737 Go-Around question

[B736]

If you press one of the TO/GA buttons within the criteria for engagement of go-around mode during a singe-channel ILS approach when you are still above the missed approach altitude, as set in the altitude window on the MCP - what would happen? I have searched through FCOM and FCTM without finding any satisfactory answers. I know what I would do if I end up in a situation like that, but I'm interested in a technical perspective.

Best regards

[FlyingStone]

Exactly the same as with the normal go-around, except that the AFDS will stay in TO/GA mode until you change the pitch mode yourself or reset the MCP altitude to something above your current altitude. In simple terms, the aircraft will climb until it reaches it's performance-limited altitude.

[B736]

Exactly the same as with the normal go-around, except that the AFDS will stay in TO/GA mode until you change the pitch mode yourself or reset the MCP altitude to something above your current altitude. In simple terms, the aircraft will climb until it reaches it's performance-limited altitude.

Thanks! Are you talking from experience or is this documented somewhere? Or maybe it’s considered obvious..

[172_driver]

It's documented, sort of, in System Description ch. 4. Read it as; in the abscense of ALT ACQ or pilot selected pitch mode, the F/D Go-Around mode isn't terminated.

[gearlever]

Why should one dial in a M/A altitude in the MCP if above?

[Chesty Morgan]

Perhaps with a platform altitude of 3000 and a missed approach altitude of 2000 for example.

[Skyjob]

Why should one dial in a M/A altitude in the MCP if above?
Look at LEMG/AGP charts for runway 13: MISAP 2000' but platform 12nm at 4200'

[eckhard]

One way around this is to press TO/GA, followed by FLCH. If done without too much pause, the Approach mode will terminate, the thrust levers will advance slightly, then reduce to a low setting compatible with the remaining descent altitude and the aircraft will continue descent to the MAP alt.

Depending on the installed FMS/APFD, the lateral mode may need to be selected to LNAV or HDG SEL.

[framer]

One way around this is to press TO/GA, followed by FLCH. If done without too much pause, the Approach mode will terminate, the thrust levers will advance slightly, then reduce to a low setting compatible with the remaining descent altitude and the aircraft will continue descent to the MAP alt.
I haven’t heard that before but I guess it would work.
You can do it nicely by retuning the Nav receivers and then engaging V/s and whatever lateral mode you think is best at the time.

[gearlever]

Look at LEMG/AGP charts for runway 13: MISAP 2000' but platform 12nm at 4200'

I know.
Oor SOP was (retired) to set 2.000 ft, or whatever G/A altitude, when below.

[B736]

SOP in our company is to set the M/A altitude when when the GS is captured. I often fly in to Stockholm (ESSA) where the missed approach is 1500 ft and the platform altitudes at the highest 4000 ft. That’s why this question have been a particular interest of mine. Thanks for all answers!

[B737900er]

This is why you brief on how you will perform the go around. Simple way of doing it.

1. Press CWS (this will take it out of APP mode)

2. LVL CHG

3. CMD A/B

This keeps the aircraft in an automatic mode and you wont need to rush when doing it.

[Switchbait]

Hallelujah and praise Father Dick!

[Vessbot]

Or you can simply fly the aircraft.

True, and I support the concept; but that's no reason not to be able to also do it by use of autopilot (with the weird sequence of commands in the edge case thought through ahead of time rather than during an actual goaround)

[RVF750]

If you want to do it simply. Why not just deselect the ILS frequency then re-select it. That will put you in raw modes. You can then select LNAV and V/S. Far smoother than LVL CHG which is a crude thing when you're near the ground. You've probably got some power on and don't want to drop onto the MA platform like a stone do you?

[B737900er]

If you want to do it simply. Why not just deselect the ILS frequency then re-select it. That will put you in raw modes. You can then select LNAV and V/S. Far smoother than LVL CHG which is a crude thing when you're near the ground. You've probably got some power on and don't want to drop onto the MA platform like a stone do you?
For a descent I would agree with you. For a climb, I would use my method. I have used it both in the sim and on the line with no problems.

[felixthecat]

On 777 it will go into an unrestricted climb, 737 and 777 are pretty similar.

Easiest way is if your given a missed approach, before you press TOGA check the altitude selected. The is very rarely a rush to do a go around. If your above the missed approach altitude (on 777 anyway) so long as your above 1500ft if you deselect approach it will default to V/S and decent to and capture the missed approach altitude. When its level then select TOGA and follow the normal procedure.

