American Airlines Flight 742 "flight control system" problems

[sevenstrokeroll]

if you roll inverted and lose sightof the traffic below your bellly....hmmmmm

upside down, is below up? no...upside down, below is still towards the ground and you should have a view of the traffic




AND STILL THE VILLIAN PURSUED HER.

[bubbers44]

Is there any reason you can't see out your windshield inverted? Once the other aircraft is passing you you have no reason to see through your floor boards. I am not saying I did anything special, I just avoided a midair doing what I knew would work, not taking a chance on him turning with me. Two seconds doesn't leave much time for thinking over the solution.

[Lord Spandex Masher]

How can you see through the floor? Simple question, simple answer.

You can see out of the window yes but the relative position of an aircraft passing above you when you're inverted is BELOW you. You can not see through the floor.

Unless you're BSing and they actually weren't that close you might have been able to see them at a longer range as the relative angle between you would be smaller. But then if they weren't that close would there be any need for such a ridiculous manuever?

Instead of rolling and pulling why not just pull? Or push?

[bubbers44]

So they had to fly manually. Good for them because they knew how to fly manually.

[Ashling]

Bubbers you said you had 2 secs to collision you still haven't answered how you role a Cessna 340 inverted in that time. You might have ended up inverted but not in 2 secs. Really don't get that bit at all.

Other thing, if you heading straight for the conflict rolling inverted will keep you pointed the same way. If you don't push the nose will drop and you lose visual, if you do push you stay in plane. You could pull up and roll, corkscrew style which would keep visual but you didn't say that you did that and you wouldn't achieve that in 2 secs either.

How long do a 340's engines run upside down ?

What harness did you have ?

[sevenstrokeroll]

wow

the cessna 300 series can roll pretty fast...I've seen one roll

as far as harnesses, if you do a roll well, you could even keep a glass of water from spilling...as RA HOOVER.

I believe bubbers saw traffic and maneuvered like hell and avoided it (the traffic) and went inverted in the process.

he didn't say he stayed inverted for a long time and I am sure the engines kept running

you can always disagree with someone over what they did...but since they are here and alive they did something right.

[Lord Spandex Masher]

So SSR to keep the water from spilling when you're inverted you have to do what?

[Lord Spandex Masher]

flying a Cessna 340 over LGB when I noticed the lighting seemed different and I was nose to nose with a single engine aircraft. Not knowing which direction he was going to turn I rolled inverted because I had only one move. When he rolled right as he should have I paralleled his wings and rolled with him clearing by about 50 ft. No reports were filed but when he first saw me I was inverted. I wish I could hear his story because probably nobody would believe him. He did the right thing but I wasn't sure he would.

I instructed aerobatics so just pulled back enough to clear him after going inverted. I could pull away more than he could push over. Birds have to be seen to be avoided. Heads down means no bird avoidance so if you are flying into an airport like TGU you need to be heads up because they are in flocks and can easily be seen if you keep your eyes open, not down pushing buttons.

SSR, original quote for you to digest.

OK465, no bother, hopefully they might start getting the message.

[BOAC]

C'est des conneries, n'est-ce-pas?

[bubbers44]

Just so everybody understands rolling inverted R A Hoover demonstrated pouring a glass of water while doing a roll so obviously negative G's only happen when you maintain level flight while inverted. Bob would have preferred a wine glass.

[bubbers44]

As I said about Sully, single pilot flying into LAX requires taking your eyes off the windshield to set up the approach properly. How did we stray off topic?

[sevenstrokeroll]

I think bubbers did fine...spandex...what is your problem? bubbers is still here and he isn't lying.

wish things were opposite with you

[Ashling]

At 200kts the FW190 rolled at @ 140 degrees a second, the Mustang at @ 90 degrees a second.

At slower speeds those rates decrease.

So SSR and Bubbers seem to be saying a Cessna 340 will outroll a Mustang. Now technology may have moved on, but .......

So far Bubbers has failed to even try to address that point.

Additionally, as any combat or aerobatics pilot will know the dynamics of Bubbers "move", as he described it, just don't stack up. If all he did was roll inverted, maintaining level, all he's achieved is to keep going the same way just upside down. To keep level he'd have to push at which point the harness becomes important, if he keeps positive G the nose drops as soon as he rolls past 90 ( yes I know it will begin to drop sooner depending on G) and then he loses visual so the only way he can roll inverted and keep visual is to pitch nose up then roll but that's not what he said he did.

If it happened it didn't happen the way Bubbers has described it

[bubbers44]

I think a C340 at cruise speed will roll inverted in one second because I did it. Just say one thousand and, that is one second.

[bubbers44]

I have bin in rolls in a P51 mustang with Steve Hinton and I assure you it does not take 4 seconds to complete a roll.

[sevenstrokeroll]

ok boys and girls...lets see who has the presence of mind to time the roll rate while avoiding traffic. if bubbers said it was some exact time in seconds...that is fine

if you think the P51 can roll faster, it probably can...why not ask bubbers as he as actually flown one...have you?

Indeed bubbers has a friend who flew the winning p51 at Reno...lets ask him.


it seems to me that planes head on would both turn right, bubbers kept going past the 90 and ended up rolling all the way around...and IF THE INTRUDER had turned left, bubbers would still be alive...as it was the intruder turned right and IF bubbers hadn't kept rolling, it would have worked out...but something told bubbers to keep rolling and I don't blame him...sometimes the eye/hand can do more than an engineering mind over thinking things.

AND we have been talking about avoiding birds...why not planes? And no, rolling an airliner to avoid a bird is not what I'm getting at.

have any of you flown P51s, FW190's or Cessna 300 series ? I've flown a 320 and I'm sure its roll rate is the same as a 340. I've even read that after WW2 the US navy put permanent wing tip fuel tanks on F6Fs and their roll rate increased. The 300 series (except 303) has tip tanks and it rolls pretty fast.

And if it turns out that bubbers really did it in three seconds, is that a huge problem for anyone? come off it.


I'll tell you how I know bubbers is who he says. We have chatted via E mail and even though we live thousands of miles apart, he knew in great detail a mutual friend. And bubbers told me all about something that only a few people in the world would know...so he is/was a pilot for a big freaking airline and flew the planes he said he has.

sheesh...I'll tell you one thing...if bubber s had been in the cockpit of Air France it wouldn't have stalled and fallen out of the sky over the atlantic.

[Ashling]

A WW2 mustang rolled at @ 90 degrees a second, varied a bit with speed.

