clive6354

Throttle Quadrant & Auto Throttle Operation

11 posts in this topic

Hello

I am using Hotas Warthog Throttle with B737NGX

As the the throttle levers are advanced for take-off then during flight  auto throttle is selected the throttle levers in a real aircraft will move in relation the the amount of engine power required but the levers on my Warthog throttle remain stationary and will not be co-rdinated, therefore, if and when return to manual throttle control how can I determine the correct position that the levers on my Wathog should be in to take manual control

Is there anyway that the Warthog throttle levers can be programmed to move in relation the the amount of power requested co-ordinated  with the thrust levers on the pedestal

 

Clive Alexander

 

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The Warthog HOTAS throttles do not have little motors in it to move the levers.  It's up to you.  I use the option that displays throttle position on the N1 gauge all the time, so it is a simple matter of lining up the throttle with the A/T position.  Normally it doesn't matter, since manual throttle is commonly only used in HOLD/ARM mode and when landing and in these cases there nothing to "line up."  However, I am in the habit of pushing my levers all the way forward after TOGA, leave them there until descent when I pull them back to idle.  I might trim during flight to match levers with A/T but it is just my OCD causing that.

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Your Warthog HOTAS is of course a replication of the real A-10C's throttle quadrant and so (notwithstanding the fact that it would have been vastly more expensive to produce with a motor function) it does not feature a motorised autothrottle function because the real A-10C Thunderbolt II of course does not have an autothrottle either, because it doesn't need one by virtue of the fact that the A10 Thunderbolt II employs a HOTAS system (i.e. hands on throttle and stick), so you hand is supposed to be on the throttle of an A-10.

It would be impractical to attempt to motorise your throttle so that it could function like the thrust levers of a 737, and even if that could be done (nothing is absolutely impossible) it certainly wouldn't be cheap or easy. So that leaves you with two options; As Dan suggests, manually moving the throttle to replicate the thrust settings the N1 gauge is showing, which is the most practical solution, or if you happen to have a few grand going spare, buying a motorised 737 throttle quadrant, which you can certainly get, but as noted, they don't come cheap.

Beyond all that, as an interesting aside, in practical terms, pilots should be familiar with the visual positions of where the throttle is positioned for various phases of flight and various speeds anyway, as it is occasionally necessary to know these things in an emergency. A terrifying example of where that was not done, would be Air France Flight AF447, which was the Airbus A330 which flew through a thunderstorm over the South Atlantic, allowing its pitot tubes and static ports to ice up and causing the autopilot to disconnect because the ASIs had stopped functioning, ultimately resulting in a crash because of poor piloting which relied too much on trusting the automation and a lack of good old stick and rudder skills.

Since the throttle power levers on an Airbus, like your Warthog throttle, do not move autonomously like those of a Boeing 737, but instead have flight regime detent settings which act as switches which are further controlled by other aircraft functions such as the flaps, when those functions failed, what the pilots of AF447 should have done, is retarded the throttles briefly in order to assume manual control of them, then positioned them at a suitable thrust setting manually and flown by pitch attitude until the pitot heads and static ports had de-iced, at which point they could have resumed automatic flight. Instead the co-pilot simply assumed that the aircraft's flight envelope protection systems would operate flawlessly despite their being no ASI data to prevent him from doing anything to risk a stall. So, ignoring the repeated stall warning audio alerts, he stupidly held the sidestick all the way back for three minutes whilst the airliner plummeted 38,000 feet down toward the sea to eventually crash, doing nothing else other than repeatedly stating that he did not understand what was happening, which is a good contender for the understatement of the decade, because he absolutely did not understand what was happening if he didn't even know that holding the stick back is not what you do when a stall warning is sounding, either in a Cessna 152 or an Airbus A330. Even if he had simply let go of the stick there is a good chance the aircraft would have recovered, because so long as the throttles are in a reasonably sensible position, a suitably trimmed aircraft will eventually settle into controlled flight. That's why it is worth knowing where things such as the throttle levers should be sitting for various flight phases.

