Dual Input Airbus
Joined: Nov 1999
Aviation Qualifications: ATPL
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From: UK
If a pilot does not flare at 10’ there isn’t really time to say I have control, you just need to take control. With a conventional yoke system, a Trainer or Captain could apply back pressure on their yoke which would save the landing and give feedback to the trainee, (followed by a debrief).
The Airbus FBW side-sticks do not move to mirror each other’s inputs - (I think they should) - so instead there is an algebraic addition of deflections. This means that in a no flare situation, the Trainer/Captain could quickly pull back and save the aircraft, but it is not correct for both pilots to be operating the controls, hence the “dual input” warning if the take-over button is not also pressed.
Airbus FBW nosewheel steering is also additive, and I once saved a Captain who suddenly veered over (for some reason) while taxying, and I grabbed my tiller and saved any embarrassment. There wasn’t time to alert him or say I have control.
The Airbus FBW side-sticks do not move to mirror each other’s inputs - (I think they should) - so instead there is an algebraic addition of deflections. This means that in a no flare situation, the Trainer/Captain could quickly pull back and save the aircraft, but it is not correct for both pilots to be operating the controls, hence the “dual input” warning if the take-over button is not also pressed.
Airbus FBW nosewheel steering is also additive, and I once saved a Captain who suddenly veered over (for some reason) while taxying, and I grabbed my tiller and saved any embarrassment. There wasn’t time to alert him or say I have control.
Joined: Mar 2006
Posts: 2,633
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From: USA
Depends on the airline. My previous company was much more aligned with Airbus SOP. We said “I have control”. Current company says “my aircraft”. They’re fairly strict on that in the training department. “My airplane” will get you slapped on the wrist.
Joined: Mar 2012
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From: Having a margarita on the beach
It works perfectly well if you know how to do it and set yourself some reasonable gates. Intervention training is generally part of upgrade courses and is a big part of TRI courses. When we do qualify TREs for base training we spend at least an hour each in the sim to practice all sort of mismanaged handling at low height, it just takes a bit of practice.
Joined: Nov 1999
Aviation Qualifications: ATPL
Posts: 3,148
Likes: 742
From: UK
Joined: Mar 2006
Posts: 2,633
Likes: 137
From: USA
It works perfectly well if you know how to do it and set yourself some reasonable gates. Intervention training is generally part of upgrade courses and is a big part of TRI courses. When we do qualify TREs for base training we spend at least an hour each in the sim to practice all sort of mismanaged handling at low height, it just takes a bit of practice.
Joined: Mar 2012
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From: Having a margarita on the beach
As Uplinker said bout the heat of the moment, sometimes there’s no time. An easy, intuitive solution to the problem they created is used by Boeing, Douglas (RIP) etc. Airbus put a lot of energy into human factors, but the uncoupled sidesticks (particularly in with the AP off) is a huge oversight, and fatal, as we’ve seen.
Regarding the AF447 You are referring to, if You end up with 10 degrees ANU and TOGA at FL350 I believe (and much more important investigation bureaus believe) it is somewhere else we need to focus on rather than the mechanical connection between the sidesticks.
Joined: Aug 2013
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From: The bush
Capt presses red button, aircraft announces, "priority left", capt lands aircraft and discusses flare technique with first officer at bay after shutdown.
No "tea n' bikkies" with management as heavy landing avoided, first officer's 21st century ego takes back seat and everyone goes home happy.
Not difficult.
No "tea n' bikkies" with management as heavy landing avoided, first officer's 21st century ego takes back seat and everyone goes home happy.
Not difficult.
Joined: Jun 2007
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From: Wanderlust
If a pilot does not flare at 10ft there isn’t really time to say I have control, you just need to take control.
Joined: Jun 1999
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From: Oztrailia
At 10’.........too late, all over red rover by then......
Joined: Jun 2007
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From: Wanderlust
Not necessarily. All you need is to break the descent. It can be done at 10ft. But if you feel it's too late then you should do it while crossing 20ft. In the aircraft some one needs to do what is required to be done. If AP doesn't then pilot, if PF doesn't then PM has to. And the last barrier needs to be defined according to individual judgment. Cannot continue accepting hard Landings till the FO develops the judgment.
Joined: Mar 2006
Posts: 2,633
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From: USA
On a more serious note, it is concerning when airlines never allow FO’s to fly in challenging conditions, then hand the keys to the jet to those same FO’s after upgrade.
