airbus touch down thrust operation

[farid 2]

i want to know what is common procedure for thrust on final approach,i saw many many videos (world air tours,pilot eyes,...)some pilots stay on A/THR active on final approach _speed managed mode)when touching down going back all the way on the thrust to idle then automatically A/THR get disabled...after that reverse and finish...many other for example at 2~4 DME from TDZE ,going back on idle trust so A/THR get disabled again automatically ,while stay on speed managed mode,and after that reverse and so on...i want to know first ,am i right in figured out this 2 ways i said?which one is common by pilots?and why some pilot choice A/THR off for approach ?!i mean A/THR on have not any bad effect any way,why they cut that off?if some body knows about that systems ,let me knowthank you in advanced

[Chock 17,769]

The book (i.e. the SOP manual for the real A320, and it's the same for other models), says that managed speed is the 'standard' way to do things for an ILS approach, but on visual approaches, the manual says: This pattern assumes the use of minimum ground speed (managed). If not, select speeds manually according to flaps configuration.What this means, and this is in fact reiterated in the SOP manual, is that the 'standard' way to do things is not a hard and fast rule, merely the recommended way, and it is always the crew's discretion to use any method they like within reason if they deem it best. Things such as runway surface condition (both contamination and water), may mean the crew want to be on the throttles themselves to enable them to pull up quickly or whatever, or they may get directions from ATC to speed up or slow down on the approach which might be better handled with manual throttle control.Sometimes atmospheric conditions may dictate the choice too. For example, in heavy rain conditions the pilot might want to brake the descent speed with more flaps so he or she can use high engine RPM settings in order to mitigate the possibility of the engine being swamped by water and flaming out. Flameouts owing to water ingestion when passing through rainclouds are rare for jet engines, but it is certainly not unknown, particularly in SE Asia during monsoon seasons, and especially on the CFM-56 before it was modified slightly with little vanes on the intake spinner to disperse water more efficiently. Even with that modification to the CFM 56, it is still recommended that the pilots keep the RPM above idle when passing through heavy rainclouds, which means they will not want to leave the N1 setting up to the computers.Having said that, there are usually some caveats in the company versions of SOP manuals you actually find in use in airliners for real, for example, some airlines don't like their pilots use the 'low' autobrake setting on an Airbus because in addition to using a bit of reverse thrust, it tends to cycle the brakes a lot, which wears them out and overheats them too, and if it is a particularly convoluted taxy back to the stand, where the brakes will be needed, then overheating them on the roll out would not be a good idea, especially since it also makes a blown tire far more likely. Another example would be, some airlines don't like their pilots to use the expedite speed functions because it burns a lot of fuel. Thus there are all kinds of little company-specific rules you find scattered about in the SOP manuals which the airline hands to their crews which alter what might be thought of as the 'standard' way of doing things. So there are airline specific rulings in the SOPs which make the pilots use certain methods over other ones, which could be a reason for differences you have seen in various cockpit videos.Al

[farid 2]

The book (i.e. the SOP manual for the real A320, and it's the same for other models), says that managed speed is the 'standard' way to do things for an ILS approach, but on visual approaches, the manual says: This pattern assumes the use of minimum ground speed (managed). If not, select speeds manually according to flaps configuration.What this means, and this is in fact reiterated in the SOP manual, is that the 'standard' way to do things is not a hard and fast rule, merely the recommended way, and it is always the crew's discretion to use any method they like within reason if they deem it best. Things such as runway surface condition (both contamination and water), may mean the crew want to be on the throttles themselves to enable them to pull up quickly or whatever, or they may get directions from ATC to speed up or slow down on the approach which might be better handled with manual throttle control.Sometimes atmospheric conditions may dictate the choice too. For example, in heavy rain conditions the pilot might want to brake the descent speed with more flaps so he or she can use high engine RPM settings in order to mitigate the possibility of the engine being swamped by water and flaming out. Flameouts owing to water ingestion when passing through rainclouds are rare for jet engines, but it is certainly not unknown, particularly in SE Asia during monsoon seasons, and especially on the CFM-56 before it was modified slightly with little vanes on the intake spinner to disperse water more efficiently. Even with that modification to the CFM 56, it is still recommended that the pilots keep the RPM above idle when passing through heavy rainclouds, which means they will not want to leave the N1 setting up to the computers.Having said that, there are usually some caveats in the company versions of SOP manuals you actually find in use in airliners for real, for example, some airlines don't like their pilots use the 'low' autobrake setting on an Airbus because in addition to using a bit of reverse thrust, it tends to cycle the brakes a lot, which wears them out and overheats them too, and if it is a particularly convoluted taxy back to the stand, where the brakes will be needed, then overheating them on the roll out would not be a good idea, especially since it also makes a blown tire far more likely. Another example would be, some airlines don't like their pilots to use the expedite speed functions because it burns a lot of fuel. Thus there are all kinds of little company-specific rules you find scattered about in the SOP manuals which the airline hands to their crews which alter what might be thought of as the 'standard' way of doing things. So there are airline specific rulings in the SOPs which make the pilots use certain methods over other ones, which could be a reason for differences you have seen in various cockpit videos.Al

Great ,Thank you Very muchand please ,i had another post about wind(since was not any body to answering)have a look ,it seems you can tell me something about that too;http://forum.avsim.net/topic/334046-mcdu-questions-about-wind/thank you again