AF447 wreckage found
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Can I check my understanding as I'm not a jet pilot..
Am I correct in thinking that the trim (auto or manual) has more control throw/authority than the side stick? In effect auto trim has changed to become a sort of "power steering" rather than just a trim?
So in direct law if you need to apply a lot of down elevator (or to get rid of a lot of up elevator) the only way is to wind it in using the trim wheel?
If that's the case a minor warning message to use manual trim seems somewhat inadequate.
Edit: I can see why the auto function might have to disconnect if the instruments that control it go faulty but why can't the function that gives more control throw from the side stick be retained?
Am I correct in thinking that the trim (auto or manual) has more control throw/authority than the side stick? In effect auto trim has changed to become a sort of "power steering" rather than just a trim?
In direct law, there is no automatic pitch trimming. The control surfaces are activated directly by the controls.
If that's the case a minor warning message to use manual trim seems somewhat inadequate.
Edit: I can see why the auto function might have to disconnect if the instruments that control it go faulty but why can't the function that gives more control throw from the side stick be retained?
Last edited by cwatters; 6th Jul 2011 at 09:32.
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Hi all
i dont know if anyone mentioned this before but i was told that the whole accident seems to be a pilot error. It seems that the pilot tried to avoid the bad weather by going over it but stalled the aircraft. Instead of sticking the nose down to increase speed and recover went on to "toga" thruttle position.
This action increase the angle of attack thus stalling again.
Will try to see if i find more detail about this rumor.
i dont know if anyone mentioned this before but i was told that the whole accident seems to be a pilot error. It seems that the pilot tried to avoid the bad weather by going over it but stalled the aircraft. Instead of sticking the nose down to increase speed and recover went on to "toga" thruttle position.
This action increase the angle of attack thus stalling again.
Will try to see if i find more detail about this rumor.
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lochais,
I suspect you're thinking of the Tupolev, some time ago, that tried to fly "over" the weather, and that "fell out of the sky" in the process.
It was mentioned in one of the AF447 theads.
I suspect you're thinking of the Tupolev, some time ago, that tried to fly "over" the weather, and that "fell out of the sky" in the process.
It was mentioned in one of the AF447 theads.
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jcjeant:-
No need to shout, mate......... 
We seem to have a continuing misunderstanding. I'm not saying that there was no 'pilot error' involved - in fact I've said several times that, IMO, it was almost certainly one of the factors involved.
All that I'm asking is HOW and WHY the automatic systems could possibly have put the THS to the full up position, and KEPT it there, in two separate all-killed accidents - one where the pilot was applying only nosedown inputs, and the other where the pilot began by commanding noseup but ended up also commanding nosedown?
Given that the BEA, in the Perpignan report, confirmed that the THS being at, and remaining at, 'full up' made it impossible for the pilot to control the aeroplane (i.e. get the nose down):-
the plane going in direct law ... no more auto trim ... and also few seconds before crash he was in alternate law .... but with the gear down (no more auto trim)
They never actuated manualy (as in the AF447 case) the trim ... they forget it ...
They never actuated manualy (as in the AF447 case) the trim ... they forget it ...
We seem to have a continuing misunderstanding. I'm not saying that there was no 'pilot error' involved - in fact I've said several times that, IMO, it was almost certainly one of the factors involved.
All that I'm asking is HOW and WHY the automatic systems could possibly have put the THS to the full up position, and KEPT it there, in two separate all-killed accidents - one where the pilot was applying only nosedown inputs, and the other where the pilot began by commanding noseup but ended up also commanding nosedown?
Given that the BEA, in the Perpignan report, confirmed that the THS being at, and remaining at, 'full up' made it impossible for the pilot to control the aeroplane (i.e. get the nose down):-
"The aeroplane rapidly regained speed under the dual effect of the increase in thrust and the pitch-down attitude. Under the combined effect of the thrust increase , the increasing speed and the horizontal stabilizer still at the pitch-up stop, the aeroplane was subject to pitch-up moment that the Captain could not manage to counter, even with the sidestick at the nose-down stop."
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Flying drones
FBW systems are very complex. Such a sophisticated piece of software also switches modes or operation states according to several constraints in real-time.
However, it is impossible for any system to deliver the expected output or best solution in an absolute way when the inputs are given by natural forces (non-finite domain). You can test the constraints by generating
variables to feed the different modules, but the sheer complexity and the amount of possible values implies the use of heuristics to deal with certain combination of inputs.
Upper and lower limits may produce an undesired behavior given unexpected situations like: a stall warning which is triggered when the pilot is actually solving the problem by feeding nose-down inputs.
At the other hand, those limits may save the aircraft in other scenario.
