That's a peculiar thing about most of the internet. People routinely comment on things they haven't the foggiest notion of.

Done it on Boeings (B737-777) and MD/DC planes when the automatics didn't wanna do what i wanted it to.

I guess it's all up to design philosophy.

Whoa there Vilas from Malaysia.

I understand this isn't about my company procedure. I brought up company procedure because I had never heard of that Airbus recommendation before and with it being so recent, I was very surprised it was never covered in our training. I asked two United pilots (both Airbus) what they knew about it and both were unfamiliar as well.

I'm wondering why this is so unfamiliar here, especially with it being such a recent change.

I sent a note off to an instructor in Training and will post when I hear back.

It would be nice if they at least prefaced their post with something stating their level of knowledge.

"I've never flown an Airbus, but...."

Just pointing out:

The original poster noted that he had misread the context back in post #14, and yet here we are at post #45 with most of them being random sniping about Airbus and automation dependency...

Been there.
Seen B737 crews run of the end of a long runway where we landed a B777 minutes before.

It's the asian 185 kts flaps5 landings gone wrong.

That was a replay to Centaurus post 19.

Edit to add: we landed with lots of runway to spare.

Altcrznav
I think you should take it easy. If your airline hasn't provided this information to you for whatever reason then you are not at fault. This procedure was in place for some years but it was circulated only through Flight Crew Bulletin. It was only removed in 2011. If your instructors were provided with the same documents then it is likely that they also don't know about it. Having said that just because your Airline didn't use it does not make it crappy. It was removed not because it was ineffective but due to improper use by some pilots.

The biggest problem with phase advance was people carrying it out below 100' RA. They click forward, click back to climb, and suddenly full climb thrust is commanded as the autothrust has turned itself off.

I have clicked off the auto systems any time they aren't doing what they should. Two clicks and you are fine. I would not want to fly with any pilot that couldn't do that and land safely. Airbus has a different philosophy but that is also why I never flew an Airbus. You are the pilot so don't let automation control you, you control automation.

Bubs - JammedStab has been trying to tell you lot since post #14 that he misunderstood the context. I replied to your post on the other thread, but the document referred to is basically saying nothing more than 'disconnect the automation via the button before moving the controls'.

The document also explicitly instructs pilots to handfly - with raw data if necessary - if the automation behaviour is doubtful.

http://www.airbus.com/fileadmin/medi..._SOP_SEQ02.pdf

(Bottom of page 7)

There it is right there. Why would you want to bounce in and out of different levels of automation on final? You don't have time to figure out what's going on if you screw it up or don't react fast enough.

That's why its a crap procedure. You cannot possibly be stabilized when your degrading automation and then upgrading it again.

Gordon Bennett - let's just have a look at what the thing actually says, shall we?

So, now we can see it in context it becomes clear that:

• The section refers only to a scenario in which behaviour is unexpected
• The document explicitly says that pilot should handfly using raw data if necessary (and in an official Airbus document no less - who'dathunkit? :rolleyes:)
• There is no restriction on manual override without disconnect if the automation is behaving as expected
• The statement from the original post simply means that disconnect must be performed before taking manual control - presumably to ensure that a malfunctioning system is definitely no longer part of the problem

In general do not override / overpower automatic systems
 

In general do not override / overpower automatic systems when there is an option to disengage via another mechanism.
Depending on the systems design / certification, overriding / overpowering can result in in some serious even hazardous situations. Older auto-throttles which interface with hydro mechanical fuel controls via 'fuel trim' systems may result in full travel trim and inadvertent over speeding /over temp or sub idle / shutdown. Slip clutches may provide some protection but in doing so can be damaged which in subsequent operation fail to work correctly.

Most modern autopilots guard against overpowering with force/displacement cut outs which minimise out of trim forces. Older autopilots may not, overriding these might result in a large opposing trim movement such that the resulting stick force cannot be managed – several upset accident reports.
Modern auto flight systems may have related characteristics, but without the force-feedback due to auto-trim follow up or similar. Remember that if you override the controls it may affect trim, trim is a control, and is very powerful.

