Manually overriding autothrust

[JammedStab]

To quote from Airbus...

"Except in emergency situations, AP and A/THR must not be overridden manually."

Just curious whether this applies to any other types. I have seen it done for a few moments on Boeings.

[Buttscratcher]

Depends what mode you're in, but on a Boeing anything, feel free if Thrust is your Speed mode and the ATC isn't keeping up nicely...... Approach as an example

[bubbers44]

What pilot would not override an autopilot or autothrottle if it wasn't doing what he wanted. No competent company would ever say don't override it if neccessary. Not even Airbus.

[Buttscratcher]

Absolutely, but if it's Speed on Pitch, then I guess you would look at other solutions
I never flew a 'Bus, but the quote sounds otherwise very odd, yeah

[bubbers44]

Don't tell me Airbus actually said that. Maybe that is why AF 447 crashed. Nobody was allowed to hand fly. When the autopilot failed because of loss of IAS maybe they were not taught how to fly pitch and power because they would have to disconnect the autopilot. I know it disconnected by itself but it might have been confusing for them.

[Altcrznav]

To quote from Airbus...

"Except in emergency situations, AP and A/THR must not be overridden manually."

Just curious whether this applies to any other types. I have seen it done for a few moments on Boeings.

Can you please reference that statement.

Seems to me we violate that directive every time we're on final.

[Capt Claret]

The Douglas/Boeing doesn't prohibit it and it's sound practice I believe on approach in blustery conditions, as it saves that sinking feeling when the speed washes off towards Vmin and the AT goes to warp power to prevent further speed loss. :8

[Buttscratcher]

As far as 'over-riding an AP' goes, I guess we don't do that on any type really ( I have been known to change modes though, or disconnect it at times)
The 'Bus is a little unusual tho and I've heard that you don't touch the controls with the AP in ....... But then, why would you want to?
ATs are a different story tho, obviously

[Wizofoz]

I think the confusion is between "Over-ride" and "Disconnect". I don't think AB is saying don't disconnect or downgrade automation if it isn't delivering what is required- but don't OVER-RIDE that is, make manual inputs while the automation is still connected, unless it's a serious, time critical problem.

In a Boeing, the same would be true of the A/P, though there's no problem "Helping" the A/T a bit if it is slow correcting the speed.

[bubbers44]

Why not override an autopilot? I did whenever it wasn't doing what I wanted. I don't even care if the autopilot works so overriding it is no big deal. Hand flying is quite simple. We all did it.

[Buttscratcher]

Don't think it's wise to override an AP, Bubs.
AT, sure at times

[Altcrznav]

Why is it not OK to override an AP? That kind of complacency and trust leads to accidents.

[framer]

A few people here are getting confused between over -ride and disconnect.

[JammedStab]

My mistake, it was referring to a runaway situation or hardover.

I believe they mean in this situation to disconnect. Only override if disconnection is not possible and an emergency situation has been created due to the malfunction.

:ouch:

[de facto]

The AT should be left alone,dont push or pull the TL when the AT is engaged.
If the AT is bit sluggish then increase the command speed and it will react,once done,reset speed to required.
Now if your AT is not behaving as it should be,(read turkish),then disconnect the:mad: and fly manually.
This overriding,push pull with full automatics on damages the AT clutch and is bad practice.

[Denti]

At least on the Boeing I fly overriding the AP is a normal feature and will degrade its function to CWS. Our SOPs call for that in a few specific situations but it is not reserved for emergencies at all.

Overriding the AT is possible, that is why there is a clutch in the first place. But it is of course not good practice to fly the whole flight that way. However is good practice to manually override for short term speed deviations. Might be a good idea for example in mountain wave situations.

[de facto]

However is good practice to manually override for short term speed deviations. Might be a good idea for example in mountain wave situations.


You mean disconnecting surely.:p

[vilas]

bubbers 44
Wizofoz is correct. There is a difference between overriding AP and disconnecting the AP. You cannot override the AP or ATHR in Airbus FBW. If you force the side stick the AP will disconnect anyway. But there is no restriction on taking over manually. That should be done with ID button on the stick. As the Thrust levers do not move and are static in CLB gate you cannot overide (overpower) them but you can control them manually. Airbus goden rule 2 "Use appropriate level of automation.means flying selected speed, disconnecting ATHR and using manual thrust or even flying manually if required. Rule4 "Take action if things do not go as expected" tells you to be proactive and make the aircraft do what is needed with or without automation.

