A320 Go-Around Speed
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A320 Go-Around Speed
Hello all,
the scenario takes place at a high elevation approach surrounded by high terrain,
a go-around is commenced, at accel altitude flaps 1, suddenly you realize that the missed approach turn (180deg) has a speed constraint of 160kts as you're climbing to the missed approach altitude of 18 thousand feet, but the airplane is accelerating to S speed of 190KTS, what do you do?
the scenario takes place at a high elevation approach surrounded by high terrain,
a go-around is commenced, at accel altitude flaps 1, suddenly you realize that the missed approach turn (180deg) has a speed constraint of 160kts as you're climbing to the missed approach altitude of 18 thousand feet, but the airplane is accelerating to S speed of 190KTS, what do you do?
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There is no acceleration altitude in missed approach. Acceleration is only allowed at missed app final altitude or MSA, eventualy on first step alt in missed app if it's published
And as safelife said, those kind of things you should realize earlier
And as safelife said, those kind of things you should realize earlier
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Cak
Then why does the PERF GA page has the THR RED/ACC and also ENG OUT ACC blocks? Even with terrain you can have an acceleration altitude provided the company has studied the terrain and it is possible. However you don't plan an approach to such demanding airport without preparation. The acceleration should have been planned after the turn. Flap 3 and 2 are take off configurations it is possible to retain it till appropriate. Any time you want to stop acceleration you pull speed or what prevents you from selecting flap 2..
There is no acceleration altitude in missed approach.
Last edited by vilas; 1st Jul 2016 at 19:14.
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Back a little to the design, in a missed approach, a 15 degree max bank angle is used, hence the speed restriction, until one gets to the missed approach altitude. Once you get to the MA altitude, that goes out the window and 25 degrees is used.
I seem to remember something about the max altitude is used for TOGA engine thrust limits with that high MAA?
I seem to remember something about the max altitude is used for TOGA engine thrust limits with that high MAA?
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1. Provided you have the constraint in the missed approach procedure in the database, managed speed should stay at the maximum speed defined by constraint. Look up "6 Ps", could be important when operating to high elevation airfields with high terrain around.
2. If you're in IMC and by some coincidence you have 180 kts, just put flaps 2, select 160 and off you go. There is no restriction on extending the flaps again once you have started to retract them - and vice versa. If you're VMC, you can obviously judge whether you have sufficient terrain clearance.
3. All this debate about "no acceleration during the missed approach". All correct, but on a normal missed approach with 2 engines, the gradient will be much much above the minimum required, so you can easily level off (or reduce ROC) at one point, clean the aircraft and continue climb.
Of course keeping the speed restrictions is still nice thing to do, so you don't hit a mountain that was not taken into account during procedure design.
2. If you're in IMC and by some coincidence you have 180 kts, just put flaps 2, select 160 and off you go. There is no restriction on extending the flaps again once you have started to retract them - and vice versa. If you're VMC, you can obviously judge whether you have sufficient terrain clearance.
3. All this debate about "no acceleration during the missed approach". All correct, but on a normal missed approach with 2 engines, the gradient will be much much above the minimum required, so you can easily level off (or reduce ROC) at one point, clean the aircraft and continue climb.
Of course keeping the speed restrictions is still nice thing to do, so you don't hit a mountain that was not taken into account during procedure design.
Only half a speed-brake
1) the aircraft on G/A does not automatically change to CLB from SRS. You need to pull >> that gives you time to think what comes next.
2) Answer to Q: Pull speed, 160 kt. Or less, down to Vls as needed. Vls for 1+F is exactly that, so use it. Or Vls+5.
PS: maybe I sense some confusion between "S" the minimum speed, at which the flaps may be retracted after takeoff / GA, and "S" the (convinient) target approach speed forconf 1+0 ?
Some companies advocate not flying below S speed on approach with 1+0. they ask for CF 2, they have their reasons. But flying below S speed with 1+F is normal, just like we do for take offs. *
* last time I tried the V2 was 159, so at V2 +10, not that slow at all
2) Answer to Q: Pull speed, 160 kt. Or less, down to Vls as needed. Vls for 1+F is exactly that, so use it. Or Vls+5.
PS: maybe I sense some confusion between "S" the minimum speed, at which the flaps may be retracted after takeoff / GA, and "S" the (convinient) target approach speed forconf 1+0 ?
Some companies advocate not flying below S speed on approach with 1+0. they ask for CF 2, they have their reasons. But flying below S speed with 1+F is normal, just like we do for take offs. *
* last time I tried the V2 was 159, so at V2 +10, not that slow at all
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There is no acceleration altitude in missed approach. Acceleration is only allowed at missed app final altitude or MSA, eventualy on first step alt in missed app if it's published
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No specific Airbus knowledge .. but several concerned thoughts ..