You would not expect the PNF to ‘help’ the PF by overriding the control (except the trainers); the fate is coarse words or a ‘clip round the ears’. An autopilot/trim is much stronger and less forgiving of such assistance; you don’t train the auto system by overriding it, it’s more likely to train you not to do it again.

If you are going to put your hands on the thrust lever/controls to override, then why not press the adjacent disengage switch – they were designed with the human in mind.
But not all designs cope with the mind of the human.

Altcrznav
It is obvious you are not taking it very well that you were not aware of this procedure. You are trying to clutch at the slightest evidence no matter how ridiculous that the procedure was crap. Kindly examine the first line of the procedure.
"During the approach, with the A/THR active, Airbus recommended to set the thrust levers above the CL detent (but below the MCT detent), in exceptional circumstances, if the speed significantly dropped below VAPP."
When speed significantly dropps below 100', you simply go around. Even in your airline. Any pilot who tried to do anything else deserves your favourite word crap.
However this procedure did not come out of thin air. DSC-22-30-90P5/14 is quoted below:
The thrust levers provide the flight crew with an immediate increase of thrust when both thrust levers are pushed above the CL detent (two engines) or the active thrust lever above the MCT detent (one engine operative).
Last but not least United Airlines manual revision shows this FCB.
Thank you.

It was NOT recent. The oldest reference I can find is from 2004. What is recent is that Airbus no longer recommends the use of such procedure.


Correct. Airbus have engineered a system and procedure that behave very differently depending of the altitude ... Confusion is probably one of the "drawbacks".

Quite justified in this scenario. A short override of the Autothrottle should not result in

In my Boeing, if you fall in a hole and need to help the ATS, you simply push the throttles up as required (or close the throttles if that's what's needed) then let go; the ATS will then move the throttles back to where it thinks they should be. There's none of this nonsense of leaving them out of a detent for too long will set off climb power. Computer game designed by boffins and out-of-touch-with-reality test pilots.

Odd, I seem to recall you bloviating quite extensively on proper procedures for operating off of ice runways, something you have never done yourself.

A squared
The question had nothing to do with ice, the answer I gave had nothing to do with ice it was you who sanctimoniously dragged the discussion to ice as if ice age has arrived and told us how you keep warm in an igloo. Thank you but I am not interested and since you won't have anything on the subject at hand I take your leave.

@Capn Bloggs:

Did you not read the extract? The restriction applies *only when the automation is not behaving as expected*.

When A/THR is engaged, the thrust levers behave differently to your Boeing, and the idea is that they remain in their detents for the duration of the flight. When A/THR is disengaged (or automatically disengages) then the thrust remains at the last setting prior to disconnect.

The only way you'll end up in the situation you're describing is if you move the thrust levers to the climb detent after disconnecting. Or if they were in the climb detent at disconnect, you'd have to "jiggle" the levers and leave them in the climb detent/region - not recommended procedure in any aircraft, including "your" Boeing!

I was going off of vilas' post. He shows a 2011 date for the bulletin.

Hi DozyWannabe,
Only if "Thrust Lock" was activated.

"Jiggling" is not necessary. Simply disengage auto thrust using the "instinctive disconnect buttons" on the T/Ls and you'd have set Climb Power.

You're right, rrr - I got myself muddled with A/THR disconnect via the FCU switch (which will, I believe, result in Thrust Lock activation). The "instinctive" switches require the levers to be set before disconnect.

Negative, at A/THR disconnect thrust could increase to climb thrust from idle prior to disconnect.

Absolutely not. The situation described by Capn Bloggs is totally accurate.

The bulletin as posted by vilas is an amendment of the original bulletin.
After 15 years on the bus I am still surprised you have never been aware of such procedure as the Flight Crew Bulletins are part of the FCOM.

