Airbus taking over command from pilot, rare?

[trauha]

I was in an aircraft that attempted to land in quite stormy weather, looking at weather stats later there were gusts up to 48m/s at the time. The pilot thought he could bring the airbus in, but after extreme wind shear the aircraft's computers took over and we were up at a sharp angle and full throttle. Very impressive as the tanks were light after more than 8 hours of flying.

Is it rare to let the plane take over like this, instead of the captain making the decision?

[Flightmech]

Oh dear:ugh:, I don't think the computers made the decision all by themselves. A go-around requires a little pilot input (one button at least):ugh:

[treadigraph]

"What are you doing Captain?" :}

[Sky Wave]

Oh dear, I don't think the computers made the decision all by themselves. A go-around requires a little pilot input (one button at least)


If windsheer caused a sufficient loss of airspeed it is possible that Alphafloor protection activated. That would give you full thrust without the pilots pressing a single button. This being the case they would have little choice but to perform a go around (this part would be pilot initiated by advancing the thrust levers to TOGA)

Also if the aircraft generated a Windsheer warning which in most airlines would mean a mandatory go around you could argue that it's the computer that made the decision for the aircraft go around!!

Just a thought!

SW

[trauha]

Surely the computer not only gives full thrust but also pulls the nose up .

The rest of the go around may be pilot controlled.

With true airspeed varying wildly and quickly plus/minus 30kts due to the gusts I can tell you we were bobbing up and down a lot and the down bobs took us way below the incline path.

But my question was how rare is it for Alphafloor to kick in.

[Load Toad]

How was this 'plane takover' announced? A PA with a booming robotic voice..

THIS IS YOUR PLANE - DO NOT BE ALARMED - I DO NOT TRUST THE PILOT - I AM TAKING CONTROL!

[trauha]

Since this was quite a dramatic flight for me my curiosity got me to talking to the crew, though much later. They were not willing to talk about the incident when it was still fresh. Even so they are not very talkative about it.

The plane was an Airbus 340-600, if this helps to surmise.
What is the computer programmed to do regarding steepness of climb in such a situation? It was way steeper and faster than any take off. And so it should and could be. With at least 100,000kilos less weight in fuel than at take off and the four Trents doing their best.

The weather was exceptional, the weather was news that day. On the beginning leg the passengers were given the option to be re-routed courtesy of the airline. I think that too is quite rare. The reason being that it would be bumpy.

[SloppyJoe]

No the aircraft does not pull the nose up. Sounds like you got half a story and some facts not quite right. In all honest I expect they said the aircraft decided to go around as a bit of a joke. If alpha floor had been triggered I do not think they would be advertising it to any passenger who asked what happened. There would be an internal investigation and I expect the CAA would want to know about it also. They would not be saying anything to passengers about it.

If alpha floor is triggered and the autopilot is in and the pilot selects toga yes the plane will pull up (usually) but if it was being flown manually it would not unless the pilot pulled back.

It is very rare to have alpha floor trigger.

Just reread your posts was it VS into HKG?

[trauha]

Like I said they were not 'advertising' it at all!
And like I said they were tight lipped about it long after the event.

Does Airbus send data to the CAA automatically? I mean would the authorities know about it automatically? Maybe the pilot has been reprimanded, for all I know, that he has not told me. This was a Lufthansa flight into Frankfurt and it was not this year or last year. Are CAA incidents publicly available to read?

[Nubboy]

Considering the amount of time it takes, for people converting onto current generation electronic aircraft, to get to grips with all the different modes, it's hardly surprising non pilots have a less than clear idea of how things work.

Any approach that results in a go around like that described is a case of being outside the operating limits of the aircraft. Such events, will always have resulted in a very high workload for the flightdeck crew. Afterwards you will normally want to gather your thoughts before discussing it with other people. The fact that the crew seemed less than chatty is not surprising. However there is an obligation to the passengers to keep them informed as to what has happened, some explanation of why, and what your going to do next.

