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A320 Single Engine Missed Approach

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A320 Single Engine Missed Approach

Old 5th Apr 2023, 14:08
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api
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Thanks for your debate Jonty and Brace Brace .
I am more than sufficed with BraceBrace’s answer regarding the “why” of said limitation. And of course, if the choice is between impacting a mountain or running toga for an extra minute the answer is a pretty clear one. No real debate.
But the question is and was more of a dispatch one, or perhaps an in-cruise planning and briefing.
Say i am in cruise with one engine and i plan my approach for landing.
What way do i have to ensure my performance during go around respect said limitation? Only thing i can think of is literally checking the estimated EO gradient (which is checked per altitude) on flysmart, getting the feet per minute and checking that i fits under 10’.
Not too bad but feels like there should be a better way in software. I dunno.

p.s

for the person who was worried about me getting fired- your worries are heartwarming. But my seniority is higher than the chief pilot of the a320. He likes me sending him some chores.
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Old 5th Apr 2023, 20:32
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Originally Posted by api
Say i am in cruise with one engine and i plan my approach for landing.
What way do i have to ensure my performance during go around respect said limitation? Only thing i can think of is literally checking the estimated EO gradient (which is checked per altitude) on flysmart, getting the feet per minute and checking that i fits under 10’.
It was a bit of tread hijack... but yes, the guessing of how much time would be needed is a good place to start (I've even known a company where checking the 400fpm single engine ROC was almost a callout).

Anyway, can only speak for myself and how I plan such "approaches". There will always be a "worst case" plan in my head purely based on terrain for the remote case the aircraft would really struggle with the required climb performance. Ie a runway centerline is always a fairly safe place up to final approach fix (and even following procedure turns opposite direction)

Last edited by BraceBrace; 5th Apr 2023 at 20:47.
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Old 6th Apr 2023, 11:32
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Originally Posted by BraceBrace
2) your question on where the limit comes from. It comes from certification, it is related to airworthiness and maintenance plans and can be found in the AFM. If 20 years ago you would have asked me (the engineer) the question, my answer would be easy: the why is unimportant, it is a result of certification tests following a laid out plan that gives you a certainty it will work for 10', and continues to work for the remainder of the flight in MCT thrust situations. If you decide to deviate and bust limitations, you are entering a grey zone where engineers might not have valid test data, and basically nobody will certify your engine will continue to work as expected until you're back on the ground after a diversion.
Thats not where the limit comes from though is it? The regulatory requirement is to be able to operate the engine at TOGA thrust setting for 5 mins, 10 mins OEI without exceeding engine limits. That actual limit the engine feels is EGT (amongst others, but this is one of the most critical) for the CFM it’s between 940 and 975 depending on type. Max continuous limit is 905 to 940. Given that EGT falls 3.5 degrees for every one degree of OAT you could argue in northern Finland in winter your not likely to ever see 900, never mind 940. So it could be that you’re nowhere near the EGT limit, even with TOGA selected. And if that is the case, why would you deselect it if you needed it to maintain the safety of the aircraft?

I’ve seen it done, time and again, where people react to the book limit without looking at what’s actually required to maintain safety.


Now going back to the original question. Airbus states that for OEI go around. “When following a published missed approach procedure, the EO ACC ALT should be the lower of the missed approach altitude or the MSA”.

So the thrust leavers should go to MCT at the end of the acceleration, which should be at MSA or the missed approach altitude.

FCTM/Procedures/Abnormal and Emergency Procedures/ENG/One Engine Inoperative - Go Around.

If you can’t achieve the gradient then do the EFP. And I would include the TOGA limit here. If you needed 12 mins of TOGA to complete the standard missed approach, do the EFP instead. Now if you were to lose the engine on the go around, and you can’t do the EFP, all bets are off. And if you need 12 mins of TOGA, use it.
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Old 6th Apr 2023, 21:26
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If you understand the technical rationale behind a certain limitation and disregard it ina n emergency with a full understanding of what you’re doing - props to you. Always better to be tried by 12 than carried by 6!

