Dual Input Airbus
 

I've come across a number of pilots who claim that during a late flare from the F/O and in order to save a potentially hard or firm landing, pump the side-stick at short intervals in a way that the dual input doesn't sound.

I have never done it, just keep my finger in the red button hoping i don't have to use it.

my understanding according to the algebraic design, is that it would be necessary to deflect ones sidestick beyond the other's deflected amount, to cause an additional elevator response.

what do you think about this underdog common practice?

I call it irresponsible and dangerous. It reminds me of a certain Captain I knew who felt that all that mattered was a super smooth touch down so he wouldn't fully retard one thrust lever so only part spoilers would deploy and hence not dump the front end of the bogey on the 330. Then all he had to do was stop the aircraft before the end, er....

Why not just call "flare" to the FO.

There plenty of auto call outs to cue the flare, vary a little of course with conditions on the day, last thing needed is another unannounced input.

I think this thought originated from incomplete understanding of the system. First thing, even a small movement out of neutral will give a command to change the pitch and depending on what the other stick is doing it will impart the LF or AoA as demanded if other stick is neutral, added if the other stick is moved in same direction or subtracted if other stick is moved in opposite direction. Dual input will sound when the sticks are moved beyond 2°. Once on two consecutive Landings the FO didn't flare at all so I flared at 10ft. and let go. He was happy with the result. I told him you didn't flare I had to flare. He said but there was no " Dual input". I said that's right there was no dual input but the single input was mine. I should have taken priority. The practice of fiddling with stick is senseless will give confusing results. The correct practice ask him to flare or press TO button and do it yourself. There's no follow me on controls in Airbus.

deja vu

My comment of "Why not just call "flare" to the FO" was for those that are worried about the FO flaring late. Not giving an extra call, unless it is required.

It is a common practice in SE Asia. I say "common" but not "right".

It can be called nervous twitch because it doesn't do any GOOD. If it did Airbus instructors would have suggested it. Pilots allowed to give takeoff and landing should be given a practice of take over with the button. It's a tricky part. Instead of fiddling with the stick you need your thumb on the button to quickly take over. As it happened in the Jetstar Australia incident the guy yanked the stick to raise pitch 21° the trainer was unable to intervene resulting in bad tail strike.

You mean like "Oh !!!!!"

My understanding is significantly different. The individual deflections are added up, and the sum then fed to the F/CTL computer. Any deflection will have an effect.

A very important aspect is to properly brief new trainees FO/Captains/Instructors on the fact that, unlike other "conventional" aircrafts where a little help is given to avoid digging a hole and spending the turn around with paperwork, on the Airbus FBW family there will be a takeover from the Captain/Training Captain should the need arise, that this is perfectly normal and there is no other way around. In my experience spending a few words with the trainees prior to their first flights and emphasising this aspect has proven beneficial in order to avoid potential demotivation and drop in performances following a low height takeover. It is then up to the trainer/captain to set their own threshold to what is acceptable and what is not according to each own's level of experience, but a takeover is always the right and only option if we are not happy with anything. It is better to have a takeover when it was not really needed than the opposite, and with time everybody can adjust their own tolerance.

Pax so disregard if displaying idiocy. If you were to input little nudges to correct, wouldn't the other guy think he had nailed it and risk embedding a wrong model in his/ her head?

Only if it wasn't debriefed when work load allowed.

FD, algebraically added. Absolutely correct.

But...Isn't that dangerous? Whatever happened to "I have control." I forget how long the take-over button takes, 5 seconds maybe

Why is "I have control" not "Mine?"

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.

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.

Sorry, but I disagree. You do have time to press the takeover pushbutton, it takes 1 millisecond regardless of the words You pronounce, if any. Being able to judge when it is appropriate to press this button is another question though and that comes also with experience, I believe we all acted with our thumb at least once either a bit too late or a bit too early (at least I did luckily without breaking anything). The basics is any time You are PM and need to act on the sidestick for whatever reason, You push the button.
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.

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.

if you are flying Airbus why do you have to say anything? The aircraft will say that for you. Priority left is same thing. Just press the take over button, flare and land. Tell the FO to do a better job next Landing.

At 10’.........too late, all over red rover by then......

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.

You are all obviously talking about the A320 variants as flaring at 10' on A330/A340/A350 will only drive the mainwheels into the ground harder! Intervention should have happened well before then.

Iceman, no! I didn't suggest flaring at 10ft. but ten ft as salvaging point in A320.

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.

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.