So, there more complex the system is, there more prone it will be to deliver unexpected outputs given a real-life situation.
At the end, AF447 was an almost fully operational aircraft that ended at the bottom of the ocean.
Are the highly trained and experienced pilots to be blamed?
Why? Because they got confused?
Ask yourself a single and simple question: Confused by whom?
However, it is impossible for any system to deliver the expected output or best solution in an absolute way when the inputs are given by natural forces (non-finite domain). You can test the constraints by generating
variables to feed the different modules, but the sheer complexity and the amount of possible values implies the use of heuristics to deal with certain combination of inputs.
Upper and lower limits may produce an undesired behavior given unexpected situations like: a stall warning which is triggered when the pilot is actually solving the problem by feeding nose-down inputs.
At the other hand, those limits may save the aircraft in other scenario.
So, there more complex the system is, there more prone it will be to deliver unexpected outputs given a real-life situation.
At the end, AF447 was an almost fully operational aircraft that ended at the bottom of the ocean.
Are the highly trained and experienced pilots to be blamed?
Why? Because they got confused?
Ask yourself a single and simple question: Confused by whom?
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I think front wheel drive cars were a godsend to the casual driver with mediocre skills. IE they are easy to drive however you will not see any serious performance car with front wheel drive only. I know this is a crappy analogy and I know our fighters are very performance driven and some of them are FBW. I do think our airliners need computers and FBW because a LOT of the pilots are NOT PERFORMANCE ORIENTATED AND HAVE FORGOTTEN HOW TO REALLY FLY. They have mediocre skills. For example the yaw damp needed to be off for landing the 9, you have any idea on a 2 mile final a captain would have the ball almost going stop to stop because he forgot what his feet were for? Maybe I am freakin old but it seems like we are (as a whole) demanding less of our pilots flying ability and decision making skills we are molding them inso systems managers without a whole lot of stick time. By stick time I do not mean sitting for hours watching the water pass under while drinking your coffee. I mean real stick time as in gliders, acro, utility etc where you actually have to not only fly but also know what and why you were doing it.
What we actually need of a pilot is a good mix of hands on flying skill, real world experience in weather, ATC, ICAO and relevant rules, and of course systems training and lots of time in the aircraft he/she will be operating.
Of course all of this comes with a cost amd the cost cannot be paid for with our cookie cutter approach, you know the so called flying academies which pump out pilots with minimal experience flying with no actual real world experience.
Our experience base now is retiring and dying, what are we replacing them with?
What we actually need of a pilot is a good mix of hands on flying skill, real world experience in weather, ATC, ICAO and relevant rules, and of course systems training and lots of time in the aircraft he/she will be operating.
Of course all of this comes with a cost amd the cost cannot be paid for with our cookie cutter approach, you know the so called flying academies which pump out pilots with minimal experience flying with no actual real world experience.
Our experience base now is retiring and dying, what are we replacing them with?
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Are the highly trained and experienced pilots to be blamed?
Why? Because they got confused?
Ask yourself a single and simple question: Confused by whom?
Why? Because they got confused?
Ask yourself a single and simple question: Confused by whom?
It all funnels into what I created many years ago now
SIPE
System induced pilot errors
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@Gretchenfrage
and all others asking the question
"How got three experienced, well trained pilots into that trap?"
For me it's a nightmare, even I'm retired. All night I'm thinking what would I have done, coming back into the flight deck and to find the s... hitting the fan.
Scary
and all others asking the question
"How got three experienced, well trained pilots into that trap?"
For me it's a nightmare, even I'm retired. All night I'm thinking what would I have done, coming back into the flight deck and to find the s... hitting the fan.
Scary
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We have so many more systems because our basic skills have deteriorated. Yes I know the airplanes are faster now, fly higher and faster and we do need a bit more systems, but how many times have both pilots (I have seen it) both look at the FMS and ask each other "WTF is it doing now"?
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Yes I know the airplanes are faster now, fly higher and faster
Go WIKI.
BUT, the planes are automated to replace, for instance, the Flight Engineer, to save costs.
Sometimes it doesn't work......
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I've always felt it my responsibility to maintain basic flying skills even though the airline doesn't. Routinely when it is appropriate use just the basic instruments and get your scan working again. Headed south climbing out to cross over Cuba on my 757 I would ignore all except standby attitude indicator, standby air speed, altimeter and whiskey compass while on a vector. If you never did it would you trust those instruments with a complete electrical failure.
If the PF on AF447 had done some of that would they still be flying today?
If the PF on AF447 had done some of that would they still be flying today?
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I mean real stick time as in gliders, acro, utility etc where you actually have to not only fly but also know what and why you were doing it.