The manufacturer however impose limitations which need to hold throughout the certified envelope.
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Old 7th Apr 2023, 09:11
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Originally Posted by Jonty
Now going back to the original question. Airbus states that for OEI go around. “When following a published missed approach procedure, the EO ACC ALT should be the lower of the missed approach altitude or the MSA”.

So the thrust leavers should go to MCT at the end of the acceleration, which should be at MSA or the missed approach altitude.

FCTM/Procedures/Abnormal and Emergency Procedures/ENG/One Engine Inoperative - Go Around.

If you can’t achieve the gradient then do the EFP. And I would include the TOGA limit here. If you needed 12 mins of TOGA to complete the standard missed approach, do the EFP instead. Now if you were to lose the engine on the go around, and you can’t do the EFP, all bets are off. And if you need 12 mins of TOGA, use it.
Well i be damned. Heres what my FCTM/Procedures/…/One Engine Inoprative - Go Around says:
A one engine inoperative go-around is similar to a go-around flown with all engines.

On the application of TOGA, the flight crew must apply rudder promptly to compensate for the increase in thrust and consequently to keep the beta target centred.

Provided the flap lever is selected to Flap 1 or greater, SRS will engage and will be followed. If SRS is not available, the initial target pitch attitude will be 12.5 °.

The lateral FD mode will be GA TRK (or NAV if option installed) and this must be considered with respect to terrain clearance.

At the engine-out acceleration altitude, apply the same technique as described earlier. Refer to Engine Failure after V1.

// END
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Old 7th Apr 2023, 16:15
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Originally Posted by api
Well i be damned. Heres what my FCTM/Procedures/…/One Engine Inoprative - Go Around says:
A one engine inoperative go-around is similar to a go-around flown with all engines.

On the application of TOGA, the flight crew must apply rudder promptly to compensate for the increase in thrust and consequently to keep the beta target centred.

Provided the flap lever is selected to Flap 1 or greater, SRS will engage and will be followed. If SRS is not available, the initial target pitch attitude will be 12.5 °.

The lateral FD mode will be GA TRK (or NAV if option installed) and this must be considered with respect to terrain clearance.

At the engine-out acceleration altitude, apply the same technique as described earlier. Refer to Engine Failure after V1.

// END
Mmmm……
That is interesting.
the only thing I would clarify is that my FCTM is for an A321, but I wouldn’t have thought it would make any difference.

Last edited by Jonty; 7th Apr 2023 at 20:40. Reason: Screen shot added
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Old 7th Apr 2023, 17:17
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It's not my idea but during training of crew of an airline their training manager had suggested that in such a situation where 10mts are being reached, bring thrust lever to MCT and then put it back to TOGA and you get a new lease for another ten minutes. He mentioned an airfield not sure but perhaps was in Australia. I hadn't come across anything before. Can someone throw some light on this?
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Old 7th Apr 2023, 20:51
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Originally Posted by Jonty