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5 hours ago, Chock said:

Since the throttle power levers on an Airbus, like your Warthog throttle, do not move autonomously like those of a Boeing 737, but instead have flight regime detent settings which act as switches which are further controlled by other aircraft functions such as the flaps, when those functions failed, what the pilots of AF447 should have done, is retarded the throttles briefly in order to assume manual control of them, then positioned them at a suitable thrust setting manually

If you are going to post things like this at least get your facts straight. As well as being irrelevant to the OP's questions, it's a misleading, simplistic and inaccurate view of a very complex accident. Moving the thrust lever out of CLB does not give you manual thrust control (the A/T disconnect buttons do that, just as in a Boeing). TOGA, MCT and CLB aren't flight regime detents, they set engine thrust ratings, as their names suggest. Flap setting does not affect that. The key to surviving the accident was recognising the stall early enough and pushing the nose down to recover. The stall warning was intermittent. It was off with the nose held high (because the AOA was invalid with such a low airspeed). Pushing the stick forward activated the warning as the high AOA signal became became valid. Little wonder the pilots got confused.

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On 9/7/2017 at 5:45 AM, kevinh said:

If you are going to post things like this at least get your facts straight. As well as being irrelevant to the OP's questions, it's a misleading, simplistic and inaccurate view of a very complex accident. Moving the thrust lever out of CLB does not give you manual thrust control (the A/T disconnect buttons do that, just as in a Boeing). TOGA, MCT and CLB aren't flight regime detents, they set engine thrust ratings, as their names suggest. Flap setting does not affect that. The key to surviving the accident was recognising the stall early enough and pushing the nose down to recover. The stall warning was intermittent. It was off with the nose held high (because the AOA was invalid with such a low airspeed). Pushing the stick forward activated the warning as the high AOA signal became became valid. Little wonder the pilots got confused.

First up, I addressed the OP's questions and then added some additional info which was of interest in the broader context of understanding one's aeroplane systems, so it wasn't irrelevant, it was in the context of knowing thrust settings in order to fly by attitude and all the systems which relate to that. So what I was alluding to here, in mentioning AF447, is that neither Roberts nor Bonin, the two subordinate co-pilots on AF447's flight deck when the problems started, had received no training on what to do when things go awry at altitude, were too reliant on automation and the misguided notion that there is no way you can stall an Airbus, which you of course can when it is not flying in Normal Law, so they panicked and exacerbated the situation by making incorrect control inputs. The point being, knowing your systems is key to piloting well. This is its relevance to the topic at hand.

Second, I was in no way attempting to write a full technical guide on how exactly one pilots an A330, nor of the accident which occurred with AF447, since to do that would require pages of text from the SOP to be quoted or alluded to. The SOP manual for the A330 is well over an inch thick with a very large number of pages (I know that because it was actually ME who produced the thing for the real aeroplane, in fact there is a copy of that SOP right in front of me on the shelf). Rather, it was a brief mention of how systems can be unusual sometimes, alluding to a lack of technical knowledge and training as being something to be avoided. In the case of losing an autothrottle on a 737 or some other automated function, which is akin to the OP's throttle not being motorised, this would mean knowing how to set thrust manually for various flight regimes and possibly also to set pitch for a phase of flight too, but even though that is all I was relating matters to, rather than writing a full technical description of how an autothrottle functions, actually you are not correct in suggesting one cannot disengage the throttle by retarding the thrust levers, although it does (if one was intending to expand on the matter and write a full description of all the possibilities, which I was not) depend on the circumstances and Systems Law in operation at the time (in the case of AF447 after the pitot and static ports became blocked, this was Abnormal Alternate Law 2). That is in fact one of the reasons why an Airbus cockpit audio alerter plays the hilarious and familiar 'retard, retard' when you are on approach, in doing so, it is telling the pilots to pull the thrust levers back out of the detent used for the approach, since retarding the thrust levers disengages the autothrottle to give you manual control of the engine thrust for the landing and roll out etc. And all I was pointing out here, was that you need to understand your throttle's automation, but... this is, or at least may be, relevant to AF447 anyway, because Bonin, the pilot in the right seat who was largely responsible for the crash by his actions on the stick, tried to use various thrust lever settings (even including TOGA at one point) to climb out of trouble, without of course realising that this could actually cause further problems when at 38,000 feet instead of typically sea level or thereabouts when TOGA is normally used, since the engines would probably be receiving too much fuel and not enough air when up at cruise altitude in bad weather; pitching to typical climb angles when using TOGA to actually take off or go around is generally in much thicker air than one encounters at 38,000 feet over the South Atlantic. As it was, several throttle positions were tried in the three minutes or so it took AF447 to crash, including them being completely retarded at two points in the fatal descent, but at impact N1 was past 100 percent, so it is apparent that various thrust lever settings were being tried, but not in combination with other correct actions, principally on the right sidestick controller. 