[Skyjob]

On 777 it will go into an unrestricted climb, 737 and 777 are pretty similar.
Easiest way is if your given a missed approach, before you press TOGA check the altitude selected. The is very rarely a rush to do a go around. If your above the missed approach altitude (on 777 anyway) so long as your above 1500ft if you deselect approach it will default to V/S and decent to and capture the missed approach altitude. When its level then select TOGA and follow the normal procedure.

737 does not allow you to deselect APP, hence deselecting ILS is better option, forcing APP to be dropped.
BTW: only selected autopilot needs deselecting, eg NAV 2 with CMD B

[RVF750]

On 777 it will go into an unrestricted climb, 737 and 777 are pretty similar.

Easiest way is if your given a missed approach, before you press TOGA check the altitude selected. The is very rarely a rush to do a go around. If your above the missed approach altitude (on 777 anyway) so long as your above 1500ft if you deselect approach it will default to V/S and decent to and capture the missed approach altitude. When its level then select TOGA and follow the normal procedure.


So you are saying you allow it to capture the missed approach altitude, then select TOGA? I'd say that's a bit dramatic.. Why not just wind a bit of speed on and clean up smoothly?

[felixthecat]

It sequences the checks and systems but does nothing else.

[Chesty Morgan]

Why not just wait until you’re below the MAA?

[felixthecat]

Because the question was what would happen if you were above it. Not particularly tidy if you were given a missed above the maa then decided to continue down below it before you decided to do the missed (a hundred feet above maybe) but just pushing the app button makes life easy.

[Chesty Morgan]

And that has been answered. The discussion has moved on to the best way to achieve a go around from above the MA.

[172_driver]

Why not just wait until you’re below the MAA?

In Stockholm you capture the G/S at 4000 ft and MAA is 1500 ft.

[Chesty Morgan]

Well yes that’s the context of the thread.

So, if you have to go around why not wait until you’re below the MAA before you press TOGA?

[felixthecat]

Because you might be asked to go around in the example at Stockholm above at say 3000 ft. Why would you descend below the 1500ft missed approach altitude? There is no need to, you would just ensure 1500ft was set and disengage the app mode. Job done.

In a climb when ATC tell you to climb 350 and your at 330 do you go through 350 and then descend back to 350?? Would make no sense would it. ATC might have words to say as well.

[Chesty Morgan]

Because you might be asked to go around in the example at Stockholm above at say 3000 ft. Why would you descend below the 1500ft missed approach altitude? There is no need to, you would just ensure 1500ft was set and disengage the app mode. Job done
1, you’ve already been told that you cannot just disengage approach mode in the 737.
2, if you go around above a lower MAA then you’ll be descending anyway.
3, I’m sure ATC won’t mind if I descend to 1499’ before I go around to 1500’, would they?

In a climb when ATC tell you to climb 350 and your at 330 do you go through 350 and then descend back to 350?? Would make no sense would it. ATC might have words to say as well.
Stupid comment.

[Chesty Morgan]

So you are going to marginally descend through just so you can press Toga and have the autopilot disconnect and a momentary large increase in commanded thrust? Cancel the disconnect alarm potentially the autothrottle now probably require PM to change a few modes on the MCP so you can select what you want on CMD A. It probably went into ALT AQC at some point so the MCP speed could be somewhere you don't want nor now potentially configured for... I'm sorry but in this case 'keeping it simple' would actually be making an arse of it.
Oh it most definitely goes into alt acq. As it should. Your speed will be fine because it will be your current speed. Then you bug up and carry on as normal. Are you any worse off than a go around from 500’ below, or 1000’ or from minima?

[Chesty Morgan]

The AP disconnects whenever you press TOGA. Not sure how being closer to the MAA is a problem.

How do you cope when ATC surprises you and sends you around just below, at or slightly above MAA?

[felixthecat]

1, you’ve already been told that you cannot just disengage approach mode in the 737.
2, if you go around above a lower MAA then you’ll be descending anyway.
3, I’m sure ATC won’t mind if I descend to 1499’ before I go around to 1500’, would they?


Stupid comment.