Joined: Dec 2003
Posts: 253
Likes: 1
From: Europe
Also an important thing to note:
dual input as opposed to pressing the takeover button can save the day sometimes. If your colleague doesn’t flare enough, the moment you press the button the flight control does what.......? Back to neutral until, your input is established, which could make matters worse temporarily.
dual input as opposed to pressing the takeover button can save the day sometimes. If your colleague doesn’t flare enough, the moment you press the button the flight control does what.......? Back to neutral until, your input is established, which could make matters worse temporarily.
Joined: Jun 2006
Posts: 240
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From: B.F.E.
Sometimes a combination of instinct and procedure is the right technique. The time that most of us will instinctively move the stick (“DUAL INPUT!!!”) before pressing the takeover PB is either a quick pull when the guy forgets to flare, or a quick lateral move when the guy over-banks suddenly. The “OH S#!T” pull will always happen before the button gets pressed! Adrenaline will ensure this!
In the opposite situation with someone over-flaring, we will naturally tend to press the button first. This will in actuality return the controls to neutral since we likely will not have actually moved the stick yet... which is exactly what we need to do.
Simply following instinct will always work, as long as we remember to press the takeover button at some point in the proceedings. To prevent a hard landing or a wing/pod strike, make the instinctive move first and then press the takeover button while applying the stick pressure. For a high/ over-flare, press the button first and then fly the airplane where you want it to be. Either way is natural and is what most of us will do without thinking about it.
In the opposite situation with someone over-flaring, we will naturally tend to press the button first. This will in actuality return the controls to neutral since we likely will not have actually moved the stick yet... which is exactly what we need to do.
Simply following instinct will always work, as long as we remember to press the takeover button at some point in the proceedings. To prevent a hard landing or a wing/pod strike, make the instinctive move first and then press the takeover button while applying the stick pressure. For a high/ over-flare, press the button first and then fly the airplane where you want it to be. Either way is natural and is what most of us will do without thinking about it.
Joined: Jun 2007
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From: Wanderlust
There's a difference between not flaring and not enough flaring. In not flaring at all the PF stick is in neutral so if the other pilot flares then it's single input and the aircraft response is normal. Not flaring enough the PF stick is out of neutral, here any input from the other side will be additive to it. Since flare and Landing is a visual manoeuvre if one is able to differentiate the change in flight path and adds his input accordingly then it will still produce the desired result even with dual input warning. The problem is if the PF for some reason pushes the side stick forward then the PM input will be cancelled and aircraft will continue it's Flight path. So the gist is if is you want to salvage the Landing you will have to do something in an approved or not approved manner. If the result is not satisfactory execute a GA. This the Achilles heal of Airbus FBW so perhaps the discomfort makes each one find his own solution.
Last edited by vilas; 26th September 2019 at 05:47.
Joined: Nov 2019
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From: unknown
I found this statement from another forum to be interesting. Perhaps not in the original design......
"There is a "dual input" audio callout. It was a early A320 mod, but I think it was standard before the A319 came out."
"There is a "dual input" audio callout. It was a early A320 mod, but I think it was standard before the A319 came out."
Psychophysiological entity
Joined: Jun 2001
Aviation Qualifications: ATPL
Posts: 3,383
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From: Walton on the Naze Essex.
I suppose flying allows one to get good at expecting the unexpected, but having got old, and sitting in an ATR watching a very able young man fly the sector, I was reasonably relaxed as we passed 200'. At some point, I'm not sure when, the concrete suddenly looked like it was coming through the windshields.
I'm not sure why it happened, or even how he managed it, other than it was flown, not mushing. What I do know is that with any delay, the aircraft would not have survived the impact. My frantic tug allowed one of those 3-point landings that don't allow the wheels to skid before spinning up. Despite my best efforts, exchanges in English were somewhat limited and I'll never understand, but it seems to me that a large aircraft, stacked with computing power, should be capable of protecting itself from pilot input that makes no sense.
As an example, was the 447 computer so deprived of sensory inputs that it couldn't protect the aircraft from nonsensical control inputs - or is there no such software? It seems incredible that systems wouldn't know inputs were illogical. I'm attempting to make a clear distinction between inputs and net flightpath.
I'm not sure why it happened, or even how he managed it, other than it was flown, not mushing. What I do know is that with any delay, the aircraft would not have survived the impact. My frantic tug allowed one of those 3-point landings that don't allow the wheels to skid before spinning up. Despite my best efforts, exchanges in English were somewhat limited and I'll never understand, but it seems to me that a large aircraft, stacked with computing power, should be capable of protecting itself from pilot input that makes no sense.
As an example, was the 447 computer so deprived of sensory inputs that it couldn't protect the aircraft from nonsensical control inputs - or is there no such software? It seems incredible that systems wouldn't know inputs were illogical. I'm attempting to make a clear distinction between inputs and net flightpath.