SSR, your beginning to get there, Bubbers exaggerated.

[sevenstrokeroll]

ashling...don't put words into my mouth!

and folks...anyone who has flown a plane with tip tanks knows that once you get it rolling, it can be easier to keep rolling than to stop.

exact chronology may be slightly imperfect, and anyone that times his rolls perfectly has my respect. and I think bubbers related his incident correctly.

[Lord Spandex Masher]

But it takes longer to get rolling. Inertia chap.

I think bubbers did fine...spandex...what is your problem?

My problem is why would anyone with half a brain cell want to waste one, two or even three seconds rolling inverted, which achieved the square root of absolutely sweet FA, when he could have just pulled, pushed, or just done the correct thing in the first place.

bubbers is still here and he isn't lying.

Can you prove that?

By the way, you didn't answer my question...

so obviously negative G's only happen when you maintain level flight while inverted.

Riiiiiiiiiiight! You say you taught aeros?

Did you encounter negative g during your amazing escape manuever?

By the way you didn't answer my questions...

[misd-agin]

Apparently this is a two shovel story.

[BOAC]

...don't forget the wheelbarrow.Can you prove that? - well, I'll volunteer he is certainly still here if it helps.

[Ashling]

SSR "exact chronology may be slightly imperfect"

You can shorten that to two words "he exagerated". He's been very specific and clear about the 2 seconds.

I've lost track of the number of posts that Bubbers refers to "teaching aerobatics" or something similar, he wears it as a badge. He then comes out with a story that clearly doesn't stack up on a host of levels which then undermines his credibility on pretty much everything else.

I could list everything I've flown and done but it would achieve little, other than to ID myself or narrow it down a-lot, but its pretty evident from my posts that I fly an Airbus (not my only airline type) and have flown in the military, lets just say a wide variety of aircraft in a wide variety of roles. People can judge from what I write whether I know what I'm on about which kind of summarises Bubbers problem at the moment. I.E. He's being judged on what he writes, not on who he actually is, its an annomymous forum after all.

[JW411]

I used to have a great notion to buy a pair of bookends made out of really solid American hardwood. Now that I have seen a pair at close quarters, I have lost the desire.

[Lord Spandex Masher]

- well, I'll volunteer he is certainly still here if it helps.

'Tis a fair cop :p

[sevenstrokeroll]

ashling...tell me, with your vast experience in flying exactly how long you were in the flare regime ( in seconds) on your flight 20 years ago?

I looked up the original testing of the cessna 310 series (which is the basis for the 340) and the test pilots were amazed at the roll rate.

(roll rates, as an aside...I recall the A4 had a roll rate of 720 degrees per second.)

now, before you tell me that I said bubbers exagerated, you go out and roll a Cessna 300 series, time the roll rate and report back.

I've noticed that there seem to be two types of pilots on pprune...real airline pilots and ''others''. I'm a real airline pilot and so is bubbers.

oh and someone who says they have been in the military and flown in a wide variety of roles...usually means they weren't good enough to fly fighters.

so , believe what you want...and any airline pilot that would chose to fly the airbus in an airline that had other choices...well that shows us all something, now doesn' t it?

[windytoo]

It depends what you call fighters. How about the Reds?

[Lord Spandex Masher]

...I'm a real airline pilot and so is bubbers.


Must be true then if you say so. :rolleyes:

I looked up the original testing of the cessna 310 series

Did you indeed? Gonna share the amazement? No?

and any airline pilot that would chose to fly the airbus in an airline that had other choices...well that shows us all something, now doesn' t it?

Yes it does, that there are more important things in life than what kit you fly.

By the way you still haven't told us how you real airline pilots can see through the floor.

P.S. SSR, I'm a real airline pilot and so is my wife.
With apologies to the Monty Pyhton team.

[Ashling]

SSR

You've told us all we need to know about you.

[jcjeant]

Hi,

Lord Spandex Masher
By the way you still haven't told us how you real airline pilots can see through the floor.Virgin launches glass-bottomed plane - Richard's Blog - Virgin.com (http://www.virgin.com/richard-branson/blog/virgin-atlantic-launches-worlds-first-ever-glass-bottomed-plane)

:)

[sevenstrokeroll]

ashling...ditto to you...

regarding cessna 310 testing...look it up yourself...you might accuse me of faking it

[bubbers44]

I have been busy enjoying the Florida Keys the last couple of days so haven't been on the computer so since I was the only one that went through that near miss, I know what happened, no one else does. I don't care if you believe my story or not but I survived doing what I did. Maybe turning right and diving might have worked, maybe not. I am here doing what I did and may still be here doing what you would do. Who knows? Isn't it about time to shut this discussion down and get back to something more productive? Out again.

[bubbers44]

You do understand if you roll right 60 degrees and push down you don't turn that much but if the other guy makes the same choice to dive now you have your wing 60 degrees up and much more likely to make contact with the other aircrafts wing rather than being parallel to his wing by watching him approach you. Once he is under your belly he is no longer a threat so you don't need floor windows as one suggests over and over. Please make this the final OUT.

[iceman50]

Bubbers

You really need to read what you write! Bank 60 degrees right and "push" to dive? Sounds like an outside turn.

In all of this "I survived did the right thing etc", you have not even considered the other pilot! He was probably thinking WTF is he doing when he saw your manoeuvre, as he was probably expecting the "correct" rules of the air response. Yes you are still here but you were lucky.

[BOAC]

Since bubbers has 'signed out' on this story, I am sure it is best to leave it now for his 'memories'?

(1400 hours C310L and R, right way up most of the time, apart from the odd harmless 'sporting' with Jags and Phantoms in the Scottish LFA in days of old:))

[misd-agin]

BOAC - with 1400 hrs in the C310 were you amazed at the roll rate?

[CONF iture]

So is your recommendation that if you are going to ditch the pilot should switch (or be switched) to direct law?
Not necessarily, the observation is more general than fitted to a single event.
As said earlier, normal law brings a disconnection between the inputs and the effective flight control movements. The pilot has actually no idea how the control surfaces are displaced. To correctly evaluate and anticipate the possible aircraft response is more of a nebulous process.
Flight control movements are transparent to the pilot.
Sully was looking for some finesse in the final act but the computers had decided otherwise.

That being said, I certainly would not mind a straightforward direct law when manually flying in final. It was a pleasure on the Boeing, don't think it would be different on the Bus ... but it would not fit too well I guess with the overall protection concept by Airbus.