1, you’ve already been told that you cannot just disengage approach mode in the 737..... but you have a method where in effect you have the same by deselecting the ILS and placing the aircraft into an attitude stabilised mode. and letting the aircraft smoothly capture the MAA.
2, if you go around above a lower MAA then you’ll be descending anyway...... your descending slightly in a g/a (50ft or so if that), in the example above it was talking about more than slight a decent. A go around from way above the MAA and then descending hundreds of feet only to pass through through it, disconnecting the AP, large increase in thrust, cancelling any oral warnings, to climb back up, level off, re-engage AP etc etc doesn't make sense to me.
3, I’m sure ATC won’t mind if I descend to 1499’ before I go around to 1500’, would they?...... your going to push the GA at 1499....impressive, then next time when you miss by 2 feet and you press it at 1501ft and you go to an unrestricted climb they might mind, and before you say you will do it slightly lower than that....how much slightly? Is there an SOP in company X that says push g/a at x number of feet below ? I would be surprised. Then there is the A/P disconnecting in the 737 because of the G/A and the large increase in thrust etc etc, why? You can do it much more efficiently and much more smoothly.

As for the stupid comment.... its the same thing, I was using that argument as a hyperbole. You don't bust levels for the sake of it. That would be stupid.

How do you cope when ATC surprises you and sends you around just below, at or slightly above MAA?........ The operative words there are just above or just below. Then you deal with it as you describe. This discussion was about when you have plenty of time.

[Chesty Morgan]

No it wasn’t. You’ve just made that up.

It’s not a level bust if you go below a MAA or we’d be having level busts every day.

[felixthecat]

I made it up? :D:D And no its not a 'level bust' because its less than 300ft. Not great handling though is it. Do it any way you want, I don't really care :)

[Chesty Morgan]

I made it up? :D:D And no its not a 'level bust' because its less than 300ft. Not great handling though is it. Do it any way you want, I don't really care :)
Yep, you were the first to mention “plenty of time” on this thread.

Fits your argument doesn’t it?

If you don’t care why are you posting?

[felixthecat]

Perhaps with a platform altitude of 3000 and a missed approach altitude of 2000 for example
In Stockholm you capture the G/S at 4000 ft and MAA is 1500 ft.
Because you might be asked to go around in the example at Stockholm above at say 3000 ft.

​​​​​​Yup, all made up:rolleyes:. We don't always go around at exactly the minima or at the MAA in the examples above. Usually in a descending go around it ATC directed and in the above examples there is a long way between 3000 and 2000 in the first point say 1min approx that example, or 4000 and 1500 in second say 2 mins approx. I would say thats 'plenty of time'. If your unable to manage to get the aircraft to smoothly intercept a given altitude and level off in that period without going through selecting TOGA etc etc then you have more problems to worry about. As I said above:

How do you cope when ATC surprises you and sends you around just below, at or slightly above MAA?........ The operative words there are just above or just below. Then you deal with it as you describe. This discussion was about when you have plenty of time.

[Chesty Morgan]

Long post for someone who doesn’t care. :rolleyes:

Good maths though.

If your unable to manage to get the aircraft to smoothly intercept a given altitude and level off in that period without going through selecting TOGA etc etc then you have more problems to worry about.

And the award for master strawmanning goes to you.

[felixthecat]

Ad hominem per chance?.:rolleyes:

[Chesty Morgan]

No, that would be an attack on your character.

I just pointed out that you intentionally misrepresented my position because it was easier to defeat.

But you still dont care...

[felixthecat]

No, that would be an attack on your character.

I just pointed out that you intentionally misrepresented my position because it was easier to defeat.

But you still dont care...
It doesn't have to be an attack on character it is an attack on the individual as opposed to the argument. As for straw man, maybe you should read the previous posts a bit closer. PS And I don't really care how YOU fly your approach . Good luck next PPC

[Chesty Morgan]

Yes, your argument was a straw man argument which I pointed out. That is not an attack on you. If if I was to say, for example, you’re a moron that would be ad hominem. I didn’t, ergo, it wasn’t.

Oooh that’s a good one - how do I fly an approach?!

[felixthecat]

I never misrepresented your position at all, I, in fact agreed with your GA from close to the MAA, but you appear to be unable to see that there are more sides than your one to this problem.

Insulting me just proves your ignorance...QED ad hominem.

[RVF750]

Chesty, I wouldn't be so confident it will go into ALT AQQ if you press TOGA just below the MAA. As the aircraft ramps up thrust and pitches up, there is a definite chance it will be unable to capture the MCP selected alt and sail through. By de-selecting the ILS and using appropriate modes you will gently, and calmly be able to manage a level off and lateral navigation to the fix. It's just so easy to do. Why you'd insist on pressing TOGA in this case is beyond me. It just sets you up for a handful of trouble. Then again, if you work for the same company as me, I would understand it quite well....

