A320 Auto thrust
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A320 Auto thrust
Question regarding the A320 Auto thrust:
Under normal ops, A Flex TO is performed, the thrust Levers are positioned to the MCT/Flex postion. To get out of Flex and into MCT, you must do one of to things. 1. Select TOGA then MCT
2. Select Climb then MCT. (ref FCOM)
Question: You are doing a flex TO, an engine fails, does the FADEC revert directly to MCT automatically or must you perform the above actions?
Under normal ops, A Flex TO is performed, the thrust Levers are positioned to the MCT/Flex postion. To get out of Flex and into MCT, you must do one of to things. 1. Select TOGA then MCT
2. Select Climb then MCT. (ref FCOM)
Question: You are doing a flex TO, an engine fails, does the FADEC revert directly to MCT automatically or must you perform the above actions?
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Hi,
Fadec dosnīt set TO thrust on itīs own, it`s commanded by the FMGC. I am unsure if it would increase to TO thrust, it would seem in line with the rest of the A/C philosophy, but I havnīt been able to find it in any book. If it does happen, it would have to be the FWCīs eng. fail output, to the DMCīs, is also picked up by the FMGC to increase thrust on the live eng. A bit like the ART on the MDī80.
Fadec dosnīt set TO thrust on itīs own, it`s commanded by the FMGC. I am unsure if it would increase to TO thrust, it would seem in line with the rest of the A/C philosophy, but I havnīt been able to find it in any book. If it does happen, it would have to be the FWCīs eng. fail output, to the DMCīs, is also picked up by the FMGC to increase thrust on the live eng. A bit like the ART on the MDī80.
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FADEC doesn't do it automatically - our SOP says option 2 AFTER you have levelled, cleaned up and are about to resume climb.
Doc -
In the A320/321, the FADEC is not controlled by the FMGC. I think you are getting the FADEC and A/THR confused. Eng failure is detected by the FADEC, not the FWC. At no time will the FMGC command an increase in thrust on the live engine, unless you move the thrust levers.
Zeke -
You won't get THR MCT until you perform one of the actions described by Coyote in his original post. What you may be thinking of is a flashing LVR MCT caption underneath the MAN FLX if an engine failure is detected and the thrustlevers are still in FLX or TOGA (assuming Accel Alt has been reached).
Don't touch Clear EO!! Unless you are ABSOLUTELY SURE you don't have an engine failure. Even then, no harm in waiting until you're on the ground...! I also believe you would get a few more indications than that if an eng had failed...
MSTR CAUTN/WRNG
HYD PTU
Lots of ECAM etc etc...
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...proceeding below Decision Height with CAUTION...
Doc -
In the A320/321, the FADEC is not controlled by the FMGC. I think you are getting the FADEC and A/THR confused. Eng failure is detected by the FADEC, not the FWC. At no time will the FMGC command an increase in thrust on the live engine, unless you move the thrust levers.
Zeke -
You won't get THR MCT until you perform one of the actions described by Coyote in his original post. What you may be thinking of is a flashing LVR MCT caption underneath the MAN FLX if an engine failure is detected and the thrustlevers are still in FLX or TOGA (assuming Accel Alt has been reached).
Don't touch Clear EO!! Unless you are ABSOLUTELY SURE you don't have an engine failure. Even then, no harm in waiting until you're on the ground...! I also believe you would get a few more indications than that if an eng had failed...
MSTR CAUTN/WRNG
HYD PTU
Lots of ECAM etc etc...
------------------
...proceeding below Decision Height with CAUTION...
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Affirmbrest,
I think you might need to check up on some things,
the A/Thr is a function in the FMGC there is no A/Thr computer, which brings me to my next point, in the event of an Alphafloor-protection the FMGC does command TOGA MAX on ALL availble engines, I know that Alphafloor is computed by both FACīs but it is never the less the FMGCīs that, via the EIUīs, commands the EECīs to TOGA MAX. As for the engine failure detection, it is correct that it is detected by the EEC, the EEC then, again via the EIU, tells the FWC, which then gives you your ECAM warnings and checklist.
[This message has been edited by DoctorA300 (edited 12 February 2001).]
I think you might need to check up on some things,
the A/Thr is a function in the FMGC there is no A/Thr computer, which brings me to my next point, in the event of an Alphafloor-protection the FMGC does command TOGA MAX on ALL availble engines, I know that Alphafloor is computed by both FACīs but it is never the less the FMGCīs that, via the EIUīs, commands the EECīs to TOGA MAX. As for the engine failure detection, it is correct that it is detected by the EEC, the EEC then, again via the EIU, tells the FWC, which then gives you your ECAM warnings and checklist.[This message has been edited by DoctorA300 (edited 12 February 2001).]
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When doing any takeoff (flex or not) when an engine fails you select TOGA on t'other as soon as the aircraft is back firmly under control don't you?
So as I see it there isnt a problem with MCT selection. You wouldnt want MCT to come in automatically as it would increase the yaw...
So as I see it there isnt a problem with MCT selection. You wouldnt want MCT to come in automatically as it would increase the yaw...
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Doc:
Oh, Okay - forgot about Alpha Floor, and follow your computer logic. Agree with your last post (I think...). Also got FAC and FWC confused...