[Centaurus]

One of the classic automatic monkey event I witnessed (n the simulator thank goodness), was a experienced Chinese captain who in the 737 rolled over nearly inverted on a coupled ILS after the AT clutch motor on one thrust lever failed while the thrust levers were at idle while slowing for flap and gear extension. As the airspeed came back to Vref+5 with landing flap, the other engine went to high thrust to maintain the selected approach speed while the idle engine stayed at idle.

Instead of disconnecting the AT system and using manual thrust on both engines, the captain thought the idle thrust engine was actually an engine failure! He called engine failure and directed his F/O to shut down the engine with the failed AT clutch motor. There was nothing wrong with the engine. The AP could not cope with the huge amount of crossed controls needed to maintain the coupled ILS on one engine and disengaged itself. At no time did the captain attempt to use rudder to correct the yaw. All the time both pilots had their hands on their knees impassively watching the 737 roll on its back and go in like a bomb. The simulator was then "frozen" to prevent further embarrassment and consequent loss of face.

[vilas]

Centaurus
This has happened in actual flight on China airlines 006 where crew failed to monitor the aircraft flight path during restart of failed no.4 engine. The disoriented crew let the aircraft go on the back and screaming dive loosing 30000ft in 2and a half minute. The pilot finally completed the barrol roll experiencing 5g was able to land safely.

[Buttscratcher]

Really?...... The last few posts make me shiver, for so many basic reasons it's not worth talking about

I guess that Airbus' just aren't tactile machinery ....that's all there is to it!

Boeings are very much so, tho..... even the Tripple is tactile for a FBW

Altcrznav..........you do understand now, Yeah?

[vilas]

A peculiar thing about this post is a question is asked about an Airbus procedure by a non Airbus pilot and also all the answers and conclusions are drawn by non Airbus people and finally ending up with favourite past time A vs B. I have flown both enjoyed both. I treated them as different concepts. I would not comment on something I don't know.

[Altcrznav]

A few people here are getting confused between over -ride and disconnect.

Explain the difference in an Airbus.

[Altcrznav]

Wizofoz

I think the confusion is between "Over-ride" and "Disconnect". I don't think AB is saying don't disconnect or downgrade automation if it isn't delivering what is required- but don't OVER-RIDE that is, make manual inputs while the automation is still connected, unless it's a serious, time critical problem.

In a Boeing, the same would be true of the A/P, though there's no problem "Helping" the A/T a bit if it is slow correcting the speed.

Making manual inputs while automation is still connected is not unusual nor abnormal. We have 4 levels of automation and, for example, changing heading to avoid a cell would simply be a change to the level of automation. Nothing is over-ridden and I don't ever remember seeing that referenced.

You don't over-ride anything but merely change levels. Level on is all automation off (occasionally final approach) and level 4 is fully automated (CRZ).

[Wizofoz]

Alt,

Changing from, say, LNAV to HDG SEL to avoid a cell is neither disconnecting nor over-riding automation, it is simply changing mode, and as such is not a manual intervention.

Manual flight implies direct control input- i.e via the yolk in a Boeing, and that would NOT be a normal input while the A/P was still connected.

If a sudden, time critical intervention was required, disconnect and manual flight would be appropriate.

[Altcrznav]

I understand that.

But this thread was started as a reference for Airbus which doesn't have an over-ride.

Why are we talking Boeing stuff?

[Wizofoz]

Fair enough, I have little knowledge about Airbi- But if you CAN'T over-ride an Airbus A/P-A/T, why does the Airbus manual contain a statement to not DO so except in an emergency?

[mutley320]

From Airbus FCTM........

I THINK NO.6 answers the question.....

Could be applied to any modern aircraft really.

1.The aircraft can be flown like any other aircraft 2.Fly, navigate, communicate - in that order 3.One head up at all times 4.Cross check the accuracy of the FMS 5.Know your FMA at all times 6.When things don't go as expected - take over 7.Use the proper level of automation for the task 8.Practice task sharing and back-up each other

[Altcrznav]

That's not over-riding the Airbus automation, its turning it off or changing to a different level of automation.