When I said what would you do if you got a stall warning I was referring to a Boeing not an Airbus in normal law. If your in a Boeing (or a Bus in alternate/direct law) what are you going to do when the stall warning goes off at 150' because your too slow.
The same thing that at 3000 ft, release some back pressure should be enough to stop the STALL warning or the stick shaker and keep the final pull for the last 50 ft.

Putting the issue of the stall warning aside, in your Boeing even if you had room to pull and you did it at 50' you'd have 4 secs to impact. Given the relatively heavy weight, and slow speed I can't see 2 degrees making much difference, it would take a finite time to achieve those 2 degrees and a finite time for the aircraft to respond to that attitude change, it's a very different thing flaring at the correct speed to trying to do so 19kts slow, the aircraft won't respond the same way or anything close to it.
You need to read the report you mentioned :
The pitch angle behavior of the airplane in the last 100 ft of flight is of interest, since changes in pitch have a strong influence on the flare and touchdown conditions. As noted above, in the last 50 ft, the angle of attack was about 3.5° below αmax and even 1.5° below αprot; consequently, there was some additional angle of attack margin available to flare the airplane and reduce the descent rate at touchdown.

[Owain Glyndwr]

CONF iture

Thank you for clarifying your position. Previously I had not realised that you were stating your personal preferences.

Two small comments and then I shall shut up.

As said earlier, normal law brings a disconnection between the inputs and the effective flight control movements.

This 'disconnection' is true for any aircraft operating under a C* law or a variant thereof. For that matter it is true of any aircraft fitted with a yaw, pitch or roll damper. F16, B777, B787 and the various Airbus designs are in the first category, Concorde in the second.

in the last 50 ft, the angle of attack was about 3.5° below αmax and even 1.5° below αprot; consequently, there was some additional angle of attack margin available to flare the airplane and reduce the descent rate at touchdown.

From memory that is an extract from the NTSB final report on the Hudson accident, finally adopted in May 2010, a year before the Roswell G650 accident. I wonder if the NTSB would use the same wording today?

[Ashling]

Confiture

With respect your reaction to the stick shaker/stallwarning/buffet, in this case, would be very different at 3000 from 150.

At 3000 you would apply the aircrafts stall recovery procedure. I believe Boeing state that you treat the approach to the stall as an actual stall so you smoothly apply nose down elevator (trimming if needed) to remove the warning. With no engines you'd need to keep the nose down longer and further to accelerate but you'd have enough room to put yourself in a much healthier situation. If your in an Airbus, as Sully was, its enough altitude to get out of Alpha Prot and improve your energy state significantly.

That is very different to just releasing the back pressure,

At 150 engines out your in huge trouble as you can't nose down so releasing the back pressure is about all you can do. I doubt it would be enough to remove the warning, or if it did the warning might soon return as the nose may still be high enough to keep your speed were it is or still decreasing just at a slower rate (remember you are @ Flap 15 so leading edges are fully deployed so lots of drag) so your alpha might not reduce enough to exit the warning which you might re-enter prior to your flare. You may also increase your rate of descent. Its also rather dependant on were you've trimmed to as well. If you've trimmed into your speed decrease releasing the back pressure will do little but if you've not trimmed you might find that your nose pitchs further forward than you intended which may be undesirable at 150' and of course cause you to pull straight back into the warning. Of course all this under huge pressure with no training in how to do it or in handling the aircraft, on a regular basis, in that regime. Good luck. I'll take the Bus for this one thankyou.

Its also important to appreciate that the aircraft has v little excess energy at F speed -19. A flare in that state is a very different thing to one at Vapp +5. In effect you are 24 kts slower than normal. This wouldn't be a flare in the normal sense or anywhere remotely close to it. It might reduce the rate of descent a touch but as you only have 3.5 degrees to play with (taking into account the error in AoA allowed for by the gap between max and stall)
the downside if you stuff it up and stall is catastrophic and you have absolutely no practise in doing this. If your rate of descent is survivable its not worth it.

[CONF iture]

Thank you for clarifying your position. Previously I had not realised that you were stating your personal preferences.
Personal preference is for the aircraft to obey the request as long as it has it in its aerodynamics, and not that it gets locked on its trajectory. When Sully decided to flare, his sidestick request was unambiguous and reasons to fear or fight PIO there were none.

This 'disconnection' is true for any aircraft operating under a C* law or a variant thereof. For that matter it is true of any aircraft fitted with a yaw, pitch or roll damper. F16, B777, B787 and the various Airbus designs are in the first category, Concorde in the second.
Whatever the manufacturer, for a pilot it is more cognitive to know that at half stick deflection he gets half travel movement of the ailerons. It tells a lot on what's happening and what to expect or not next.
Also, if at full stick deflection the ailerons can move full travel but the next second because one oleo momentarily compressed the ailerons are only allowed half deflection it is somehow confusing to the pilot. That' s what we learned from the report in Hamburg and don't look for such info in the FCOM ...

From memory that is an extract from the NTSB final report on the Hudson accident, finally adopted in May 2010, a year before the Roswell G650 accident. I wonder if the NTSB would use the same wording today?
AFAIK the final report has not been amended.
The G650 was in flight testing to validate theory, the 320 was under 20 years of operation, I expect them to know what's behind alpha management by now ...
When the manufacturer largely publicizes its ability to operate safely at alpha max it is questionable how when requested the aircraft keeps 4 deg short of that setting.

[Owain Glyndwr]

CONF iture

The G650 was in flight testing to validate theory, the 320 was under 20 years of operation, I expect them to know what's behind alpha management by now ...


You are missing the point. You say that the aircraft had 3.5 deg (now escalated to 4 deg see below) margin to stall, but this is based on free air values. The Roswell accident showed that in ground effect alphastall can be reduced by as much as 3.65 deg below the free air value, which would remove all your presumed margin.

When the manufacturer largely publicizes its ability to operate safely at alpha max it is questionable how when requested the aircraft keeps 4 deg short of that setting.

Again you miss the point. You did not dissent earlier in this discussion when I pointed out that the system does allow one to get to alpha max as shown by Habsheim. The system does however take note of the rate at which alpha max is being approached and if it looks likely that alpha max will be exceeded when proximity to the limit and rate of change are taken together then it acts to prevent any overshoot towards stall. That is what happened here.

[Ashling]

Thanks OK and Owain

Much more succinct and eloquents than anything I've written on it of late.
I did'nt appreciate that Alpha could increase that much in ground effect. You learn something new etc

Still a bit concerned that all Conf would do with a stall warning at 3000 is to release the back pressure.

