airbus touch down thrust operation
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airbus touch down thrust operation
im new here ,please take it easy on me!
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 know
thank you in advanced
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 know
thank you in advanced
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Hi Farid,
A/THR can be disconnected for several reasons. It could be playing up or you have a problem with it, it may not be coping well with the conditions (i.e. turbulence) and the pilot may wish the keep the engines at a set thrust instead of chasing a speed.
It may just be that when you have seen it disconnected, the pilot was practicing a manual thrust approach. Airlines have different policies on this...
To Disconnect, as you say, select thrust idle at touch down. If you are doing the manual thrust approach, it is important to ensure you bring the maximum thrust back to what the current N1 is on the display. If you don't you risk the aircraft either entering THR LOCK, where the thrust doesn't change, or worse you disconnect using the instinctive disconnect button on the side of the thrust levers and the N1 shoots up to climb thrust and you make a meal of your approach.
I hope this helps.
(This post is not intended to teah anyone to fly or arguing Airbus operational philosophy, just a bit of info I have picked up.)
A/THR can be disconnected for several reasons. It could be playing up or you have a problem with it, it may not be coping well with the conditions (i.e. turbulence) and the pilot may wish the keep the engines at a set thrust instead of chasing a speed.
It may just be that when you have seen it disconnected, the pilot was practicing a manual thrust approach. Airlines have different policies on this...
To Disconnect, as you say, select thrust idle at touch down. If you are doing the manual thrust approach, it is important to ensure you bring the maximum thrust back to what the current N1 is on the display. If you don't you risk the aircraft either entering THR LOCK, where the thrust doesn't change, or worse you disconnect using the instinctive disconnect button on the side of the thrust levers and the N1 shoots up to climb thrust and you make a meal of your approach.
I hope this helps.
(This post is not intended to teah anyone to fly or arguing Airbus operational philosophy, just a bit of info I have picked up.)
Hello and welcome, Farid,
I shall speak for the A320 family. If you discuss this with pilots you will find that there are many different ideas about how to control thrust on short finals (that is, the last 4 nm). Most pilots would agree, though, that they use different techniques according to the circumstances on the day. One thing I hope everyone would agree is that, except below 50 ft, you should never close the throttles if the A/THR is calling for thrust above idle. See (4) below.
(1) Some pilots ALWAYS use A/THR, only disconnecting it when the "gringo" shouts "RETARD!" On an autoland, that is definitely the best technique, because the A/THR will be automatically reducing thrust to idle. Otherwise, it wastes runway, because the thrust will usually be increasing before the system calls "retard".
(2) Then there are pilots that ALWAYS use A/THR, but – if they are doing a manual landing – quickly close the throttle levers at about the same time as they start the flare (say, 30 or 20 feet). This works well.
(3) Then there are other pilots that ALWAYS use A/THR, but – if they are doing a manual landing – slowly close the throttle levers during the flare. This is not very satisfactory, in my opinion, because you cannot be monitoring the thrust indicators while you are looking out of the window. So you don't really know what the thrust is doing.
(4) Then there are those who ALWAYS use A/THR for the approach, but – if they are doing a manual landing – cancel A/THR at or below 200 ft.
NOTE: The problem with this is that, if you are going to keep good control of thrust during the transition, you need to watch the "doughnuts" on the thrust indicators as you pull back the throttle levers, and – when they match the existing thrust – disconnect the A/THR with the throttle button. During this procedure, you are not seeing the runway very well, and also vulnerable to wind shear.
(5) There are also those who – if they are doing a manual landing and the weather is quite good – like to disconnect the A/THR as soon as the L/G and flaps are in the landing configuration, PROVIDED they are visual with the runway by about 1000ft. If the approach has been flown up to that point using the AP, it can be useful to keep the AP until manual thrust has been established. If the runway has not been sighted by about 400 ft, they will elect to retain A/THR. See NOTE in (4), above.
(6) And finally there are those who – if they are doing a manual landing and the weather is quite good – like to disconnect the A/THR sometime between top of descent and before landing flaps have been set. If you do it at top of descent or in the descent, A/THR can be disconnected without affecting the thrust: merely by closing the throttle levers. Using manual thrust from way out is fine if the weather is good, traffic is light, and you and the other pilot are experienced on type and know the airfield well. Otherwise, it's not a good idea because it increases the workload of the PF at a time when the PNF is often too busy to monitor the airspeed. For the same reason, it is best to use the AP where possible, and extended use of manual thrust with AP is not to be recommended.
The A/THR on the A320 usually works very well in managed speed, when available. There is normally no argument for using it in selected speed, because you lose the protection of the excellent GS-Mini, which Airbus pioneered as an automatic system. But you must insert a sensible surface-wind (W/V) into the FMGS. On a windy day, some pilots used to be tempted to put in a stronger wind than reported, or use the gust wind. This raises the Vapp, but reduces the GS-Mini protection against a sudden loss of headwind (tailwind shear).