Again, you DO NOT over-ride Airbus automation. You downgrade it to a different level.

[Elephant and Castle]

There used to be an airbus procedure that sugested momentarily pushing the thust levers above the climb detent if the autothrust was slow to correct an underspeed in approach. It is a technique that I have used (only rearly I may add) and it worked ok.

I can no longer find a reference for the procedure, has it been taken out?

[Altcrznav]

I hope so because it'll get you into trouble.

Fifteen years on the Bus and I've never heard of that recommendation.

[Clandestino]

Just curious whether this applies to any other types.

It applies to any classic controls, autopilot equipped type (e.g. A300 and 310). Don't fight the autopilot. Just don't.

For those who want to know more, IIRC back in late 1990ies Richard L Collins reported about experiment in which GA pilots were put in Malibu simulator and given "soft" AP failure with descent initiated in altitude hold. Quite a lot of them thought they can just pull a bit back on the yoke while keeping the AP engaged to return the aeroplane back to altitude and keep it there. Many of them were eventually simulated killed through dive into ground coming from extreme nose down trim introduced by AP. Interestingly, Nagoya A300 catastrophe was quite similar; pilot was fighting the pitchup with down elevator and still active AP fought it by trimming the stab up.

Explain the difference in an Airbus.
N/A for FBW Airbi. Attempt to override (introduce manual input through stick with AP engaged) will invariably lead to AP discon. Quote that started the thread is from general brand A operations note, dealing with their entire catalogue.

Making manual inputs while automation is still connected is not unusual nor abnormal.Provided hand is coupled to FCU, not to stick. That needs not be everyone's (or even majority's) definition of manual.

[Altcrznav]

Provided hand is coupled to FCU, not to stick. That needs not be everyone's (or even majority's) definition of manual.

I don't understand your comment. Its superfluous.

If your hand is "coupled" to the stick and your making inputs, you're going to disconnect the autopilot.

You cannot make stick inputs with the AP on in the Airbus - period.

[CONF iture]

Fifteen years on the Bus and I've never heard of that recommendation.
Then you probably never got the chance to read the Flight Crew Bulletins, part of the FCOM.

I can no longer find a reference for the procedure, has it been taken out?
I think you're wright !
It appears such procedure is not mentioned anymore ... Airbus did not publicize much why they now think it is better not to mention it any longer ... ?

[vilas]

WIZOFOZ, Elephant and Castel, Altcrznav
Further to my Post#18
1. Override in A320 means disconnecting AP by forcing the side stick. Since it unusual way may be done in emergency.
2. Elephant and castle is right there was a procedure to push thrust levers slightly beyond CLB to get better response.
3. Atcrznav I am surprised you did not know it for 15 years. Anyway you need not know it now. Below is from FCOM Flight Crew bulletins.

Ident.:FCB-FCB24-00013125.0001001 / 31 MAR 11

Applicable to: ALL

REASON FOR ISSUE

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. However this procedure is not trained and proved to have more drawbacks than advantages. Therefore, Airbus no longer recommends to use this procedure. The procedure is deleted from the operational documentation.
If the A/THR performance is not satisfactory, the flight crew should take over,and control the thrust manually.

[Altcrznav]

1. Override in A320 means disconnecting AP by forcing the side stick. Since it unusual way may be done in emergency.

That's another odd (rather stupid) procedure. Why would you risk jamming the sidestick with enough force to overcome the lock and risk putting the aircraft in an inadvertent attitude when you have an ICO right there?

Unusual is a mild way to describe that technique to say the least.

I don't have an FCOM in from of my as my company has its own manuals for training, but does Airbus use the term "override" and "autopilot" together or does it use "disconnect"?


3. Atcrznav I am surprised you did not know it for 15 years. Anyway you need not know it now. Below is from FCOM Flight Crew bulletins.

Ident.:FCB-FCB24-00013125.0001001 / 31 MAR 11

Applicable to: ALL

REASON FOR ISSUE

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. However this procedure is not trained and proved to have more drawbacks than advantages. Therefore, Airbus no longer recommends to use this procedure. The procedure is deleted from the operational documentation.
If the A/THR performance is not satisfactory, the flight crew should take over,and control the thrust manually.

