AF 447 Thread No. 5
pull vs. push
A mixup (PF wants to push and pulls instead) is out of the world.
During my instructing air combat maneuvers in the F4 it never was very difficult to get the students to pull on the stick hard enough, but it was work to prevent him to exceed the allowed g-limit.
On the other hand it was hard work to train the students an effective extension maneuver with close to zero G. At the beginning most just relaxed back stick somewhat and felt unloaded with still 1.5 G on the frame or thaught they had a good unloading maneuver going with 3/4 G.
Same for the duration of the maneuver. Whilst students pulled all the way into the buffet and staying there all day until speed was gone, i never ever had to tell one to terminate his unloading maneuver. Those where most times too short and therefore not effective enough. We taught to unload for 5 seconds, most ended after 2 seconds.
Situation as described above where agrevated by a nose high position, where a hard pull disipated more speed rapidly and the unload had to be way longer until the nose was below the horizon.
It is natural behaviour to pull more and longer than needed and not to push hard and long enough to get a desired unload of the AC, at least in fast flying jets.
How often does an air transport pilot push (not relax) on the SS and feel less than 1 G? And how often in an unplanned situation under stress?
During my instructing air combat maneuvers in the F4 it never was very difficult to get the students to pull on the stick hard enough, but it was work to prevent him to exceed the allowed g-limit.
On the other hand it was hard work to train the students an effective extension maneuver with close to zero G. At the beginning most just relaxed back stick somewhat and felt unloaded with still 1.5 G on the frame or thaught they had a good unloading maneuver going with 3/4 G.
Same for the duration of the maneuver. Whilst students pulled all the way into the buffet and staying there all day until speed was gone, i never ever had to tell one to terminate his unloading maneuver. Those where most times too short and therefore not effective enough. We taught to unload for 5 seconds, most ended after 2 seconds.
Situation as described above where agrevated by a nose high position, where a hard pull disipated more speed rapidly and the unload had to be way longer until the nose was below the horizon.
It is natural behaviour to pull more and longer than needed and not to push hard and long enough to get a desired unload of the AC, at least in fast flying jets.
How often does an air transport pilot push (not relax) on the SS and feel less than 1 G? And how often in an unplanned situation under stress?
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Hi franzl,
Thanks. Very interesting comments regarding pilot sensed g's.
- Never in the simulator, where he did his approach to the stall training.
In the simulator, apart from mild turbulence, there is no sensation of vertical acceleration (motion legs only have about 3 m of travel). I have witnessed over controlling during TCAS events due to the lack of the sensation of delta g. The "sinking feeling" on entry to the stall would be something the pilot had never experienced on type or in the sim.
Thanks. Very interesting comments regarding pilot sensed g's.
How often does an air transport pilot push (not relax) on the SS and feel less than 1 G?
In the simulator, apart from mild turbulence, there is no sensation of vertical acceleration (motion legs only have about 3 m of travel). I have witnessed over controlling during TCAS events due to the lack of the sensation of delta g. The "sinking feeling" on entry to the stall would be something the pilot had never experienced on type or in the sim.
Last edited by rudderrudderrat; 27th Jul 2011 at 11:54. Reason: entry to stall (thanks to Mr. Optimistic)
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Push the trackpoint, pull the joystick...
Hi JD-EE
I was fortunate to spend a year working in a college near Buffalo, NY. One of the professors there was a proficient touch-typist in both QWERTY (his laptop PC) and DVORAK (his desktop PC). All he had to do was to hit an 'alt+key' sequence to switch between the two modes and start typing. Hence, I don't think a pilot is going to confuse his side stick with his track point. That said, however, I am concerned about the switch from the LHS seat to the RHS seat. What amount of 'hand flying' experience are the pilots given in each seat?
I was fortunate to spend a year working in a college near Buffalo, NY. One of the professors there was a proficient touch-typist in both QWERTY (his laptop PC) and DVORAK (his desktop PC). All he had to do was to hit an 'alt+key' sequence to switch between the two modes and start typing. Hence, I don't think a pilot is going to confuse his side stick with his track point. That said, however, I am concerned about the switch from the LHS seat to the RHS seat. What amount of 'hand flying' experience are the pilots given in each seat?
Sensed motion. Presumably the initial falling sensation could have been misinterpreted as turbulence, after that once at terminal velocity they would sense near enough 1 g wouldn't they ?
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JD-EE
This is nothing to do with circling (thermalling) in a steady moving air mass (which was the question).
It seems to approximate a description of dynamic soaring through an altitude range with a wind gradient i.e. the flight of the Albatross (which wasn't the question)
=== Retired F4 ===
A useful observation (about low to zero 'g' sensations) I think. I also think there is no chance the pilot got his 'ups & downs' & 'push & pulls' wrong - if he did there is one massive question to be raised over the whole airline industry for years to come
This is exactly the situation with weight control Vs aerod control (bar Vs stick) aircraft.. one pushes, the other pulls for the same effect.