Finally, the A320 throttle levers are a joy to use in manual thrust – the best of the six jet types I flew. It's a good idea to learn to use them when there is a sensible opportunity. You still use managed speed, and retain GS-Mini protection, which greatly reduces the need for thrust changes – provided you use managed speed as a TARGET speed, not a minimum speed. Most pilots prefer to use manual thrust for single-engine work. That's partly because – with the Airbus FBW throttle lever not being driven forwards or backwards in A/THR – the only indication you have that the A/THR is calling for more thrust is from the gauges. It goes without saying that, every time the thrust changes on the live engine, rudder and rudder trim have to be adjusted. If you are moving the throttle by hand, you merely have to remember to move the rudder pedals slightly to reflect the throttle movement.
I have made this rather long, but hope it helps. If you are ever flying Airbuses, safe landings!
Chris
PS
I must add a caution for "young" aviators. If anything written above is in conflict with your airline's SOPs, you must follow the SOP. SOPs are designed not only to be the best way of doing things; just as importantly to avoid misunderstandings between pilots, and achieve smooth cockpit management. If you disagree with an SOP, talk nicely to them in the office.
I shall speak for the A320 family. If you discuss this with pilots you will find that there are many different ideas about how to control thrust on short finals (that is, the last 4 nm). Most pilots would agree, though, that they use different techniques according to the circumstances on the day. One thing I hope everyone would agree is that, except below 50 ft, you should never close the throttles if the A/THR is calling for thrust above idle. See (4) below.
(1) Some pilots ALWAYS use A/THR, only disconnecting it when the "gringo" shouts "RETARD!" On an autoland, that is definitely the best technique, because the A/THR will be automatically reducing thrust to idle. Otherwise, it wastes runway, because the thrust will usually be increasing before the system calls "retard".
(2) Then there are pilots that ALWAYS use A/THR, but – if they are doing a manual landing – quickly close the throttle levers at about the same time as they start the flare (say, 30 or 20 feet). This works well.
(3) Then there are other pilots that ALWAYS use A/THR, but – if they are doing a manual landing – slowly close the throttle levers during the flare. This is not very satisfactory, in my opinion, because you cannot be monitoring the thrust indicators while you are looking out of the window. So you don't really know what the thrust is doing.
(4) Then there are those who ALWAYS use A/THR for the approach, but – if they are doing a manual landing – cancel A/THR at or below 200 ft.
NOTE: The problem with this is that, if you are going to keep good control of thrust during the transition, you need to watch the "doughnuts" on the thrust indicators as you pull back the throttle levers, and – when they match the existing thrust – disconnect the A/THR with the throttle button. During this procedure, you are not seeing the runway very well, and also vulnerable to wind shear.
(5) There are also those who – if they are doing a manual landing and the weather is quite good – like to disconnect the A/THR as soon as the L/G and flaps are in the landing configuration, PROVIDED they are visual with the runway by about 1000ft. If the approach has been flown up to that point using the AP, it can be useful to keep the AP until manual thrust has been established. If the runway has not been sighted by about 400 ft, they will elect to retain A/THR. See NOTE in (4), above.
(6) And finally there are those who – if they are doing a manual landing and the weather is quite good – like to disconnect the A/THR sometime between top of descent and before landing flaps have been set. If you do it at top of descent or in the descent, A/THR can be disconnected without affecting the thrust: merely by closing the throttle levers. Using manual thrust from way out is fine if the weather is good, traffic is light, and you and the other pilot are experienced on type and know the airfield well. Otherwise, it's not a good idea because it increases the workload of the PF at a time when the PNF is often too busy to monitor the airspeed. For the same reason, it is best to use the AP where possible, and extended use of manual thrust with AP is not to be recommended.
The A/THR on the A320 usually works very well in managed speed, when available. There is normally no argument for using it in selected speed, because you lose the protection of the excellent GS-Mini, which Airbus pioneered as an automatic system. But you must insert a sensible surface-wind (W/V) into the FMGS. On a windy day, some pilots used to be tempted to put in a stronger wind than reported, or use the gust wind. This raises the Vapp, but reduces the GS-Mini protection against a sudden loss of headwind (tailwind shear).
Finally, the A320 throttle levers are a joy to use in manual thrust – the best of the six jet types I flew. It's a good idea to learn to use them when there is a sensible opportunity. You still use managed speed, and retain GS-Mini protection, which greatly reduces the need for thrust changes – provided you use managed speed as a TARGET speed, not a minimum speed. Most pilots prefer to use manual thrust for single-engine work. That's partly because – with the Airbus FBW throttle lever not being driven forwards or backwards in A/THR – the only indication you have that the A/THR is calling for more thrust is from the gauges. It goes without saying that, every time the thrust changes on the live engine, rudder and rudder trim have to be adjusted. If you are moving the throttle by hand, you merely have to remember to move the rudder pedals slightly to reflect the throttle movement.
