There are good reasons why Airbus have not been publicly gloating over the B737 MCAS screwup, and Habsheim, AF447, are some of them.
Boeing got crucified over MCAS but the Airbus stall warner suppression < 60kt IAS is in the same category.
Antonio wrote:
What will be the next situation that nobody ever thought of? I for one would like a pilot in control to take care of that one.
Exactly.
Habsheim and AF447 are not even situations nobody ever thought of. They are very predictable occurrences if you spend enough time thinking about the downsides of disconnecting the pilot from the control surfaces, or the pilots from each other.
If I ever get in the shit (and I hope I won’t, but am not arrogant enough to presume I won’t) then I want the control surfaces and engine(s) to respond exactly as I request. I don’t want them to do something different because (according to the design philosophy) they know better. I said in a post earlier this evening that I couldn’t think of a more dumb modification than disconnecting the dual controls from each other: well, I just did – adding a ‘smart’ layer to the control interface that might decide I don’t really mean it when I move the stick.
Graham wrote:
Habsheim and AF447 are not even situations nobody ever thought of. They are very predictable occurrences if you spend enough time thinking about the downsides of disconnecting the pilot from the control surfaces, or the pilots from each other.
I would wager that the Airbus engineers spent years considering similar scenarios, and decided to go ahead anyway. It doesn’t seem like the sort of design decision that you make on a whim, and whilst some of their other choices were perhaps not those that a stick’n rudder pilot would make, perhaps they weren’t wrong.
Take the Voyager incident as a counterexample. My understanding is that the captain got his camera wedged between the seat and the joystick. When he moved his seat forward, the seat pushed the camera which pushed the joystick and the aircraft went into a bunt. The captain pulled back but the aircraft didn’t respond. He assumed the problem was with the autopilot and tried to disengage it. Luckily the copilot had an independent sidestick and saved the day, but had the joysticks been connected, it seems to me that this might not have been possible. You win some, and sadly you lose some.
The report contains the following gem: “As the aircraft pitched down the co-pilot was lifted to the cabin roof and, whilst experiencing weightlessness managed to re-enter the flight deck via the cabin door. With his feet on the flight deck roof, the co-pilot reached down to disengage the autopilot by pulling back on his side-stick…” Chapeau. Let nobody say that pilots with the Right Stuff don’t fly Airbuses.
Gentlemen,
I see that this discussion is drifting towards “I have seen it on youtube and now I know better”.
I am leaving this topic as I dont have time nor need to discuss theories with people without any actual experience on the subject.
Please go, rent full flight sim, have fun and we can talk later.
If somebody would like to ask about real life on 320 or 321 – feel free.
Peter wrote:
the Airbus stall warner suppression < 60kt IAS is in the same category.
As speed gets lower, any stall warner must stop at some point. Even “steam” stall warners"like those on a C172 or PA28 will turn off eventually. The question is where to draw the line.
kwlf wrote:
had the joysticks been connected, it seems to me that this might not have been possible
ON large aircraft, it is required to have independent primary flight controls by Part-25 .
If control columns are mechanically connected by design, a disconnect mechanism must be available.
Typically there is a force-driven LH vs RH control column disconnect. When a certain force threshold is exceeded they disconnect from one another and control pitch independently. Roll-wise and depending on the aircraft type, rudder can be accepted as an independent lateral control.
IN fact, in one of my airline assignments, we had a few dispatch delay incidents from “column disconnect” messages resulting from overagressive flight control checks by the pilots, when in strong wind prior to departure. This required engineer action to re-connect prior to next flight.
Airborne_Again wrote:
The question is where to draw the line.
Yes, you don-t want them acting up all the time on the ground when taxying in 30 kts winds
Do they? I thought the tab in the leading edge is being pushed upwards – and the circuit completed and the buzzer going off – by the airflow as the aircraft descends at high alpha?
If the forward airspeed becomes very slow, does the tab stop being pushed upwards? I’d assumed it would always be pushed upwards with the airflow detached and the wing descending, unless of course the aircraft becomes inverted.
@Raven I don’t see any references to YouTube. Real life, where 99.9% of the time nothing happens, is not really the topic. It’s disappointing that you choose to exit the discussion rather than explain why you think unlinked controls for the two pilots are a good thing. And perhaps somewhat insulting to suggest that because people don’t fly an Airbus they aren’t worth talking to. EuroGA is a discussion forum, not a ‘transmit only’ forum where you explain and others learn.
Antonio wrote:
ON large aircraft, it is required to have independent primary flight controls by Part-25 .
[…]
When a certain force threshold is exceeded they disconnect from one another and control pitch independently. Roll-wise and depending on the aircraft type, rudder can be accepted as an independent lateral control.
Does that mean that you will get less authority from each individual control column if they are disconnected from each other?
you don-t want them acting up all the time on the ground when taxying in 30 kts winds
Use the squat switches?
Or the wheel spin-up, which is used on some types to auto deploy thrust reversers.