Its quite obvious from the bulletin that it was a crappy procedure and the key there is the it was not trained. My company never adopted it and it was never brought up. I've asked other Airbus drivers about this on our pilot board and none have ever heard of this either - some with many more years than I in the Bus.

[Uplinker]

You CAN override the autopilot on the Airbus, (but you shouldn't).

If you move the rudder pedals or the side stick with the autopilot engaged, the autopilot will disconnect.

The side stick is locked in neutral when the autopilot is on, but you can move it with enough force, at which point, as I say, the autopilot will disconnect. I suppose this allows an emergency reaction from a pilot given something really sudden and bad, such as a potential collision?

We used to be allowed to "Phase advance" the thrust levers by pushing them just out of the CLB gate and straight back into the gate again to increase revs on approach if the autothrust was being lazy, but this now has been outlawed. (I personally thought it was a very useful procedure, but a lot of pilots obviously misunderstood it and left the levers forward of the CLB gate for too long (i.e. more than a second, and ended up overspeeding).

All other actions, as others have said, are mode changes.

(sorry Alt - think we crossed there)

[Elephant and Castle]

For me it was not needed often but very ocassionally it was quite useful. It was not trained? Not sure what is there to train. If the autothrust is not reacting to a slow speed in approach you move the levers just forward of the climb gate and back into the gate. That wakes the autothrust up so to speak. Hardly rocket science. Crappy procedure? How do you know, presumably you have never tried it.

AB now recomends disconnecting the autothrust all together if it is not performing. Fine, but this also involves overiding the automation momentarily to match the thrust lever position to the current thrust before pressing the disconnect button. Otherwise you end up with a sudden rush of climb thrust until you retard the levers.

[vilas]

Altcrznav
Jammed stab's quote I have not seen yet but was explaining the implications in Airbus FBW.
As you are aware you cannot override/overpower AP in Airbus it will disengage. There are three ways you can disconnect the AP only one is recommended i.e. ID button, the other two are from FCU and forcing the side stick which are not normal ways. The only emergency situation I can foresee is when you quickly want to take over to change the flight path and the ID button doesn't work then may be you force the side stick. The FCB in question crappy or otherwise was Airbus recommended procedure. Here we are not discussing your company procedures. ATHR disconnect procedure is part of training syllabus while this procedure was not and few pilots obviously have messed up approaches may be by leaving THR LVR in MCT. So now Airbus recommends disconnecting ATHR and use manual thrust instead. If you mess this up you are responsible since you were taught how to. The procedure was useful if you needed quick thrust response.

[Centaurus]

Manual flight implies direct control input- i.e via the yolk in a Boeing, and that would NOT be a normal input while the A/P was still connected

It could be argued the above comment is in contradiction to the flight technique for severe turbulence.

The B737 Supplementary Procedures recommends the autopilot be set to CWS mode. The pilot then is required to manually "fly" the aircraft through the CWS mode. Control forces are slightly higher than in no automatic flight, which in turn decreases the potential for over-controlling in gusts. This is especially important at high altitude where rapid use of aileron causes spoiler actuation and the scene is set for over-controlling by the pilot.

[flyboyike]

A peculiar thing about this post is a question is asked about an Airbus procedure by a non Airbus pilot and also all the answers and conclusions are drawn by non Airbus people and finally ending up with favourite past time A vs B. I have flown both enjoyed both. I treated them as different concepts. I would not comment on something I don't know.


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

[Capt. Inop]

To quote from Airbus...

"Except in emergency situations, AP and A/THR must not be overridden manually."

Just curious whether this applies to any other types. I have seen it done for a few moments on Boeings.

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.

[Altcrznav]

Here we are not discussing your company procedures. ATHR disconnect procedure is part of training syllabus while this procedure was not and few pilots obviously have messed up approaches may be by leaving THR LVR in MCT. So now Airbus recommends disconnecting ATHR and use manual thrust instead. If you mess this up you are responsible since you were taught how to. The procedure was useful if you needed quick thrust response.

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.

[Altcrznav]

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

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...."

[DozyWannabe]

Just pointing out:

My mistake, it was referring to a runaway situation or hardover.