Third, we know Bonin held the sidestick controller back, but because the sidesticks are not interlinked, Roberts - the guy in the right seat - had no idea Bonin was doing that until very near the point of impact when Bonin eventually said: 'But I've had the stick back the whole time!' at which point Roberts and the Captain, who had by that time returned to the cockpit, figured out his error. But until Bonin actually said that, they could not see Bonin doing it because the starboard stick is obscured from their viewpoint from the left seat or pedestal positions, nor is its movement replicated on the port sidestick controller since they are not mechanically linked; they both probably would have been able to correct matters if they had known that and it is perhaps a poor design feature of the Airbus A330 that those sticks are not interlinked mechanically. Sadly, it was at around 2,000 feet ASL when they determined this, and the aircraft had been descending at rates of up to 10,000 FPM, so there was little they could do. Worse, even when the other two pilots realised Bonin's error and tried to correct it, incredibly, Bonin again held the stick back without telling his colleagues he was doing so, despite this having achieved nothing when he was doing it previously, and with him having been told to relinquish control. Since he was doing that, and the other pilots were making other control inputs to try to recover the aeroplane, the inputs effectively cancelled each other out. In fact, because of Bonin's actions, the FDRs show that the elevators never dropped below 15 degrees elevation for the entire length of the incident whilst the aeroplane was in its fatal descent, so he must have been really hauling back on that stick, because even in Abnormal Law 2, the A330 will try to pitch the nose down if you let go of the sidestick. 

Fourth, Whilst it is true that the stall warning was sounding intermittently as you say, this was indeed because the aircraft was constantly flipping between being stalled with valid airspeed data and stalled without valid airspeed data as a result of a combination of the ports being blocked and the angle of attack producing wildly varying readings. But it did nevertheless sound many times (I forget the number of times it sounded, but it is certainly a lot). So of course the correct action was to pitch down although this is not quite as basic as it sounds, you can in fact let go of the controls and the aeroplane will do that automatically, although it probably makes more sense to manually pitch it down, G load protection is still in effect in Abnormal Law 2 but, as noted, the system does also automatically induce a progressive nose down pitch input even with system protection degraded, which you can override with the sidestick, which is precisely what Bonin was doing when holding the stick back all the time.

As noted, my comment was in no way intended to be a precise treatise on everything required and all that was going on aboard AF447, but rather it was a pointer to knowing thrust settings without being reliant on automation, this is why it was relevant to the OP's query. Yes there were complexities in the crash of AF447, but ultimately it was indeed a case of a pilot not knowing his systems well, not thinking critically about basic stick and rudder skills, and poor CRM.

So rather than leaping on my comments, just to pull me up (pun intended) about the veracity of the very obviously broad strokes it used, why not instead attempt to leap onto requests for assistance, as I had done? That would be more helpful.

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33 minutes ago, Chock said:

First up, I addressed the OP's questions and then added some additional info which was of interest in the broader context of understanding one's aeroplane systems, so it wasn't irrelevant, it was in the context of knowing thrust settings in order to fly by attitude and all the systems which relate to that. So what I was alluding to here, in mentioning AF447, is that neither Roberts nor Bonin, the two subordinate co-pilots on AF447's flight deck when the problems started, had received no training on what to do when things go awry at altitude, were too reliant on automation and the misguided notion that there is no way you can stall an Airbus, which you of course can when it is not flying in Normal Law, so they panicked and exacerbated the situation by making incorrect control inputs. The point being, knowing your systems is key to piloting well. This is its relevance to the topic at hand.