[CONF iture]

You are missing the point. You say that the aircraft had 3.5 deg (now escalated to 4 deg see below) margin to stall
No ... 4 deg margin to alpha max ... add another 3 deg for alpha stall.
G650 and G4 have different wings with different characteristics as Gulfstream learned.
What about the A320 wing now ... .

Ground effect would help to an improved touchdown if only the elevators were to follow the full backstick by Sully for the last 2 seconds.

Again you miss the point. You did not dissent earlier in this discussion when I pointed out that the system does allow one to get to alpha max as shown by Habsheim.
Have we talk about Habsheim yet ?
Alpha max there ... ?
Where are your data ?

[CONF iture]

Still a bit concerned that all Conf would do with a stall warning at 3000 is to release the back pressure.
Don't be too concerned - Same applies at initial stick shaker activation during GPWS procedure - Is the procedure, for your best interest, to push all the way or simply maintain on the edge of it if necessary ?

Critical scenarios for a stall situation have more chances to develop in one try to get over an obstacle or to abusively try to extend a glide or over bank to align, none was applicable to the Hudson as Sully took very early on that sensible decision to go there for that unobstructed and 'unlimited runway'.

[CONF iture]

With a stabilized no thrust descent rate of somewhere around -1500 FPM at green dot or VFE, -700 FPM with speed decaying is already well into 'the flare'. Even with the additional AOA margin indicated on the gage, I would tend to hold what I had under these conditions at 50', or at least be extremely gentle.
I hear you OK and what you write is worthy.
In the meantime Sully fully pulled for the last 2 seconds not because he was ignorant at flying as Clandestino put it but because he thought it was the appropriate thing to do in this late stage, and the NTSB did not disapprove did they ?
If Sully would have thought he would have stalled by doing so, I do presume he would not have proceeded that way and would have also opted for an extremely gentle way instead but only him could confirm.

What I do find interesting is how simulating the Hudson in full direct law has not been tested ... ?
Would it produce the catastrophic scenarios Airbus or Ashling are prone to sell or could it simply give nicer touchdowns ... ?

You're not one of them, but what about that sudden absolute need to be stall protected ?
Did all the unprotected aircrafts that had to glide ended stalled ?

Is the 787 the dreamliner and the 320 the lifesaver ...

[Owain Glyndwr]

add another 3 deg for alpha stall.

That is your number. I have yet to see any published numerical data from AI to support stall at 20.5 deg AoA with CONF 2 (or 3).


What about the A320 wing now ... .

You are ducking the issue. Even if the A320 number is less than 3.65 deg the margin to stall will be reduced in ground effect.
For me your presumed margin to stall is too high on two counts.

Ground effect would help to an improved touchdown if only the elevators were to follow the full backstick by Sully for the last 2 seconds.


Not so. Ground effect is there irrespective of elevator deflection

Have we talk about Habsheim yet ?

You are ducking the issue here also. The point of my remarks was that pitch rate is important. You continually ignore this effect.

[Ashling]

I think there's every reason to be concerned. If you get a stall warning you treat it as such and move the column centraly forward until the warning ceases. Best not to confuse the how we should respond to a stall warning, there have been quite enough fatalities recently. I of course accept that if you have something to avoid, particularly without engines, you may have to trade energy but that is a different matter as is GPWS and you simply stated 3000' v 150'. I certainly hope thats not representative of your attitude to stall warnings in commercial aircraft but it would explain your thoughts on what is sensable in that speed regime.

BTW I remembered that the 737 adjusts the feel on the column to force you to pull harder as the speed enters the approach to stall regime so by releasing back pressure you may get a nasty shock depending were you've trimmed to of course.

Sully knew he wouldn't stall as he knew he was in direct law which he achieved by starting the APU out of sequence so he could pull full back with impunity and leave the aircraft to figure it out. As the NTSB said the aircraft max performed

I have no difficulty whatsoever in saying that a Boeing flown at the correct speeds would have been as successfull as the 320 and neither would Airbus. Might have been better. What I have trouble with is saying that in the speed regime that the aircraft was actually flown in.

The difficulty I have with your case is not that its impossable, theoreticaly, to squeeze a degree or 2 more out of it but that practicaly it doesn't stack up. You want us to believe that a pilot under immense pressure and a huge workload in an unfamiliar environment who has already allowed his speed to decrease dangerously low is going to be able to tickle the buffet with a stick shaker and stall warner/GPWS going off bearing in mind he has had no training in doing this ! Bear in mind too that the reason the stick shaker is there is because it has a low buffet to stall margin in some configs and this will mask feel of said buffet on the stick and of course he will have no idea what his actual margin is and as Owain says as he enters ground effect his alpha will increase.

Maybe an experienced pilot after a few goes in the sim might achieve something by trial and error (I know sim fidelity in the stall is good but not wholly perfect) but for me its not real world, but I agree it would be interesting to see the outcomes.

In that speed regime I'm still in a Bus

A footnote: I was wrong to refer to Owain saying alpha will increase in ground effect, it is alpha stall that reduces which is what he said earlier. My mistake, see posts below.

[Owain Glyndwr]

Ashling

and as Owain says as he enters ground effect his alpha will increase.

That is not at all what I am saying :=

As he enters ground effect the lift at a given alpha will increase and the drag at a given CL will decrease. This is not the same as saying that alpha will increase.
With regard to the effect of ground on stall, the maximum lift coefficient is hardly affected, but the AoA at which it is achieved is reduced, as is the stall AoA. This effect was mentioned by IIRC one of the Boeing lecturers at the recent RAeS conference on flight testing of stalls, but the relevant graph was not dimensioned.

[Ashling]

Thankyou Owain

I apologise for misrepresenting what you said earlier. Duly re-educated

Am I correct in saying that it is the value of Alpha Stall that decreases rather than the AoA increasing?

As I said earlier I was blissfully unaware this happened

[Owain Glyndwr]

Ashling

Am I correct in saying that it is the value of Alpha Stall that decreases rather than the AoA increasing?

Yes, that is correct.

Plenty of early NACA evidence that on straight wings the loss is 2 to 3 degrees, but jolly difficult to find anything for modern swept wings (proprietary information I expect). Wouldn't be surprised to find that loss is bigger on swept wings with the tips closer to the ground, but the G650 values I think took everyone by surprise. I think a value around 3 deg would not be an unreasonable assumption.