I found when teaching some stick-centric pilots would get it wrong... whereas I never could imagine a situaton, in an aircraft or on a computer sim of getting it wrong, despite flying h/gs and powered h/gs lot, despite initially flying with a stick (from age 16) how could one not make that switch immeditaely and correctly... ? Proviso, as long as one kept a picture in your minds eye.. so are we saying there may be people flying by rote, like learning things parrot fashion instead of understanding the basics and working up from there, the exam tick box generation OMG
No, that has to be ruled out, PF meant NU, UP, CLB, SLOWER or he had already given up focusing on the task of speed & pitch stabilisation by then.
As RetiredF4 suggests between the lines, unless you have been in a stall and been taken through the ND inputs, wait for pitch and speed to come back, steady (constant 'g' if poss) recovery and pullout etc THEN I suppose, how would you know what was required, or indeed, how long it might take..
IMHO - It is unonscionable that pilots have not acquired high manual handling skills in conventionally controlled aircraft before being accepted for Commercial Flying of almost any nature.
Fiddling with the stick for a few seconds to see what happens with the stall warning, if that is what we think may have happened, is the sign of trainee, not an experienced airline pilot
I am not suggesting PF nor PNF had or hadn't those skills
The same way a tacking sailboat can go faster than the wind. If you hit the wind at the right angle with an airfoil you can acquire energy from the wind. Of course, the sailboat has its keel to make this effect more pronounced. That allows its crumby airfoil called a sail to work. The sailplane has only its mass to provide the effect.
It seems to approximate a description of dynamic soaring through an altitude range with a wind gradient i.e. the flight of the Albatross (which wasn't the question)
=== Retired F4 ===
A useful observation (about low to zero 'g' sensations) I think. I also think there is no chance the pilot got his 'ups & downs' & 'push & pulls' wrong - if he did there is one massive question to be raised over the whole airline industry for years to come
This is exactly the situation with weight control Vs aerod control (bar Vs stick) aircraft.. one pushes, the other pulls for the same effect.
I found when teaching some stick-centric pilots would get it wrong... whereas I never could imagine a situaton, in an aircraft or on a computer sim of getting it wrong, despite flying h/gs and powered h/gs lot, despite initially flying with a stick (from age 16) how could one not make that switch immeditaely and correctly... ? Proviso, as long as one kept a picture in your minds eye.. so are we saying there may be people flying by rote, like learning things parrot fashion instead of understanding the basics and working up from there, the exam tick box generation OMG
No, that has to be ruled out, PF meant NU, UP, CLB, SLOWER or he had already given up focusing on the task of speed & pitch stabilisation by then.
As RetiredF4 suggests between the lines, unless you have been in a stall and been taken through the ND inputs, wait for pitch and speed to come back, steady (constant 'g' if poss) recovery and pullout etc THEN I suppose, how would you know what was required, or indeed, how long it might take..
IMHO - It is unonscionable that pilots have not acquired high manual handling skills in conventionally controlled aircraft before being accepted for Commercial Flying of almost any nature.
Fiddling with the stick for a few seconds to see what happens with the stall warning, if that is what we think may have happened, is the sign of trainee, not an experienced airline pilot
I am not suggesting PF nor PNF had or hadn't those skills
Last edited by HarryMann; 27th Jul 2011 at 13:33. Reason: Typos, typis, tapas
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Hand flying
andianjul
From the responses that I have had, so far, " not if I can avoid it."
Some earlier generation training aircraft had the throttle in the left and stick in the right hand - others had their hands and controls the opposite way round. I do not recall that it was a problem. Some of the transport aircraft had nose wheel steering from the Left seat, others had auto-pilot controls out-board of the Left seat. Whichever pilot whose " leg" this was, would sit in the left seat. Until, in the UK in the mid sixties, we became "seat-rated". Training Captains and few Senior F/Os, who could act as Second Captains were allowed to sit in either seat, checked on alternate Base Checks. Flying with a very Senior Captain ( non Training) who was operating from the Right hand seat, I asked him if he was Right hand seat qualified. I knew that he was not.
He told me to B#### - Off. ( Should I take offence, NOW ?)
Having had to do my hour at a time hand flying, because the A/P seldom worked on some of the aircraft that I flew in the fifties, I still tended to hand fly to F/L10.0 when not too busy. Approaches were all manual, except for just two in very clear conditions - the aircraft only had a single channel. ( A " Practice Emergency G.C.A.", down to touch-down, whenever practicable would be good for all of us.)
From the responses that I have had, so far, " not if I can avoid it."