CONF iture,rudderrudderrat
1. If ATHR is disengaged from ID button thrust needles will catch up with the doghnut where ever they are. To CLB if levers are in CLB. That is why you set it prior to disconnect.
2. If ATHR is disconnected from FCU, thrust will freeze in the present with thrust lock and ECAM warning.
3. If ATHR fails it will freeze with Thrust lock and ECAM.
The FOB in question is very old. ACNav is unable to digest it.
All this will invite another comment from bubbers44. That is his priviledge but it is not possible to conduct type rating through this channel.

Not necessarily, the THRUST LOCK function would not activate when the thrust levers are out of the CL detent.

Vilas,
Not necessarily, See 22,30,90: Thrust Lock Function

"The Thrust Lock function is activated when the thrust levers are in the CL detent (or the MCT detent with one engine out), and:-
The flight crew pushes the A/THR pb on the FCU, or -
The A/THR disconnects due to a failure.

The thrust is locked at its level prior to disconnection. Moving the thrust levers out of CL or MCT suppresses the thrust lock and gives the flight crew manual control with the thrust levers."

I prefer the FCOM explanation thanks.

CONF iture, RRR
In my reply I had assumed normal position of thrust levers in auto position which is in CLB. However if for some reason the thrust levers are not in CLB while stil in active auto thrust then thrust lock won't activate and thrust will remain at the present position when disconnected.

Me first. No wonder those beggars over the Atlantic didn't know what was going on... Is that an aeroplane you guys are flying or something the professor in "Back to the Future" made??

Not necessarily - Thrust could also increase depending where the THR LVRS have been left.


To get a good and complete knowledge on the A/THR, the system requires a fair amount of regular home work and experiments on the sim or the line.
Nothing like the Boeing you know where the thrust is generally where the thrust lever is ... but was it too simplistic for Airbus ?

Just watched Back To The Future again last week. Great flick. You may be right.

Guess I 'll stick to a Boeing.

Good choice!

I must admit to a bit of misunderstanding regarding AT and bumping it into MCT.
While enroute, I bumped the levers out of CLB and into MCT thinking I'd lose AT as well and I didn't. The EPR started climbing, obviously, and putting them back into the CLB detent returned everything to normal.

It was as dramatic a shift in automation levels - more of a hybrid change! but it was easily returned to the previous level.

Always learning on the Bus.

Exactly - A lot to be learned and practiced to not forget - Already not easy for us flying the thing to understand and remember everything, so I am at lost when some with NO experience on the bus or even on a flight deck show up and pretend to explain how works the A/THR ...

For the record, I was working off an old set of notes which were possibly incomplete - they didn't mention the CL/MCT detent in combination with the FCU A/THR button. I made a mistake, I put my hands up to it - no big deal.

So correct procedure has the pilot match the "doughnut" to the current thrust level before using the instinctive disconnect button - doesn't seem particularly onerous to me. The FCU button allows for a way to manually ensure that Thrust Lock mode is activated, which seems like a sensible thing to provide.

As you obviously don't have the tools, no more the knowledge or the experience to comment on how is working the A/THR on the bus, just quit on doing it. You create more disinfo than anything else.

Another piece of your disinfo as no one is looking forward to activate the Thrust Lock function. That's something you want to suppress, not to activate.

Oh really?

Dozy, you're so confused in your 'knowledge' that you don't even realize the difference between engaging the A/THR and activating the Thrust Lock function …
Keep showing your ignorance on this specific subject at your own pace.

As you yourself say, disengaging A/THR using the FCU button with the thrust lever in the CL or MCT detent will trigger the Thrust Lock function, and in that post you claimed to use the FCU panel button "all the time". So if engaging Thrust Lock is to be avoided, why would you do that rather than use the "instinctive disconnect" buttons?

Exact same reply for you dozy.