Mmmm……
That is interesting.
the only thing I would clarify is that my FCTM is for an A321, but I wouldn’t have thought it would make any difference.
My FCTM (A321) says the same as api’s. Its a 2017 DU though while yours is Feb 23 so maybe that’s been a more recent change. For what it’s worth our procedure is to do almost exactly what your FCTM says, EO acc at the go-around altitude, but I can’t find anywhere in our manuals that actually spells it out the way your FCTM does.
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Old 7th Apr 2023, 23:17
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Originally Posted by vilas
It's not my idea but during training of crew of an airline their training manager had suggested that in such a situation where 10mts are being reached, bring thrust lever to MCT and then put it back to TOGA and you get a new lease for another ten minutes. He mentioned an airfield not sure but perhaps was in Australia. I hadn't come across anything before. Can someone throw some light on this?
Our procedures at INN where this is a likely scenario if you lose an engine late on the approach or when going around simply require selecting MCT when you hit the TOGA limit and performance is more than sufficient in this case.
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Old 10th Apr 2023, 07:18
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Originally Posted by Jwscud
Our procedures at INN where this is a likely scenario if you lose an engine late on the approach or when going around simply require selecting MCT when you hit the TOGA limit and performance is more than sufficient in this case.
If after 10mts MCT is sufficient then where is the problem? My point was if even after 10mts TOGA MCT won't do then reducing TOGA to MCT and then setting TOGA again is it ok? It appears to meet the maximum TOGA limitation.
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Old 10th Apr 2023, 09:49
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In my outfit we always level off at 1500 feet AAL on single engine during a missed approach. If we can not comply with the missed approach climb gradient we will follow the EOSID..
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Old 10th Apr 2023, 15:12
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Originally Posted by pineteam
In my outfit we always level off at 1500 feet AAL on single engine during a missed approach. If we can not comply with the missed approach climb gradient we will follow the EOSID..
How do you account for the level off in deciding whether you can meet the missed approach climb requirements?
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Old 10th Apr 2023, 16:14
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I guess we don’t. We always comply with the terrain clearance when we level off at 1500 feet AAL. We do not operate in mountainous areas.
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Old 10th Apr 2023, 16:15
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Originally Posted by vilas
If after 10mts MCT is sufficient then where is the problem? My point was if even after 10mts TOGA MCT won't do then reducing TOGA to MCT and then setting TOGA again is it ok? It appears to meet the maximum TOGA limitation.
That’s not what crews should have to be doing.
If you can’t make the published stop altitude or MSA within 10 mins of TOGA, then the procedure needs to be changed - not the number of engine cycles at TOGA.

Crews should be able to determine the maximum landing weight which would give them enough performance on an engine out GA to comply with one application of GA thrust of <10 mins.

We had that necessary software enabled.


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Old 10th Apr 2023, 19:16
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Originally Posted by Goldenrivett
That’s not what crews should have to be doing.
If you can’t make the published stop altitude or MSA within 10 mins of TOGA, then the procedure needs to be changed - not the number of engine cycles at TOGA.

Crews should be able to determine the maximum landing weight which would give them enough performance on an engine out GA to comply with one application of GA thrust of <10 mins.

We had that necessary software enabled.
I agree with that. Though the problem will be takeoff from there then OEI and during landing back and go around. I am not certain whether that will restrict takeoff weight also.
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Old 10th Apr 2023, 22:34
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Originally Posted by vilas
I agree with that. Though the problem will be takeoff from there then OEI and during landing back and go around. I am not certain whether that will restrict takeoff weight also.
If the intention is to land back at the departure airport and it’s known that performance may be limiting they should probably be checking the OEI landing / go-around performance prior to departure.
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Old 10th Apr 2023, 22:53
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Indeed - and a TO alternate selected. See again the Austrian alps (INN/SZG)
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Old 27th Apr 2023, 11:19
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There are some explanation from Airbus in "Airbus-Win" public website.

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Old 27th Apr 2023, 20:57
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I tried to review all posts, if I am not missed, one important and controversial point is not mentioned at all.

That is: Go around gradient value calculated with the tool (e.g Flysmart now on I will mention as FSA) at the hand of pilot calculating landing performance HAS NO USAGE from the perspective of pilot
It can never be compared with the design gradient of Missed Approach procedure, which is defaulted as 2.5 % if the terrain along the path is not requiring more.
This is correct, regardless what the calculated value is either 2.1 % (minimum as approach climb gradient for two engine airplane) or 15%
As a requirement of Procedure Design Gradient (PDG) of ICAO DOC 8168 Part I or 2 (also known as PAN-OPS), the MAP gradient has NO interest with the number of engine of the airplane and how good their performance while going around or flying Missed approach Procedure

Whereas, Approach Climb Gradient (see note) is a requirement stated by CS 25 or FAR 25
These two docs guides the manufacturer how they should make their plane to be good enough to comply with the certification standards which are safe enough to carry human species. Those docs have no interest in which terrain condition the plane will fly the missed approach. This gradient requirement confines the manufacturer to advertise their airplane to the customer as "this airplane can land with this weight at this condition".
I mean, regulation says "hey Mr/Mrs manufacturer, when you are praising your plane in terms of landing weight you cannot tell fabulous numbers; your max number (weight) which you can advertise should not be more than the weight which can hinder an MOMENTARY (valid only for a fraction of second) 2.1% gradient (two engine airplane). (I remind, as you aware, this is only the one of the landing weight requirements of many, probably most difficult one to visualize)

