You are correct Sir.

The overall system is more complex than we think.
FCOM is fine (or is it ... ?)
Flight Crew Training Manual provides instructive reading.
In flight, a lot happens but time does not always allow to analyse properly.
Best option is the Flight simulator to take advantage of the frozen position and try to understand what's going on ?

There are so many possible combinations depending if you're flying manually or not, A/THR ON or OFF, FD ON or OFF, if you follow them or not, there are the numerous mode reversions, the mode protections ... and altitude AGL interfer as well ...

Anyway, a lot to check in your Flight Management Annunciator if you want to have a chance to monitor all these subtleties. No wonder not so much spare time to monitor the geese outside ...

Among the Airbus drivers, the are many things we are made aware one day but cannot remember days further. It takes a lot of continuous reading and Pprune is a good tool for that purpose. No one has to believe what's written on this site but it's a good place to dig deeper and many opportunities for learning or ... reminding.

Absolutely correct, it's what many guys do, it's what I personally do and get comfortable with ... but still, I don't think I should as the day I need to press the red button and keep it pressed I won't be in my usual setting with the armrest becoming useless.

Question :
Anyone made an estimate regarding the GW of US1549. I was thinking somewhere between 60 and 65 tons ?

Sorry.....don't know how to make those pretty blue boxes with the quote in them.

CONF iture -
"Originally Posted by DC-ATE
It appears to me that you A-320 drivers can't agree on just what goes on with your FBW systems during various phases of flight.
You are correct Sir.
The overall system is more complex than we think.
FCOM is fine (or is it ... ?)
Flight Crew Training Manual provides instructive reading.
In flight, a lot happens but time does not always allow to analyse properly.
Best option is the Flight simulator to take advantage of the frozen position and try to understand what's going on ?
There are so many possible combinations depending if you're flying manually or not, A/THR ON or OFF, FD ON or OFF, if you follow them or not, there are the numerous mode reversions, the mode protections ... and altitude AGL interfer as well ...
Anyway, a lot to check in your Flight Management Annunciator if you want to have a chance to monitor all these subtleties. No wonder not so much spare time to monitor the geese outside ..."


Thank you for that. It just makes me all that more uncomfortable thinking about the whole system. What ever happened to K.I.S.S.?

I flew the 737-300 for a spell and had to constantly tell the Co-Pilot (sorry, First Officer) to get his head out of the cockpit and FLY the airplane!

Anyone made an estimate regarding the GW of US1549?
 

CONF iture, I'd vote for 65000kg. I'm not sure which type of tons you refer to!


DC-ATE: re KISS.

In the 70's you probably had an Operations Manual and a Flight Manual. Easy to distinguish.
Then some bright chap invented the Flight Crew Operating Manual. Since when there's been a generation of trainees wondering... now is that the ops manual or the flight manual...

Not sure what KISS is for exactly but I can guess the concept behind and approve it.
Nowadays, one of the most common advice you will hear during a sim training is : Read your FMA ! (in other words : stay inside)

Thanks Dysag, tonnes would be probably more appropriate ...

No news from the French authorities still?

Nothing personal but..........Keep it Simple, Stupid.

I disagree with your hand position. The sidestick is designed to be held with the thumb on top, putting your index finger comfortably near the Transmit switch - if you can't fly and transmit simultaneously you are not in control of the situation. (Ask Sully). And a small movement is far more difficult to achieve holding the sidestick near the base - there is a breakout force to overcome, which is easier with a longer lever. (Ask the TP's).
Regards
TP (Not a TP)

TyroPicard;

Yes, the stick is designed to fit the hand. That said, the hand doesn't necessarily stay in one position for all regimes. At any one time the hand can slide down the stick to "dampen" inputs for example in turbulence on approach, and move further up for slightly more authority when needed - there's no hard/fast rule, nor should there be.

Also, I disagree with your comment on the hand position & transmit button statement "as a rule", but yes, that certainly works when required as in the Hudson River case. Normally, the PNF is doing the radio work and cockpit discipline would mandate that only one pilot do the communications work unless the captain deems that circumstances require otherwise, of course.

