A320 TOGA selection and Go around mode

[Bagot_Community_Locator]

Quote from FCOM 1 :


GO AROUND (GA) :

Go-around mode combines the speed reference system (SRS) vertical mode with the GA TRK lateral mode.

ENGAGEMENT CONDITIONS :

Setting at least one thrust lever to the TOGA detent engages both SRS/GA TRK modes,
if :
– The flaps lever is at least in position 1, and
– The aircraft is in flight, or
– The aircraft has been on ground for less than 30 seconds (AP disengages and can be re-engaged five seconds after lift-off).
The FMA displays “SRS” and “GA TRK” in green.

Ok, that all makes sense, however if this is so, then why doesn't the auto flight engage the go around mode when you select MAN TOGA airborne after an engine failure after take off ? All that happens is the setting of MAN TOGA thrust with no change to the other modes.

[Boroda]

Because you already in SRS mode. Try setting TOGA in SRS after take off in comparence with accelaration when slats/flaps out - you will do feel the difference, with OEI or both operative - no matter.

[tom775257]

Because you are not in the approach phase. You can set TOGA in the climb, not much will happen apart from MAN TOGA, and depending on your altitude, an increase in thrust; although at higher altitudes, bugger all will happen.

[Bagot_Community_Locator]

Because you already in SRS mode

yes, but you are not in GA TRK mode, and you meet all the prescribed FCOM criteria (at least config 1 in flight) for the engagement of the GA MODE.

[Bagot_Community_Locator]

Because you are not in the approach phase

Yes, I thought this was how it worked. However recently I selected MAN TOGA during climb with flap out (in the simulator) and it went into the Go Around Mode :eek:

[PENKO]

By that logic, the same could be asked why you don't get GA TRK if you go from flex to full TO power. Probably the first answer you got is the correct one! Don't dig too deep, you could hurt yourself :)

[Boroda]

Not probably, it is for sure. Approach phase has nothing in common with it, you will have automatically GA phase and to return to normal flight - just fly the aircraft, that is use needed modes. When convinient - activate approach phase and go to climb phase by inserting cruise level.

[Iceman49]

Or you can go to the prog page, put in your current cruise alt...and the FMS will go to the cruise mode. Much easier.

[TyroPicard]

Bagot..
I think it is to do with FMGS flight phase.. and the SRS speed targets..
The FMGS is in TAKEOFF phase, SRS is controlling at V2+10 or V2 (OEI). There are also disengagement conditions for the various modes for us to think about - selection of TOGA does not disengage the Takeoff SRS mode, it is done by selection of a different pitch mode, or reaching acceleration altitude.

When you push V/S to level off at acceleration altitude the pitch mode changes and - if you now go from FLEX to TOGA with Flap 1 or more you will get G/A modes. So if you wish to use TOGA do so before AA...

In other words, you get the G/A combined mode in any phase except TAKEOFF.

If Airbus wrote everything in FCOM ... we would need brains the size of a planet.

[Bagot_Community_Locator]

If Airbus wrote everything in FCOM ... we would need brains the size of a planet.

Yes, but its not nice when you learn these things by accident in the sim or real aircraft because it is not written anywhere :ooh:

[TyroPicard]

But it is in FCOM - but under disengagement conditions for Takeoff SRS mode......

Yes, but its not nice when you learn these things by accident in the sim or real aircraft because it is not written anywhere

Why would you want G/A mode with an EFTO? (If that is what you mean). It is not logical, Captain.

[Boroda]

Iceman

May be you are right about much easiest way of coming to cruise or climb phase, but as for my test flights - that would not help. You have to do it just this way - activate and only than insert whatever you like. See switching conditions FCOM 4.02.20 p.11.

Tyro

Fully agree with 11.51 post

[Bagot_Community_Locator]

Why would you want G/A mode with an EFTO? (If that is what you mean). It is not logical, Captain.