Some earlier generation training aircraft had the throttle in the left and stick in the right hand - others had their hands and controls the opposite way round. I do not recall that it was a problem. Some of the transport aircraft had nose wheel steering from the Left seat, others had auto-pilot controls out-board of the Left seat. Whichever pilot whose " leg" this was, would sit in the left seat. Until, in the UK in the mid sixties, we became "seat-rated". Training Captains and few Senior F/Os, who could act as Second Captains were allowed to sit in either seat, checked on alternate Base Checks. Flying with a very Senior Captain ( non Training) who was operating from the Right hand seat, I asked him if he was Right hand seat qualified. I knew that he was not.
He told me to B#### - Off. ( Should I take offence, NOW ?)
Having had to do my hour at a time hand flying, because the A/P seldom worked on some of the aircraft that I flew in the fifties, I still tended to hand fly to F/L10.0 when not too busy. Approaches were all manual, except for just two in very clear conditions - the aircraft only had a single channel. ( A " Practice Emergency G.C.A.", down to touch-down, whenever practicable would be good for all of us.)
JD-EE;
The sidestick position symbol is only displayed on the PFD during takeoff.
I know about the small "stick" in the middle of a laptop keyboard - I think the HP has the same arrangement.
I think there is no connection between the way another control device might work and either the yoke or a sidestick in terms of muscular or cognitive habit which would confuse or alter a psychomotor response, even under stress.
If anything, the response would more likely be exaggerated, but in the correct direction. In fact I have always thought that that's where the initial two stall warnings came from right after the AP disconnect...a strong, quick pull on the stick, followed by a relaxation, (unloading, to use Retired F4's term). The continued aft stick after the stall entry is another matter I think. One considers the Airborne Express DC8 accident when thinking about this. (That said, we will never know why the Colgan captain pulled instead of pushed the stick; the explanation has usually been the notion that on that particular design, the T-tail can stall in icing, (several (NASA?) videos were referenced) and the unloading of the tail (stalled tail) would pitch the nose down. The response was to pull back, (not sure why, if the tail was "stalled" but there it was)).
I've flown in both seats while teaching and there is a difference when switching sides if one doesn't do it often. We've had the discussion about who was sitting where and why, (who replaces captain, licensing issues, First BEA Report, etc).
While possible, I don't think that played a decisive (primary) role here. But because sitting in one's familiar physical place does have a psychological and even physiological effect, (IOW, it does make a difference), I think the question of who was sitting where is still important for secondary, cognitive reasons. When one is not in one's normal seat, one needs to intellectualize responses somewhat, (think about the hand's position when reaching for a switch on the overhead panel, etc etc), rather than operating out of pure habit.
The poster who worked the mouse and typed with opposite hands makes an interesting point. There may be some minor similarities between this example and cockpit psychomotor skill but I think that that example doesn't fully translate in terms of analyzing or fully explaining cockpit behaviours. It doesn't take into account thorough training and the establishing of behaviour through long and frequent repetition both of which greatly reduce the effects of high stress and not being in one's familiar place.
That isn't meant to dismiss the effect; there is the need to examine it. My view has always been, the loss of airspeed information wasn't itself an emergency but it quickly turned into one due to the pitch up and we need to know why that happened. Large physiological responses are natural when under stress; is that what happened here? Perhaps the next BEA Report will address this, if so.
Part of the reason training is so thorough and realistic (up to a point, as sims can't reproduce 'g' or aircraft behaviour in unusual attitudes), is to reduce the effect of the sympathetic nervous system "fight or flight" response and provide ways built through habit, of controlling the stress response.
It is known that the stress response has a natural "pace" or curve where heightened senses and acute physiological responses quickly diminish under high, continuous stress. IIRC, the report on the Alaska Airlines MD80 stabilizer jackscrew accident off the California coast near LAX mentioned this. Whether this is a factor here would be something for the final report to comment upon.
To your question, I think an instinctual response which "confused" push and pull is not likely, given the complete/total absence of such a control movement/requirement in all aircraft. In other words, there are no QWERTY and DVORAK aircraft!
kind regards.
The sidestick position symbol is only displayed on the PFD during takeoff.
I know about the small "stick" in the middle of a laptop keyboard - I think the HP has the same arrangement.
I think there is no connection between the way another control device might work and either the yoke or a sidestick in terms of muscular or cognitive habit which would confuse or alter a psychomotor response, even under stress.
If anything, the response would more likely be exaggerated, but in the correct direction. In fact I have always thought that that's where the initial two stall warnings came from right after the AP disconnect...a strong, quick pull on the stick, followed by a relaxation, (unloading, to use Retired F4's term). The continued aft stick after the stall entry is another matter I think. One considers the Airborne Express DC8 accident when thinking about this. (That said, we will never know why the Colgan captain pulled instead of pushed the stick; the explanation has usually been the notion that on that particular design, the T-tail can stall in icing, (several (NASA?) videos were referenced) and the unloading of the tail (stalled tail) would pitch the nose down. The response was to pull back, (not sure why, if the tail was "stalled" but there it was)).