First, one presumes that the miss is associated with a sensibly planned escape .. which should include prescribed speed control as the procedure evolves. Generally, the concerns are minimal for AEO presuming that the procedure has been planned to account for the OEI case. Speed control, though, is critical to cover the case where one motor ceases to make noise ..
There is no acceleration altitude in missed approach
One still has to reconfigure from the missed to the clean configuration .. not a concern with "normal" climbs to a safe height but will need to be factored in by the ops engineers designing the procedure to keep within engine limitations in nasty tiger country.
a 15 degree max bank angle is used, hence the speed restriction
The reason being that, for a given bank angle, turn radius is tied to speed. If you want to miss that hill, best stick with the speed prescribed for the procedure.
If you're in IMC and by some coincidence you have 180 kts, just put flaps 2, select 160 and off you go
The concern here relates to the apparent fact that the earlier part of the procedure has been varied from plan .. where is the aircraft, right now, with respect to the planned terrain clearance ? Not always quite so simple as reconfiguring on the fly.
If you're VMC, you can obviously judge whether you have sufficient terrain clearance.
Generally a bad gameplan. At the very shallow climb gradients, OEI, eyeball assessment on the fly is pretty well hopeless. It all needs to have been done in the backroom ahead of time.
keeping the speed restrictions is still nice thing to do, so you don't hit a mountain that was not taken into account during procedure design
If the speed restriction wasn't predicated on that nasty mountain, why might it be there ? The chances that a researched escape would miss a major obstacle is low .. mind you, I have seen a few strange things occur with incorrect or misinterpreted data.
First, one presumes that the miss is associated with a sensibly planned escape .. which should include prescribed speed control as the procedure evolves. Generally, the concerns are minimal for AEO presuming that the procedure has been planned to account for the OEI case. Speed control, though, is critical to cover the case where one motor ceases to make noise ..
There is no acceleration altitude in missed approach
One still has to reconfigure from the missed to the clean configuration .. not a concern with "normal" climbs to a safe height but will need to be factored in by the ops engineers designing the procedure to keep within engine limitations in nasty tiger country.
a 15 degree max bank angle is used, hence the speed restriction
The reason being that, for a given bank angle, turn radius is tied to speed. If you want to miss that hill, best stick with the speed prescribed for the procedure.
If you're in IMC and by some coincidence you have 180 kts, just put flaps 2, select 160 and off you go
The concern here relates to the apparent fact that the earlier part of the procedure has been varied from plan .. where is the aircraft, right now, with respect to the planned terrain clearance ? Not always quite so simple as reconfiguring on the fly.
If you're VMC, you can obviously judge whether you have sufficient terrain clearance.
Generally a bad gameplan. At the very shallow climb gradients, OEI, eyeball assessment on the fly is pretty well hopeless. It all needs to have been done in the backroom ahead of time.
keeping the speed restrictions is still nice thing to do, so you don't hit a mountain that was not taken into account during procedure design
If the speed restriction wasn't predicated on that nasty mountain, why might it be there ? The chances that a researched escape would miss a major obstacle is low .. mind you, I have seen a few strange things occur with incorrect or misinterpreted data.
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If the speed restriction wasn't predicated on that nasty mountain, why might it be there ?
Ac such as 737/320, have no problem with a bank angle of 25 to 30 degrees, and in some tailored procedures, this is used extensively to miss obstacles.
Generally, the concerns are minimal for AEO presuming that the procedure has been planned to account for the OEI case.
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The speed restriction is due to a max bank angle of 15 degrees on the turn radius.
Precisely. The turn radius will be important either for terrain or things such as PRD avoidance etc. Generally the pilot won't know the background to the story and, especially IMC, one needs to peg the prescribed speed (or speed range) to keep one's nose clean.
Ac such as 737/320, have no problem with a bank angle of 25 to 30 degrees
AEO but not, I suggest, OEI during a miss escape procedure. Were you suggesting, above, that some aircraft have an AEO bank restriction of 15 deg (other than for the usual initial speed transition period or low level turns) ?
FAA/ICAO design criteria do not account for OEI
That's all fine and beaut .. are you suggesting that one (ie corporate masters/pilots) need not worry about an engine failure during the miss .. on such a basis ? If one has a failure, those same design criteria may prove not to be of much value to the situation in which the pilot finds himself/herself ...
very, very few public missed approach procedures will have OEI tracks
Again, fine and beaut. The AOC holder/pilot, though, ought to have a corporate/personal interest in OEI escapes for tiger country runways.
I would not like to be in the box as an expert witness arguing that the smoking hole, post OEI, was OK on the basis that the Regulator's routine prescriptions didn't require a look at OEI problems ... "they were just having a bad hair day, Your Honour"
As always, the rulebook prescribes absolute minimum standards .. not, necessarily, sensible risk management standards for the responsible AOC holder ...