[Ashling]

Thanks for that. I'm guessing the RAeS lecture you refer to is the joint Boeing Airbus one. Must get round to watching it.

[CONF iture]

Sully knew he wouldn't stall as he knew he was in direct law which he achieved by starting the APU out of sequence so he could pull full back with impunity and leave the aircraft to figure it out.
What kind of statement is it ... ?
Sully started the APU to make sure to keep optimum electrical and hydraulic power, and certainly not to maintain what is called normal law BTW, to allow him to 'pull full back with impunity and leave the aircraft to figure it out'.
Would you challenge Sully face to face on that one ?

As the NTSB said the aircraft max performed
Has been already addressed (http://www.pprune.org/7773216-post241.html).

The difficulty I have with your case is not that its impossable, theoreticaly, to squeeze a degree or 2 more out of it but that practicaly it doesn't stack up. You want us to believe that a pilot under immense pressure and a huge workload in an unfamiliar environment who has already allowed his speed to decrease dangerously low is going to be able to tickle the buffet with a stick shaker and stall warner/GPWS going off bearing in mind he has had no training in doing this ! Bear in mind too that the reason the stick shaker is there is because it has a low buffet to stall margin in some configs and this will mask feel of said buffet on the stick and of course he will have no idea what his actual margin is and as Owain says as he enters ground effect his alpha will increase.
You're the one to see and fear stall scenarios at every corner - Relax ... there was none.
OTOH there was an opportunity to improve the touchdown, but the System is not programmed for it.

[CONF iture]

That is your number. I have yet to see any published numerical data from AI to support stall at 20.5 deg AoA with CONF 2 (or 3).
"Around 20 deg"
Gordon Corps - FLIGHT INTERNATIONAL - AUG 86

Not so. Ground effect is there irrespective of elevator deflection
But respective of attitude and rate of descent that elevator deflection would influence.

You are ducking the issue here also. The point of my remarks was that pitch rate is important. You continually ignore this effect.
It is certainly important to note that the pitch rate was even negative for the last 4 sec and so even if full back stick was applied for the last 2 sec ...

[Owain Glyndwr]

Conf iture

"Around 20 deg"
Gordon Corps - FLIGHT INTERNATIONAL - AUG 86Explain to me please how a remark made by Gordon during a demonstration of the FBW concept on an A300 a year before the A320 ever flew becomes a definitive statement of A320 performance?

BTW, the pitch was actually constant over the last 3 seconds according to the detailed plots in the NTSB Performance Group Report, and you still refuse to address the possibility that it was the pitch rate in the previous 8 seconds that triggered the command restriction, neither do you recognise that there are other flare techniques that have been shown to give better results even using the current laws.

[Ashling]

Couple of quotes from the NTSB

The NTSB concludes that, despite being unable to complete the Engine Dual Failure checklist, the captain started the APU, which improved the outcome of the ditching by ensuring that a primary source of electrical power was available to the airplane and that the airplane remained in normal law and maintained the flight envelope protections, one of which protects against a stall.

Despite not reaching this portion of the Engine Dual Failure checklist, the captain stated during postaccident interviews that he thought that he had obtained green dot speed immediately after the bird strike, maintained that speed until the airplane was configured for landing, and, after deploying the flaps, maintained a speed “safely above VLS,” which is the lowest selectable airspeed providing an appropriate margin to the stall speed. However, FDR data indicated that the airplane was below green dot speed and at VLS or slightly less for most of the descent, and about 15 to 19 knots below VLS during the last 200 feet.

The flight envelope protections allowed the captain to pull full aft on the sidestick without the risk of stalling the airplane.

[Ashling]

More from the BEA this time

In alternate law, considering the airspeed management and flap configuration, it is likely that stall alarms would have been triggered several times during the descent, and the risk of actually stalling would have been high

A stall alarm during the flare would have had severe consequences, the only way to avoid stall being to reduce the pitch angle

In fact, the phugoid oscillation damping function only prevented the pilot from increasing the AoA, because the energy management during the descent did not make it possable to reduce the vertical speed at impact.

In reality phugoid oscillations induce pitch variations that can have more severe consequences than a high vertical speed when entering water

[Ashling]

Confiture

There was no risk of stalling in normal law and they were in normal law because Sully started the APU. I credit him for knowing that.

If your in alternate law or a 737 at VLS -19, or equivelant, there is a very high risk of a stall. Fact. If you think there isn't a risk of a stall in that speed regime you are a dangerous fool.

You reckon you could fly a 737 that slow with stall warners and shake shakers going off and flare it under that pressure ....... well do you

I will continue to be tense and uptight about stalls thankyou very much, at the heights Sully was at there would be no coming back from one, you would be well advised to take heed and not suggest incorrect stall recovery procedures as you clearly have.

Oh and I wouldn't challenge Sully about a thing, as the NTSB and BEA have made clear, he did a great job, I fully concur. I would however challenge the mantra that pretends it was all perfect. That denies us the opportunity to learn what could have been improved and to train to that end. I would hope that we could agree on at least that.

[DozyWannabe]

@Ashling:

I don't think CONF iture really cares about the minutae of the Hudson ditching. As he hinted at earlier, what this is really about for him is his theory that if the flight control logic gave Capt. Asseline just a couple of extra degrees of pitch at Habsheim, the trees would have been cleared and all would have been well.

For him this is akin to religious conviction, and no amount of evidence to the contrary will sway him from his quest.

[Capn Bloggs]

For him this is akin to religious conviction, and no amount of evidence to the contrary will sway him from his quest.
The same could be said about others around here...

[CONF iture]

Explain to me please how a remark made by Gordon during a demonstration of the FBW concept on an A300 a year before the A320 ever flew becomes a definitive statement of A320 performance?
Any reason it would have changed ... ?
But as you do think to know better than Gordon ... I'm listening.

BTW, the pitch was actually constant over the last 3 seconds according to the detailed plots in the NTSB Performance Group Report, and you still refuse to address the possibility that it was the pitch rate in the previous 8 seconds that triggered the command restriction
I don't refuse anything ... One deg every 2 sec is your concern ?

neither do you recognise that there are other flare techniques that have been shown to give better results even using the current laws.
Did I refute so ?

[CONF iture]

There was no risk of stalling in normal law and they were in normal law because Sully started the APU. I credit him for knowing that.
You don't start an APU to be stall protected.
You start an APU to secure a main source for electrical power.