Yes, exactly, I did NOT want G/A mode, it is not logical, but it did happen. :eek:

Let me further explain :

I experienced an engine fire after take off during the initial climb before acceleration altitude (no power loss).
I shut down the engine on fire (in accordance with ECAM)
We were above acceleration altitude now and I had to select speed to prevent acceleration to 250 knots with one engine inoperative.
I selected TOGA (for better climb performance until we reach the engine out acceleration altitude)....but then the stupid thing went into G/A mode when I did not want it to !!

Not logical. :confused:
Not what I wanted. :{

You can say that it went into the G/A mode because I selected TOGA with flap out and that this meets the engagement conditions for the G/A mode. I agree, in accordance with FCOM :ok:

However why doesn't it enagage the G/A mode when you select TOGA before the acceleration altitude ? It is not in the G/A mode but you do meet all the prescribed conditions for engagement.

My instructor said that if you select TOGA below the acceleration altitude, then it will not engage the G/A mode. However if you set TOGA with flap out above the acceleration altitude, it will then engage the G/A mode. It would be nice if it clarified this in the FCOM.

If if does say this, then I can't find it anywhere. :confused:

[PENKO]

Ah ok, it all becomes clear now. You were accelerating already. The fact that you were accelerating means you pushed V/S or the ALT button, because the A320 does not accelerate out of its own on single engine. If it did, I dare say that it is a sim fault. But nevermind that, the fact that you accelerate means that SRS is not active anymore, you were probably in V/S or ALT mode. That means that if you subsequently select TOGA....you get the G/A mode. I know, I did the same not too long ago when I wanted to speed things up after the n'th engine failure for the day ;)

That's how you learn!

I'm not sure what your instructor is saying about the acceleration altitude itself having any effect on things. It's too early to open my FCOM.

[Bagot_Community_Locator]

means you pushed V/S or the ALT button

No, I pulled speed actually to maintain speed, as at it changed from SRS to CLB mode on its own (passing through the acceleration altitude)

does not accelerate out of its own on single engine

We had an engine fire and both engines were still producing power until I shut one down

Yes, I agree, looks like thats how to learn. By making mistakes in the sim and learning things which are not perhaps documented very well.

Like I believe somewhere in the FCOM it should say that "it will NOT engage the G/A mode if still in SRS mode after takeoff (if this is how it works)"

[PENKO]

Hmmm...I'm struggling with the chronology of events, but if you passed acceleration altitude before shutting down one of the engines then for sure you would have been in CLB green automatically. Hence the acceleration, disengagement of SRS. And hence the activation of GA TRK when you went for TOGA.

As far as I can see it behaved by the book.

[TyroPicard]

Yes, exactly, I did NOT want G/A mode, it is not logical, but it did happen.
We were above acceleration altitude now and I had to select speed to prevent acceleration to 250 knots with one engine inoperative.
I selected TOGA (for better climb performance until we reach the engine out acceleration altitude)....but then the stupid thing went into G/A mode when I did not want it to !!

Now I understand.. the a/c behaved exactly as designed. You may not have wanted G/A but you asked for it by selecting TOGA after disengagement of SRS mode. If it happens all you have to do is select the mode you want without panic or calling the a/c "stupid" .. pull ALT to achieve OP CLB or push V/S to stay level.

Like I believe somewhere in the FCOM it should say that "it will NOT engage the G/A mode if still in SRS mode after takeoff (if this is how it works)"
Remember that to engage a mode you have to meet the disengage conditions for the existing mode. Suggest you read the disengagement conditions for SRS mode in FCOM 1.22.30 p.47, and the note about Engine Out procedures.