I believe they mean in this situation to disconnect. Only override if disconnection is not possible and an emergency situation has been created due to the malfunction.

:ouch:

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...

[Capt. Inop]

loss of face.

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.

[vilas]

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.

[tom775257]

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.

[bubbers44]

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.

[DozyWannabe]

I have clicked off the auto systems any time they aren't doing what they should. Two clicks and you are fine.

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/media_gallery/files/safety_library_items/AirbusSafetyLib_-FLT_OPS_SOP_SEQ02.pdf

(Bottom of page 7)

[Altcrznav]

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.


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.

[DozyWannabe]

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

VII.3 Take actions if things do not go as expected

This is the Golden Rule number 4. If doubt exists regarding the aircraft flight path or speed control, the flight crew should not try to reprogram the automated systems.

The flight crew should use Selected Guidance or hand flying together with the use of navaids raw data, until time and conditions permit a reprogramming of the AP/FD or FMS.

If the aircraft does not follow the intended flight path, check the AP and A/THR engagement status.

If engaged, disconnect the AP and/or A/THR using the associated instinctive disconnect push button(s), to revert to hand flying (with FD guidance or with reference to raw data) and/or to manual thrust control.
In hand flying, the PF must follow FD commands; otherwise the flight crew must remove the FD from the PFD.

AP and A/THR must not be overridden manually.

If AP or A/THR operation needs to be overridden (i.e., following a runaway or hardover), immediately disconnect the affected system by pressing the associated instinctive disconnect push button.

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

[safetypee]

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.

[vilas]

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.

[CONF iture]

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.
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.


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.

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

[Capn Bloggs]

random sniping about Airbus
Quite justified in this scenario. A short override of the Autothrottle should not result in

They click forward, click back to climb, and suddenly full climb thrust is commanded as the autothrust has turned itself off

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.

[A Squared]

I would not comment on something I don't know.

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

[vilas]

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.

[DozyWannabe]

@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!

[Altcrznav]

CONF iture wrote:

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.


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

[rudderrudderrat]

Hi DozyWannabe,
When A/THR is disengaged (or automatically disengages) then the thrust remains at the last setting prior to disconnect.
Only if "Thrust Lock" was activated.

The only way you'll end up in the situation you're describing is.....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!
"Jiggling" is not necessary. Simply disengage auto thrust using the "instinctive disconnect buttons" on the T/Ls and you'd have set Climb Power.

[DozyWannabe]

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.

[CONF iture]

When A/THR is disengaged (or automatically disengages) then the thrust remains at the last setting prior to disconnect.
Negative, at A/THR disconnect thrust could increase to climb thrust from idle 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.
Absolutely not. The situation described by Capn Bloggs is totally accurate.

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

[vilas]

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.

[CONF iture]

If ATHR is disconnected from FCU, thrust will freeze in the present with thrust lock and ECAM warning.
Not necessarily, the THRUST LOCK function would not activate when the thrust levers are out of the CL detent.

[rudderrudderrat]

Vilas,
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.
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.

[vilas]

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.

[Capn Bloggs]

All this will invite another comment from bubbers44.
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??

[CONF iture]

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


Is that an aeroplane you guys are flying or something the professor in "Back to the Future" made??
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 ?

[bubbers44]

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

[latetonite]

Guess I 'll stick to a Boeing.

[bubbers44]

Good choice!

[Altcrznav]

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.

[CONF iture]

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 (http://www.pprune.org/8076059-post59.html) with NO experience on the bus or even on a flight deck show up and pretend to explain how works the A/THR ...

[DozyWannabe]

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.

[CONF iture]

For the record, I was working off an old set of notes which were possibly incomplete
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.

The FCU button allows for a way to manually ensure that Thrust Lock mode is activated, which seems like a sensible thing to provide.
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.

[DozyWannabe]

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?

We use [the FCU A/THR button] every time we want to arm or activate again the A/THR following a voluntary disconnection. No ABNORMAL situation involved.

[CONF iture]

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.

[DozyWannabe]

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?

[CONF iture]

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 (http://www.pprune.org/8082658-post78.html) for you dozy.

[vilas]

Dozy
FCU ATHR and AP buttons are used to engage while ID buttons are used to disengage.