I've flown in both seats while teaching and there is a difference when switching sides if one doesn't do it often. We've had the discussion about who was sitting where and why, (who replaces captain, licensing issues, First BEA Report, etc).
While possible, I don't think that played a decisive (primary) role here. But because sitting in one's familiar physical place does have a psychological and even physiological effect, (IOW, it does make a difference), I think the question of who was sitting where is still important for secondary, cognitive reasons. When one is not in one's normal seat, one needs to intellectualize responses somewhat, (think about the hand's position when reaching for a switch on the overhead panel, etc etc), rather than operating out of pure habit.
The poster who worked the mouse and typed with opposite hands makes an interesting point. There may be some minor similarities between this example and cockpit psychomotor skill but I think that that example doesn't fully translate in terms of analyzing or fully explaining cockpit behaviours. It doesn't take into account thorough training and the establishing of behaviour through long and frequent repetition both of which greatly reduce the effects of high stress and not being in one's familiar place.
That isn't meant to dismiss the effect; there is the need to examine it. My view has always been, the loss of airspeed information wasn't itself an emergency but it quickly turned into one due to the pitch up and we need to know why that happened. Large physiological responses are natural when under stress; is that what happened here? Perhaps the next BEA Report will address this, if so.
Part of the reason training is so thorough and realistic (up to a point, as sims can't reproduce 'g' or aircraft behaviour in unusual attitudes), is to reduce the effect of the sympathetic nervous system "fight or flight" response and provide ways built through habit, of controlling the stress response.
It is known that the stress response has a natural "pace" or curve where heightened senses and acute physiological responses quickly diminish under high, continuous stress. IIRC, the report on the Alaska Airlines MD80 stabilizer jackscrew accident off the California coast near LAX mentioned this. Whether this is a factor here would be something for the final report to comment upon.
To your question, I think an instinctual response which "confused" push and pull is not likely, given the complete/total absence of such a control movement/requirement in all aircraft. In other words, there are no QWERTY and DVORAK aircraft!
kind regards.
grity, about that right hand left hand thing you mentioned ...
Ten years ago, I was made aware of the risks of carpal tunnel syndrome.
I use computers a lot.
I am right handed.
I chose to begin to use my mouse left handed. (Still do)
It took very little time to adapt to left hand.
I had decided to play a favorite computer game (about eleven years ago) that I used to play right handed, left handed. It was very mouse intensive. (For those interested, it was a dungeon crawl called Diablo, not a flight sim) I found that while I initially was a bit clumsy, it wasn't long before I was able to run the little computer animation around the screen and activate mouse button commands with little problem.
Due to the set up of power and stick on most planes I flew, I was never able to try and teach my left hand how to fly that way. I did however, get to be good at gently flying with my left hand while writing things down on my knee board (right handed) very early in my flying career.
Put another way, with enough practice, left handed flying seems to be a teachable skill ... but you need to practice it. How much time does one get to do that? I've yet to see any of the SS pilots complain about having to fly left handed on the stick. Is this really a problem? (I taught a number of left handed people how to fly, in the RH stick LH power set up, and they seemed to do just fine). I doubt very much that PNF not taking the controls sooner had anything to do with "I don't fly very well with my left hand" concerns.
PS: I broke my right hand in 2004, punching something (no, not someone). I still had to go to work and type reports. So, I did, with just my left hand, for a few weeks. It didn't take that long to adapt, but it was slower.
Conlcusion? Adaptability seems to me the rule, not the exception.
PS#2: JD-EE.
Helicopter pilots who initially flew the V-22 reported some non-intuitive monkey skill issues with the flight controls of that aircraft. Had a long talk on that score some years ago with a test pilot who had flown with me in another squadron. Bottom line, took a bit of getting used to, but adaptation wasn't major. You can probably do a search for the V-22's teething problems, and maybe using "ergonimics" or "flight control differences" search terms to find some of the articles written about this a couple of decades ago. Might answer your question.
The test pilots at Patuxent River and the Marines in New River did revise twice, at least, the proposed training pipeline mix of rotary wing and fixed wing (from initial training) for their prospective Osprey pilots. The multi-engine training balance was increased on one of those reviews, as they felt the helicopter bit was over emphasized.
I am not sure what they have done since, been some years since I was (tangentially) involved with such programs.
Also worth noting:
The initial flying in a helicopter, if one began in fixed wing, could be confusing since power forward, push with left hand, in a plane is the same as power reduction, push with left hand, in a helicopter.
Howerver, you usually translate into helicopters in a VFR training environment where pull is up and push is down with the left hand. That, and being taught a collective isn't a throttle, doesn't take long to adapt to.