I know many pilots who got tired of being system managers and renewed their glider license to regain both: control and joy beside their jobs.
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Well to all those by the seats of your pants aces out there, I too would love to fly manually from take off to TOC and TOD to touchdown without use of FDs or just relying on the standby instruments. However I have been warned that should anything undesirable happen and subsequent technical enquiries reveal that I had not used all the automation as designed, I will be deemed to be guilty of not following company SOPs wrt use of automation to accomplish a safe, smooth and comfortable flight. The company and the regulatory authorities take a dim view of anyone wanting to " improvise " to hone their basic manual flying skills!
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TP, I agree that is the real way to stay sharp but it costs bucks. I towed sailplanes, flew them and taught aerobatics loving every minute of it. I was just showing the cheap route of getting some hand flying for free. Most pilots are too cheap to go out and rent a Citabria or sailplane at todays prices. I put myself in that group. Remember when a Citabria was 17.00 per hr? Probably not because you are too young.
I instructed for the very famous Art Scholl in the 60's at his aerobatic school at Flabob Airport, Riverside, Ca. I cherished the opportunity of meeting Bob Hoover and his well known pilot friends on a regular basis. We still see them at the Reno Air Races every year. I never let my basic flying skills go away because that is all you have when things start falling apart. You owe it to yourself and your passengers to be better than what the pilot mills can put out.
Airbus tried to put out a crashproof airplane but you still need someone to take over when all that automation fails at the worst time.
I instructed for the very famous Art Scholl in the 60's at his aerobatic school at Flabob Airport, Riverside, Ca. I cherished the opportunity of meeting Bob Hoover and his well known pilot friends on a regular basis. We still see them at the Reno Air Races every year. I never let my basic flying skills go away because that is all you have when things start falling apart. You owe it to yourself and your passengers to be better than what the pilot mills can put out.
Airbus tried to put out a crashproof airplane but you still need someone to take over when all that automation fails at the worst time.
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VP, sorry you work for that company. If you don't use your initiative to hone your flying skills and go along with company logic you will lose your flying skills gradually. Hopefully you don't just settle into this job and accept it as the wave of the future. You can probably just do it anyway or if the company is a stickler for no handflying find a safer job.
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Interesting comments regarding gliding experience.
Giving a clue to my age, about 50 years ago in NZ, a DC3 was caught on the wrong side of a standing wave and sank about 7,000 feet into the side of a mountain in a nose high attitude on full power.
The general view of the gliding community at the time was that had the pilots had any sailplane experience they would have recognized their predicament and flown out of it.
Obviously no standing waves out in the Atlantic, but the situation for the crew seems eerily similar
Giving a clue to my age, about 50 years ago in NZ, a DC3 was caught on the wrong side of a standing wave and sank about 7,000 feet into the side of a mountain in a nose high attitude on full power.
The general view of the gliding community at the time was that had the pilots had any sailplane experience they would have recognized their predicament and flown out of it.
Obviously no standing waves out in the Atlantic, but the situation for the crew seems eerily similar
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before landing check list -
All good points, but what good will it do to have the pilot as experienced as you want him when he can't have TOTAL control over this FBW cr*p ?!?! Correct me if I'm wrong, but I don't think there's a way to TOTALLY, manually fly this stuff. The side stick, throttles, etc. are not connected to anything but electrical wires.
All good points, but what good will it do to have the pilot as experienced as you want him when he can't have TOTAL control over this FBW cr*p ?!?! Correct me if I'm wrong, but I don't think there's a way to TOTALLY, manually fly this stuff. The side stick, throttles, etc. are not connected to anything but electrical wires.
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CRAP or CREPE??
Well DC-ATE, as you can read in the BEA preliminary report, the airplane reacted in a totally normal way, as soon as a proper stick input was given: when the stick was pushed forward, the pitch attitude lowered and the AOA decreased.
Unfortunately the proper stick input was not maintained long enough to effect complete recovery from the stalled situation.
Nothing really crappy about aircraft response there, Fly By Wire or not.
"Even" an Airbus is a totally normal airplane if you treat it as such.
Do not get confused by Airbus being FBW, it is not statically unstable as an F-16 is. I am not gonna explain that further, that has been done very well by old Gums a lot of postings ago already.
Unfortunately the proper stick input was not maintained long enough to effect complete recovery from the stalled situation.
Nothing really crappy about aircraft response there, Fly By Wire or not.
"Even" an Airbus is a totally normal airplane if you treat it as such.
Do not get confused by Airbus being FBW, it is not statically unstable as an F-16 is. I am not gonna explain that further, that has been done very well by old Gums a lot of postings ago already.