You reckon you could fly a 737 that slow with stall warners and shake shakers going off and flare it under that pressure ....... well do you
Flying the stick shaker into a glide is not the objective, unless you want to practice slow flight on the edge of a stall warning when the slightest touch on the control column allows control of the AoA.

One single stick shaker activation on the Hudson would have unambiguously warned Sully that his attention on the speed was not ideal. Instead of it the system acted on the elevators independently of the stick position, masking the reality. Transparency has much better taste.

I will continue to be tense and uptight about stalls thankyou very much, at the heights Sully was at there would be no coming back from one, you would be well advised to take heed and not suggest incorrect stall recovery procedures as you clearly have.
Where ?
You would be well advised to quote ...

Opting for one of the airports around would have been an invitation for stalling, but not the Hudson, that's where that crew did so well.
But you're all over stall ... and there was none.
Any idea how unprotected aircrafts managed to glide without stalling ?

[Owain Glyndwr]

Any reason it would have changed ... ?

Yes - it's called flight testing.


neither do you recognise that there are other flare techniques that have been shown to give better results even using the current laws. Did I refute so ?

So you accept that the current laws are capable to being used to better effect?

[Ashling]

Confiture

You said you would recover from a stall warning at 150 the same way you would at 3000, by releasing the backpressure.

That is incorrect

[CONF iture]

Yes - it's called flight testing.
Good ... I'm still listening ...

So you accept that the current laws are capable to being used to better effect?
Did I ever say the contrary ?

You said you would recover from a stall warning at 150 the same way you would at 3000, by releasing the backpressure.
That is incorrect
If it's enough to return the AoA to the level where stick shaker was absent, why would it be incorrect ?

[Owain Glyndwr]

Good ... I'm still listening ...
And I'm still waiting for you to supply evidence to justify your value of 20.5 degrees for alphastall.


Quote:
So you accept that the current laws are capable to being used to better effect?
Did I ever say the contrary ?I'll take that as a yes then.

[CONF iture]

And I'm still waiting for you to supply evidence to justify your value of 20.5 degrees for alphastall.
You don't accept the word fron an Airbus guy ... but have nothing to advance.
You can always try Ashling ... "As you rightly state, Alpha Max is not Alpha stall. I think the gap is 3 degrees or so"
Maybe he has the Official post flight test document to state that alpha stall is around 20 deg ... ?

[Owain Glyndwr]

You don't accept the word fron an Airbus guy ... but have nothing to advance.Oh I would accept Gordon's word - he was a friend of mine, and I wish he were still around because I would relish reading his comments on some of the things written about his work.

What I don't accept is the calm acceptance that nothing changed after he made that remark to a journalist. At that point in time, before flight test, he would have been obliged to rely on information from wind tunnel tests corrected for Reynolds Number effects using empirical corrections based on experience with other aircraft designs tested in the same wind tunnel. That work was done in the UK so I have some knowledge of it. Small differences between these predictions and flight test results are not uncommon.

Like you I am limited by the absence of any published definitive post-flight data for the aircraft, so like you I cannot offer a definitive value. What I can say is based on memory and that tells me that the stall AoA ('g' break) varies slightly with flap angle but generally lies around 19 degrees.

[Ashling]

Confiture

You are of course correct, the aim of the initial part of a stall recovery is to reduce the AoA to remove the warning or break the stall.

However you talked about releasing the back pressure to achieve this which is incorrect, you move the stick forward, reducing power or moving the stab trim if needed to gain control authority.

It's an important difference as just releasing the back pressure may not work if the aircraft has auto trimmed or you have manually trimmed.

Both Boeing and Airbus recomend moving the stick forward at the first symptom of the stall, warning, shaker, buffet etc.

At 150', with no engines, well, as Alex Ferguson says, it's squeaky bum time.

[Ashling]

Sorry guy's no definitive data

[CONF iture]

you move the stick forward, reducing power or moving the stab trim if needed to gain control authority.
Generic procedure not realistic with the scenario YOU set me in initially.

[CONF iture]

Small differences between these predictions and flight test results are not uncommon.
Small differences as the alpha max which was at 17 deg at the time of the article but is now 17.5 so more than anything the alpha stall might well have followed a similar trend …
But whatever the figure you consider as to be reliable, the key point of that discussion is still the following one :
there was some additional angle of attack margin available to flare the airplane and reduce the descent rate at touchdown

[Owain Glyndwr]

Originally Posted by NTSB
there was some additional angle of attack margin available to flare the airplane and reduce the descent rate at touchdown


Did I ever say there wasn't?

[Clandestino]

there was some additional angle of attack margin available to flare the airplane and reduce the descent rate at touchdown

Would you be so kind to provide reference to that?

The A320 alpha-protection mode incorporates features that can attenuate pilot sidestick pitch inputs. Because of these features, the airplane could not reach the maximum AOA attainable in pitch normal law for the airplane weight and configuration; however, the airplane did provide maximum performance for the weight and configuration at that time.

If you think there isn't a risk of a stall in that speed regime you are a dangerous fool.I beg to differ. This is specialist knowledge and if such a belief is held by a person that has no access to flight controls anywhere, anytime, (s)he absolutely can't be labeled as either dangerous or foolish. As these are anonymous forums the origins of the contributions may be opposite to what may be apparent. In fact the press may use it, or the unscrupulous, or sciolists, to elicit certain reactions.

Now if a real pilot would operate his aeroplane while believing it, that would be entirely different ballgame.

[CONF iture]

Did I ever say there wasn't?
Sorry, I thought you were from your remarks.
If you aren't then that's OK isn't it ?

[Ashling]

Been away

Confiture

My question

When I said what would you do if you got a stall warning I was referring to a Boeing not an Airbus in normal law. If your in a Boeing (or a Bus in alternate/direct law) what are you going to do when the stall warning goes off at 150' because your too slow.

You replyed

The same thing that at 3000 ft, release some back pressure should be enough to stop the STALL warning or the stick shaker and keep the final pull for the last 50 ft.

YOU mentioned 3000 not me, it's you who don't appreciate or give enough credence to correct stall recovery procedures. That "Generic" stall recovery procedure happens to be the initial stages of the one used by both Boeing and Airbus, strange that.

Point being in your Boeing releasing the back pressure may do little as you may have trimmed back, If you haven't you may or may not succeed in getting rid of your warning but at the price of a higher rate of descent for no or very little speed gain. At 150ft they were going down at @ 1200 fpm 19 kts below VLS @ 25 kts slow on F speed. Your solution would increase that rate of descent and the only way you would have to recover would be to pull back into the warning with no idea what your margin is.