By the time you are in flight above translational lift, or in instrument flight regimes, you have already learned what the push or pull does, and the confusion does not arise. If it had ever been present,,and remained, the instructor would probably suggest you go back to flying fixed wing.
Ten years ago, I was made aware of the risks of carpal tunnel syndrome.
I use computers a lot.
I am right handed.
I chose to begin to use my mouse left handed. (Still do)
It took very little time to adapt to left hand.
I had decided to play a favorite computer game (about eleven years ago) that I used to play right handed, left handed. It was very mouse intensive. (For those interested, it was a dungeon crawl called Diablo, not a flight sim) I found that while I initially was a bit clumsy, it wasn't long before I was able to run the little computer animation around the screen and activate mouse button commands with little problem.
Due to the set up of power and stick on most planes I flew, I was never able to try and teach my left hand how to fly that way. I did however, get to be good at gently flying with my left hand while writing things down on my knee board (right handed) very early in my flying career.
Put another way, with enough practice, left handed flying seems to be a teachable skill ... but you need to practice it. How much time does one get to do that? I've yet to see any of the SS pilots complain about having to fly left handed on the stick. Is this really a problem? (I taught a number of left handed people how to fly, in the RH stick LH power set up, and they seemed to do just fine). I doubt very much that PNF not taking the controls sooner had anything to do with "I don't fly very well with my left hand" concerns.
PS: I broke my right hand in 2004, punching something (no, not someone). I still had to go to work and type reports. So, I did, with just my left hand, for a few weeks. It didn't take that long to adapt, but it was slower.
Conlcusion? Adaptability seems to me the rule, not the exception.
PS#2: JD-EE.
Helicopter pilots who initially flew the V-22 reported some non-intuitive monkey skill issues with the flight controls of that aircraft. Had a long talk on that score some years ago with a test pilot who had flown with me in another squadron. Bottom line, took a bit of getting used to, but adaptation wasn't major. You can probably do a search for the V-22's teething problems, and maybe using "ergonimics" or "flight control differences" search terms to find some of the articles written about this a couple of decades ago. Might answer your question.
The test pilots at Patuxent River and the Marines in New River did revise twice, at least, the proposed training pipeline mix of rotary wing and fixed wing (from initial training) for their prospective Osprey pilots. The multi-engine training balance was increased on one of those reviews, as they felt the helicopter bit was over emphasized.
I am not sure what they have done since, been some years since I was (tangentially) involved with such programs.
Also worth noting:
The initial flying in a helicopter, if one began in fixed wing, could be confusing since power forward, push with left hand, in a plane is the same as power reduction, push with left hand, in a helicopter.
Howerver, you usually translate into helicopters in a VFR training environment where pull is up and push is down with the left hand. That, and being taught a collective isn't a throttle, doesn't take long to adapt to.
By the time you are in flight above translational lift, or in instrument flight regimes, you have already learned what the push or pull does, and the confusion does not arise. If it had ever been present,,and remained, the instructor would probably suggest you go back to flying fixed wing.
Last edited by Lonewolf_50; 27th Jul 2011 at 15:05.
stick and momentum
- We never had a left-handed side stick.
- We never had problems with lefties using a stick mounted just above and to the right of one's right knee
Many of us were worried about our newbies ( Ell Tees right outta pilot training) forgetting how to fly a "real" plane. It didn't happen, and many went to other jets and commercial airliners. The Reserve unit I helped check out had many commercial airline pilots, and they flew the Viper and a host of heavies every week. We always thot the Viper would be the easiest plane for someone to hijack, as the average pinball wizard could simply "point" the thing. I have a feeling that the 'bus is harder to fly than the Viper due to momentum.....
I know my assertion of duplicating the stall entry is brash. However, JD and others have done energy calculations and such that seem to support my assertion of entering a stall before the confusers can react. Unlike the Viper, the 'bus appears to command less than one gee according to pitch. e.g. 30 degree nose up would be a 0.87 gee command ( also commands more than one gee if in a bank). Our little jet used a pilot-commanded gee. So Retired's example of unloading is a good one. Several of our pilots would trim for zero gee before entering a fight. Letting go of the stick resulted in a 'perfect' zero gee "extension" to gain energy. Conversely, at extreme pitch attitudes and a one gee trim, the jet would slowly raise the nose to achieve one gee.
The point of "feeling" the reduced gee may play a role here with the pilot back stick input. All the pilots here KNOW, they KNOW that you cannot trust your senses in IFR or even a dark night. So the old saw about pitch and power procedure has legs.
Lastly, most of us with lottsa hours have prolly had a static or pitot failure due to freezing. Easy to recognize and to apply the "power/pitch" law. Some of the new jets don't have pneumatic tubing directly connected to the displays or "meters" - the displays are electronic so the raw air data is converted to electrons along the way. So is it an electronics problem or a real lack of pressure in the tubing? Worse, the confusers use the electronic signals in any FBW system. Our system had separate pneumatic sensor systems - one for the FBW system and the other for navigation and weapon delivery purposes. Our basic airspeed indicator was a steam gauge!!! The HUD and other displays were electronic conversions.