I have made this rather long, but hope it helps. If you are ever flying Airbuses, safe landings!
Chris
PS
I must add a caution for "young" aviators. If anything written above is in conflict with your airline's SOPs, you must follow the SOP. SOPs are designed not only to be the best way of doing things; just as importantly to avoid misunderstandings between pilots, and achieve smooth cockpit management. If you disagree with an SOP, talk nicely to them in the office.
Last edited by Chris Scott; 30th Apr 2011 at 16:33. Reason: Typos. PS added.
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Super summery Chris Scott
I fly A330/A340 and have flown A319 and I use option 2 provided all is stable. If there is a decel trend I might leave the thrust on a few secs longer. I do however believe we need to be promoting more Manual Thrust landings on the Airbus fleets. For the pilots who don't fly light aircraft outside of the airlines the speed control scan and thrust adjustment reaction is quickly falling by the wayside. I'm a firm believer in appropriate behavior and I don't advocate a manual thrust landing after a 13 hr flight in trying conditions, but on a nice day do it to keep your hand in. It might just save your bacon one day.
DH
I fly A330/A340 and have flown A319 and I use option 2 provided all is stable. If there is a decel trend I might leave the thrust on a few secs longer. I do however believe we need to be promoting more Manual Thrust landings on the Airbus fleets. For the pilots who don't fly light aircraft outside of the airlines the speed control scan and thrust adjustment reaction is quickly falling by the wayside. I'm a firm believer in appropriate behavior and I don't advocate a manual thrust landing after a 13 hr flight in trying conditions, but on a nice day do it to keep your hand in. It might just save your bacon one day.
DH
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i just did my Type rating few months back on A320.
According to my little experience i noticed that:-
When approaching the threshold with 2 whites and 2 reds(at say around 70-80 ft) i increase the V/S and when on the runway i start flaring
when the Auto-callout says RETARD RETARD RETARD i put the thrust levers to idle(making sure the pitch doesnt exceed 11 deg). This Has given me much smoother landing.
i just observed these while watching cockpit DVD's.
now my Question is :-
Can i come 3 red 1 white at say 100Ft RA so that i land on the 1000' TDZ?
I would appreciate if anyone please narrate their techniques to make a crosswind landings?
Thankyou
According to my little experience i noticed that:-
When approaching the threshold with 2 whites and 2 reds(at say around 70-80 ft) i increase the V/S and when on the runway i start flaring
when the Auto-callout says RETARD RETARD RETARD i put the thrust levers to idle(making sure the pitch doesnt exceed 11 deg). This Has given me much smoother landing.
i just observed these while watching cockpit DVD's.
now my Question is :-
Can i come 3 red 1 white at say 100Ft RA so that i land on the 1000' TDZ?
I would appreciate if anyone please narrate their techniques to make a crosswind landings?
Thankyou
So glad I fly a Boeing and don't have to remember all that.
Throttle position always corresponds to commanded thrust and with autothrottle
on is fully backdriven.
No confusion, no need to remember what its doing and a constant physical reminder providing complete situational awareness.
Throttle position always corresponds to commanded thrust and with autothrottle
on is fully backdriven.
No confusion, no need to remember what its doing and a constant physical reminder providing complete situational awareness.
Superbly stated Chris. Following these observations will keep one situationally-aware and avoid problems. There are no issues at all with the Airbus thrust levers - it's just a matter of experience and knowing one's airplane well, and disconnecting everything if one doesn't like what the autoflight is doing.
PJ2
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Something to keep in mind. On FAN engines, 75% of the thrust is produced by the fan, 25% by the hot air. The N1 fan is freewheeling, nothing connected to it therefore it acts like a giant flywheel. When you close the TRs, N2 will immediately decelerate, but N1 (the fan) will slowly reduce RPM. Since N1 is producing 75% of the thrust, the deceleration is not as rapid as with the older non fan jets (DC8,DC9,727 etc).
That being the case, at 50 feet, slowly start closing the TLs so that at 30 ft the power is at idle, then at about 10 to 15 feet bring the pitch up to 6 degrees and hold it there for a smooth touchdown right on the 1,000 foot marker.
Holding the power till the retard call makes for a long flare and landing much past the proper point. Know your airplane.
My 2 cents worth.
That being the case, at 50 feet, slowly start closing the TLs so that at 30 ft the power is at idle, then at about 10 to 15 feet bring the pitch up to 6 degrees and hold it there for a smooth touchdown right on the 1,000 foot marker.
Holding the power till the retard call makes for a long flare and landing much past the proper point. Know your airplane.
My 2 cents worth.