The point of the original comment is, there is a tendency to "stir the pot" with large stick movements, particularly in turbulence, even to the point where the stops are reached. That's not the way to fly fbw aircraft as the computers and control surfaces are already doing their best to maintain the last position requested by the stick. Airbus recommends small corrections, not large ones.

Back on thread?
 

Sorry to be a bore but ....

Has anybody got any "Rumours and News" that has anything to do with this accident?

DC-ATE;

Sometimes discussing techniques and even how the 320 works is like watching a roomful of economists come to an agreement. Sometimes they're talking about the same thing but the language gets in the way and sometimes mistakes in knowledge, judgement or memory are made. The airplane "behind the panel" is complex but flying it is not.

NoD is correct in his responses as far as they go, (including the similarity to Boeing in V/S in the circumstances described and the Alpha modes as Lemurian indicates), but in descent, the airplane operates as described and this is an important point because in "IDLE - OPEN DESCENT" mode, the airplane does not operate like a Boeing.

The speed is indeed "on the elevator" in descent, (thank you again NoD for the clarification in the climb case - my year-and-a-half retirement is catching up with me I think!) and the engine power will not increase until and unless the altitude set in the altitude window on the Flight Control Unit panel, (glareshield panel), is captured.

If the pilot pulls back slightly on the stick, the speed will decrease and continue to do so until reaching a speed just above the "lowest selectable" speed, (Vls in the graphic) at which time the descent mode will change from Idle-Open Descent to Vertical Speed and the autothrust reverts to "SPEED". This "mode reversion" occurs in other autothrust-manual flight circumstances as part of the protections under "Normal (fbw) Law".

This design was the result of an accident at Bangalore, India in which the altitude selected was set too low to be captured during the approach and the autothrust stayed in the "Idle - Open Descent" mode until ground contact. The Flight Director system was similarly change so that if either or both FD's were switched off, the A/T system reverted to SPEED, to bring the power up. Previous to this accident, this was not the case.

The prevention of this accident was straightforward, and the same as any other airplane - take over the airplane, in this case by pushing the thrust levers forward, commanding a thrust increase from the engines to arrest the rate of descent - no different than the Boeing or a C152. The crew failed to do this and the airplane performed exactly as commanded by the crew.

Normally in descent when approaching the cleared altitude, one reaches for the throttles and pushes them up as a natural reaction (on the '8 for example), but not in the 320 (and Boeing with A/T's on, for that matter) - the autothrust will bring up the engines when the altitude is captured. But if the airplane is leveled off above the selected altitude as described, the 320's engines will not accelerate. To demonstrate the speed decay a bit I would ask transition line indoc students on the airplane to fly manually and "level off" just above the altitude selected in the FCU window. When the speed began to decay a few knots, one could pull the speed knob which maintained the current speed or one could turn the F/D's off to revert to the SPEED mode. The importance of this was to show why IDLE-OPEN DESCENT mode was never to be used below 1000ft AGL and if it did occur, how to handle it - fly the 320 like a 152.

In my view, airline managments and training departments alike do not emphasize nearly enough the fact that the 320 is just another airplane and can and should be disconnected entirely from the automation - it hand-flies beautifully. I know crews today are still reluctant to disengage the autothrust because they are not taught properly how to and are reluctant to grab a mitt-full of throttle and push when needed. It's still an airplane - clearly, Scully is keenly aware of that fact.

The airplane is indeed complex and difficult to explain in text in a forum - afer one flies the aircraft for a period of time, say six months, it becomes second nature.

Actually, both FD's need to be switched off.
Switching off only one of them won't allow the system to revert to SPEED mode ... That's one of the catches !

And for Sonic Bam, still nothing on the horizon ...

Thanks for all that PJ2.

The more I read, the happier I am that I'm outta there!

How things work
 

People born in the early 1900s could probably figure out how a steam engine works.

People under 30 don't even ask "how does my cellphone send photos?" It's obviously not necessary to know.

And in between, there's the rest of us.

I grew up knowing how my car worked. After all, I had to take it apart a lot. Now I have no idea, it's just too full of black boxes.