- We never had problems with lefties using a stick mounted just above and to the right of one's right knee
Many of us were worried about our newbies ( Ell Tees right outta pilot training) forgetting how to fly a "real" plane. It didn't happen, and many went to other jets and commercial airliners. The Reserve unit I helped check out had many commercial airline pilots, and they flew the Viper and a host of heavies every week. We always thot the Viper would be the easiest plane for someone to hijack, as the average pinball wizard could simply "point" the thing. I have a feeling that the 'bus is harder to fly than the Viper due to momentum.....
I know my assertion of duplicating the stall entry is brash. However, JD and others have done energy calculations and such that seem to support my assertion of entering a stall before the confusers can react. Unlike the Viper, the 'bus appears to command less than one gee according to pitch. e.g. 30 degree nose up would be a 0.87 gee command ( also commands more than one gee if in a bank). Our little jet used a pilot-commanded gee. So Retired's example of unloading is a good one. Several of our pilots would trim for zero gee before entering a fight. Letting go of the stick resulted in a 'perfect' zero gee "extension" to gain energy. Conversely, at extreme pitch attitudes and a one gee trim, the jet would slowly raise the nose to achieve one gee.
The point of "feeling" the reduced gee may play a role here with the pilot back stick input. All the pilots here KNOW, they KNOW that you cannot trust your senses in IFR or even a dark night. So the old saw about pitch and power procedure has legs.
Lastly, most of us with lottsa hours have prolly had a static or pitot failure due to freezing. Easy to recognize and to apply the "power/pitch" law. Some of the new jets don't have pneumatic tubing directly connected to the displays or "meters" - the displays are electronic so the raw air data is converted to electrons along the way. So is it an electronics problem or a real lack of pressure in the tubing? Worse, the confusers use the electronic signals in any FBW system. Our system had separate pneumatic sensor systems - one for the FBW system and the other for navigation and weapon delivery purposes. Our basic airspeed indicator was a steam gauge!!! The HUD and other displays were electronic conversions.
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Hi,
Can the pilot think he was in a inverted flight ?
A useful observation (about low to zero 'g' sensations) I think. I also think there is no chance the pilot got his 'ups & downs' & 'push & pulls' wrong - if he did there is one massive question to be raised over the whole airline industry for years to come
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I haven't been impressed by your earlier posts, but this one takes the biscuit.....
Quite apart from the fact that everything indicates so far that the attitude displays were functional.
"Weird and wonderful" remarks such as yours only "pollute" the discussions.
PS.... in (roughly) -1g inverted flight, he could have been blinded by the sandwich crumbs, dried Brazilian mud, a few pencils and pens, and other extraneous matter, all "rising" from the cockpit floor.
Nice theory, but no sigar.....
Quite apart from the fact that everything indicates so far that the attitude displays were functional.
"Weird and wonderful" remarks such as yours only "pollute" the discussions.
PS.... in (roughly) -1g inverted flight, he could have been blinded by the sandwich crumbs, dried Brazilian mud, a few pencils and pens, and other extraneous matter, all "rising" from the cockpit floor.
Nice theory, but no sigar.....
Not to mention the coffee splashing about, and perhaps even some old cigar butts that had been stashed in some corners ...
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Originally Posted by A33Zab
ADR Single and ADR Dual faults are detected by ADR itself.
A Triple ADR Failure message (ADR 1+2+3 FAULT) only exist if the BUSS option is installed, this is a level 3 (Red & Master Warning).
This Triple ADR monitoring was NOT installed on the A/C.
A local ADR fault without ECAM message doesn't seem logical to ECAM protocol.
A Triple ADR Failure message (ADR 1+2+3 FAULT) only exist if the BUSS option is installed, this is a level 3 (Red & Master Warning).
This Triple ADR monitoring was NOT installed on the A/C.
A local ADR fault without ECAM message doesn't seem logical to ECAM protocol.
2) My concern about ADR self-monitoring is to explain why ADR DISAGREE wasn't triggered following the PROBE-PITOT fault even if the three CAS were rejected by those monitoring functions. My explanation is that it was a "triple ADR fault"; hence, it was not detected at internal level. No "outlier" ADR could be rejected, being all erroneous while passing (or failing) the comparative test two-by-two.
This test condition required to reject the first ADR (CAS) is: 16 kt difference during 10 seconds.
It means that ADR 1+2 / ADR 1+3 / ADR 2+3 all passed or failed this test when CAS dropped. Hence, ADR2 was also affected like the two other recored CAS from ADR1 and ADR3; all 3 speeds went down from coherent and valid values to erroneous values:
- passing succesfully the test, hence staying consistent (c)
- failing the test, hence being inconsistent (d).