In terms of reporting it, all airlines and regulatory authorities have schemes in place defining which incidents have to be reported. The flight data recorders on modern aircraft are downloaded as a matter of routine, not just after interesting flights, and the reults analysed to produce trend reports.

[trauha]

Are you saying the 340-600 would never override the captain's decision to try and make a landing on the first go? Are there no Alpha Protection laws that pull the nose up?

[Load Toad]

So it didn't happen this year, didn't happen last year and your information as to what happened came from the cabin crew? Is that it. What flight number and date - if you were on the 'plane you must know that yes? And then maybe someone can advise you.

[FlightDetent]

Are there no Alpha Protection laws that pull the nose up? Exactly. The installed Alpha Protection function of flight control system in fact pushes the nose down, once activated.
The installed Alpha Floor function of autothrust system in fact may command automatic selection of full take-off&go-around thrust, if engagement conditons are met. That is, without pilot input.

Neither of these systems or combination of their functions will change aircraft's guidance from approach to go-around. The only way to change from approach mode to go-around mode is to have pilot activate the go-around mode manually. The subsequent go-around can be executed with autopilot engaged, or flown manually by pulling the stick. To activate the go-around mode on Airbus, pilot need to push thrust levers full forward (commanding maximum thrust during the process). Once the full forward stop is reached the guidance mode will change from approach to go-around.

A windshear (sudden change in wind velocity and or direction) may seriously affect the airspeed of aircraft; close to ground it is a very dangerous phenomenon. Modern aircraft are equipped with forward-looking "predictive windshear" system. On Airbus it has 2 levels of warnings. The hard level warning is associated with "W/S AHEAD" displayed in red on Navigation display and aural, repetitive "GO AROUND, WINDSHEAR AHEAD" synthetic voice.

Manufacturer says:
- Windshear ahead is an emergency procedure.
- Windshear procedure is to be applied from memory without referring to paper.
As far as the procedure itself, again, manufacturer's words:
W/S AHEAD red, landing phase > Go-around .... PERFORM.

While there are several warning systems with a number of different aural warnings, the described PWS function is the only one when the aircraft will scream at you to go-around. Hence the pilot's comments I would say.

Sincerely,
FD (the un-real)

[trauha]

thanks Flight Detent! This was a very helpful description as to the way things work.

Having landed at Frankfurt quite often, it *seemed* as if the captain had made a choice to fly UNDER the wind. Is this a strategy for high winds?

We were under the normal incline slope to start off with and very very close to the ground at times due to the violent bobbing up and down even though we were still quite far from the airfield. The winds were difficult: watching other planes land after landing, I counted 5 go arounds in one hour to the one runway that I could see.

[Fernanjet]

This does seem a bit of a joke post...highlighted by this particular snippet...

On the beginning leg the passengers were given the option to be re-routed courtesy of the airline. I think that too is quite rare. The reason being that it would be bumpy.

I too would say that this is so rare it was untrue.

Stupid almost.....

[trauha]

No, it is true, the airline was Southwest and the flight was from Miami to Chicago. I can get the dates for you if need help with the truth. Southwest does have a better relation with pax than most. That certainly may help you understand. Lufthansa offered no such possibility for the Chicago to Frankfurt leg.

As to the stupidity bit, It is in the airline's interest (and therefore smart rather than stupid) to make sure the passenger experience is as positive as possible.

[Fernanjet]

So Southwest....the originial loco, offered a free transfer to their pax in case the flight was a bit bumpy?!!!

:mad::mad::mad:

I still don't believe you - if it is true, then they are advertising turbulence as a legitimate reason for transferring for no extra charge - pathetic.

[trauha]

It was not "a bit bumpy" but extreme weather that was headline news, and the term they used was actually "rough ride".

[Fernanjet]

ok...."rough ride"

still not a good reason to offer a free change is it....

i just dont buy into that at all.....

are you sure it wasnt overbooked and they offered people the chance to change?