No, I pulled speed actually to maintain speed, as at it changed from SRS to CLB mode on its own (passing through the acceleration altitude)
This mode change should not happen OEI - are you sure you remember the sequence of events correctly?
And although the managed speed target jumps to 250 KT (or the initial climb speed to be exact) when you pull ALT for OP CLB the target reverts to Green Dot OEI.
Hope that helps

[Boroda]

Bagot

All your chronology is logical. Fire in SRS, manual engine shutdown in CLB despite the FIRE in SRS. As there were no engine out conditions met SRS successfully transfered to CLB with respective target speed (ECON CLB - 250 in your case). You started ECAM - but speed was rising, you selected it, then shutdown according to ECAM. You set TOGA and you are in an unwritten situation in FCOM.
ECAM handling is high priority in FIRE. So even accelaration altitude is reccomended to be delayed untill agent dischargment - your speed selection is good. But after that you should level off for retraction and manage speed - the target will be now green dot, no need to select it. There is no need for TOGA, but even if it is set when out of SRS, just select/manage whatever you like.
No accurate reference for your request in FCOM, some usefull only 4.04.30 p.10-16a, 4.05.80 p.1, 1.22.30 p.56a, 57.

yes, it is not good when you met something not described, and moreover when you punished for that.

[Bagot_Community_Locator]

Remember that to engage a mode you have to disengage the existing mode

Sorry, I do not understand what you mean here.

This mode change should not happen OEI - are you sure you remember the sequence of events correctly?


We were not OEI passing through the acceleration altitude. We had one engine on fire but it was still producing thrust. We were not OEI until the engine of fire was shutdown, which was once we were above the acceleration altitude.

[PENKO]

Bagot, is your question answered? ;) Or is there still a problem that I have overlooked? As far as I can see, the sim performed as it should! But I agree with you, it takes time and a lot of FCOM reading and re-reading to understand more or less how the system works.

[TyroPicard]

Remember that to engage a mode you have to disengage the existing mode
I'm not surprised you don't understand, I did not explain at all well! I will try again...

To change a mode the conditions must be right both to engage the new mode and also disengage the present mode.

On take-off the a/c is in the "Common" mode TAKEOFF; this combines vertical and lateral modes which can be disengaged separately.
The SRS mode can be disengaged in three ways.. (FCOM 1.22.30 P.47)
1. Automatically at ACC ALT or if ALT* engages to capture the FCU ALT.
2. Crew selects another pitch mode (e.g pull ALT knob, push V/S to level off).
3. Crew pulls SPD knob for selected speed.

Notice that selecting TOGA is not one of the three, so it will not change the pitch mode. The lateral mode will be NAV, HDG, or RWY TRK by now and because SRS does not disengage the lateral mode will not change.

Now imagine you are established on the ILS, and have a look at FCOM 1.22.30 p.51 for the disengagement conditions for LOC and G/S modes and you will find
"- Engages the go-around mode" in the list, so selection of TOGA makes the mode change to the "Common" G/A mode, giving you SRS and G/A TRK.

Hope that is a better explanation!

[xxqTpxx]

i think itt explain as to why go around mode engages!
BUT IF YOU think!
if you have a engine fire
AND FMGC DETECTS it

"One engine master switch off, or
N2 below idle, or
One thrust lever angle is below 5° with the other above 22°, or
The FADEC shows an engine fault."

IT wouldnt have levelved off to accelarate in the first place,(maybe becos yo have mentioned that your engines were still producing power)
chances are fmgc thought you are on both engines

in my opinion
in a case like that ! if your engine out accelaration alt is higher than accelaration alt . you should select speed! if not at accelaration alt push v/s 0, to clean up!

and performance criteria for flex ! assumes that you will clear all obstacles on flx temp on an assumes engine failure after v1!
unless theres something unusual which would effect your climb
( structural damage, higher temp.... )
you will not require TOGA

since your fmgc thought you are still on both engines
it shifted from TAKEOFF to CLIMB phase!

that could be the reason why you got GO AROUND TRK on application of TOGA!

GO AROUND MODE ENGAGEMENT


The flaps lever is at least in position 1, and
The aircraft is in flight, or
The aircraft has been on ground for less than 30 seconds (AP disengages and can be re-engaged five seconds after lift-off).
The FMA displays "SRS" and "GA TRK" in green.