SB - The aeroplane has to be able to meet climb performance with FLX thrust on 1 eng - that is one of the parameters which determine your allowable FLX. There is debate whether to apply TOGA on the live engine if 1 fails:
FOR appying TOGA:
1. better climb perf
2. faster accel/clean up
AGAINST applying TOGA:
1. want to look after live engine! both engines are usually 'identical', built at the same time, serviced at the same time by the same people etc. - so why has the first one failed?
2. Control issue (though you mention that)
My current philosophy is: if ROC low (2-300fpm), or big mountain/crane etc in the way (OCP SID), go TOGA. If aircraft is otherwise making the required performance to 1500' then why bother?
Horses for courses, really.
Oh, and following on from your last point: I have a feeling that MCT is typically a lower EPR than FLX. Don't know for sure though. And as for automatic thrust/yaw changes causing a problem - flying manually on 1 engine with the A/THR in is not actually that difficult, though I prefer using MAN THR for the reason mentioned.
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...proceeding below Decision Height with CAUTION...
[This message has been edited by AffirmBrest (edited 12 February 2001).]
Oh, Okay - forgot about Alpha Floor, and follow your computer logic. Agree with your last post (I think...). Also got FAC and FWC confused...
SB - The aeroplane has to be able to meet climb performance with FLX thrust on 1 eng - that is one of the parameters which determine your allowable FLX. There is debate whether to apply TOGA on the live engine if 1 fails:
FOR appying TOGA:
1. better climb perf
2. faster accel/clean up
AGAINST applying TOGA:
1. want to look after live engine! both engines are usually 'identical', built at the same time, serviced at the same time by the same people etc. - so why has the first one failed?
2. Control issue (though you mention that)
My current philosophy is: if ROC low (2-300fpm), or big mountain/crane etc in the way (OCP SID), go TOGA. If aircraft is otherwise making the required performance to 1500' then why bother?
Horses for courses, really.
Oh, and following on from your last point: I have a feeling that MCT is typically a lower EPR than FLX. Don't know for sure though. And as for automatic thrust/yaw changes causing a problem - flying manually on 1 engine with the A/THR in is not actually that difficult, though I prefer using MAN THR for the reason mentioned.
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...proceeding below Decision Height with CAUTION...
[This message has been edited by AffirmBrest (edited 12 February 2001).]
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Ok sounds like one must select TOGA or CL then MCT to ensure MCT is selected. Is this assumption correct?, If any one can find a reference to this particular (?) would be appreciated.
Here is my next Question:
You are now in MCT, and there is a selected speed of (220) or whatever, does the auto thrust limit it self to this speed?
(selected guidance has priority over Managed guidance theory).
On the the thrust lever quadrant the A/thr active range is labelled from the Flex/MCT position to The 0^ TLA position.
Here is my next Question:
You are now in MCT, and there is a selected speed of (220) or whatever, does the auto thrust limit it self to this speed?
(selected guidance has priority over Managed guidance theory).
On the the thrust lever quadrant the A/thr active range is labelled from the Flex/MCT position to The 0^ TLA position.
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Affirm Brest - interesting, everday's a school day!! All good stuff but as for the MCT being lower, I'd be suprised (in our operation anyway) as flex tends to be 50 degrees ish all the time, but I'll have a think!!
As for MCT isnt it a max power setting only (not a specific one if you see what I mean) and so A/C will fly any selected speed up to that which is the maximum with MCT... Affirm??
PS my previous post was supposed to be a smile and not a wink but nobody seems to have been offended anyway!
As for MCT isnt it a max power setting only (not a specific one if you see what I mean) and so A/C will fly any selected speed up to that which is the maximum with MCT... Affirm??
PS my previous post was supposed to be a smile and not a wink but nobody seems to have been offended anyway!
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Coyoteugly:
If takeoff is performed with FLX and an engine fails the remaining engine will supply sufficient pwr to continue T/O & initial climb (performance already calculated) and hence no need to select TOGA. But I think selecting TOGA is a wise thing to be added to company SOP taking into account the rare happening of such a failure.
Now to go from FLX to MCT pwr you are right about performing any of the two actions you mentioned in yr post. however, going to TOGA will re-engage the GA modes (SRS & GA TRK at least on older A320s) so I believe going to CLB then to MCT is a better choice.
Regarding the clearing of ENG OUT on FMGC, in fact it does not do any harm to a/c. this provision (CLR ENG OUT) is there to be used for cases of spurios detection of eng out by FMGC.
For the A/THR to maintain 220 kts it has to be active (engaged). If the levers are in MCT, the A/THR is not active (if two engs running)and cannot maintain speed.
But if an eng out, the A/THR can be active if lever in MCT or lower.
If takeoff is performed with FLX and an engine fails the remaining engine will supply sufficient pwr to continue T/O & initial climb (performance already calculated) and hence no need to select TOGA. But I think selecting TOGA is a wise thing to be added to company SOP taking into account the rare happening of such a failure.
Now to go from FLX to MCT pwr you are right about performing any of the two actions you mentioned in yr post. however, going to TOGA will re-engage the GA modes (SRS & GA TRK at least on older A320s) so I believe going to CLB then to MCT is a better choice.
Regarding the clearing of ENG OUT on FMGC, in fact it does not do any harm to a/c. this provision (CLR ENG OUT) is there to be used for cases of spurios detection of eng out by FMGC.
For the A/THR to maintain 220 kts it has to be active (engaged). If the levers are in MCT, the A/THR is not active (if two engs running)and cannot maintain speed.
But if an eng out, the A/THR can be active if lever in MCT or lower.