Second, I was in no way attempting to write a full technical guide on how exactly one pilots an A330, nor of the accident which occurred with AF447, since to do that would require pages of text from the SOP to be quoted or alluded to. The SOP manual for the A330 is well over an inch thick with a very large number of pages (I know that because it was actually ME who produced the thing for the real aeroplane, in fact there is a copy of that SOP right in front of me on the shelf). Rather, it was a brief mention of how systems can be unusual sometimes, alluding to a lack of technical knowledge and training as being something to be avoided. In the case of losing an autothrottle on a 737 or some other automated function, which is akin to the OP's throttle not being motorised, this would mean knowing how to set thrust manually for various flight regimes and possibly also to set pitch for a phase of flight too, but even though that is all I was relating matters to, rather than writing a full technical description of how an autothrottle functions, actually you are not correct in suggesting one cannot disengage the throttle by retarding the thrust levers, although it does (if one was intending to expand on the matter and write a full description of all the possibilities, which I was not) depend on the circumstances and Systems Law in operation at the time (in the case of AF447 after the pitot and static ports became blocked, this was Abnormal Alternate Law 2). That is in fact one of the reasons why an Airbus cockpit audio alerter plays the hilarious and familiar 'retard, retard' when you are on approach, in doing so, it is telling the pilots to pull the thrust levers back out of the detent used for the approach, since retarding the thrust levers disengages the autothrottle to give you manual control of the engine thrust for the landing and roll out etc. And all I was pointing out here, was that you need to understand your throttle's automation, but... this is, or at least may be, relevant to AF447 anyway, because Bonin, the pilot in the right seat who was largely responsible for the crash by his actions on the stick, tried to use various thrust lever settings (even including TOGA at one point) to climb out of trouble, without of course realising that this could actually cause further problems when at 38,000 feet instead of typically sea level or thereabouts when TOGA is normally used, since the engines would probably be receiving too much fuel and not enough air when up at cruise altitude in bad weather; pitching to typical climb angles when using TOGA to actually take off or go around is generally in much thicker air than one encounters at 38,000 feet over the South Atlantic. As it was, several throttle positions were tried in the three minutes or so it took AF447 to crash, including them being completely retarded at two points in the fatal descent, but at impact N1 was past 100 percent, so it is apparent that various thrust lever settings were being tried, but not in combination with other correct actions, principally on the right sidestick controller. 

Third, we know Bonin held the sidestick controller back, but because the sidesticks are not interlinked, Roberts - the guy in the right seat - had no idea Bonin was doing that until very near the point of impact when Bonin eventually said: 'But I've had the stick back the whole time!' at which point Roberts and the Captain, who had by that time returned to the cockpit, figured out his error. But until Bonin actually said that, they could not see Bonin doing it because the starboard stick is obscured from their viewpoint from the left seat or pedestal positions, nor is its movement replicated on the port sidestick controller since they are not mechanically linked; they both probably would have been able to correct matters if they had known that and it is perhaps a poor design feature of the Airbus A330 that those sticks are not interlinked mechanically. Sadly, it was at around 2,000 feet ASL when they determined this, and the aircraft had been descending at rates of up to 10,000 FPM, so there was little they could do. Worse, even when the other two pilots realised Bonin's error and tried to correct it, incredibly, Bonin again held the stick back without telling his colleagues he was doing so, despite this having achieved nothing when he was doing it previously, and with him having been told to relinquish control. Since he was doing that, and the other pilots were making other control inputs to try to recover the aeroplane, the inputs effectively cancelled each other out. In fact, because of Bonin's actions, the FDRs show that the elevators never dropped below 15 degrees elevation for the entire length of the incident whilst the aeroplane was in its fatal descent, so he must have been really hauling back on that stick, because even in Abnormal Law 2, the A330 will try to pitch the nose down if you let go of the sidestick. 

Fourth, Whilst it is true that the stall warning was sounding intermittently as you say, this was indeed because the aircraft was constantly flipping between being stalled with valid airspeed data and stalled without valid airspeed data as a result of a combination of the ports being blocked and the angle of attack producing wildly varying readings. But it did nevertheless sound many times (I forget the number of times it sounded, but it is certainly a lot). So of course the correct action was to pitch down although this is not quite as basic as it sounds, you can in fact let go of the controls and the aeroplane will do that automatically, although it probably makes more sense to manually pitch it down, G load protection is still in effect in Abnormal Law 2 but, as noted, the system does also automatically induce a progressive nose down pitch input even with system protection degraded, which you can override with the sidestick, which is precisely what Bonin was doing when holding the stick back all the time.