It's not an easy adjustment to make, and when your life depends on stuff working properly, it can be uncomfortable.

But just because we can't take it apart to see how it works, it's not necessarily exotic any more.

The 4700 Airbus A318/319/320/321/330/340/380s in service have a flight control system which is now the norm, not the exception.

Good points, and even steam engines exploded and scalded people, nothings' perfect, I appreciate DC-ATE's points of view - same era - but we have to accept that life moves on. Not easy.

PJ2
The sidestick has a fixed breakout force. This is easier to overcome, with more control, if your hand is near the top - simple levers/moments theory.
A "small" movement at the base is a "larger" movement at the top - the same "small" movement at the top is a "smaller" movement at the base.
It ain't rocket surgery.

PJ2... You really are making me get back in the books here ;)

The Reversion you quote is correct for older A320 series aircraft... newer or modified ones just turn the FDs off and go to SPEED.

What I do disagree with is IMHO this is nothing to do with FBW... It can occur in any law in which FDs are available, and is part of the FMS (Flight Management / Guidance System).

My "recollection" (which maybe wrong) is that (Idle) OP DES is pretty much like FLCH is a B757/767...

NoD

All this discussion about mode reversions is a bit confusing and re-inforces the prejudiced one's bias aginst modern flight management systems.
Be it a Airbus, or an Embraer, a Boeing...or any brand one cares to mention, the principles are the same as those that have been used since flight controls have been used :
A pilot has at his disposal a pitch control and an engine. Full stop.
The rest is a matter of flight path management, which in turn breaks down to "Energy Management". That is, exactly, what piloting is about.
From that principle, a pilot can elect to have :

• either a fixed engine output - idle, climb, max continuous, TOGA - and control the desired speed with the pitch control, or
• follow a fixed vertical path of his choice -vertical speed, Vnav, or an electric glide path of any sort, in which case the speed is controlled by the pitch control and the engine is used to control the vertical trajectory. (There is nothing new, nothing hidden lurking behind the pilot as that is the way we're taught to fly an ILS).

Now, a pilot is supposed to know what he wants, isn't he ?

• either he flies "raw data" and he does it exactly like he would a Cessna 172, a DC-8 or a 777,
• or he uses the accuracy brought by the flight director, he will get the help of the command bars, but first he has to sign a contract with the FD : "I want to fly with the thrust at hand, you help me control the speed I want with the stick/yoke. As a proof of your agreement I want you to show me , on the FMA, a fixed thrust mode (Idle / Clb / Max Cont / TOGA ) and the Open mode / FLT CHG.
• If I need a fixed path, I want to see on the FMA that you'll take care of the engine, therefore I want to see "THRust" and a confirmation of the path you'll help me follow : VNav, GP...
• I said there was a contract. "If I don't follow the pitch command bar, you are allowed to "revert" to a mode that will keep our energy management on the safe side, and tell me at once what you've done through an alert and a clearly stated mode change."

That is all there it is about Flight management, and, to me, these "reversions" are quite logical and straightforward.
I might also add that in circumstances where the "FD or A/P acts funny", the -very easy - solution is "BACK TO BASICS" AND REPROGRAM THE DAMN THING ! In most occasions, the pilot has been distracted and hasn't followed the terms of the original contract.

Dysag -
Well, Dysag, and others: You boys stick with your new fangled toys and I'll just go along with my old needle/ball and airspeed and hopefully, we'll all get to wherever it is we're going safely.

I follow your logic here, but still, I'd like to disagree on it :
Except when AP is engaged, I don't really feel any breakout force, there is a neutral point for sure but that's it.
There is more precision to be gained when using the tip of 2 fingers than when soliciting the wrist.
Just my own appreciation, but I feel more comfortable the way PJ2 put it than the way you describe it, even if I do think you are correct.

Anyway, it does not hurt talking of these things as the BEA still does not communicate on Perpignan ... at least directly.

During this time, the report on the Etihad 346 in TLS is now available in English ... but people still remain silent even if the BEA report is a blatant inconsistency !

CONF .. agreed .. PIO is the likely result of trying to fly it like a flight sim toy..