Example (CAS_1, CAS_2, CAS_3); T_1 = T_0 + 10 seconds:
.... T_0 -> (274, 275, 275) => all valid and coherent values
a).. T_1 -> (61, 275, 275) => ADR_1 ("bad") would be rejected due to ADR 1+2 and ADR 1+3 test.
b).. T_1 -> (61, 275, 77) => ADR_2 ("good") would be rejected due to ADR 1+2 and ADR 2+3 test.
c).. T_1 -> (61, 70, 77) => all values consistents (no fault) but 3 ADR erroneous.
d).. T_1 -> (61, 99, 150) => all values inconsistents (triple fault) and 3 ADR erroneous.
In case of (d), ECAM messages (FLR) are compiled into Current Flight Report (CFR) sent by ACARS when they are linked to the same fault (having the same ATA). The priority would simply be PROBE-PITOT fault over ADR fault during the correlation window.
In this case, ADR 1+2+3, being not displayed (no BUSS), it would nonetheless trigger three ECAMs:
- ADR 1+2
- ADR 1+3
- ADR 2+3
3) FCOM:
"If one ADR is correct but the other two ADRs provide the same erroneous output
or if all three ADRs provide consistent and erroneous data:
The systems will reject the “good” ADR and will continue to operate using the two “bad” ADRs."
Like I said before about this quote, something is obviously missing here:
The system could only reject the "good" ADR in the first case (one is "good", two "bad").
In the second case, the system will continue to operate using the three "bad" ADRs. This should have been added to this sentence. The consequences are the same in both case (erroneous output could be used), but the logic would be restablished.
It should be our case to be considered excepted that CAS was rejected by external monitoring functions => CAS monitoring (EFCS) and ADR monitoring (AFS).
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A mixup (PF wants to push and pulls instead) is out of the world.
...
Situation.... agrevated by a nose high position,....
It is natural behaviour to pull more and longer than needed and not to push hard and long enough to get a desired unload of the AC, at least in fast flying jets.
How often does an air transport pilot push (not relax) on the SS and feel less than 1 G? And how often in an unplanned situation under stress?
...
Situation.... agrevated by a nose high position,....
It is natural behaviour to pull more and longer than needed and not to push hard and long enough to get a desired unload of the AC, at least in fast flying jets.
How often does an air transport pilot push (not relax) on the SS and feel less than 1 G? And how often in an unplanned situation under stress?
The way human (and animal) mechanical and control mechanisms work is that the control is conditioned by feedback coming from the object of the action, from the motion, and the result of the motion.
A simple experiment/example is the opening of an umbrella. If there is no wind, I can open the umbrella with a quick, short action. In wind, I need a stronger, and prolonged opening action, until I defeat the wind's reaction, and see the umbrella opened.
A similar behavior is shown by an experiment with a dog, or cat,, for instance an attempt to pull a toy from my hand. There will be a stronger, and prolonged action of the dog, or cat, if I don't release the toy immediately.
It's clearly a reflex built deeply in our motion control systems.
Back to the A/C, the A/C was in turbulent air, and thus the A/C's response to a certain control, could be delayed by the countering effect of the random direction and force of the turbulent air motion.
Additionally, it was instrument based flying, and the perception of the A/C response was through the instruments. Was that as fast as normal visual perception reflex?
If the PF's first action on the stick encountered such a delayed perception of the A/C response, the natural reflex - referred above - is that the action will be stronger, and prolonged, until the A/C is responding to the stick action.
An additional element, which could amplify the effect of the reflex is how the duration of the action on the stick is translated into the actuating of the control surface action.
Is the excursion/amplitude of the actuating of a control surface proportional to the duration of a certain stick action?
If that's the case, it's clear, that the longer duration, is equivalent to a stronger action on the stick, which adds to the already stronger stick action driven by the reflex.
Deprogramming the reflex mentioned above, and reprogramming the pilot's hand control reflex mechanisms when is at the A/C controls only, requires training, and practice, which may be different from one individual to another.... How stress worked in blurring the new reflex, with the old/natural reflex?
An additional perception factor was the angle of the ice crystals - likely present - hitting the windshield. Where they in an angle giving the perception that the A/C is nose down?
I hope that a transcript of the full cockpit sound recordings will be made available with the next BEA report, along with data from data recordings.
Last edited by airtren; 27th Jul 2011 at 17:21.
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We'll never know what they thought. Question is could the aircraft, through failure or some human interface factor in design, have convinced them they were inverted.
Very unlikely. As someone kindly pointed out to me a while back when I conjectured that they lost attitude: in the roll axis, control was maintained (albeit with some large excursions possibly due to stall). Without attitude indication at night / in IMC, I don't think they would have have kept wings anywhere near level.