In the event the Bus managed to reduce their descent rate all the way to splashdown.

Maybe as Clandestino suggests, your not a dangerous fool, your just not a pilot

[CONF iture]

Point being in your Boeing releasing the back pressure may do little as you may have trimmed back
If trimmed back no back pressure is needed ... Make your mind.

Maybe as Clandestino suggests, your not a dangerous fool, your just not a pilot
Just don't tell anyone else ... :suspect:

[Ashling]

Depends how far back you trim, essential point being you have to ensure you lower the nose to remove the warning

Thought this was interesting from the performance study relating to the accident

The elevator response plotted in Figure 15b indicates that during this time, the elevators move trailing-edge up starting at 15:30:37, reaching about 4° at 15:30:38, and then move abruptly down to about -1° at 15:30:39 before increasing again to about 4.5° at 15:30:41. In the last 2 seconds of flight, the elevator deflection increases about 1°, from 4.5° to 5.5°.

Figure 7 shows that between 15:30:36 and the touchdown at 15:30:43, the pitch angle increases from 9.5° to 11° and then settles back to 9.5°, even though in the last two seconds the left longitudinal side stick is at its aft limit, and α is below αmax.

… the aircraft was in angle-of attack (AoA) protection from about 150 ft RA. When in AoA protection law, stick command is AoA objective. Stick neutral commands alpha-prot and full back stick commands alpha-max.

However, AoA protection shall take care of the A/C trajectory and, thus, looks after phugoid damping as well as AoA control: there are feedbacks within the AoA protection law aiming at damping the phugoid mode (low frequency mode). The feedbacks are CAS and pitch attitude variations. Without these feedbacks, an aircraft upset from its stabilized flight point up to constant high AoA would enter a phugoid (which is, by definition, a constant AoA oscillation) without possibility to stabilize the trajectory. As a consequence, commanded AoA is modulated as a function of speed and attitude variations: for instance, if A/C speed is decreasing and/or pitch attitude is increasing, pilot's commanded AoA is lowered in order to avoid such a situation to degrade.

On the last 10 sec of the "Hudson" event, it is confirmed that pitch attitude is increasing and CAS decreasing. Then, the phugoid damping terms are non nul and are acting in the sense to decrease the finally commanded AoA vs. the stick command, in order to prevent the aircraft from increasing the phugoid features.

[CONF iture]

Depends how far back you trim
No - If you were in trim there would be no back pressure in the first place.

[White Knight]

bubbers44 - It is always better to counter arguments by refuting what was said rather than what was not said. No one said 'it is ok for your pilots to lose airspeed and pull up into an 11 degree pitch up attitude at FL350 which we all know will result in a full stall'. I can see you are not an Airbus pilot and therefore have limited grasp of the situation, but the whole point of an Airbus is that normally you cannot stall it. 'Lack of pilot skills', as you describe it, is not simply stick and rudder proficiency, all very good as that is. Operating a large passenger jet like an Airbus requires a whole host of other skills, including a thorough grasp of the failure modes and being able to separate the wood from the trees in a high stress environment - a rare skill in my experience. Unfortunately the aircraft in this case had degraded into a reduced flight law status, which was not recognised by the crew. Furthermore you say that 'at FL350 level flight AOA would be nose attitude'. That statement does not entirely make sense to me, but from what I understand you are saying that if the pitch attitude on the artificial horizon (PFD in Airbus parlance) says 2 deg then you would see that as an accurate readout of AoA. That is absolutely not the case and the crew's misunderstanding of that was ultimately what killed everyone. It is entirely possible to have the pitch attitude around 2-3 degrees and still have an AoA of 20-25 degrees, which was the case here. They got into a stall because they pulled back on the sidestick in a reduced flight mode (Alternate Law in Airbus-speak). That induced a stall (an aural warning went off 75 times in the descent sating, 'Stall, Stall' but they never acknowledged it once). The actual attitude on the horizon was only a few degrees but their AoA was massive - something they never recognised. There were two compouding factors - the RHS First Officer for some reason (overwhelming anxiety?) kept his sidestick deflected fully back throughout the whole experience which was not spotted by the LHS First Officer and it therefore made his inputs largely redundant. The second factor was that they had experienced an erroneous speed indication earlier on one side, due to icing of a pitot probe, that had completely blown their mental understanding of the situation. Combine that with a host of strange warnings they could not process, night time, bad weather, no Captain present to take absolute control clearly and positively - you have a cocktail for catastrophe present. There is absolutely no doubt their training was inadequate, but that is another issue. To simply see them as two idiots who lacked basic flying skills is a gross and unhelpful simplification of the situation. Were they ultimately to blame? Without a doubt. Were there a number of other factors which contributed to a totally recoverable situation? Absolutely.

As an Airbus trainer and examiner (check airman in US-speak), my observation would be that if a genuinely unexpected loss of airspeed takes place (not one everyone is expecting because that is what they are doing in that particular recurrent training cycle) it has about a 50% chance of being recovered by the crew. Many would disagree with that view, but that is my view nonetheless. Crashes are rarely one cause as we know - a whole series of events come together in a particular moment of time which together lead to disaster. Many lessons have already been learnt by Airbus operators about this accident - including the need to have stall training on an aircraft that is not theoretically able to stall! When I did my type rating many years ago we never did stall training. That has now changed dramatically and I believe that the vast majority of Airbus pilots facing the same situation as the AF447 crew would be able to recover the aircraft to safe flight. Sadly, it often takes an accident for the right training to be in place.



Total :mad:! Bubbers is correct; 10 pitch-up is not what you want at FL350. It was a basic lack of SA.... No excuses at a large Euro airline.

No need for extra stall training (which as PILOTS we should all know from our C-152 days). Just need crew who can FLY an aeroplane:rolleyes:

[White Knight]

This shows the splashdown from surveilance video. It looks pretty normal to me.

Yep. As normal as a SPLASHDOWN in a modern airliner is!!!!

[Ashling]

Confiture you misunderstand


Trimming does not mean you are in trim. How far the nose travels, and in which direction, when you release the stick will depend on were you or the aircraft have trimmed to. I made the point about trimming to illustrate one reason why releasing the back pressure is an inappropriate response to a stall warning. You have to lower the nose attitude, to reduce AoA, by looking out the front or, if IMC, at your AI or PFD.

No one disputes that there was an AoA margin spare, the issue is whether you can access it. In a 737 you would be into the shaker so you wouldn't do any better unless your into ignoring stall warnings which would be insane.