IN all Phases only time you will have flaps lever 1 is APPCH PHS/Takeoff phs, the little time spent accelarating after takeoff phase to flaps 0(climb phase)
so GO around can engage provided it meets other requirements

[dream747]

Hi folks,

Sorry to bring this thread alive again!

Missed approach altitude: 4000 ft and 4000 set on the FCU.
Thr Red/Acc: 1500/1500 in the FMGC
Go-around was executed at 1800 for example with thrust levers set at TOGA.

SRS will engage to my understanding but would it revert to CLB/OP CLB mode immediately or would it remain in SRS until ALT* mode to capture 4000 ft? Am I right to assume LVR CLB would immediately start flashing as well?

Couldn't get a clear answer from FCOM for this scenario since we're above Acc altitude. Appreciate any information for those in the know!

[Valmont]

To my understanding, you will be in TOGA with LVR CLB on FMA and the speed will automatically increase toward GDot with CLB/OPCLIMB engaged as you are above GA ACC ALT.

[tubby linton]

This is why Airbus have come up with their Approach cancellation procedure.

[Valmont]

Tubby, approach cancellation is when you are above FCU selected altitude.

[tubby linton]

Thank you Valmont for the reminder. On my old Airbus we used the approach cancellation procedure if we were higher than 1000ft aal at the point of go around and TOGA if we were below it.It made for a smoother transition to the go around phase

[vilas]

dream747 tubby linton
In approach when above acceleration altitude if TOGA is applied GA phase will engage and SRS will become active pitch mode. It will not change unless you pull to OP CLB because the lower ACC ALT cannot be captured. If you don't do it then SRS will continue till ALT capture. CLB is not available in GA.
tuby, the procedure mentioned by you is very strange. I am sure you are mistaken because if you do not engage TOGA above 1000ft AAL your flight plan will be sequenced and there will be no approach for next attempt.

[Goldenrivett]

vilas,
your flight plan will be sequenced and there will be no approach for next attempt.
Unless you were smart enough to have a copy in the secondary, then only a couple of button pushes are required.

[vilas]

Goldenrivett
Have you come across a company GA procedure that forbids you to use standard GA just because you are above 1000ft AAL? At SOCHI ATC instead of asking the crew to GA told them to stop descent, climbt to 2000ft.(from 1200ft.) and turn right on 100hdg it resulted in fatal CFIT accident. I cannot believe any company would adopt this as standard procedure.

[vilas]

Bagot_Community_Locator
SRS is available for take off phase and for GA phase for vertical plane. Once SRS is engaged in take off it cannot be changed to GA phase unless it is disengaged first (to CLB/OP CLB, V/S0) before it can be engaged again another mode like GA. OEI and engine fire have different implications at. EO ACC ALT is like scratch pad, it is a reminder. It does not enter into the computer. When engine failure below AEO ACC ALT is detected by FADEC the AEO ACC ALT is dashed and SRS remains engaged till pilot changes to any of the modes mentioned above. Engine fire is not detected by FADEC till the engine is shut down and before that if you reach ACC ALT then it will change to CLB or OP CLB for take off and OP CLB for GA(CLB is NA for GA). After change of SRS to any other mode if you select TOGA it will engage GA mode. SRS is a managed speed mode, when in GA mode you go speed select it will disengage to OP CLB mode similarly if you are in approach with select speed on engagement of GA speed will become managed.

[tubby linton]

Vilas I did say that it was an old(non-fbwA306 )Airbus.. The pitch achieved during a go around could be quite alarming.
The company adopted the approach discontinuation procedure after an A320 operator made a mess of a go-aroundand bust the go-around altitude by a wide margin.

Airbus discuss the Go-Around procedure in the Jan 14 edition of Safety First which can be downloaded here:
http://www.ukfsc.co.uk/information/safety-briefings-presentations/335-airbus-safety-first-magazine