[poldek77]

When we look again at ILS 26 at ESSA: Final Approach Point is at D7.5/2500' and missed approach procedure says CLIMB 1500'. If I go around from let's say 2000 feet then I am simply not able to comply - it is quite difficult to climb from 2000 to 1500 ;). I hope ATC is aware of that and can provide alternate instructions immediately.

[Chesty Morgan]

Chesty, I wouldn't be so confident it will go into ALT AQQ if you press TOGA just below the MAA. As the aircraft ramps up thrust and pitches up, there is a definite chance it will be unable to capture the MCP selected alt and sail through. By de-selecting the ILS and using appropriate modes you will gently, and calmly be able to manage a level off and lateral navigation to the fix. It's just so easy to do. Why you'd insist on pressing TOGA in this case is beyond me. It just sets you up for a handful of trouble. Then again, if you work for the same company as me, I would understand it quite well....
I haven’t insisted on anything.

[Capn Bloggs]

When we look again at ILS 26 at ESSA: Final Approach Point is at D7.5/2500' and missed approach procedure says CLIMB 1500'. If I go around from let's say 2000 feet then I am simply not able to comply - it is quite difficult to climb from 2000 to 1500 https://www.pprune.org/images/smilies/wink2.gif. I hope ATC is aware of that and can provide alternate instructions immediately.
Poldek, I am sure that procedure was written assuming you were below the MAA. Let's not get too literal...

[underfire]

Poldek, I am sure that procedure was written assuming you were below the MAA.
It is written, assuming you are following the procedure.

When we look again at ILS 26 at ESSA: Final Approach Point is at D7.5/2500' and missed approach procedure says CLIMB 1500'. If I go around from let's say 2000 feet then I am simply not able to comply - it is quite difficult to climb from 2000 to 1500 ;). I hope ATC is aware of that and can provide alternate instructions immediately./

Poldek, the DA for ILS 26 at ESSA is 460/490, (CAT A/B).
If you want to GA at 2000, you still need to follow the procedure. That means follow the flightpath including the missed approach procedure. What does the procedure tell you to do? CAT A or CAT B, follow the flightpath to 430/460, then turn right and climb to 1500.
IF you are at 2000 and you cannot continue as noted above (the procedure), then you are not on the approach procedure, and must inform ATC that you are discontinuing the approach, and ask for further instructions.

Bottom line, you are on a procedure and are cleared for that procedure. Follow it. You cannot simply follow parts of it. Follow it as presented, or get permission to do something else. You cannot GA at 2000 when the DA is at 460, and expect to follow the simplistic "turn right onto 300 and climb to 1500" without instruction, you are, afterall, turning into the flightpath for RW19....(and that runways missed approach procedure)

[B737900er]

It is written, assuming you are following the procedure.



Poldek, the DA for ILS 26 at ESSA is 460/490, (CAT A/B).
If you want to GA at 2000, you still need to follow the procedure. That means follow the flightpath including the missed approach procedure. What does the procedure tell you to do? CAT A or CAT B, follow the flightpath to 430/460, then turn right and climb to 1500.
IF you are at 2000 and you cannot continue as noted above (the procedure), then you are not on the approach procedure, and must inform ATC that you are discontinuing the approach, and ask for further instructions.

Bottom line, you are on a procedure and are cleared for that procedure. Follow it. You cannot simply follow parts of it. Follow it as presented, or get permission to do something else. You cannot GA at 2000 when the DA is at 460, and expect to follow the simplistic "turn right onto 300 and climb to 1500" without instruction, you are, afterall, turning into the flightpath for RW19....(and that runways missed approach procedure)



Underfire - What would you do if there was an approach ban? or the RVR is below minima? You dont make any turns until you are at the missed approach point.

The fact you a telling us if you were told to go around or cancel the approach above the MAA you would continue to DA tells us all you obviously dont fly commercial operations or dont have a good understanding.

Look at LEPA/PMI plates they have a low go around altitude also.

Ive also had to cancel an approach in BCN and was still asked to descend to a lower altitude when I was already in APP mode - to allow for a vueling A320 to cut in. The above method mentioned above worked in this case.

[poldek77]

(...) You cannot GA at 2000 when the DA is at 460,


That's interesting. Any reference please...?

[RVF750]

I haven’t insisted on anything.
I stand corrected and apologise.