troop did in AF447? I don't think so.
There are some here that have used and maybe are currently using a HUD in the commercial flying bidness. The suckers take about 5 seconds to interpret and feel comfortable. For those who have not used one, try it. The bad news is that the company will try to cram all the magenta line crapola on the display when all you really want is some basic nav guidance and your flight path vector to achieve the desired profile.
Sorry if I continue to rant, but I went thru all the advances in avionics and displays since 1971. I never had to see the FMS stuff and the "magenta line" due to my bidness. I never flew a jet that had auto-throttle, or an otto that flew the climb to altitude with all the heading changes and such. I used otto for heading hold and altitude hold and such, especially on long missions while I snacked on a candy bar or ate a box lunch. Think 13 hours in the chair you are in right now reading this.
We have many tech capabilities to help the crews, but we still have to possess basic flying skills and use all the available tools/displays and such of our planes to get where are trying to go. I have a problem with crew coordination, as most of my time was single-seat. So I defer to those here with all the experience.
So that's my input for today.
The HUD's in the military aircraft since 1968 use the inertial system to display the flight path marker/vector and the pitch lines WRT to the Earth. Early ones had some small drift - think one mile in one hour. Short interval data was prolly a thousandth of a degree off from the real world. The A-7 used a doppler system to help keep the inertial very stable, and you could actually takeoff and align the inertial using the doppler in 15 minutes or so. Then we had GPS. With GPS we could align the inertial in a few minutes.
So negative comments about gyros and such for the HUD/main display flight path should look at the record of reliability and accuracy of such systems since the late 60's. The things work without any air data at all!!!! Think AF447, et al, and loss of air data, but a fully operational inertial system that only uses GPS for some positional data now and then, but displays your actual flight path. Would you keep pulling back stick as the troop did in AF447? I don't think so.
There are some here that have used and maybe are currently using a HUD in the commercial flying bidness. The suckers take about 5 seconds to interpret and feel comfortable. For those who have not used one, try it. The bad news is that the company will try to cram all the magenta line crapola on the display when all you really want is some basic nav guidance and your flight path vector to achieve the desired profile.
Sorry if I continue to rant, but I went thru all the advances in avionics and displays since 1971. I never had to see the FMS stuff and the "magenta line" due to my bidness. I never flew a jet that had auto-throttle, or an otto that flew the climb to altitude with all the heading changes and such. I used otto for heading hold and altitude hold and such, especially on long missions while I snacked on a candy bar or ate a box lunch. Think 13 hours in the chair you are in right now reading this.
We have many tech capabilities to help the crews, but we still have to possess basic flying skills and use all the available tools/displays and such of our planes to get where are trying to go. I have a problem with crew coordination, as most of my time was single-seat. So I defer to those here with all the experience.
So that's my input for today.
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There is still a world of difference between unreliable speed info due to CADC causing technological problems with the kit due to icing and
screaming up to service ceiling and back a few times . . .
I don`t agree on the need to address, in training, further depths of the system - although - that would not be a bad thing in itself, per se`
We must re-emphasise - "get it off the system!!" Get flying - get it S&L and/or leave the b
r alone, but get it off the system - then, somebody drives it - PF, while PM figres out WIHIH! Not as the usual `in the loop ECAM procedures - but as a distinct and absolute 1 pilot flying and 1 pilot (+any extra pilots present in the crew) figuring out all the inobvious and surreal stuff that has just popped up and ruined your evening.
That way - the 233 ton airliner will sail merrily on its way - until the technological anomolies of the moment have been identified and sorted out. The PF is quite capable of doing the flying AND the nav - right from basic training.
THAT must be a procedure - THAT must, MUST be an SOP and a big fat SOP too!
This gives future crews two distinct advantages - 1., PM assured that the aeroplane is safely flying is not affected by the . . emergency . . ? . .situation and therefoe has an undistracted mind to deal with this new load of . . . questions. Same pilots has complete artistic freedom fot eh same reason - he is NOT therefoe concerned with urgent self preservation. instincts kicking in.
screaming up to service ceiling and back a few times . . .
I don`t agree on the need to address, in training, further depths of the system - although - that would not be a bad thing in itself, per se`
We must re-emphasise - "get it off the system!!" Get flying - get it S&L and/or leave the b
r alone, but get it off the system - then, somebody drives it - PF, while PM figres out WIHIH! Not as the usual `in the loop ECAM procedures - but as a distinct and absolute 1 pilot flying and 1 pilot (+any extra pilots present in the crew) figuring out all the inobvious and surreal stuff that has just popped up and ruined your evening.That way - the 233 ton airliner will sail merrily on its way - until the technological anomolies of the moment have been identified and sorted out. The PF is quite capable of doing the flying AND the nav - right from basic training.
THAT must be a procedure - THAT must, MUST be an SOP and a big fat SOP too!
This gives future crews two distinct advantages - 1., PM assured that the aeroplane is safely flying is not affected by the . . emergency . . ? . .situation and therefoe has an undistracted mind to deal with this new load of . . . questions. Same pilots has complete artistic freedom fot eh same reason - he is NOT therefoe concerned with urgent self preservation. instincts kicking in.
Last edited by Natstrackalpha; 20th Jun 2013 at 21:42.
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......Very sad ....
EDiT jun 27. :
I was sad after seeing jcjeant banned. I did not knew how to say that. It is difficult to continue discussion when suddenly somebody is missing from his empty armchair and you do not know why, is it due to banning or deleting one's own posts. It starts possible misunderstanding (Natstrackalpha was thinking his post did me sad...). Brainstorming is not perfectly sterilized.
But now welcome back jcjeant !
@gums
As usual your post tells us the good FBW state of art.
EDiT jun 27. :
I was sad after seeing jcjeant banned. I did not knew how to say that. It is difficult to continue discussion when suddenly somebody is missing from his empty armchair and you do not know why, is it due to banning or deleting one's own posts. It starts possible misunderstanding (Natstrackalpha was thinking his post did me sad...). Brainstorming is not perfectly sterilized.
But now welcome back jcjeant !
@gums
As usual your post tells us the good FBW state of art.
Last edited by roulishollandais; 27th Jun 2013 at 11:13.