The following is from Airbus's submission to the NTSB

"During the remaining portion of the flight, the Aircraft remained in Normal Law, and on occasion was flown within the alpha protection range. Notably from approximately 150 ft down to the water impact the Aircraft was in slats/flaps configuration 2. During this time period the Aircraft was in the alpha protection mode which allowed the flight crew to remain focused on their priorities, conversely if the Aircraft had been a non fly-by-wire aircraft, the flight crew would have had to fly in and out of the stick shaker to maintain the desired descent profile."

[GGR]

I wouldnt fly in anything with a pilot who could not spell altimeter. (''altimiter)

[Capn Bloggs]

I made the point about trimming to illustrate one reason why releasing the back pressure is an inappropriate response to a stall warning.
Nonsense. If you're holding back pressure, the aircraft, by definition, is not in trim, and releasing the back pressure will reduce the AoA and may well stop the stall warning. When pulling too hard on the base turn, invoking the stick shaker, releasing back pressure may well stop the stick shaker. Real aeroplanes only, of course.

[Ashling]

It's not nonsense, what is nonsense is a pilot suggesting that the correct way to recover from a stall warning in a commercial jet is to release the back pressure.

You reduce the AoA by moving the stick forward as per Boeing and Airbus QRH, anything else is unacceptable. Both QRH's also refer to the possibility that you may need to reduce power and trim the THS forward in order to gain enough elevator authority if moving the stick alone is ineffective.

Depending on the aircrafts trim you could be holding a high stick load, none or anything in between its even feasible, especially with electric/auto trim, that you could be trimmed fully nose up. If your holding lots of stick force then maybe releasing the pressure will remove the warning, no guarantee, but that response will reduce the closer to in trim the aircraft is and that is why saying "release the back pressure" is wrong and dangerous.

As for pulling to the shake sticker on a base turn! What aircraft and operation are you referring to that would advocate releasing any back pressure is an adequate response?

[BOAC]

I do believe this handbagging has gone on long enough - can you both accept that a reduction in alpha is required? Whether it be from relaxing the 'backpressure' when pulling or physically moving the c/c (or stick) forward when not, is it not the same?

Maybe then we can return to "American Airlines Flight 742 "flight control system" problems"

[Capn Bloggs]

Whether it be from relaxing the 'backpressure' when pulling or physically moving the c/c (or stick) forward when not, is it not the same?

Yes it is, and it's the thing you do when trying to unstall the wing. Ashling appears not to understand what the stick will do if let go when untrimmed/holding backpressure. Perhaps he is an Airbus pilot...

It's not nonsense, what is nonsense is a pilot suggesting that the correct way to recover from a stall warning in a commercial jet is to release the back pressure.
So what will happen to the stick and the AoA when I let it go (oops release the back pressure) after holding back pressure?

Handbagging at 20 paces. :D I just what to confirm that one of the handbaggers understands what is going on.

As for pulling to the shake sticker on a base turn! What aircraft and operation are you referring to that would advocate releasing any back pressure is an adequate response?
I can see why Confiture has left this. I did NOT say it was an adequate response. I said exactly as you did: it may well remove the warning. Well now, no stall warning: what're we gunna do now, Hoskins? Keep pushing??

[Ashling]

Sorry BOAC,

While I can happily agree that a reduction in AoA is required I cannot accept that releasing backpressure is the correct response to a stall warning, it may be effective but it may not. Stall recovery procedures do not say "release any backpressure then if ineffective move the control column centrally forward". There is a reason for that. There are too many variables, rate of speed reduction, trim, power setting, nose attitude, bank angle, g load, control authority etc.

In the right circumstances releasing backpressure may be sufficient to remove a warning but what we have to have is a procedure that works and for people to understand that there is no ambiguity in how it is applied, that is why Boeing and Airbus rewrote their procedures in the light of recent tragic events.

If we're talking max rate turns or air combat in the buffet then things are different but that's a specialised environment.

[BOAC]

I am basically with you but trying to draw this endless thread somewherehttp://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif. It is certainly NOT 'the correct response' as a rote, but it might be an effective one sometimes. Whatever, alpha reduced is the aim. How about that? After all, 'relaxing the back pressure' is in fact 'pushing' the stick forward.:hmm:

[Ashling]

BAOC

I appreciate your frustration and am quite happy to accept that releasing any back pressure MAY be enough to remove a warning and that it MIGHT be effective sometimes, in fact I've said that already I think. It's just I can't accept it as the "correct technique", ex standards QFI, hence being a touch pedantic. There is a difference between releasing a pressure and a positive forward movement of the stick IMHO. The later emphasises the need to keep going until the warning/ stall is broken, the former does not.

After recent events it would seem to be something worth being pedantic about!

[CONF iture]

Trimming does not mean you are in trim.
Maybe in your world ... not in mine as the goal for trimming is precisely to be in trim. But I'm not supposed to be a pilot here after all ...

[sevenstrokeroll]

releasing back pressure may work. pushing forward on the controls/stick DOES work.

maybe you will only have one chance...so PUSH THE THING FORWARD.

and yes, you will probably lose altitude. but if you got into a stall at all...well, shame on you (training aside)

[sevenstrokeroll]

white knight you are right

boys and girls...situational awareness...flying along, airspeed normal, altitude constant, power setting normal, pitch normal for speed at cruise.

I was once in a plane with a moron captain...he didn't have his pitot heat on (i did) and we entered cloud....his airspeed fell off to zero, he started panicing like a little girl.

I said calm down, we are trimmed for level cruise flight with cruise power and no indication of turbulence, I then reached over and turned on his pitot heat.

a few seconds later, everything was fine

and if and i mean IF we had NO accurate airspeed indications I sure wouldn't PULL BACK ON THE STICK

and maybe the LHS pilot should have pressed the I've got it button and pushed forward.

a long time ago in a galaxy far far away we assumed one thing would be wrong and looked for other ways to KNOW what was going on.

[misd-agin]

^^^. What type of a/c?

[Clandestino]

Maybe then we can return to "American Airlines Flight 742 "flight control system" problems" We can't. There were none.

[nitpicker330]

Airbus 330 Memory item checklist for Stall Warning says:--

"-Nose down pitch control --- Apply

This will reduce the Aoa"

Couldn't be clearer.

Next. :mad:

[BOAC]

We can't. There were none. - aha! The penny finally drops!

[Lonewolf_50]

BOAC, it only took 18 pages. :ok: Happy days.