Very unlikely. As someone kindly pointed out to me a while back when I conjectured that they lost attitude: in the roll axis, control was maintained (albeit with some large excursions possibly due to stall). Without attitude indication at night / in IMC, I don't think they would have have kept wings anywhere near level.
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flightglobal
Just found that attached (link) report on "FlighGlobal" in "Safety" and "Recent Accidents" on the page that opens it says on the right column - "Last AF447 News from the web"
An Airbus Captain’s Take on the Air France Disaster | Autopia | Wired.com
I think rather interesting to have a statement like this.
Looking foreward to Friday
An Airbus Captain’s Take on the Air France Disaster | Autopia | Wired.com
I think rather interesting to have a statement like this.
Looking foreward to Friday
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Hi Annex14,
Until today, there was not a single press article quoting a "real" A330 captain (one being not an anonymous). This one (article) is no exception as I can't believe that a real captain would really know so few about his aircraft.
Hence, interest is very limited.
Originally Posted by Annex14
I think rather interesting to have a statement like this.
Hence, interest is very limited.
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limited interest
takata
correct what you say and I too agree that if someone has to say anything about that accident before the facts become public, he/ she should stand it by name !
Seen al the mess that was published in the past by the media I understand the reluctance to any report that even looks like that "Quality Journalism"
Nevertheless I thought it worth to mention and show the link, but also that - hopefully - the puzzle is layed to a picture on Friday.
correct what you say and I too agree that if someone has to say anything about that accident before the facts become public, he/ she should stand it by name !
Seen al the mess that was published in the past by the media I understand the reluctance to any report that even looks like that "Quality Journalism"
Nevertheless I thought it worth to mention and show the link, but also that - hopefully - the puzzle is layed to a picture on Friday.
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jcjeant
No. There was no inverted flight. Nor backwards flight, nor spin.
A different look at the descent?
"Mainly Nose UP". Did they know they were Stalled? They did.
Then why the "Mainly Nose UP"? Especially with that rod? 10,000fpm?
The nose never fell below 30degrees NU? YES. BEA say so, and I believe it.
Wait. "Mainly Nose UP" means there were other inputs to the Stick?
Yes, of course. Mainly Nose DOWN. But the Nose? Yes, unable to drop below 30 degrees; less Pitch was UNAVAILABLE.
PITCH was at its lowest with stick back, or stick forward? Stick back.
Every pilot will push the stick to get the Nose down, and if 30 degrees had been the 'lowest' result of stick forward, PF would maintain ND input. Instead, it looks like Stick back was the default (preferred) position. What did the a/c do with ND? Probably go NU? Buffet like she was coming apart? Increase descent?
Guess? Something BAD.
Some possibilities show these guys did everything by the Book. Even the procedure at the STALL Warning. Both of them.
Alarming to me that when presented with a possibility that mitigates the 'PE', or is critical of the 'platform', the popular drift tends to migrate toward the PE.
I predict that with new data, these pilots will be seen in a new light.
No. There was no inverted flight. Nor backwards flight, nor spin.
A different look at the descent?
"Mainly Nose UP". Did they know they were Stalled? They did.
Then why the "Mainly Nose UP"? Especially with that rod? 10,000fpm?
The nose never fell below 30degrees NU? YES. BEA say so, and I believe it.
Wait. "Mainly Nose UP" means there were other inputs to the Stick?
Yes, of course. Mainly Nose DOWN. But the Nose? Yes, unable to drop below 30 degrees; less Pitch was UNAVAILABLE.
PITCH was at its lowest with stick back, or stick forward? Stick back.
Every pilot will push the stick to get the Nose down, and if 30 degrees had been the 'lowest' result of stick forward, PF would maintain ND input. Instead, it looks like Stick back was the default (preferred) position. What did the a/c do with ND? Probably go NU? Buffet like she was coming apart? Increase descent?
Guess? Something BAD.
Some possibilities show these guys did everything by the Book. Even the procedure at the STALL Warning. Both of them.
Alarming to me that when presented with a possibility that mitigates the 'PE', or is critical of the 'platform', the popular drift tends to migrate toward the PE.
I predict that with new data, these pilots will be seen in a new light.
In case of (d), ECAM messages (FLR) are compiled into Current Flight Report (CFR) sent by ACARS when they are linked to the same fault (having the same ATA). The priority would simply be PROBE-PITOT fault over ADR fault during the correlation window.
In this case, ADR 1+2+3, being not displayed (no BUSS), it would nonetheless trigger three ECAMs:
- ADR 1+2
- ADR 1+3
- ADR 2+3
In this case, ADR 1+2+3, being not displayed (no BUSS), it would nonetheless trigger three ECAMs:
- ADR 1+2
- ADR 1+3
- ADR 2+3