As noted, my comment was in no way intended to be a precise treatise on everything required and all that was going on aboard AF447, but rather it was a pointer to knowing thrust settings without being reliant on automation, this is why it was relevant to the OP's query. Yes there were complexities in the crash of AF447, but ultimately it was indeed a case of a pilot not knowing his systems well, not thinking critically about basic stick and rudder skills, and poor CRM.

So rather than leaping on my comments, just to pull me up (pun intended) about the veracity of the very obviously broad strokes it used, why not instead attempt to leap onto requests for assistance, as I had done? That would be more helpful.

Yes you did address the OP's issue, which is why I didn't comment on that any further. It had been thoroughly answered. My issue was your aside.

For someone who clearly knows so much about the A330 you gave a rather inaccurate precis of what happened on AF447 in your first post. People read this forum and assume what is posted is correct unless someone challenges it. Your post created a very odd impression of how the Airbus autothrust works. Was I wrong in what I said about what you posted? If not please acknowledge that and don't try and cover it up with a very long post about what actually did happen.

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On 9/7/2017 at 2:04 PM, kevinh said:

Yes you did address the OP's issue, which is why I didn't comment on that any further. It had been thoroughly answered. My issue was your aside.

For someone who clearly knows so much about the A330 you gave a rather inaccurate precis of what happened on AF447 in your first post. People read this forum and assume what is posted is correct unless someone challenges it. Your post created a very odd impression of how the Airbus autothrust works. Was I wrong in what I said about what you posted? If not please acknowledge that and don't try and cover it up with a very long post about what actually did happen.

Nope, you were not wrong, but as I wrote, the point I was making was not to go into massively accurate technical detail about exactly how stuff works or exactly what pilots should do in every emergency, particularly since it is easy to be a Monday morning quarterback, but to point out that it is nice to know about that stuff when you are driving an aeroplane, either simulated or real if you like doing this properly. And, what can happen if one doesn't know that stuff. There are plenty of manuals out there for people who really want to know the minutiae of aeroplane systems, and if anyone is truly curious about all of the tragic details of AF447 and how training was something which was severely lacking, they can read the BEA's report on it and check out the CVR transcript.

Thus it's not an attempt to 'cover it up' because there is nothing to cover up, it was never intended to be massively accurate in all details, it was merely pointing out that systems can have stuff going on which aren't always intuitive, which can confuse us sometimes, so it is useful to find out how things work.

Yes people can read stuff and assume it is correct, but nobody, or at least nobody with any sense, is going to regard a broad aside comment on an internet forum about one function among the many of an A330's autothrottle in various Law modes possibly adding to confusion, nor regard it as some kind of comprehensive authoritative guide to flying the real thing and dealing with emergencies, conveniently condensed down into one handy paragraph which will miraculously render the real aeroplane's SOP as redundant lol. Or even how to do that a simulation of it for that matter, which you can't anyway since there is no accurately simulated A330 for a home PC. If it was intended to be that, I'd have said so, not to mention that it would have been probably fifty pages long, which it quite clearly wasn't. As noted, I've already done that for real for a few big passenger aeroplanes, and it is a pain in the derrière as an Air France pilot might say, necessitating a lot of work, so I've no inclination to do it again, at least not without EADS and a few airlines paying me again for the effort.  :biggrin:

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Don't you just hate it when someone quotes an entire, verbose post in their post rather than snippets of it? :happy:

As a layman I find this discussion of Airbus throttles fascinating - I knew they didn't move, unlike Boeing's, but never paid much attention to the graphics in sim. Not sure if Thomas Ruth's A330 shows my physical throttle position on the EICAS. I'll have to investigate. Usually when I've activated the autothrottle, I pull my Thrustmaster HOTAS X throttle back as it make a nice handrest!!

On the real deal, are there actual physical detents at the TOGA, FLX MCT, CL positions so that you can feel it notch into place?