Precisely. The turn radius will be important either for terrain or things such as PRD avoidance etc. Generally the pilot won't know the background to the story and, especially IMC, one needs to peg the prescribed speed (or speed range) to keep one's nose clean.
Ac such as 737/320, have no problem with a bank angle of 25 to 30 degrees
AEO but not, I suggest, OEI during a miss escape procedure. Were you suggesting, above, that some aircraft have an AEO bank restriction of 15 deg (other than for the usual initial speed transition period or low level turns) ?
FAA/ICAO design criteria do not account for OEI
That's all fine and beaut .. are you suggesting that one (ie corporate masters/pilots) need not worry about an engine failure during the miss .. on such a basis ? If one has a failure, those same design criteria may prove not to be of much value to the situation in which the pilot finds himself/herself ...
very, very few public missed approach procedures will have OEI tracks
Again, fine and beaut. The AOC holder/pilot, though, ought to have a corporate/personal interest in OEI escapes for tiger country runways.
I would not like to be in the box as an expert witness arguing that the smoking hole, post OEI, was OK on the basis that the Regulator's routine prescriptions didn't require a look at OEI problems ... "they were just having a bad hair day, Your Honour"
As always, the rulebook prescribes absolute minimum standards .. not, necessarily, sensible risk management standards for the responsible AOC holder ...
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are you suggesting that one (ie corporate masters/pilots) need not worry about an engine failure during the miss .. on such a basis ?
Currently, the FAA requires all operators to have their OWN OEI procedures which must be approved by the FAA. Thus, most operators tend to use the published procedures, but evaluate the flight plan looking at the local conditions, especially temperature. The ac is then loaded according to those parameters, being weight limited as the performance changes per aircraft.
Given the multitude of configurations, it would be difficult to design OEI procedures without many caveats, hence the regulators usually put this on the operators. A public procedure, using the lowest common denominator, would be useless and an unreasonable constraint on most operators. (this is why the usual published OEI are something like a straight line to an altitude)
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It appears that we were in heated agreement all the time ... 
Main message to get across to the punters, as you observe, is that the AIP (or equivalent) published miss generally only applies AEO.
Salut.
Main message to get across to the punters, as you observe, is that the AIP (or equivalent) published miss generally only applies AEO.
Salut.
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1) the aircraft on G/A does not automatically change to CLB from SRS. You need to pull >> that gives you time to think what comes next.
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@vilas
It seams that you are mixing things. Airbus's FMS design and features don't have anything to do with design of the procedures. You can put whatever you want for ACC height, but legaly you are not allowed to accelerate before reaching missed app altitude or MSA.
As FlyingStone said, in most modern aircrafts it's not a problem to accelerate before because you will have initialy much better climb gradient then minimum required, but if something goes wrong, lawyers will blame you for sure for acting against rules
It seams that you are mixing things. Airbus's FMS design and features don't have anything to do with design of the procedures. You can put whatever you want for ACC height, but legaly you are not allowed to accelerate before reaching missed app altitude or MSA.
As FlyingStone said, in most modern aircrafts it's not a problem to accelerate before because you will have initialy much better climb gradient then minimum required, but if something goes wrong, lawyers will blame you for sure for acting against rules
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Cak
"but legaly you are not allowed to accelerate before reaching missed app altitude or MSA."
--------
Could You provide me reference document that prescribes this one.
Thanks in advance
"but legaly you are not allowed to accelerate before reaching missed app altitude or MSA."
--------
Could You provide me reference document that prescribes this one.
Thanks in advance
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CAK and avoka
The real mix up is in your interpretation of PAN-OPS VOL I, in which the acceleration segment is deleted. That does not mean it is legally forbidden but the responsibility to ensure it's safety is on the operator. All those airlines who have acceleration altitude in GA are not doing illegally because there procedures are not secret to the authority and they would loose their permit.
legaly you are not allowed to accelerate before reaching missed app altitude or MSA
Last edited by vilas; 4th Jul 2016 at 10:37.
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It's not a mix up. If it says: "No more acceleration segment", that is exactly what it means. Operator can be responsible for some things, but final responsibility is yours in all cases. And I am pretty sure that international regulations are legaly above any operators' rules
avoka
ICAO PANS-OPS DOC 8168
Acceleration altitude existed until Volume 4 was published
avoka
ICAO PANS-OPS DOC 8168
Acceleration altitude existed until Volume 4 was published
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Cak
My statement was not correctly worded. So I corrected my post. It is that the amendment does not state acceleration segment any more. It does not forbid it. And I say again that the responsibility is with the operator. Rightly so considering the different aircrafts and their performance the ICAO possible could not state acceleration segment befitting all.
My statement was not correctly worded. So I corrected my post. It is that the amendment does not state acceleration segment any more. It does not forbid it. And I say again that the responsibility is with the operator. Rightly so considering the different aircrafts and their performance the ICAO possible could not state acceleration segment befitting all.