MOMENTARY is the important point, no FSA (or likewise) calculated GA gradient is a continuous gradient. That is impossible because whatever the number is, let's say 5% that is only valid for that altitude and ambient conditions, as you climb your TAS will increase (accelerate, even for fixed CAS) and Thrust will decrease. Conclusion, an airplane in this scenario, cannot maintain a straight climb path; It starts with 5% but 2000 feet above it may be 1.5%. Therefore this 5% even as even greater than PDG (2.5%), cannot guarantee that following MAP is flyable


Note for only for those gents who may be away from some definitions: Shown GA gradient after the calculation by FSA is more limiting of either Approach Climb Gradient or Landing Climb Gradient (according to Airbus, for two engine plane always the second, LCG, is limiting)

Limiting(in terms of ACG) means the max permissible weight where you can start the approach, assuming either then or at the go around
one engine failed (out of whatever number was there)



There are more controversial things about engine 10 min usage limit as well, but later if required

Last edited by JABBARA; 29th Apr 2023 at 19:24.
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Old 29th Apr 2023, 14:57
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Originally Posted by JABBARA
I tried to review all posts, if I am not missed, one important and controversial point is not mentioned at all.

That is: Go around gradient value calculated with the tool (e.g Flysmart now on I will mention as FSA) at the hand of pilot calculating landing performance HAS NO USAGE from the perspective of pilot
It can never be compared with the design gradient of Missed Approach procedure, which is defaulted as 2.5 % if the terrain along the path is not requiring more.
This is correct, regardless what the calculated value is either 2.1 % (minimum as approach climb gradient for two engine airplane) or 15%
As a requirement of Procedure Design Gradient (PDG) of ICAO DOC 8168 Part I or 2 (also known as PAN-OPS), the MAP gradient has NO interest with the number of engine of the airplane and how good their performance while going around or flying Missed approach Procedure

Whereas, Approach Climb Gradient (see note) is a requirement stated by CS 25 or FAR 25
These two docs guides the manufacturer how they should make their plane to be good enough to comply with the certification standards which are safe enough to carry human species. Those docs have no interest in which terrain condition the plane will fly the missed approach. This gradient requirement confines the manufacturer to advertise their airplane to the customer as "this airplane can land with this weight at this condition".
I mean, regulation says "hey Mr/Mrs manufacturer, when you are praising your plane in terms of landing weight you cannot tell fabulous numbers; your max number (weight) which you can advertise should not be more than the weight which can hinder an MOMENTARY (valid only for a fraction of second) 2.1% gradient (two engine airplane). (I remind, as you aware, this is only the one of the landing weight requirements of many, probably most difficult one to visualize)

MOMENTARY is the important point, no FSA (or likewise) calculated GA gradient is a continuous gradient. That is impossible because whatever the number is, let's say 5% that is only valid for that altitude and ambient conditions, as you climb your TAS will increase (accelerate, even for fixed CAS) and Thrust will decrease. Conclusion, an airplane in this scenario, cannot maintain a straight climb path; It starts with 5% but 2000 feet above it may be 1.5%. Therefore this 5% even as even greater than PDG (2.5%), cannot guarantee that following MAP is flyable


Note for only for those gents who may be away from some definitions: Shown GA gradient after the calculation by FSA is more limiting of either Approach Climb Gradient or Landing Climb Gradient (according to Airbus, for two engine plane always the second, LCG, is limiting)

Limiting(in terms of LCG) means the max permissible weight where you can start the approach, assuming either then or at the go around
one engine failed (out of whatever number was there)



There are more controversial things about engine 10 min usage limit as well, but later if required
Hi JABBARA

it must be a typo but the LCG is never limiting. Probably You meant ACG.

Originally Posted by JABBARA

no FSA (or likewise) calculated GA gradient is a continuous gradient
Flysmart does have an option to select the required GA gradient and the target altitude until it is required. In that case I believe the results do take care of varying conditions as you have detailed.


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