Thanks, Gents.

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On 9/8/2017 at 0:17 AM, HighBypass said:

Don't you just hate it when someone quotes an entire, verbose post in their post rather than snippets of it? :happy:

As a layman I find this discussion of Airbus throttles fascinating - I knew they didn't move, unlike Boeing's, but never paid much attention to the graphics in sim. Not sure if Thomas Ruth's A330 shows my physical throttle position on the EICAS. I'll have to investigate. Usually when I've activated the autothrottle, I pull my Thrustmaster HOTAS X throttle back as it make a nice handrest!!

On the real deal, are there actual physical detents at the TOGA, FLX MCT, CL positions so that you can feel it notch into place?

Thanks, Gents.

Yes, the real thing does have 'feelable' deternts which are the correct settings when operating the thing normally. It is a bit weird if one is used to the 'Boeing ethos', but as long as everything is working, it does make sense; it is when things go tits up that knowing how things work as a 'stick and rudder pilot'  become important; something which is lacking among many jetliner pilots. I will concede that I've had a weed up my word not allowed for this for years and have complained to the authorities and written numerous letters about it dating back to the early nineties. Specifically, I complained numerous times about the decision to remove spin training from the JAR PPL, in preference to teaching 'spin avoidance' , since I am of the opinion that teaching pilots how to avoid stuff, but not how to to deal with matters if they don't avoid it, is bordering on criminal. You can check the history of me having been vocal about that for years in numerous publications, so this is no 'after the fact' judgement on my part, and I will honestly claim that accidents such as AF447 have vindicated my issues with regard to such complaints. I am, frankly, disgusted with the levels of pilot training required for airliner crews.

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On 07/09/2017 at 3:01 PM, Chock said:

Nope, you were not wrong, but as I wrote, the point I was making was not to go into massively accurate technical detail about exactly how stuff works or exactly what pilots should do in every emergency, particularly since it is easy to be a Monday morning quarterback, but to point out that it is nice to know about that stuff when you are driving an aeroplane, either simulated or real if you like doing this properly. And, what can happen if one doesn't know that stuff. There are plenty of manuals out there for people who really want to know the minutiae of aeroplane systems, and if anyone is truly curious about all of the tragic details of AF447 and how training was something which was severely lacking, they can read the BEA's report on it and check out the CVR transcript.

Thus it's not an attempt to 'cover it up' because there is nothing to cover up, it was never intended to be massively accurate in all details, it was merely pointing out that systems can have stuff going on which aren't always intuitive, which can confuse us sometimes, so it is useful to find out how things work.

Thank you, so I was not wrong and you were not right. The thing is, you shoehorned AF447 into a discussion about how to align the throttles in the NGX, and now you say you were trying to avoid massively accurate technical detail. But you went into accurate technical detail about AF447 in your reply to me. Why do that if you were trying to avoid it? Of course such detail can be confusing, but if you were trying to say that the A330 autothrust system operation isn't intuitive then you need to get the facts of that right, otherwise it's you who are doing the confusing.

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22 hours ago, HighBypass said:

Don't you just hate it when someone quotes an entire, verbose post in their post rather than snippets of it? :happy:

As a layman I find this discussion of Airbus throttles fascinating - I knew they didn't move, unlike Boeing's, but never paid much attention to the graphics in sim. Not sure if Thomas Ruth's A330 shows my physical throttle position on the EICAS. I'll have to investigate. Usually when I've activated the autothrottle, I pull my Thrustmaster HOTAS X throttle back as it make a nice handrest!!

On the real deal, are there actual physical detents at the TOGA, FLX MCT, CL positions so that you can feel it notch into place?

Thanks, Gents.

Sorry about that, I hate it too. Where's the ooops smilie gone when I need it?

Yes, it will show the EPR or N1 thrust setting corresponding to thrust lever position. But then again a Boeing aircraft with EEC will also present that on EICAS. In a PC sim of a Boeing you see where the software throttle is of course with autothrottle engaged of course, not your physical throttle. PMDG's option to display that is a very useful feature.

Yes they are physical detents. You can set the thrust limit by feel, without needing to look at ECAM or the pedestal.

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