[vilas]

CONF iture, RRR, Altcrznav
I was surprised to read the following in the latest FCOM. Read the first condition. There seems to be a modification. So with this MOD the ATHR can be just clicked of without thrust increase to climb. Sensible I would say.

Applicable to: 18-CMHE, 18-IMHE

TheThrust Lock function is activated when the thrust levers are in the CL detent(or the MCT detent withone engine out), and:

‐ The flight crew pushes the instinctive disconnect pb onthe thrust levers, or

‐ 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 leversout of CL or MCT suppressesthe thrust lock and gives the flight crew manual control with the thrust levers.
The next para is
Applicable to: 18-CMTE, 18-CMTEH, 18-CUHE, 18-CUTE, 18-CUTEH, 18-IMTE, 18-IUHE, 18-IUTE


Here the first line is missing.

[Capn Bloggs]

There seems to be a modification. So with this MOD the ATHR can be just clicked of without thrust increase to climb. Sensible I would say.

Correct. That's why Boeings have always done it that way. :}

[Uplinker]

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.

Yes, the point is when the thrust levers are moved forward out of the CLB detent, 2 things happen:

1. The thrust goes that commanded by the actual thrust lever position,*

2. Autothrust disengages - but REMAINS ARMED, (unless you are below 100'). So if you then return the thrust levers to the CLB gate, autothrust will re-engage. (This was how phase advance worked, but it was very poorly taught and therefore very poorly understood by most pilots, who then got it wrong).



*A slightly fuller description: With the thrust levers in the CLB gate and auto-thrust engaged, the auto thrust will vary engine power as required between idle and CLB power. It does not backdrive the thrust levers, which do not therefore move, but one can easily imagine the 'virtual' thrust levers moving between idle and CLB and see it on the EWD gauges. When one pushes the thrust levers forward of the CLB gate, the auto-thrust dis-engages and the FADECs increase power from what might have only been idle, to the thrust commanded by the actual lever position. This could be a very large increase if it got all the way to above CLB power from idle, so phase advance was just intended to be a second or so out of the CLB gate and back in again. This would start accelerating the engines towards CLB, giving the speed increase required, but after that second, putting the levers back to the CLB gate to re-engage autothrust, which would then return the engines to idle. 'Click out' - 'click back' in, in about the time it takes to say that, is all that was needed.

PS
If you pull the thrust levers back from CLB, I think the auto-thrust stays engaged, but the engine thrust would then limited between idle and the new thrust lever position. I guess this would be so one could instinctively reduce power in the event of an overspeed I suppose?, but I've never done it that way. (The ECAM would ask you to return the levers to CLB soon after - giving it control of the full range again).

[CONF iture]

There seems to be a modification. So with this MOD the ATHR can be just clicked of without thrust increase to climb.
Then it is another new thing, but not applicable to all, another matter for confusion. 25 years later still modifying something that was supposed to be simple ...

Thanks for the information.

[BARKINGMAD]

F A D E C.
Grumpy old F/E in Classic 747 assured me we had FADEC on the -100/200 series.

Fingers

All

Direct

Engine

Control

*"@§'ing USE them if you have to!!??

"Me first. No wonder those beggars over the Atlantic didn't know what was going on... Is that an aeroplane you guys are flying.....?"

Thanks Capt Bloggs, your comment SEZ IT ALL!!!!

[vilas]

Captbloggs and BARKINGMAD
China Airlines 747SP suffered flameout on NO.4 at 41000ft with AP on, no big deal really ( I was 747 Capt). The capt. did a barrol roll and in few seconds lost 30000ft. Had it been at 30000ft it would have met the same fate as AF447. He was flying a real aeroplane not a FBW. He was an experienced captain and not a rookie copilot. Nobody blamed 747. Things happen you know.

[bubbers44]

Some stupid pilots get lucky, some don't. Learn to really fly, then fly. Even stupid pilots can do stupid things and get lucky and not crash. Others aren't quite so lucky so everybody dies. AF 447 was one of those.

[bubbers44]

I saw that twisted up 747 at SFO for quite some time. Quite impressive of his ability to recover from a roll because an engine failed and he didn't follow any procedures. He is probably his home town hero. They probably don't know how to fly either.